title:
Regularization of the slip length divergence in water nanoflows by
  inhomogeneities at the Angstrom scale

abstract:
  We performed non-equilibrium Molecular Dynamics simulations of water flow in
nano-channels with the aim of discriminating {\it static} from {\it dynamic}
contributions of the solid surface to the slip length of the molecular flow. We
show that the regularization of the slip length divergence at high shear rates,
formerly attributed to the wall dynamics, is controlled instead by its static
properties. Surprisingly, we find that atomic displacements at the Angstrom
scale are sufficient to remove the divergence of the slip length and realize
the no-slip condition. Since surface thermal fluctuations at room temperature
are enough to generate these displacements, we argue that the no-slip condition
for water can be achieved also for ideal surfaces, which do not present any
surface roughness.


title: Few interacting fermions in one-dimensional harmonic trap

abstract:
  We study spin-1/2 fermions, interacting via a two-body contact potential, in
a one-dimensional harmonic trap. Applying exact diagonalization, we investigate
their behavior at finite interaction strength, and discuss the role of the
ground-state degeneracy which occurs for sufficiently strong repulsive
interaction. Even low temperature or a completely depolarizing channel may then
dramatically influence the system's behavior. We calculate level occupation
numbers as signatures of thermalization, and we discuss the mechanisms to break
the degeneracy.


title:
Synthesis of Dispersed Metal Particles for Applications in
  Photovoltaics, Catalysis, and Electronics

abstract:
  In colloid and nanoparticle chemistry, particle size, shape, crystallinity,
surface morphology and composition are controlled by employing the mechanisms
of burst nucleation, diffusional growth, aggregation, or their combinations.
Here we review and survey practical examples of recently developed methods for
preparing metal colloids and nanoparticles for industrial applications such as
photovoltaics, catalysis, and consumer electronics. We discuss relevant
theoretical models, many of which are general, and identify growth mechanisms
that play a major role in other systems and applications as well.


title:
Using the decay \psi(4160) -> X(3872) \gamma\ to probe the molecular
  content of the X(3872)

abstract:
  The X(3872) has non-charmonium-like properties, such as decay processes that
seem to violate isospin, and a mass that lies unexpectedly close to the
neutral-D-plus-neutral-D-excited-state threshold. An EFT that includes both
charmonium-like (short distance) and molecule-like (meson bound state)
properties is used to analyze the X(3872) as it is produced in the decay of
\psi(4160). This is a route that BESIII may be able to measure. We find that
the correlation between the angular distribution of the outcoming photon (or
X(3872)) and the polarization of the \psi(4160) source may be used to provide
information on whether short-distance or long-distance effects dominate.


title: On Convexity of Error Rates in Digital Communications

abstract:
  Convexity properties of error rates of a class of decoders, including the
ML/min-distance one as a special case, are studied for arbitrary
constellations, bit mapping and coding. Earlier results obtained for the AWGN
channel are extended to a wide class of noise densities, including unimodal and
spherically-invariant noise. Under these broad conditions, symbol and bit error
rates are shown to be convex functions of the SNR in the high-SNR regime with
an explicitly-determined threshold, which depends only on the constellation
dimensionality and minimum distance, thus enabling an application of the
powerful tools of convex optimization to such digital communication systems in
a rigorous way. It is the decreasing nature of the noise power density around
the decision region boundaries that insures the convexity of symbol error rates
in the general case. The known high/low SNR bounds of the convexity/concavity
regions are tightened and no further improvement is shown to be possible in
general. The high SNR bound fits closely into the channel coding theorem: all
codes, including capacity-achieving ones, whose decision regions include the
hardened noise spheres (from the noise sphere hardening argument in the channel
coding theorem) satisfies this high SNR requirement and thus has convex error
rates in both SNR and noise power. We conjecture that all capacity-achieving
codes have convex error rates. Convexity properties in signal amplitude and
noise power are also investigated. Some applications of the results are
discussed. In particular, it is shown that fading is convexity-preserving and
is never good in low dimensions under spherically-invariant noise, which may
also include any linear diversity combining.


title: Geometry of quantum dynamics and optimal control for mixed states

abstract:
  Geometric effects make evolution time vary for different evolution curves
that connect the same two quantum states. Thus, it is important to be able to
control along which path a quantum state evolve to achieve maximal speed in
quantum calculations. In this paper we establish fundamental relations between
Hamiltonian dynamics and Riemannian structures on the phase spaces of unitarily
evolving finite-level quantum systems. In particular, we show that the
Riemannian distance between two density operators equals the infimum of the
energy dispersions of all possible evolution curves connecting the two density
operators. This means, essentially, that the evolution time is a controllable
quantity. The paper also contains two applied sections. First, we give a
geometric derivation of the Mandelstam-Tamm estimate for the evolution time
between two distinguishable mixed states. Secondly, we show how to equip the
Hamiltonians acting on systems whose states are represented by invertible
density operators with control parameters, and we formulate conditions for
these that, when met, makes the Hamiltonians transport density operators along
geodesics.


title:
The amazing dynamics of stochastic pattern formation and growth models
  inspired by the Conway's Game of Life

abstract:
  Several modifications of the famous mathematical Game of Life are introduced
by making Game of Life rules stochastic and mutual influence of cells in their
8-neighborhood on a rectangular lattice spatially non-uniform. Results are
reported of experimental investigation of evolutionary dynamics of the
introduced models. A number of new phenomena in the evolutionary dynamics of
the models and collective behavior of patterns they generate are revealed,
described and illustrated: formation of maze-like patterns as fixed points of
the models, "self-controlled growth", "eternal life" in a bounded space and
"coherent shrinkage".


title: The PSR J1124-5916 wind nebula in the near-infrared

abstract:
  The young radio pulsar J1124-5916 is associated with a Cas A like supernova
remnant G292.0+1.8. It powers a compact torus-like pulsar wind nebula with a
jet first detected in X-rays and then identified in the optical and
mid-infrared. We carried out deep near-infrared observations of the pulsar
field to identify the pulsar and its nebula in this range. The direct imaging
mode of the NACO adaptive optics instrument at the ESO VLT in the H and Ks
bands was used. In both bands we detected a faint, H=21.30(10) and
Ks=20.45(10), extended elliptical object, whose center position is consistent
with the X-ray position of the pulsar. The morphology of the object and the
orientation of its major axis are in a good agreement with those observed for
the pulsar torus-like nebula in the mid-infrared, optical, and X-rays. This
suggests that it is the near-infrared counterpart of the nebula. The measured
fluxes compiled with the data in other ranges show a complicated unabsorbed
power law spectrum of the torus-like nebula with several steep breaks between
the near-infrared and mid-infrared, the optical and X-rays, and possibly in the
mid-infrared. This implies a multiple relativistic particle population
responsible for the synchrotron emission of the nebula in different spectral
ranges. We have not resolved the pulsar counterpart from its nebula and place
only upper limits on its brightness, H >= 23.9$ and Ks >= 22.7. Based on that,
its contribution to the total near-infrared flux of the pulsar+nebula system is
<= 10%, which is comparable with the expected contribution in the optical.


title: Inner Accretion Disk Edges in a Kerr-Like Spacetime

abstract:
  According to the no-hair theorem, astrophysical black holes are uniquely
described by the Kerr metric. In order to test this theorem with observations
in either the electromagnetic or gravitational-wave spectra, several Kerr-like
spacetimes have been constructed which describe potential deviations from the
Kerr spacetime in parametric form. For electromagnetic tests of the no-hair
theorem, such metrics allow for the proper modeling of the accretion flows
around candidate black holes and the radiation emitted from them. In many of
these models, the location of the inner edge of the accretion disk is of
special importance. This inner edge is often taken to coincide with the
innermost stable circular orbit, which can serve as a direct probe of the spin
and the deviation from the Kerr metric. In certain cases, however, an innermost
stable circular orbit does not exist, and the inner edge of an accretion disk
is instead determined by an instability against small perturbations in the
direction vertical to the disk. In this paper, I analyze the properties of
accretion disks in the Kerr-like metric proposed by Johannsen and Psaltis
[Phys. Rev. D 83, 124015 (2011)], whose inner edges are located at the radii
where this vertical instability occurs. I derive expressions of the energy and
axial angular momentum of disk particles that move on circular equatorial
orbits and calculate the locations of the inner disk edges. As a possible
observable of such accretion disks, I simulate profiles of relativistically
broadened iron lines and show that they depend significantly on the values of
the spin and the deviation parameter.


title: Quantum Chromodynamics with massive gluons

abstract:
  It is shown that the Lagrangian of Quantum Chromodynamics can be modified by
the adding gluon masses. On mass-shell renormalizability of the resulting
theory is discussed.


title: Entropy, Optimization and Counting

abstract:
  In this paper we study the problem of computing max-entropy distributions
over a discrete set of objects subject to observed marginals. Interest in such
distributions arises due to their applicability in areas such as statistical
physics, economics, biology, information theory, machine learning,
combinatorics and, more recently, approximation algorithms. A key difficulty in
computing max-entropy distributions has been to show that they have
polynomially-sized descriptions. We show that such descriptions exist under
general conditions. Subsequently, we show how algorithms for (approximately)
counting the underlying discrete set can be translated into efficient
algorithms to (approximately) compute max-entropy distributions. In the reverse
direction, we show how access to algorithms that compute max-entropy
distributions can be used to count, which establishes an equivalence between
counting and computing max-entropy distributions.


title: Unlinkable content playbacks in a multiparty DRM system

abstract:
  We present a solution to the problem of privacy invasion in a multiparty
digital rights management scheme. (Roaming) users buy content licenses from a
content provider and execute it at any nearby content distributor. Our
approach, which does not need any trusted third party--in contrast to most
related work on privacy-preserving DRM--is based on a re-encryption scheme that
runs on any mobile Android device. Only a minor security-critical part needs to
be performed on the device's smartcard which could, for instance, be a SIM
card.


title:
Theory of the Spontaneous Emission in Photonic and Plasmonic
  Nanoresonators

abstract:
  We provide a self-consistent electromagnetic theory of the coupling between
dipole emitters and dissipative nanoresonators. The theory that relies on the
concept of quasi-normal modes with complex frequencies provides an accurate
closed-form expression for the electromagnetic local density of states (LDOS)
of any photonic or plasmonic resonator with strong radiation leakage,
absorption and material dispersion. It represents a powerful tool to calculate
and conceptualize the electromagnetic response of systems that are governed by
a small number of resonance modes. We use the formalism to revisit Purcell's
factor. The new formula substantially differs from the usual one; in
particular, it predicts that a spectral detuning between the emitter and the
resonance does not necessarily result in a Lorentzian response in the presence
of dissipation. Comparisons with fully-vectorial numerical calculations for
plasmonic nanoresonators made of gold nanorods evidence the high accuracy of
the predictions achieved by our semi-analytical treatment.


title:
Superfluid phases of ultracold Fermi gases on a checkerboard
  superlattice

abstract:
  We analyze the ground-state phase diagram of two-component Fermi gases loaded
into a two-dimensional checkerboard superlattice, i.e. a double-well optical
lattice, potential within the BCS mean-field theory. We show that, by coupling
the two s-wave sublattice superfluid order parameters, a checkerboard potential
gives rise to a Hamiltonian that has the form of a two-band superfluidity with
three (two intraband and an interband) nonlocal order parameters. We study the
evolution of these order parameters as a function of particle filling,
interaction strength and checkerboard potential, and find that the system
always prefers the 0-phase solutions, i.e. the phase difference between
sublattice order parameters is 0, but never the $\pi$-phase one. In addition,
we find that the ground-state of the system undergo a superfluid-normal quantum
phase transition at half fillings beyond a critical checkerboard potential $C$,
the threshold of which is precisely determined by the magnitude of the order
parameter at $C = 0$, and that the normal state rapidly turns into a
checkerboard insulator as $C$ increases.


title: Power-Spectrum Analysis of Reconstructed DAMA Data

abstract:
  Claims by the DAMA (DArk MAtter) collaboration to have detected an annually
varying signal consistent with models of dark matter appear to be at variance
with results from other dark-matter searches. To further understand the DAMA
results, we have carried out an independent analysis of DAMA data reconstructed
from published figures. In addition to reexamining the Lomb-Scargle and
chi-square analyses previously carried out by the DAMA collaboration, we carry
out two new likelihood analyses and a new chi-square analysis, focusing
attention on the treatment of experimental errors and binning. We confirm the
existence of an annual oscillation, with a maximum in early June, but at a
lower significance level than previously reported.


title:
Modification of electromagnetic structure functions for the $\gamma
  Z$-box diagram

abstract:
  The $\gamma Z$-box diagram for parity violating elastic $e$-$p$ scattering
has recently undergone a thorough analysis by several research groups. Though
all now agree on the analytic form of the diagram, the numerical results differ
due to the treatment of the structure functions, $F_{1,2,3}^{\gamma Z}(x,Q^2)$.
Currently, $F_{1,2,3}^{\gamma Z}(x,Q^2)$ at low $Q^2$ and $W^2$ must be
approximated through the modification of existing fits to electromagnetic
structure function data. We motivate and describe the modification used to
obtain $F_{1,2}^{\gamma Z}(x,Q^2)$ in our previous work. We also describe an
alternative modification and compare the result to our original calculation.
Finally, we present a new modification procedure to acquire $F_3^{\gamma
Z}(x,Q^2)$ in the resonance region and calculate the axial contribution to the
$\gamma Z$-box diagram. Details of these modifications will illuminate where
discrepancies between the groups arise and where future improvements can be
made.


title: Alberg and Miller Reply to arXiv:arXiv:1206.3671

abstract:
  In a recent Comment [arXiv:1206.3671] on our calculation of the pion
contributions to the self-energy of the nucleon [arXiv:1201.4184], Ji,
Melnitchouk and Thomas (JMT) correctly state that we obtain the same result as
given by the pseudovector (PV) theory. We point out that this result is
expected by the equivalence theorem, since our pion-nucleon effective theory
puts the intermediate nucleon on its mass shell. We make no claim that
pseudoscalar (PS) and pseudovector interactions are equivalent in general. JMT
also argue that our theory will not give the correct PV result for the pion
momentum distribution $f^N_{\pi}$. We note that the discrepancies are much
smaller than the uncertainties due to $\pi N$ form factors. To summarize,
nothing in the Comment by JMT changes the conclusions or numerical results of
our work in any substantive way.


title: Some symmetry group aspects of perfect plane plasticity system

abstract:
  In this paper, all the known classical solutions of plane perfect plasticity
system under Saint Venant -- Tresca -- von Mises yield criterion are associated
with some group of point symmetries. The equations of slip-line families for
all solutions are constructed, which permits to determine explicitly boundaries
of plastic areas.
  It is shown, how one can determine the compatible velocity solution for known
stresses, considering symmetries. Some invariant solutions of velocities for
Prandtl stresses are constructed. The mechanical sense of obtained velocity
fields is discussed.


title: Pulsar scintillation patterns and strangelets

abstract:
  We propose that interstellar extreme scattering events, usually observed as
pulsar scintillations, may be caused by a coherent agent rather than the
usually assumed turbulence of $\rm H_2$ clouds. We find that the penetration of
a flux of ionizing, positively charged strangelets or quark nuggets into a
dense interstellar hydrogen cloud may produce ionization trails. Depending on
the specific nature and energy of the incoming droplets, diffusive propagation
or even capture in the cloud are possible. As a result, enhanced electron
densities may form and constitute a lens-like scattering screen for radio
pulsars and possibly for quasars.


title:
Estimating the properties of hard X-ray solar flares by constraining
  model parameters

abstract:
  We compare four different methods of calculating uncertainty estimates in
fitting parameterized models to RHESSI X-ray spectra, considering only
statistical sources of error. Three of the four methods are based on estimating
the scale-size of the minimum in a hypersurface formed by the weighted sum of
the squares of the differences between the model fit and the data as a function
of the fit parameters, and are implemented as commonly practiced. The fourth
method uses Bayesian data analysis and Markov chain Monte Carlo (MCMC)
techniques to calculate an uncertainty estimate. Two flare spectra are modeled:
one from the GOES X1.3 class flare of 19 January 2005, and the other from the
X4.8 flare of 23 July 2002. The four methods give approximately the same
uncertainty estimates for the 19 January 2005 spectral fit parameters, but lead
to very different uncertainty estimates for the 23 July 2002 spectral fit. This
is because each method implements different analyses of the hypersurface,
yielding method-dependent results that differ greatly depending on the shape of
the hypersurface. For the 23 July 2002 flare data, there is a 95% probability
that the low energy cutoff lies below approximately 40 keV, and a 68%
probability that it lies in the range 7-36 keV. The low-energy cutoff for the
19 January 2005 flare is more tightly constrained to 107+/-4 keV (68%
probability). Using the Bayesian/MCMC approach, we also estimate for the first
time probability density functions (PDFs) for the total number of flare
accelerated electrons and the energy they carry. For the 23 July 2002 event,
these PDFs are asymmetric with long tails orders of magnitude higher than the
most probable value, caused by the poorly constrained value of the low-energy
cutoff. For the 19 January 2005 flare spectrum, the PDFs for the total number
of flare accelerated electrons and their energy are much more symmetric and
narrow.


title:
Fuzzy equilibrium existence for Bayesian abstract fuzzy economies and
  applications to random quasi-variational inequalities with random fuzzy
  mappings

abstract:
  In this paper, we introduce a Bayesian abstract fuzzy economy model and we
prove the Bayesian fuzzy equilibrium existence. As applications, we prove the
existence of the solutions for two types of random quasi-variational
inequalities with random fuzzy mappings and we also obtain random fixed point
theorems.


title:
Non-trivial spin-texture of the coaxial Dirac cones on the surface of
  topological crystalline insulator SnTe

abstract:
  We present first principles calculations of the nontrivial surface states and
their spin-textures in the topological crystalline insulator SnTe. The surface
state dispersion on the [001] surface exhibits four Dirac-cones centered along
the intersection of the mirror plane and the surface plane. We propose a simple
model of two interacting coaxial Dirac cones to describe both the surface state
dispersion and the associated spin-texture. While the out-of-the-plane spin
polarization is zero due to the crystalline and time-reversal symmetries, the
in-plane spin texture shows helicity with some distortion due to the
interaction of the two coaxial Dirac cones, indicating a nontrivial mirror
Chern number of -2, distinct from the value of -1 in $Z_{2}$ topological
insulator such as Bi/Sb alloys or Bi$_2$Se$_3$. The surface state dispersion
and its spin-texture would provide an experimentally accessible way to
determine the nontrivial mirror Chern number.


title:
Event mixing does not reproduce single particle acceptance convolutions
  for nonuniform pseudorapidity distributions

abstract:
  We point out that the mixed-event method for two-particle acceptance
correction, widely used in particle correlation measurements at RHIC and LHC,
is wrong in cases where the single particle pseudorapidity distribution is
significantly nonuniform. The correct acceptance should be the convolution of
two single-particle efficiency$\times$acceptance functions. The error of the
mixed-event method, which guarantees a uniform $\Delta\eta$ two-particle
combinatorial density, is, however, small in correlation analyses where the two
particles are integrated over an extended pseudorapidity $\eta$ range. With one
particle fixed in $\eta$ and the right acceptance correction, the
background-subtracted correlated pair density may reveal not only a short-range
but also a long-range $\Delta\eta$ dependence. This has important physics
implication, and may provide crucial information to disentangle physics
mechanisms for the recently observed long-range ridge correlation in asymmetric
proton-lead collisions at the LHC.


title:
Confronting measured near and sub-barrier fusion cross-sections for
  20O+12C with a microscopic method

abstract:
  Recently measured fusion cross-sections for the neutron-rich system 20O+12C
are compared to dynamic, microscopic calculations using time-dependent density
functional theory. The calculations are carried out on a three-dimensional
lattice and performed both with and without a constraint on the density. The
method has no adjustable parameters, and its only input is the Skyrme effective
NN interaction. While the microscopic DC-TDHF calculations lie closer to the
experimental data than standard fusion systematics they underpredict the
experimental data significantly.


title:
New perturbative method for solving the gravitational N-body problem in
  the general theory of relativity

abstract:
  We present a new approach to describe the dynamics of an isolated,
gravitationally bound astronomical $N$-body system in the weak field and
slow-motion approximation of the general theory of relativity. Celestial bodies
are described using an arbitrary energy-momentum tensor and assumed to possess
any number of internal multipole moments. The solution of the gravitational
field equations in any reference frame is presented as a sum of three terms: i)
the inertial flat spacetime in that frame, ii) unperturbed solutions for each
body in the system that is covariantly transformed to the coordinates of this
frame, and iii) the gravitational interaction term. We use the harmonic gauge
conditions that allow reconstruction of a significant part of the structure of
the post-Galilean coordinate transformation functions relating global
coordinates of the inertial reference frame to the local coordinates of the
non-inertial frame associated with a particular body. The remaining parts of
these functions are determined from dynamical conditions, obtained by
constructing the relativistic proper reference frame associated with a
particular body. In this frame, the effect of external forces acting on the
body is balanced by the fictitious frame-reaction force that is needed to keep
the body at rest with respect to the frame, conserving its relativistic
three-momentum. The resulting post-Galilean coordinate transformations have an
approximate group structure that extends the Poincar'e group of global
transformations to the case of accelerating observers in a gravitational field
of $N$-body system. We present and discuss the structure of the metric tensors
corresponding to the reference frames involved, the rules for transforming
relativistic gravitational potentials, the coordinate transformations between
frames and the resulting relativistic equations of motion.


title: How well do we know the polar hydrogen distribution on the Moon?

abstract:
  A detailed comparison is made of results from the Lunar Prospector Neutron
Spectrometer (LPNS) and the Lunar Exploration Neutron Detector Collimated
Sensors for EpiThermal Neutrons (LEND CSETN). Using the autocorrelation
function and power spectrum of the polar count rate maps produced by these
experiments, it is shown that the LEND CSETN has a footprint that is at least
as big as would be expected for an omni-directional detector at an orbital
altitude of 50 km. The collimated flux into the field of view of the collimator
is negligible. Arguments put forward asserting otherwise are considered and
found wanting for various reasons. The maps of lunar polar hydrogen with the
highest contrast, i.e. spatial resolution, are those resulting from pixon image
reconstructions of the LPNS data. These typically provide weight percentages of
water equivalent hydrogen that are accurate to 30% within the polar craters.


title:
Derivation of conditions for a Brans-Dicke coupling constant of order
  unity be consistent with solar system bounds

abstract:
  We provide proofs of some assumptions recently made by F. O. Minotti to
conclude on the possibility that an additional scalar field minimally coupled
to gravity may help to reconcile a Brans-Dicke coupling constant $\omega$ of
the order unity with solar system bounds.


title: On Discrete Preferences and Coordination

abstract:
  An active line of research has considered games played on networks in which
payoffs depend on both a player's individual decision and also the decisions of
her neighbors. Such games have been used to model issues including the
formation of opinions and the adoption of technology. A basic question that has
remained largely open in this area is to consider games where the strategies
available to the players come from a fixed, discrete set, and where players may
have different intrinsic preferences among the possible strategies. It is
natural to model the tension among these different preferences by positing a
distance function on the strategy set that determines a notion of "similarity"
among strategies; a player's payoff is determined by the distance from her
chosen strategy to her preferred strategy and to the strategies chosen by her
network neighbors. Even when there are only two strategies available, this
framework already leads to natural open questions about a version of the
classical Battle of the Sexes problem played on a graph.
  We develop a set of techniques for analyzing this class of games, which we
refer to as discrete preference games. We parametrize the games by the relative
extent to which a player takes into account the effect of her preferred
strategy and the effect of her neighbors' strategies, allowing us to
interpolate between network coordination games and unilateral decision-making.
When these two effects are balanced, we show that the price of stability is
equal to 1 for any discrete preference game in which the distance function on
the strategies is a tree metric; as a special case, this includes the Battle of
the Sexes on a graph. We also show that trees form the maximal family of
metrics for which the price of stability is 1, and produce a collection of
metrics on which the price of stability converges to a tight bound of 2.


title: Robust Spectral Compressed Sensing via Structured Matrix Completion

abstract:
  The paper explores the problem of \emph{spectral compressed sensing}, which
aims to recover a spectrally sparse signal from a small random subset of its
$n$ time domain samples. The signal of interest is assumed to be a
superposition of $r$ multi-dimensional complex sinusoids, while the underlying
frequencies can assume any \emph{continuous} values in the normalized frequency
domain. Conventional compressed sensing paradigms suffer from the basis
mismatch issue when imposing a discrete dictionary on the Fourier
representation. To address this issue, we develop a novel algorithm, called
\emph{Enhanced Matrix Completion (EMaC)}, based on structured matrix completion
that does not require prior knowledge of the model order. The algorithm starts
by arranging the data into a low-rank enhanced form exhibiting multi-fold
Hankel structure, and then attempts recovery via nuclear norm minimization.
Under mild incoherence conditions, EMaC allows perfect recovery as soon as the
number of samples exceeds the order of $r\log^{4}n$, and is stable against
bounded noise. Even if a constant portion of samples are corrupted with
arbitrary magnitude, EMaC still allows exact recovery, provided that the sample
complexity exceeds the order of $r^{2}\log^{3}n$. Along the way, our results
demonstrate the power of convex relaxation in completing a low-rank multi-fold
Hankel or Toeplitz matrix from minimal observed entries. The performance of our
algorithm and its applicability to super resolution are further validated by
numerical experiments.


title:
Topological mixing for some residual sets of interval exchange
  transformations

abstract:
  We show that a residual set of non-degenerate IETs on more than 3 letters is
topologically mixing. This shows that there exists a uniquely ergodic
topologically mixing IET. This is then applied to show that some billiard flows
in a fixed direction in an L-shaped polygon are topologically mixing.


title: Quantum secret sharing with continuous-variable cluster states

abstract:
  We extend the formalism of cluster state quantum secret sharing, as presented
in Markham and Sanders [Phys. Rev. A 78, 042309 (2008)] and Keet et al. [Phy.
Rev. A 82, 062315 (2010)], to the continuous-variable regime. We show that both
classical and quantum information can be shared by distributing
continuous-variable cluster states through either public or private channels.
We find that the adversary structure is completely denied from the secret if
the cluster state is infinitely squeezed, but some secret information would be
leaked if a realistic finitely squeezed state is employed. We suggest
benchmarks to evaluate the security in the finitely squeezed cases. For the
sharing of classical secrets, we borrow techniques from the continuous-variable
quantum key distribution to compute the secret sharing rate. For the sharing of
quantum states, we estimate the amount of entanglement distilled for
teleportation from each cluster state.


title: Local Correctability of Expander Codes

abstract:
  In this work, we present the first local-decoding algorithm for expander
codes. This yields a new family of constant-rate codes that can recover from a
constant fraction of errors in the codeword symbols, and where any symbol of
the codeword can be recovered with high probability by reading $N^\epsilon$
symbols from the corrupted codeword, where $N$ is the block-length of the code.
  Expander codes, introduced by Sipser and Spielman, are formed from an
expander graph $G = (V,E)$ of degree $d$, and an inner code of block-length $d$
over an alphabet $\Sigma$. Each edge of the expander graph is associated with a
symbol in $\Sigma$. A string in $\Sigma^{E}$ will be a codeword if for each
vertex in $V$, the symbols on the adjacent edges form a codeword in the inner
code.
  We show that if the inner code has a smooth reconstruction algorithm in the
noiseless setting, then the corresponding expander code has an efficient
local-correction algorithm in the noisy setting. Instantiating our construction
with inner codes based on finite geometries, we obtain novel locally decodable
codes with rate approaching one. This provides an alternative to the
multiplicity codes of Kopparty, Saraf and Yekhanin (STOC '11) and the lifted
codes of Guo, Kopparty and Sudan (ITCS '13).


title:
Infinite volume and continuum limits for gluon propagator in 3d SU(2)
  lattice gauge theory

abstract:
  We study the Landau gauge gluon propagator D(p) in the 3d SU(2) lattice gauge
theory. We show that in the infinite-volume limit the expectation values over
the Gribov region \Omega, are different (in the infrared) from that calculated
in the fundamental modular region \Gamma. Also we show that this conclusion
does not change when spacing $a$ tends to zero.


title: Suppressing Isocurvature Perturbations of QCD Axion Dark Matter

abstract:
  We propose a novel mechanism to suppress the isocurvature perturbations of
the QCD axion. The point is that the QCD interactions become strong at an
intermediate or high energy scale in the very early Universe, if the Higgs
field has a sufficiently large expectation value. The effective QCD scale can
be even higher in the presence of extra colored particles. We show that the QCD
axion then becomes so heavy during inflation that its isocurvature
perturbations are significantly suppressed, thereby relaxing the constraint on
the inflation scale.


title: Local Graph Clustering Beyond Cheeger's Inequality

abstract:
  Motivated by applications of large-scale graph clustering, we study
random-walk-based LOCAL algorithms whose running times depend only on the size
of the output cluster, rather than the entire graph. All previously known such
algorithms guarantee an output conductance of $\tilde{O}(\sqrt{\phi(A)})$ when
the target set $A$ has conductance $\phi(A)\in[0,1]$. In this paper, we improve
it to $$\tilde{O}\bigg( \min\Big\{\sqrt{\phi(A)},
\frac{\phi(A)}{\sqrt{\mathsf{Conn}(A)}} \Big\} \bigg)\enspace, $$ where the
internal connectivity parameter $\mathsf{Conn}(A) \in [0,1]$ is defined as the
reciprocal of the mixing time of the random walk over the induced subgraph on
$A$.
  For instance, using $\mathsf{Conn}(A) = \Omega(\lambda(A) / \log n)$ where
$\lambda$ is the second eigenvalue of the Laplacian of the induced subgraph on
$A$, our conductance guarantee can be as good as
$\tilde{O}(\phi(A)/\sqrt{\lambda(A)})$. This builds an interesting connection
to the recent advance of the so-called improved Cheeger's Inequality [KKL+13],
which says that global spectral algorithms can provide a conductance guarantee
of $O(\phi_{\mathsf{opt}}/\sqrt{\lambda_3})$ instead of
$O(\sqrt{\phi_{\mathsf{opt}}})$.
  In addition, we provide theoretical guarantee on the clustering accuracy (in
terms of precision and recall) of the output set. We also prove that our
analysis is tight, and perform empirical evaluation to support our theory on
both synthetic and real data.
  It is worth noting that, our analysis outperforms prior work when the cluster
is well-connected. In fact, the better it is well-connected inside, the more
significant improvement (both in terms of conductance and accuracy) we can
obtain. Our results shed light on why in practice some random-walk-based
algorithms perform better than its previous theory, and help guide future
research about local clustering.


title: Soft Gluons and Jets at the LHC

abstract:
  We address aspects of jet physics at the Large Hadron Collider focusing on
features of recent jet measurements which challenge the theory. We discuss
examples illustrating the role of QCD parton showers, nonperturbative
corrections, soft multi-gluon emission.


title: Predicting the tau strange branching ratios and implications for V_{us}

abstract:
  Hadronic tau decays provide several ways to extract the
Cabbibo-Kobashi-Maskawa (CKM) matrix element V_{us}. The most precise
determination involves using inclusive tau decays and requires as input the
total branching ratio into strange final states. Recent results from
B-factories have led to a discrepancy of about 3.4 sigma from the value of
V_{us} implied by CKM unitarity and direct determination from Kaon
semi-leptonic modes. In this paper we predict the three leading strange tau
branching ratios, using dispersive parameterizations of the hadronic form
factors and taking as experimental input the measured Kaon decay rates and the
tau -> K pi nu_tau decay spectrum. We then use our results to reevaluate
V_{us}, for which we find |V_{us}|=0.2207 \pm 0.0027, in better agreement with
CKM unitarity.


title:
From Hierarchical Partitions to Hierarchical Covers: Optimal
  Fault-Tolerant Spanners for Doubling Metrics

abstract:
  In this paper we devise an optimal construction of fault-tolerant spanners
for doubling metrics. Specifically, for any $n$-point doubling metric, any
$\eps > 0$, and any integer $0 \le k \le n-2$, our construction provides a
$k$-fault-tolerant $(1+\eps)$-spanner with optimal degree $O(k)$ within optimal
time $O(n \log n + k n)$.
  We then strengthen this result to provide near-optimal (up to a factor of
$\log k$) guarantees on the diameter and weight of our spanners, namely,
diameter $O(\log n)$ and weight $O(k^2 + k \log n) \cdot \omega(MST)$, while
preserving the optimal guarantees on the degree $O(k)$ and the running time
$O(n \log n + k n)$.
  Our result settles several fundamental open questions in this area,
culminating a long line of research that started with the STOC'95 paper of Arya
et al.\ and the STOC'98 paper of Levcopoulos et al.
  On the way to this result we develop a new technique for constructing
spanners in doubling metrics. Our spanner construction is based on a novel
\emph{hierarchical cover} of the metric, whereas most previous constructions of
spanners for doubling and Euclidean metrics (such as the net-tree spanner) are
based on \emph{hierarchical partitions} of the metric. We demonstrate the power
of hierarchical covers in the context of geometric spanners by improving the
state-of-the-art results in this area.


title: Perfectly normal type-2 fuzzy interpolation B-spline curve

abstract:
  In this paper, we proposed another new form of type-2 fuzzy data
points(T2FDPs) that is perfectly normal type-2 data points(PNT2FDPs). These
kinds of brand-new data were defined by using the existing type-2 fuzzy set
theory(T2FST) and type-2 fuzzy number(T2FN) concept since we dealt with the
problem of defining complex uncertainty data. Along with this restructuring, we
included the fuzzification(alpha-cut operation), type-reduction and
defuzzification processes against PNT2FDPs. In addition, we used interpolation
B-soline curve function to demonstrate the PNT2FDPs.


title: Constraining Type II 2HDM in Light of LHC Higgs Searches

abstract:
  We study the implication of the LHC Higgs search results on the Type II Two
Higgs-Doublet Model. In particular, we explore the scenarios in which the
observed 126 GeV Higgs signal is interpreted as either the light CP-even Higgs
$h^0$ or the heavy CP-even Higgs $H^0$. Imposing both theoretical and
experimental constraints, we analyze the surviving parameter regions in $m_H$
($m_h$), $m_A$, $m_{H^\pm}$, $\tan\beta$ and $\sin(\beta - \alpha)$. We further
identify the regions that could accommodate a 126 GeV Higgs with cross sections
consistent with the observed Higgs signal. We find that in the $h^0$-126 case,
we are restricted to narrow regions of $\sin(\beta-\alpha) \approx \pm 1$ with
$\tan\beta$ up to 4, or an extended region with $0.55 < \sin(\beta-\alpha) <
0.9$ and $1.5 < \tan\beta < 4$. The values of $m_H$, $m_A$ and $m_{H^\pm}$,
however, are relatively unconstrained. In the $H^0$-126 case, we are restricted
to a narrow region of $\sin(\beta-\alpha) \sim 0$ with $\tan\beta$ up to about
8, or an extended region of $\sin(\beta-\alpha) $ between $-0.8$ to $-0.05$,
with $\tan\beta$ extended to 30 or higher. $m_A$ and $m_{H^\pm}$ are nearly
degenerate due to $\Delta\rho$ constraints. Imposing flavor constraints shrinks
the surviving parameter space significantly for the $H^0$-126 case, limiting
$\tan\beta \lesssim 10$, but has little effect in the $h^0$-126 case. We also
investigate the correlation between $\gamma\gamma$, $VV$ and $bb/\tau\tau$
channels. $\gamma\gamma$ and $VV$ channels are most likely to be highly
correlated with $\gamma\gamma:VV \sim 1$ for the normalized cross sections.


title:
Chiral edge states and fractional charge separation in interacting
  bosons on a Kagome lattice

abstract:
  We consider the extended hard-core Bose-Hubbard model on a Kagome lattice
with boundary conditions on two edges. We find that the sharp edges lift the
degeneracy and freeze the system into a striped order at 1/3 and 2/3 filling
for zero hopping. At small hopping strengths, holes spontaneously appear and
separate into fractional charges which move to the edges of the system. This
leads to a novel edge liquid phase, which is characterized by fractional
charges near the edges and a finite edge compressibility but no superfluid
density. The compressibility is due to excitations on the edge which display a
chrial symmetry breaking that is reminiscent of the quantum Hall effect and
topological insulators. Large scale Monte Carlo simulations confirm the
analytical considerations.


title: Conformal Blocks in the Large D Limit

abstract:
  We derive conformal blocks in an inverse spacetime dimension expansion. In
this large D limit, the blocks are naturally written in terms of a new
combination of conformal cross-ratios. We comment on the implications for the
conformal bootstrap at large D.


title:
Discovery of spectral curvature in the shock downstream region: CIZA
  J2242.8+5301

abstract:
  Giant cluster radio relics are thought to form at shock fronts in the course
of collisions between galaxy clusters. Via processes that are still poorly
understood, these shocks accelerate or re-accelerate cosmic-ray electrons and
might amplify magnetic fields. The best object to study this phenomenon is the
galaxy cluster CIZA J2242.8+5301 as it shows the most undisturbed relic. By
means of Giant Metrewave Radio Telescope (GMRT) and Westerbork Synthesis Radio
Telescope (WSRT) data at seven frequencies spanning from 153 MHz to 2272 MHz,
we study the synchrotron emission in this cluster. We aim at distinguishing
between theoretical injection and acceleration models proposed for the
formation of radio relics. We also study the head-tail radio sources to reveal
the interplay between the merger and the cluster galaxies. We produced spectral
index, curvature maps and radio colour-colour plots and compared our data with
predictions from models. We present one of the deepest 153 MHz maps of a
cluster ever produced, reaching a noise level of 1.5 mJy/beam. We derive
integrated spectra for four relics in the cluster, discovering extremely steep
spectrum diffuse emission concentrated in multiple patches. We find a possible
radio phoenix embedded in the relic to the south of the cluster. The spectral
index of the northern relic retains signs of steepening from the front towards
the back of the shock also at the radio frequencies below 600 MHz. The spectral
curvature in the same relic also increases in the downstream area. The data is
consistent with the Komissarov-Gubanov injection models, meaning that the
emission we observe is produced by a single burst of spectrally-aged
accelerated radio electrons.


title: Un-Fermi Liquids: Unparticles in Strongly Correlated Electron Matter

abstract:
  Since any non-trivial infrared dynamics in strongly correlated electron
matter must be controlled by a critical fixed point, we argue that the form of
the single-particle propagator can be deduced simply by imposing scale
invariance. As a consequence, the unparticle picture proposed by
Georgi\cite{georgi} is the natural candidate to describe such dynamics.
Unparticle stuff is scale-invariant matter with no particular mass. Scale
invariance dictates that the propagator has an algebraic form which can admit
zeros and hence is a candidate to explain the ubiquitous pseudogap state of the
cuprates. The non-perturbative electronic state formed out of unparticles we
refer to as an un-Fermi liquid. We show that the underlying action of the
continuous mass formulation of unparticles can be recast exactly as an action
in anti de Sitter space. We find that this mapping fixes the scaling dimension
of the unparticle to be $d_U=d/2+\sqrt{d^2+4}/2$ and ensures that the
corresponding propagator has zeros with $d$ the spacetime dimension of the
unparticle field. Should $d=2+1$, unparticles acquire the non-trivial phase
$2\pi d_U$ upon interchange. Because $d_U$ is non-integer and in general not
half-integer, clockwise and counterclockwise interchange of unparticles do not
lead to the same phase and time reversal symmetry is broken spontaneously as
reported in numerous experiments in the pseudogap phase of the cuprates. The
possible relevance of this mechanism to such experiments is discussed. We then
formulate the analogous BCS gap using unparticles and find that in contrast to
the Fermi liquid case, the transition temperature increases as the attractive
interaction strength decreases, indicating that unparticles are highly
susceptible to a superconducting instability.


title: Energy Correlation Functions for Jet Substructure

abstract:
  We show how generalized energy correlation functions can be used as a
powerful probe of jet substructure. These correlation functions are based on
the energies and pair-wise angles of particles within a jet, with (N+1)-point
correlators sensitive to N-prong substructure. Unlike many previous jet
substructure methods, these correlation functions do not require the explicit
identification of subjet regions. In addition, the correlation functions are
better probes of certain soft and collinear features that are masked by other
methods. We present three Monte Carlo case studies to illustrate the utility of
these observables: 2-point correlators for quark/gluon discrimination, 3-point
correlators for boosted W/Z/Higgs boson identification, and 4-point correlators
for boosted top quark identification. For quark/gluon discrimination, the
2-point correlator is particularly powerful, as can be understood via a
next-to-leading logarithmic calculation. For boosted 2-prong resonances the
benefit depends on the mass of the resonance.


title: Probing Dark Energy through Scale Dependence

abstract:
  We consider the consequences of having no prior knowledge of the true dark
energy model for the interpretation of cosmological observations. The magnitude
of redshift-space distortions and weak-lensing shear is determined by the
metric on the geodesics of which galaxies and light propagate. We show that,
given precise enough observations, we can use these data to completely
reconstruct the metric on our past lightcone and therefore to measure the
scale- and time-dependence of the anisotropic stress and the evolution of the
gravitational potentials in a model-independent manner. Since both dark matter
and dark energy affect the visible sector only through the gravitational field
they produce, they are inseparable without a model for dark energy: galaxy bias
cannot be measured and therefore the distribution of dark matter determined;
the peculiar velocity of dark matter can be identified with that of the
galaxies only when the equivalence principle holds. Given these limitations, we
show how one can nonetheless build tests for classes of dark energy models
which depend on making measurements at multiple scales at a particular
redshift. They are null tests on the model-independent observables, do not
require modeling evolution in time and do not require any parametrization of
the free functions of these models, such as the sound speed. We show how one
can rule out or constrain the whole class of the most-general scalar-tensor
theories even without assuming the quasi-static limit.


title: Cosmological constraints on Lorentz violating dark energy

abstract:
  The role of Lorentz invariance as a fundamental symmetry of nature has been
lately reconsidered in different approaches to quantum gravity. It is thus
natural to study whether other puzzles of physics may be solved within these
proposals. This may be the case for the cosmological constant problem. Indeed,
it has been shown that breaking Lorentz invariance provides Lagrangians that
can drive the current acceleration of the universe without experiencing large
corrections from ultraviolet physics. In this work, we focus on the simplest
model of this type, called ThetaCDM, and study its cosmological implications in
detail. At the background level, this model cannot be distinguished from
LambdaCDM. The differences appear at the level of perturbations. We show that
in ThetaCDM, the spectrum of CMB anisotropies and matter fluctuations may be
affected by a rescaling of the gravitational constant in the Poisson equation,
by the presence of extra contributions to the anisotropic stress, and finally
by the existence of extra clustering degrees of freedom. To explore these
modifications accurately, we modify the Boltzmann code CLASS. We then use the
parameter inference code Monte Python to confront ThetaCDM with data from
WMAP-7, SPT and WiggleZ. We obtain strong bounds on the parameters accounting
for deviations from LambdaCDM. In particular, we find that the discrepancy
between the gravitational constants appearing in the Poisson and Friedmann
equations is constrained at the level 1.8%.


title: Initial conditions for cold dark matter particles and General Relativity

abstract:
  We describe the irrotational dust component of the universe in terms of a
relativistic gradient expansion and transform the resulting synchronous metric
to a Newtonian coordinate system. The two metrics are connected via a
space-like displacement field and a time-like perturbation, providing a
relativistic generalization of the transformation from Lagrangian to Eulerian
coordinates. The relativistic part of the displacement field generates already
at initial time a non-local density perturbation at second order. This is a
purely relativistic effect since it originates from space-time mixing. We give
two options, the passive and the active approach, on how to include the
relativistic corrections for example in N-body simulations. In the passive
approach we treat the corrections as a non-Gaussian modification of the initial
Gaussian field (primordial non-Gaussianity could be incorporated as well). The
induced non-Gaussianity depends on scale and the redshift at which initial
conditions are set, with f_NL ~ few for small enough scales and redshifts. In
the active approach we show how to use the relativistic trajectory to obtain
the initial displacement and velocity of particles for N-body simulations
without modifying the initial Gaussian field.


title: Emergent Lorentz invariance from Strong Dynamics: Holographic examples

abstract:
  We explore the phenomenon of emergent Lorentz invariance in strongly coupled
theories. The strong dynamics is handled using the gauge/gravity
correspondence. We analyze how the renormalization group flow towards Lorentz
invariance is reflected in the two-point functions of local operators and in
the dispersion relations of the bound states. The deviations of these
observables from the relativistic form at low energies are found to be
power-law suppressed by the ratio of the infrared and ultraviolet scales. We
show that in a certain subclass of models the velocities of the light bound
states stay close to the emergent `speed of light' even at high energies. We
comment on the implications of our results for particle physics and condensed
matter.


title:
Misaligned streamers around a galactic centre black hole from a single
  cloud's infall

abstract:
  We follow the near radial infall of a prolate cloud onto a 4 x 10^6 Msun
supermassive black hole in the Galactic Centre using smoothed particle
hydrodynamics (SPH). We show that a prolate cloud oriented perpendicular to its
orbital plane naturally produces a spread in angular momenta in the gas which
can translate into misaligned discs as is seen in the young stars orbiting
Sagittarius A*. A turbulent or otherwise highly structured cloud is necessary
to avoid cancelling too much angular momentum through shocks at closest
approach. Our standard model of a 2 x 10^4 Msun gas cloud brought about the
formation of a disc within 0.3 pc from the black hole and a larger, misaligned
streamer at 0.5 pc. A total of 1.5 x 10^4 Msun of gas formed these structures.
Our exploration of the simulation parameter space showed that when star
formation occurred, it resulted in top-heavy IMFs with stars on eccentric
orbits with semi-major axes 0.02 to 0.3 pc and inclinations following the gas
discs and streamers. We suggest that the single event of an infalling prolate
cloud can explain the occurrence of multiple misaligned discs of young stars.


title:
The $\mathcal{N}=1$ algebra $\mathcal{W}_\infty[\mu]$ and its
  truncations

abstract:
  The main objective of this work is to construct and classify the most general
classical and quantum $\mathcal{N}=1$ $\mathcal{W}_\infty$-algebras generated
by the same spins as the singlet algebra of $N$ fermions and $N$ bosons in the
vector representation of $O(N)$ in the $N\to\infty$ limit. This type of
algebras appears in a recent $\mathcal{N}=1$ version of the minimal model
holography. Our analysis strongly suggests that there is a one parameter family
$\mathcal{W}_\infty[\mu]$ of such algebras at every given central charge.
Relying on this assumption, we identify various truncations of
$\mathcal{W}_\infty[\mu]$ with, on the one hand, (orbifolds of) the
Drinfel'd-Sokolov reductions of the Lie superalgebras $B(n,n)$, $B(n-1,n)$,
$D(n,n)$ and $D(n+1,n)$, and, on the other hand, (orbifolds of) three
$\mathcal{N}=1$ cosets. After a closer inspection we show that these cosets can
be realized as a Drinfel'd-Sokolov reduction of $B(n,n)$, $D(n,n)$ and
$D(n+1,n)$. We then discuss the implications of our findings for the quantum
version of the $\mathcal{N}=1$ minimal model holography.


title:
Framework for maximum likelihood analysis of neutron beta decay
  observables to resolve the limits of the V-A law

abstract:
  We assess the ability of future neutron beta decay measurements of up to
O(10^{-4}) precision to falsify the standard model, particularly the V-A law,
and to identify the dynamics beyond it. To do this, we employ a maximum
likelihood statistical framework which incorporates both experimental and
theoretical uncertainties. Using illustrative combined global fits to Monte
Carlo pseudodata, we also quantify the importance of experimental measurements
of the energy dependence of the angular correlation coefficients as input to
such efforts, and we determine the precision to which ill-known "second-class"
hadronic matrix elements must be determined in order to exact such tests.


title:
Inferring ground truth from multi-annotator ordinal data: a
  probabilistic approach

abstract:
  A popular approach for large scale data annotation tasks is crowdsourcing,
wherein each data point is labeled by multiple noisy annotators. We consider
the problem of inferring ground truth from noisy ordinal labels obtained from
multiple annotators of varying and unknown expertise levels. Annotation models
for ordinal data have been proposed mostly as extensions of their
binary/categorical counterparts and have received little attention in the
crowdsourcing literature. We propose a new model for crowdsourced ordinal data
that accounts for instance difficulty as well as annotator expertise, and
derive a variational Bayesian inference algorithm for parameter estimation. We
analyze the ordinal extensions of several state-of-the-art annotator models for
binary/categorical labels and evaluate the performance of all the models on two
real world datasets containing ordinal query-URL relevance scores, collected
through Amazon's Mechanical Turk. Our results indicate that the proposed model
performs better or as well as existing state-of-the-art methods and is more
resistant to `spammy' annotators (i.e., annotators who assign labels randomly
without actually looking at the instance) than popular baselines such as mean,
median, and majority vote which do not account for annotator expertise.


title: Retrograde resonance in the planar three-body problem

abstract:
  We continue the investigation of the dynamics of retrograde resonances
initiated in Morais & Giuppone (2012). After deriving a procedure to deduce the
retrograde resonance terms from the standard expansion of the three-dimensional
disturbing function, we concentrate on the planar problem and construct
surfaces of section that explore phase-space in the vicinity of the main
retrograde resonances (2/-1, 1/-1 and 1/-2). In the case of the 1/-1 resonance
for which the standard expansion is not adequate to describe the dynamics, we
develop a semi-analytic model based on numerical averaging of the unexpanded
disturbing function, and show that the predicted libration modes are in
agreement with the behavior seen in the surfaces of section.


title: On Gauge Invariance and Minimal Coupling

abstract:
  The principle of minimal coupling has been used in the study of Higgs boson
interactions to argue that certain higher dimensional operators in the
low-energy effective theory generalization of the Standard Model are suppressed
by loop factors, and thus smaller than others. It also has been extensively
used to analyze beyond-the-standard-model theories. We show that in field
theory, and even in quantum mechanics, the concept of minimal coupling is
ill-defined and inapplicable as a general principle, and give many pedagogical
examples which illustrate this fact. We also clarify some related
misconceptions about the dynamics of strongly coupled gauge theories. Many
arguments in the literature on Higgs boson interactions that use minimal
coupling, particularly in pseudo-Goldstone Higgs theories, are inherently
flawed.


title: The tensor hierarchy algebra

abstract:
  We introduce an infinite-dimensional Lie superalgebra which is an extension
of the U-duality Lie algebra of maximal supergravity in D dimensions, for D
between 3 and 7. The level decomposition with respect to the U-duality Lie
algebra gives exactly the tensor hierarchy of representations that arises in
gauge deformations of the theory described by an embedding tensor, for all
positive levels p. We prove that these representations are always contained in
those coming from the associated Borcherds-Kac-Moody superalgebra, and we
explain why some of the latter representations are not included in the tensor
hierarchy. The most remarkable feature of our Lie superalgebra is that it does
not admit a triangular decomposition like a (Borcherds-)Kac-Moody
(super)algebra. Instead the Hodge duality relations between level p and D-2-p
extend to negative p, relating the representations at the first two negative
levels to the supersymmetry and closure constraints of the embedding tensor.


title:
Do organic and other exotic superconductors fail universal scaling
  relations?

abstract:
  Universal scaling relations are of tremendous importance in science, as they
reveal fundamental laws of nature. Several such scaling relations have recently
been proposed for superconductors; however, they are not really universal in
the sense that some important families of superconductors appear to fail the
scaling relations, or obey the scaling with different scaling pre-factors. In
particular, a large group of materials called organic (or molecular)
superconductors are a notable example. Here, we show that such apparent
violations are largely due to the fact that the required experimental
parameters were collected on different samples, with different experimental
techniques. When experimental data is taken on the same sample, using a single
experimental technique, organic superconductors, as well as all other studied
superconductors, do in fact follow universal scaling relations.


title: Image Compression By Embedding Five Modulus Method Into JPEG

abstract:
  The standard JPEG format is almost the optimum format in image compression.
The compression ratio in JPEG sometimes reaches 30:1. The compression ratio of
JPEG could be increased by embedding the Five Modulus Method (FMM) into the
JPEG algorithm. The novel algorithm gives twice the time as the standard JPEG
algorithm or more. The novel algorithm was called FJPEG (Five-JPEG). The
quality of the reconstructed image after compression is approximately
approaches the JPEG. Standard test images have been used to support and
implement the suggested idea in this paper and the error metrics have been
computed and compared with JPEG.


title:
Dark matter coupling to electroweak gauge and Higgs bosons: an effective
  field theory approach

abstract:
  If dark matter is a new species of particle produced in the early universe as
a cold thermal relic (a weakly-interacting massive particle-WIMP), its present
abundance, its scattering with matter in direct-detection experiments, its
present-day annihilation signature in indirect-detection experiments, and its
production and detection at colliders, depend crucially on the WIMP coupling to
standard-model (SM) particles. It is usually assumed that the WIMP couples to
the SM sector through its interactions with quarks and leptons. In this paper
we explore the possibility that the WIMP coupling to the SM sector is via
electroweak gauge and Higgs bosons. In the absence of an ultraviolet-complete
particle-physics model, we employ effective field theory to describe the
WIMP--SM coupling. We consider both scalars and Dirac fermions as possible
dark-matter candidates. Starting with an exhaustive list of operators up to
dimension 8, we present detailed calculation of dark-matter annihilations to
all possible final states, including gamma gamma, gamma Z, gamma h, ZZ, Zh, W+
W-, hh, and f fbar, and demonstrate the correlations among them. We compute the
mass scale of the effective field theory necessary to obtain the correct
dark-matter mass density, and well as the resulting photon line signals.


title:
Fundamental Physics with Charged Particle Measurements at the Cherenkov
  Telescope Array

abstract:
  Cosmic electrons, positrons, protons, and antiprotons carry essential
information about both astrophysical processes and fundamental physics. Charged
particles provide signatures of dark matter annihilation or decay, \emph{in
situ} in the universe, that are complementary to the other messengers of
indirect dark matter detection, gamma rays and neutrinos. We discuss the
science potential for measurements of charged particles by the Cherenkov
Telescope Array (CTA), an instrument under development primarily for the study
of cosmic gamma rays with energies $30\ \textrm{GeV} - 200\ \textrm{TeV}$.


title:
Phenomenological Study of the Interplay between IR-Improved DGLAP-CS
  Theory and the Precision of an NLO ME Matched Parton Shower MC

abstract:
  We present a phenomenological study of the current status of the application
of our approach of {\it exact} amplitude-based resummation in quantum field
theory to precision QCD calculations, by realistic MC event generator methods,
as needed for precision LHC physics. We discuss recent results as they relate
to the interplay of the attendant IR-Improved DGLAP-CS theory of one of us and
the precision of exact NLO matrix-element matched parton shower MC's in the
Herwig6.5 environment as determined by comparison to recent LHC experimental
observations on single heavy gauge boson production and decay. The level of
agreement between the new theory and the data continues to be a reason for
optimism. In the spirit of completeness, we discuss as well other approaches to
the same theoretical predictions that we make here from the standpoint of
physical precision with an eye toward the (sub-)1% QCD \otimes EW total
theoretical precision regime for LHC physics.


title: Equivariant Vector Bundles on T-Varieties

abstract:
  Let X be a T-variety, where T is an algebraic torus. We describe a fully
faithful functor from the category of T-equivariant vector bundles on X to a
certain category of filtered vector bundles on a suitable quotient of X by T.
We show that if X is factorial, this functor gives an equivalence of
categories. This generalizes Klyachko's description of equivariant vector
bundles on toric varieties. We apply our machinery to show that vector bundles
of low rank on projective space which are equivariant with respect to special
subtori of the maximal torus must split, generalizing a theorem of Kaneyama.
Further applications include descriptions of global vector fields on
T-varieties, and a study of equivariant deformations of equivariant vector
bundles.


title: Einstein static Universe in hybrid metric-Palatini gravity

abstract:
  Hybrid metric-Palatini gravity is a recent and novel approach to modified
theories of gravity, which consists of adding to the metric Einstein-Hilbert
Lagrangian an f(R) term constructed a la Palatini. It was shown that the theory
passes local tests even if the scalar field is very light, and thus implies the
existence of a long-range scalar field, which is able to modify the dynamics in
galactic and cosmological scales, but leaves the Solar System unaffected. In
this work, motivated by the possibility that the Universe may have started out
in an asymptotically Einstein static state in the inflationary universe
context, we analyse the stability of the Einstein static Universe by
considering linear homogeneous perturbations in the respective dynamically
equivalent scalar-tensor representation of hybrid metric-Palatini gravity.
Considering linear homogeneous perturbations, the stability regions of the
Einstein static universe are parametrized by the first and second derivatives
of the scalar potential, and it is explicitly shown that a large class of
stable solutions exists in the respective parameter space, in the context of
hybrid metric-Palatini gravity.


title:
Comments on two papers by Galliano Valent, concerning integrable
  Hamiltonian systems admitting quartic and cubic integrals

abstract:
  In this note we comment on two recently published papers by G. Valent: The
1st is the preprint "On a Class of Integrable Systems with a quartic First
Integral, arXiv:1304.5859. April 22, (2013)". We show that the two integrable
Hamiltonian systems introduced in this reprint as original results are not new.
They are special cases of two systems introduced by the present author in 2006
in two papers [6] and [5]. The second paper is "On a Class of Integrable
Systems with a Cubic First Integral, Commun. Math. Phys. 299, 631{649 (2010),
In that paper two integrable Hamiltonian systems admitting a cubic integral
were introduced. Those systems were referred to as original results by Tsiganov
in [12], Vershilov and Tsiganov in [13], Bialy and Mironov in [15] and by
Gibbons et al in [14]. We show that those systems are not new. Both can be
obtained as special cases of one system introduced by us in [4] (2002) and one
of them is a special case of a much earlier version [1] published 24 years
earlier.


title: On the multifractal structure of fully developed turbulence

abstract:
  The appearance of vortex filaments, the power-law dependence of velocity and
vorticity correlators and their multiscaling behavior are derived from the
Navier-Stokes equation. This is possible due to interpretation of the
Navier-Stokes equation as an equation with multiplicative noise, and remarkable
properties of random matrix products.


title: Late-Time Dust Emission from the Type IIn Supernova 1995N

abstract:
  The Type IIn supernovae (SNe IIn) have been found to be associated with
significant amounts of dust. These core-collapse events are generally expected
to be the final stage in the evolution of highly-massive stars, either while in
an extreme red supergiant phase or during a luminous blue variable phase. Both
evolutionary scenarios involve substantial pre-supernova mass loss. I have
analyzed the SN IIn 1995N in MCG -02-38-017 (Arp 261), for which mid-infrared
archival data obtained with the Spitzer Space Telescope in 2009 (~14.7 yr after
explosion) and with the Wide-field Infrared Survey Explorer (WISE) in 2010
(~15.6--16.0 yr after explosion) reveal a luminous (~2e7 L_sun) source detected
from 3.4 to 24 micron. These observations probe the circumstellar material, set
up by pre-SN mass loss, around the progenitor star and indicate the presence of
~0.05--0.12 M_sun of pre-existing, cool dust at ~240 K. This is at least a
factor ~10 lower than the dust mass required to be produced from SNe at high
redshift, but the case of SN 1995N lends further evidence that highly massive
stars could themselves be important sources of dust.


title: Magnetic Field of Cosmic Strings in the Early Universe

abstract:
  Cosmic strings are topological defects which can be formed as a result of
phase transitions with a spontaneous symmetry breaking in the early Universe.
The possibility of the generation of a magnetic field around a cosmic string on
the Grand Unification energy scale (GUT scale) in the early Universe
immediately after the termination of the deconfinement-confinement phase
transition has been analyzed. It is found that a circular current and a
magnetic field directed along the string are induced around the string in the
vacuum of a pseudoscalar matter consisting of charged pions. We also have
studied the interaction between the magnetic flux tube surrounding the string
(the string magnetosphere) and the cosmic plasma in the early Universe. A
possibility of magnetization of the cosmic plasma surrounding the string owing
to its interaction with the string magnetic field has been analyzed.


title:
A least-squares method for sparse low rank approximation of multivariate
  functions

abstract:
  In this paper, we propose a low-rank approximation method based on discrete
least-squares for the approximation of a multivariate function from random,
noisy-free observations. Sparsity inducing regularization techniques are used
within classical algorithms for low-rank approximation in order to exploit the
possible sparsity of low-rank approximations. Sparse low-rank approximations
are constructed with a robust updated greedy algorithm which includes an
optimal selection of regularization parameters and approximation ranks using
cross validation techniques. Numerical examples demonstrate the capability of
approximating functions of many variables even when very few function
evaluations are available, thus proving the interest of the proposed algorithm
for the propagation of uncertainties through complex computational models.


title: Universal scaling in disordered systems and non-universal exponents

abstract:
  The effect of an electric field on conduction in a disordered system is an
old but largely unsolved problem. Experiments cover an wide variety of systems
- amorphous/doped semiconductors, conducting polymers, organic crystals,
manganites, composites, metallic alloys, double perovskites - ranging from
strongly localized systems to weakly localized ones, from strongly correlated
ones to weakly correlated ones. Theories have singularly failed to predict any
universal trend resulting in separate theories for separate systems. Here we
discuss an one-parameter scaling that has recently been found to give a
systematic account of the field-dependent conductance in two diverse, strongly
localized systems of conducting polymers and manganites. The nonlinearity
exponent, \textit{x} associated with the scaling was found to be nonuniversal
and exhibits structure. For two-dimensional (2D) weakly localized systems, the
nonlinearity exponent \textbf{\textit{x}} is $\geqslant 7$ and is roughly
inversely proportional to the sheet resistance. Existing theories of weak
localization prove to be adequate and a complete scaling function is derived.
In a 2D strongly localized system a temperature-induced scaling-nonscaling
transition (SNST) is revealed. For three-dimensional (3D) strongly localized
systems the exponent lies between -1 and 1, and surprisingly is quantized
(\textit{x} $\approx$ 0.08 \textit{n}). This poses a serious theoretical
challenge. Various results are compared with predictions of the existing
theories.


title: Construction of PMDS and SD Codes extending RAID 5

abstract:
  A construction of Partial Maximum Distance Separable (PMDS) and Sector-Disk
(SD) codes extending RAID 5 with two extra parities is given, solving an open
problem. Previous constructions relied on computer searches, while our
constructions provide a theoretical solution to the problem.


title:
Vanadium dioxide as a natural disordered metamaterial: perfect thermal
  emission and large broadband negative differential thermal emittance

abstract:
  We experimentally demonstrate that a thin (~150 nm) film of vanadium dioxide
(VO2) deposited on sapphire has an anomalous thermal emittance profile when
heated, which arises due to the optical interaction between the film and the
substrate when the VO2 is at an intermediate state of its insulator-metal
transition (IMT). Within the IMT region, the VO2 film comprises nanoscale
islands of metal- and dielectric-phase, and can thus be viewed as a natural,
disordered metamaterial. This structure displays "perfect" blackbody-like
thermal emissivity over a narrow wavelength range (~40 cm-1), surpassing the
emissivity of our black soot reference. We observed large broadband negative
differential thermal emittance over a >10 {\deg}C range: upon heating, the
VO2/sapphire structure emitted less thermal radiation and appeared colder on an
infrared camera. We anticipate that emissivity engineering with thin film
geometries comprising VO2 will find applications in infrared camouflage,
thermal regulation, infrared tagging and labeling.


title:
Regret Minimization in Non-Zero-Sum Games with Applications to Building
  Champion Multiplayer Computer Poker Agents

abstract:
  In two-player zero-sum games, if both players minimize their average external
regret, then the average of the strategy profiles converges to a Nash
equilibrium. For n-player general-sum games, however, theoretical guarantees
for regret minimization are less understood. Nonetheless, Counterfactual Regret
Minimization (CFR), a popular regret minimization algorithm for extensive-form
games, has generated winning three-player Texas Hold'em agents in the Annual
Computer Poker Competition (ACPC). In this paper, we provide the first set of
theoretical properties for regret minimization algorithms in non-zero-sum games
by proving that solutions eliminate iterative strict domination. We formally
define \emph{dominated actions} in extensive-form games, show that CFR avoids
iteratively strictly dominated actions and strategies, and demonstrate that
removing iteratively dominated actions is enough to win a mock tournament in a
small poker game. In addition, for two-player non-zero-sum games, we bound the
worst case performance and show that in practice, regret minimization can yield
strategies very close to equilibrium. Our theoretical advancements lead us to a
new modification of CFR for games with more than two players that is more
efficient and may be used to generate stronger strategies than previously
possible. Furthermore, we present a new three-player Texas Hold'em poker agent
that was built using CFR and a novel game decomposition method. Our new agent
wins the three-player events of the 2012 ACPC and defeats the winning
three-player programs from previous competitions while requiring less resources
to generate than the 2011 winner. Finally, we show that our CFR modification
computes a strategy of equal quality to our new agent in a quarter of the time
of standard CFR using half the memory.


title: Computing the residue of the Dedekind zeta function

abstract:
  Assuming the Generalized Riemann Hypothesis, Bach has shown that one can
calculate the residue of the Dedekind zeta function of a number field K by a
clever use of the splitting of primes p < X, with an error asymptotically
bounded by 8.33 log D_K/(\sqrt{X}\log X), where D_K is the absolute value of
the discriminant of K. Guided by Weil's explicit formula and still assuming
GRH, we make a different use of the splitting of primes and thereby improve
Bach's constant to 2.33. This results in substantial speeding of one part of
Buchmann's class group algorithm.


title: GPU accelerated Trotter-Suzuki solver for quantum spin dynamics

abstract:
  The resolution of dynamics in out of equilibrium quantum spin systems lies at
the heart of fundamental questions among Quantum Information Processing,
Statistical Mechanics and Nano-Technologies. Efficient computational
simulations of interacting many-spin systems are extremely valuable tools for
tackling such questions. Here, we use the Trotter-Suzuki (TS) algorithm, a
well-known strategy that provides the evolution of quantum systems, to address
the spin dynamics. We present a GPU implementation of a particular TS version,
which has been previously implemented on single cores in CPUs. We develop a
massive parallel version of this algorithm and compare the efficiency between
CPU and GPU implementations. This method reduces the execution time
considerably and is capable of dealing with systems of up to 27 spins (only
limited by GPU memory).


title: Conservative 3+1 General Relativistic Boltzmann Equation

abstract:
  We present a new derivation of the conservative form of the general
relativistic Boltzmann equation and specialize it to the 3+1 metric. The
resulting transport equation is intended for use in simulations involving
numerical relativity, particularly in the absence of spherical symmetry. The
independent variables are lab frame coordinate basis spacetime position
components and comoving frame curvilinear momentum space coordinates. With an
eye towards astrophysical applications---such as core-collapse supernovae and
compact object mergers---in which the fluid includes nuclei and/or nuclear
matter at finite temperature, and in which the transported particles are
neutrinos, we examine the relationship between lepton number and four-momentum
exchange between neutrinos and the fluid.


title: Atomistics of vapor-liquid-solid nanowire growth

abstract:
  Vapor-liquid-solid (VLS) route and its variants are routinely used for
scalable synthesis of semiconducting nanowires yet the fundamental growth
processes remain unknown. Here, we employ atomic-scale computations based on
model potentials to study the stability and growth of gold-catalyzed silicon
nanowires (SiNWs). Equilibrium studies uncover segregation at the solid-like
surface of the catalyst particle, a liquid AuSi droplet, and a silicon-rich
droplet-nanowire interface enveloped by heterogeneous truncating facets.
Supersaturation of the droplets leads to rapid 1D growth on the truncating
facets and much slower nucleation-controlled 2D growth on the main facet.
Surface diffusion is suppressed and the excess Si flux occurs through the
droplet bulk which, together with the Si-rich interface and contact line,
lowers the nucleation barrier on the main facet. The ensuing step flow is
modified by Au diffusion away from the step edges. Our study highlights key
interfacial characteristics for morphological and compositional control of
semiconducting nanowire arrays.


title:
Nuclear-electronic spin systems, magnetic resonance, and quantum
  information processing

abstract:
  A promising platform for quantum information processing is that of silicon
impurities, where the quantum states are manipulated by magnetic resonance.
Such systems, in abstraction, can be considered as a nucleus of arbitrary spin
coupled to an electron of spin one-half via an isotropic hyperfine interaction.
We therefore refer to them as "nuclear-electronic spin systems". The
traditional example, being subject to intensive experimental studies, is that
of phosphorus doped silicon (Si:P) which couples a spin one-half electron to a
nucleus of the same spin, with a hyperfine strength of 117.5 MHz. More
recently, bismuth doped silicon (Si:Bi) has been suggested as an alternative
instantiation of nuclear-electronic spin systems, differing from Si:P by its
larger nuclear spin and hyperfine strength of 9/2 and 1.4754 GHz respectively.
The aim of this thesis has been to develop a model that is capable of
predicting the magnetic resonance properties of nuclear-electronic spin
systems. The theoretical predictions of this model have been tested against
experimental data collected on Si:Bi at 4.044 GHz, and have proven quite
successful. Furthermore, the larger nuclear spin and hyperfine strength of
Si:Bi, compared with that of Si:P, are predicted to offer advantages for
quantum information processing. Most notable amongst these is that magnetic
field-dependent two-dimensional decoherence free subspaces, called optimal
working points, have been identified to exist in Si:Bi, but not Si:P.


title: A note on replicating a CDS through a repo and an asset swap

abstract:
  In this note we show how to replicate a stylized CDS with a repurchase
agreement and an asset swap. The latter must be designed in such a way that, on
default of the issuer, it is terminated with a zero close-out amount. This
break clause can be priced using the well known unilateral credit/debit
valuation adjustment formulas.


title: A Tutorial on Time-Evolving Dynamical Bayesian Inference

abstract:
  In view of the current availability and variety of measured data, there is an
increasing demand for powerful signal processing tools that can cope
successfully with the associated problems that often arise when data are being
analysed. In practice many of the data-generating systems are not only
time-variable, but also influenced by neighbouring systems and subject to
random fluctuations (noise) from their environments. To encompass problems of
this kind, we present a tutorial about the dynamical Bayesian inference of
time-evolving coupled systems in the presence of noise. It includes the
necessary theoretical description and the algorithms for its implementation.
For general programming purposes, a pseudocode description is also given.
Examples based on coupled phase and limit-cycle oscillators illustrate the
salient features of phase dynamics inference. State domain inference is
illustrated with an example of coupled chaotic oscillators. The applicability
of the latter example to secure communications based on the modulation of
coupling functions is outlined. MatLab codes for implementation of the method,
as well as for the explicit examples, accompany the tutorial.

categories: physics.data-an nlin.AO nlin.CD physics.comp-ph physics.med-ph


title:
Studying the kinematics of the giant star-forming region 30 Doradus. I.
  The data

abstract:
  We present high-quality VLT-FLAMES optical spectroscopy of the nebular gas in
the giant star-forming region 30 Doradus. In this paper, the first of a series,
we introduce our observations and discuss the main kinematic features of 30
Dor, as revealed by the spectroscopy of the ionized gas in the region. The
primary data set consists of regular grid of nebular observations, which we
used to produce a spectroscopic datacube of 30 Dor, centered on the massive
star cluster R136 and covering a field-of-view of 10'x10'. The main emission
lines present in the datacube are from Halpha and [NII]6548,6584. The Halpha
emission-line profile varies across the region from simple single-peaked
emission to complex, multiple-component profiles, suggesting that different
physical mechanisms are acting on the excited gas. To analyse the gas
kinematics we fit Gaussian profiles to the observed Halpha features.
Unexpectedly, the narrowest Halpha profile in our sample lies close to the
supernova remnant 30 Dor B. We present maps of the velocity field and velocity
dispersion across 30 Dor, finding five previously unclassified expanding
structures. These maps highlight the kinematic richness of 30 Dor (e.g.
supersonic motions), which will be analysed in future papers.


title: Roth's Theorem in the Piatetski-Shapiro primes

abstract:
  Let $\mathbf{P}$ denote the set of prime numbers and, for an appropriate
function $h$, define a set $\mathbf{P}_{h}=\{p\in\mathbf{P}:
\exists_{n\in\mathbb{N}}\ p=\lfloor h(n)\rfloor\}$. The aim of this paper is to
show that every subset of $\mathbf{P}_{h}$ having positive relative upper
density contains a nontrivial three-term arithmetic progression. In particular
the set of Piatetski--Shapiro primes of fixed type $71/72<\gamma<1$, i.e.
$\{p\in\mathbf{P}: \exists_{n\in\mathbb{N}}\ p=\lfloor n^{1/\gamma}\rfloor\}$
has this feature. We show this by proving the counterpart of Bourgain--Green's
restriction theorem for the set $\mathbf{P}_{h}$.


title: The Quantum Closet

abstract:
  The equivalence postulate approach to quantum mechanics entails a derivation
of quantum mechanics from a fundamental geometrical principle. Underlying the
formalism there exists a basic cocycle condition, which is invariant under
D-dimensional finite Mobius transformations. The invariance of the cocycle
condition under finite Mobius transformations implies that space is compact.
Additionally, it implies energy quantisation and the undefinability of quantum
trajectories. I argue that the decompactification limit coincides with the
classical limit. Evidence for the compactness of the universe may exist in the
Cosmic Microwave Background Radiation.


title:
Strict comparison of projections and positive combinations of
  projections in certain multiplier algebras

abstract:
  In this paper we investigate whether positive elements in the multiplier
algebras of certain finite C*-algebras can be written as finite linear
combinations of projections with positive coefficients (PCP). Our focus is on
the category of underlying C*-algebras that are separable, simple, with real
rank zero, stable rank one, finitely many extreme traces, and strict comparison
of projections by the traces. We prove that the strict comparison of
projections holds also in the multiplier algebra of the stabilizer algebra.
Based on this result and under the additional hypothesis that the multiplier
algebra has real rank zero, we characterize which positive elements of the
multiplier algebra are PCP.


title: Finite type domains with hyperbolic orbit accumulation points

abstract:
  In this paper, finite type domains with hyperbolic orbit accumulation points
are studied. We prove, in case of $\mathbb{C}^2$, it has to be a (global)
pseudoconvex domain, after an assumption of boundary regularity. Moreover, one
of the applications will realize the classification of domains within this
class, precisely the domain is biholomorphic to one of the ellipsoids $\lbrace
(z, w): | z|^{2m}+| w|^2<1, m\in\mathbb{Z}^+\rbrace$. This application
generalizes \cite{BP98} in which the boundary is assumed to be real analytic
for the case of hyperbolic orbit accumulation points.


title: Dictionary LASSO: Guaranteed Sparse Recovery under Linear Transformation

abstract:
  We consider the following signal recovery problem: given a measurement matrix
$\Phi\in \mathbb{R}^{n\times p}$ and a noisy observation vector $c\in
\mathbb{R}^{n}$ constructed from $c = \Phi\theta^* + \epsilon$ where
$\epsilon\in \mathbb{R}^{n}$ is the noise vector whose entries follow i.i.d.
centered sub-Gaussian distribution, how to recover the signal $\theta^*$ if
$D\theta^*$ is sparse {\rca under a linear transformation}
$D\in\mathbb{R}^{m\times p}$? One natural method using convex optimization is
to solve the following problem: $$\min_{\theta} {1\over 2}\|\Phi\theta - c\|^2
+ \lambda\|D\theta\|_1.$$ This paper provides an upper bound of the estimate
error and shows the consistency property of this method by assuming that the
design matrix $\Phi$ is a Gaussian random matrix. Specifically, we show 1) in
the noiseless case, if the condition number of $D$ is bounded and the
measurement number $n\geq \Omega(s\log(p))$ where $s$ is the sparsity number,
then the true solution can be recovered with high probability; and 2) in the
noisy case, if the condition number of $D$ is bounded and the measurement
increases faster than $s\log(p)$, that is, $s\log(p)=o(n)$, the estimate error
converges to zero with probability 1 when $p$ and $s$ go to infinity. Our
results are consistent with those for the special case $D=\bold{I}_{p\times p}$
(equivalently LASSO) and improve the existing analysis. The condition number of
$D$ plays a critical role in our analysis. We consider the condition numbers in
two cases including the fused LASSO and the random graph: the condition number
in the fused LASSO case is bounded by a constant, while the condition number in
the random graph case is bounded with high probability if $m\over p$ (i.e.,
$#text{edge}\over #text{vertex}$) is larger than a certain constant. Numerical
simulations are consistent with our theoretical results.


title:
Effective Polyakov line action from strong lattice couplings to the
  deconfinement transition

abstract:
  We calculate the effective Polyakov line action corresponding to SU(2)
lattice gauge theory on a 16^3 X 4 lattice via the "relative weights" method.
We consider a variety of lattice couplings, ranging from beta=1.2 in the
strong-coupling domain, to beta=2.3 at the deconfinement transition, in order
to study how the effective action evolves with beta. Comparison of Polyakov
line correlators computed in the effective theory and the underlying gauge
theory is used to test the validity of the effective action for beta > 1.4,
while for beta=1.2, 1.4 we can compare our effective action to the one obtained
from a low-order strong-coupling expansion. Very good agreement is found at all
couplings. We find that the effective action is given by a simple expression
bilinear in the Polyakov lines. The range of the bilinear term, away from
strong coupling, grows rapidly in lattice units as beta increases.


title: Lyapunov exponents for surface groups representations

abstract:
  Let (\rho_\la)_{\la\in \La} be a holomorphic family of representations of a
surface group \pi_1(S) into PSL(2,C), where S is a topological (possibly
punctured) surface with negative Euler characteristic. Given a structure of
Riemann surface of finite type on S we construct a bifurcation current on the
parameter space \La, that is a (1,1) positive closed current attached to the
bifurcations of the family. It is defined as the $dd^c$ of the Lyapunov
exponent of the representation with respect to the Brownian motion on the
Riemann surface S, endowed with its Poincare metric. We show that this
bifurcation current describes the asymptotic distribution of various
codimension 1 phenomena in \La. For instance, the random hypersurfaces of \La
defined by the condition that a random closed geodesic on S is mapped under
\rho_\la to a parabolic element or the identity are asymptotically
equidistributed with respect to the bifurcation current. The proofs are based
on our previous work "Random walks, Kleinian groups, and bifurcation currents",
and on a careful control of a discretization procedure of the Brownian motion.


title:
A multi-wavelength view of cooling vs. AGN heating in the X-ray luminous
  cool-core of Abell 3581

abstract:
  We report the results of a multi-wavelength study of the nearby galaxy group,
Abell 3581 (z=0.0218). This system hosts the most luminous cool core of any
nearby group and exhibits active radio mode feedback from the super-massive
black hole in its brightest group galaxy, IC 4374. The brightest galaxy has
suffered multiple active galactic nucleus outbursts, blowing bubbles into the
surrounding hot gas, which have resulted in the uplift of cool ionised gas into
the surrounding hot intragroup medium. High velocities, indicative of an
outflow, are observed close to the nucleus and coincident with the radio jet.
Thin dusty filaments accompany the uplifted, ionised gas. No extended star
formation is observed, however, a young cluster is detected just north of the
nucleus. The direction of rise of the bubbles has changed between outbursts.
This directional change is likely due to sloshing motions of the intragroup
medium. These sloshing motions also appear to be actively stripping the X-ray
cool core, as indicated by a spiraling cold front of high metallicity, low
temperature, low entropy gas.


title: Revealing social networks of spammers through spectral clustering

abstract:
  To date, most studies on spam have focused only on the spamming phase of the
spam cycle and have ignored the harvesting phase, which consists of the mass
acquisition of email addresses. It has been observed that spammers conceal
their identity to a lesser degree in the harvesting phase, so it may be
possible to gain new insights into spammers' behavior by studying the behavior
of harvesters, which are individuals or bots that collect email addresses. In
this paper, we reveal social networks of spammers by identifying communities of
harvesters with high behavioral similarity using spectral clustering. The data
analyzed was collected through Project Honey Pot, a distributed system for
monitoring harvesting and spamming. Our main findings are (1) that most
spammers either send only phishing emails or no phishing emails at all, (2)
that most communities of spammers also send only phishing emails or no phishing
emails at all, and (3) that several groups of spammers within communities
exhibit coherent temporal behavior and have similar IP addresses. Our findings
reveal some previously unknown behavior of spammers and suggest that there is
indeed social structure between spammers to be discovered.


title:
On the Limit Set of Root Systems of Coxeter Groups acting on Lorentzian
  spaces

abstract:
  The notion of limit roots of a Coxeter group W was recently introduced (see
arXiv:1112.5415 and arXiv:1303.6710): they are the accumulation points of
directions of roots of a root system for W. In the case where the root system
lives in a Lorentzian space W admits a faithful representation as a discrete
reflection group of isometries on a hyperbolic space; the accumulation set of
any of its orbits is then classically called the limit set of W. In this
article we show that the limit roots of a Coxeter group W acting on a
Lorentzian space is equal to the limit set of W seen as a discrete reflection
group of hyperbolic isometries. We aim for this article to be as self-contained
as possible in order to be accessible to the community familiar with reflection
groups and root systems and to the community familiar with discrete subgroups
of isometries in hyperbolic geometry.


title: Weak valued statistics as fundamental explanation of quantum physics

abstract:
  Recently, weak measurements have attracted a lot of interest as an
experimental method for the investigation of non-classical correlations between
observables that cannot be measured jointly. Here, I explain how the complex
valued statistics observed in weak measurements relate to the operator algebra
of the conventional Hilbert space formalism and show that the algebra of
operators originates from more fundamental relations between the physical
properties of a quantum system that can be expressed in terms of complex
conditional probabilities. In particular, commutation relations can be
identified with fundamental imaginary correlations that characterize the
relations between physical properties in terms of their transformation
dynamics. Non-commutativity thus originates from a definition of relations
between physical properties that replaces the assumption of joint reality with
a complex-valued probability reflecting the dynamical response of the system to
external forces, e.g. in measurement interactions.


title:
Spin polarization of Ru in superconducting
  Ba(Fe$_{0.795}$Ru$_{0.205}$)$_2$As$_2$ studied by x-ray resonant magnetic
  scattering

abstract:
  We have employed the x-ray resonant magnetic scattering (XRMS) technique at
the Ru $L_2$ edge of the Ba(Fe$_{1-x}$Ru$_x$)$_2$As$_2$ ($x = 0.205$)
superconductor. We show that pronounced resonance enhancements at the Ru $L_2$
edge are observed at the wave vector which is consistent with the
antiferromagnetic propagation vector of the Fe in the undoped BaFe$_2$As$_2$.
We also demonstrate that the XRMS signals at the Ru $L_2$ edge follow the
magnetic ordering of the Fe with a long correlation length, $\xi_{ab} >
2850\pm400$ \AA . Our experimental observation shows that the Ru is
spin-polarized in Ba(Fe$_{1-x}$Ru$_x$)$_2$As$_2$ compounds.


title: Constraints on the Brans-Dicke gravity theory with the Planck data

abstract:
  Based on the new cosmic CMB temperature data from the Planck satellite, the 9
year polarization data from the WMAP, the BAO distance ratio data from the SDSS
and 6dF surveys, we place a new constraint on the Brans-Dicke theory. We adopt
a parametrization $\zeta=\ln(1+1/\omega})$, where the general relativity (GR)
limit corresponds to $\zeta = 0$. We find no evidence of deviation from general
relativity. At 95% probability, $-0.00246 < \zeta < 0.00567$, correspondingly,
the region $-407.0 < \omega <175.87$ is excluded. If we restrict ourselves to
the $\zeta>0$ (i.e. $\omega >0$) case, then the 95% probability interval is
$\zeta<0.00549$, corresponding to $\omega> 181.65$. We can also translate this
result to a constraint on the variation of gravitational constant, and find the
variation rate today as $\dot{G}=-1.42^{+2.48}_{-2.27} \times 10^{-13}
$yr$^{-1} $ ($1\sigma$ error bar), the integrated change since the epoch of
recombination is $\delta G/G = 0.0104^{+0.0186}_{-0.0067} $ ($1\sigma$ error
bar). These limits on the variation of gravitational constant are comparable
with the precision of solar system experiments.