title: Capacity Considerations for Secondary Networks in TV White Space

abstract:
  The so-called `TV white spaces' (TVWS) - representing unused TV channels in
any given location as the result of the transition to digital broadcasting -
designated by U.S. Federal Communications Commission (FCC) for unlicensed use
presents significant new opportunities within the context of emerging 4G
networks for developing new wireless access technologies that meet the goals of
the US National Broadband Plan (notably true broadband access for an increasing
fraction of the population). There are multiple challenges in realizing this
goal; the most fundamental being the fact that the available WS capacity is
currently not accurately known, since it depends on a multiplicity of factors -
including system parameters of existing incumbents (broadcasters), propagation
characteristics of local terrain as well as FCC rules. In this paper, we
explore the capacity of white space networks by developing a detailed model
that includes all the major variables, and is cognizant of FCC regulations that
provide constraints on incumbent protection. Real terrain information and
propagation models for the primary broadcaster and adjacent channel
interference from TV transmitters are included to estimate their impact on
achievable WS capacity. The model is later used to explore various trade-offs
between network capacity and system parameters and suggest possible amendments
to FCC's incumbent protection rules in the favor of furthering white space
capacity.


title: The Variable Optical Polarization of J0948+0022

abstract:
  The results of monitoring the optical polarization and the gamma-ray flux for
the radio-loud narrow-line Seyfert 1 galaxy is reported. We have detected a
weak correlation between the gamma-ray variability and the optical variability.
However, these observations do not provide conclusive evidence that the
emissions are due to a relativistic jet oriented close to the line-of-sight to
the observer.


title:
The MSSM Higgs sector at a high $M_{SUSY}$: reopening the low tan$\beta$
  regime and heavy Higgs searches

abstract:
  One of the main implications of the LHC discovery of a Higgs boson with a
mass $M_h \approx 126$ GeV is that the scale of supersymmetry-breaking in the
Minimal Supersymmetric Standard Model (MSSM) might be rather high, $M_S \gg
M_Z$. In this paper, we consider the high $M_S$ regime and study the spectrum
of the extended Higgs sector of the MSSM, including the LHC constraints on the
mass and the rates of the observed light $h$ state. In particular, we show that
in a simplified model that approximates the important radiative corrections,
the unknown scale $M_S$ (and some other leading SUSY parameters) can be traded
against the measured value of $M_h$. One would be then essentially left with
only two free parameters to describe the Higgs sector, tan$\beta$ and the
pseudoscalar Higgs mass $M_A$, even at higher orders. The main phenomenological
consequence of these high $M_S$ values is to reopen the low tan$\beta$ region,
tan$\beta \lsim 3-5$, which was for a long time buried under the LEP constraint
on the lightest $h$ mass when a low SUSY scale was assumed. We show that, in
this case, the heavier MSSM neutral $H/A$ and charged $H^\pm$ states can be
searched for in a variety of interesting final states such as decays into gauge
and lighter Higgs bosons (in pairs on in mixed states) and decays into heavy
top quarks. Examples of sensitivity on the $[tan\beta, M_A]$ parameter space at
the LHC in these channels are given.


title: Unimodularity and preservation of volumes in nonholonomic mechanics

abstract:
  The equations of motion of a mechanical system subjected to nonholonomic
linear constraints can be formulated in terms of a linear almost Poisson
structure in a vector bundle. We study the existence of invariant measures for
the system in terms of the unimodularity of this structure. In the presence of
symmetries, our approach allows us to give necessary and sufficient conditions
for the existence of an invariant volume, that unify and improve results
existing in the literature. We present an algorithm to study the existence of a
smooth invariant volume for nonholonomic mechanical systems with symmetry and
we apply it to several concrete mechanical examples.


title: Effective Field Theory of Precision Electroweak Physics at One Loop

abstract:
  The one loop effects of two dimension-six operators on gauge boson self
energies are computed within an effective field theory framework. These self
energies are translated into effects on precision electroweak observables, and
bounds are obtained on the operator coefficients. The effective field theory
framework allows for the divergences that arise in the loop calculations to be
properly handled, and for unambiguous bounds on the coefficients to be
obtained. We find that the coefficients are only weakly bounded, in contrast to
previous calculations that obtained much stronger bounds. We argue that the
results of these previous calculations are specious.


title:
Upgraded Approximation of Non-Binary Alphabets for Polar Code
  Construction

abstract:
  An algorithm is presented for approximating a single-user channel with a
prime input alphabet size. The result is an upgraded version of the channel
with a reduced output alphabet size. It is shown that this algorithm can be
used to reduce the output alphabet size to the input alphabet size in most
cases.


title:
Probing the Pulsar Origin of the Anomalous Positron Fraction with AMS-02
  and Atmospheric Cherenkov Telescopes

abstract:
  Recent observations by PAMELA, Fermi-LAT, and AMS-02 have conclusively
indicated a rise in the cosmic-ray positron fraction above 10 GeV, a feature
which is impossible to mimic under the paradigm of secondary positron
production with self-consistent Galactic cosmic-ray propagation models. A
leading explanation for the rising positron fraction is an additional source of
electron-positron pairs, for example one or more mature, energetic, and
relatively nearby pulsars. We point out that any one of two well-known nearby
pulsars, Geminga and Monogem, can satisfactorily provide enough positrons to
reproduce AMS-02 observations. A smoking-gun signature of this scenario is an
anisotropy in the arrival direction of the cosmic-ray electrons and positrons,
which may be detectable by existing, or future, telescopes. The predicted
anisotropy level is, at present, consistent with limits from Fermi-LAT and
AMS-02. We argue that the large collecting area of Atmospheric Cherenkov
Telescopes (ACTs) makes them optimal tools for detecting such an anisotropy.
Specifically, we show that much of the proton and gamma-ray background, which
affects measurements of the cosmic-ray electron-positron spectrum with ACTs,
may be controlled in the search for anisotropies. We conclude that observations
using archival ACT data could already constrain or substantiate the pulsar
origin of the positron anomaly, while upcoming instruments (such as the
Cherenkov Telescope Array) will provide strong constraints on the source of the
rising positron fraction.


title: Properties of Two-Dimensional Silicon grown on Graphene Substrate

abstract:
  The structure and electrical properties of a two-dimensional (2D) sheet of
silicon on a graphene substrate are studied using first-principles
calculations. A new corrugated rectangular structure of silicon is proposed to
be the most energetically favorable structure. The shifting of the Fermi energy
level indicates self-doping. Calculation of electron density shows a weak
coupling between the silicon layer and graphene substrate. The 2D silicon sheet
turns to be metallic and has a much higher value of transmission efficiency
(TE) than the underlying graphene substrate.


title: Thermotropic nematic order upon nano-capillary filling

abstract:
  Optical birefringence and light absorption measurements reveal four regimes
for the thermotropic behavior of a nematogen liquid (7CB) upon sequential
filling of parallel-aligned capillaries of 12 nm diameter in a monolithic,
mesoporous silica membrane. No molecular reorientation is observed for the
first adsorbed monolayer. In the film-condensed state (up to 1 nm thickness) a
weak, continuous paranematic-to-nematic (P-N) transition is found, which is
shifted by 10 K below the discontinuous bulk transition at T_IN=305K. The
capillary-condensed state exhibits a more pronounced, albeit still continuous
P-N reordering, located 4 K below T_IN. This shift vanishes abruptly on
complete filling of the capillaries, which we tentatively trace to a 10 MPa
tensile pressure release associated with the disappearance of concave menisci
in the confined liquid.

categories: cond-mat.soft cond-mat.mes-hall cond-mat.mtrl-sci physics.chem-ph


title: Is every matrix similar to a polynomial in a companion matrix?

abstract:
  Given a field $F$, an integer $n\geq 1$, and a matrix $A\in M_n(F)$, are
there polynomials $f,g\in F[X]$, with $f$ monic of degree $n$, such that $A$ is
similar to $g(C_f)$, where $C_f$ is the companion matrix of $f$? For infinite
fields the answer is easily seen to positive, so we concentrate on finite
fields. In this case we give an affirmative answer, provided $|F|\geq n-2$.
Moreover, for any finite field $F$, with $|F|=m$, we construct a matrix $A\in
M_{m+3}(F)$ that is not similar to any matrix of the form $g(C_f)$.
  Of use above, but also of independent interest, is a constructive procedure
to determine the similarity type of any given matrix $g(C_f)$ purely in terms
of $f$ and $g$, without resorting to polynomial roots in $F$ or in any
extension thereof. This, in turn, yields an algorithm that, given $g$ and the
invariant factors of any $A$, returns the elementary divisors of $g(A)$. It is
a rational procedure, as opposed to the classical method that uses the Jordan
decomposition of $A$ to find that of $g(A)$.
  Finally, extending prior results by the authors, we show that for an
integrally closed ring $R$ with field of fractions $F$ and companion matrices
$C,D$ the subalgebra $R< C,D>$ of $M_n(R)$ is a free $R$-module of rank
$n+(n-m)(n-1)$, where $m$ is the degree of $\gcd (f,g)\in F[X]$, and a
presentation for $R< C,D>$ is given in terms of $C$ and $D$. A counterexample
is furnished to show that $R< C,D>$ need not be a free $R$-module if $R$ is not
integrally closed. The preceding information is used to study $M_n(R)$, and
others, as $R[X]$-modules.


title: Dynamics of a Stabilized Radion and Duality

abstract:
  We construct the effective theory of the graviscalar radion in the
Randall-Sundrum scenario, taking into account effects arising from the
stabilization of the extra dimension through the Goldberger-Wise mechanism. We
explore the conditions under which the radion can remain light, and determine
the corrections to its couplings to Standard Model (SM) states when the effects
of stabilization are taken into account. We show that in the theories of
interest for electroweak symmetry breaking that have a holographic dual, the
presence of a light radion in the spectrum is not a robust prediction of the
framework, but is in fact associated with mild tuning. We find that corrections
to the form of the radion couplings to Standard Model particles arising from
effects associated with brane stabilization are suppressed by the square of the
ratio of the radion mass to the Kaluza-Klein scale. These corrections are small
in theories where the radion is light, and are generally subleading, except in
the case of couplings to the SM gluons and photon, when they can sometimes
dominate. The AdS/CFT correspondence relates the radion in Randall-Sundrum
models to the dilaton in theories where a strongly coupled conformal symmetry
is spontaneously broken. We show that the discrepancies in the literature
between the results for the dilaton and the radion can be traced to the
omission of self-interaction terms that would otherwise dominate the potential
for the Goldberger-Wise scalar near the infrared brane. In the dual picture,
this corresponds to neglecting the corrections to the scaling behavior of the
operator that breaks conformal symmetry when it grows large. With the inclusion
of these self-interaction terms, we find good agreement between the results on
the two sides of the correspondence.


title: The Round Complexity of Small Set Intersection

abstract:
  The set disjointness problem is one of the most fundamental and well-studied
problems in communication complexity. In this problem Alice and Bob hold sets
$S, T \subseteq [n]$, respectively, and the goal is to decide if $S \cap T =
\emptyset$. Reductions from set disjointness are a canonical way of proving
lower bounds in data stream algorithms, data structures, and distributed
computation. In these applications, often the set sizes $|S|$ and $|T|$ are
bounded by a value $k$ which is much smaller than $n$. This is referred to as
small set disjointness. A major restriction in the above applications is the
number of rounds that the protocol can make, which, e.g., translates to the
number of passes in streaming applications. A fundamental question is thus in
understanding the round complexity of the small set disjointness problem. For
an essentially equivalent problem, called OR-Equality, Brody et. al showed that
with $r$ rounds of communication, the randomized communication complexity is
$\Omega(k \ilog^r k)$, where$\ilog^r k$ denotes the $r$-th iterated logarithm
function. Unfortunately their result requires the error probability of the
protocol to be $1/k^{\Theta(1)}$. Since na\"ive amplification of the success
probability of a protocol from constant to $1-1/k^{\Theta(1)}$ blows up the
communication by a $\Theta(\log k)$ factor, this destroys their improvements
over the well-known lower bound of $\Omega(k)$ which holds for any number of
rounds. They pose it as an open question to achieve the same $\Omega(k \ilog^r
k)$ lower bound for protocols with constant error probability. We answer this
open question by showing that the $r$-round randomized communication complexity
of ${\sf OREQ}_{n,k}$, and thus also of small set disjointness, with {\it
constant error probability} is $\Omega(k \ilog^r k)$, asymptotically matching
known upper bounds for ${\sf OREQ}_{n,k}$ and small set disjointness.


title:
On magnetic-field-induced dissipationless electric current in helicoidal
  graphene nanoribbons

abstract:
  We argue that twisted (helicoidal) graphene nanoribbons may support
dissipationless electric current in the presence of static uniform magnetic
field. The non-resistive charge transfer in this parity-odd system should be
enhanced by thermal fluctuations.


title: Two-dimensional S-matrices from unitarity cuts

abstract:
  Using unitarity methods, we compute, for several massive two-dimensional
models, the cut-constructible part of the one-loop 2->2 scattering S-matrices
from the tree-level amplitudes. We apply our method to various integrable
theories, finding evidence that for supersymmetric models the one-loop S-matrix
is cut-constructible, while for models without supersymmetry (but with
integrability) the missing rational terms are proportional to the tree-level
S-matrix and therefore can be interpreted as a shift in the coupling. Finally,
applying our procedure to the world-sheet theory for the light-cone gauge-fixed
AdS_5 x S^5 superstring we reproduce, at one-loop in the near-BMN expansion,
the S-matrix known from integrability techniques.


title:
Intrinsic and extrinsic mirror symmetry breaking in anti-dot spin-wave
  waveguides

abstract:
  We theoretically study the spin-wave spectra in magnonic waveguides
periodically patterned with square anti-dots in nanoscale with pinned
magnetization at the edges. We show that the breaking of the mirror symmetry of
the waveguide by the structural changes can result in a magnonic band gap
closing. These intrinsic symmetry breaking can be compensated by properly
chosen asymmetric external bias magnetic field, i.e. in an extrinsic way. As a
result the magnonic gaps existing in the ideal symmetric structure can be
recovered. The model used for the explanation also suggests that this idea
could be generic both for exchange and dipolar interaction regimes of
spin-waves and also for other types of waves, e.g., electrons in the graphene
ribbons.


title: Effective Hamiltonian for the hybrid double quantum dot qubit

abstract:
  Quantum dot hybrid qubits formed from three electrons in double quantum dots
represent a promising compromise between high speed and simple fabrication for
solid state implementations of single qubit and two qubits quantum logic ports.
We derive the Schrieffer-Wolff effective Hamiltonian that describes in a simple
and intuitive way the qubit by combining a Hubbard-like model with a projector
operator method. As a result, the Hubbard-like Hamiltonian is transformed in an
equivalent expression in terms of the exchange coupling interactions between
pairs of electrons. The effective Hamiltonian is exploited to derive the
dynamical behaviour of the system and its eigenstates on the Bloch sphere to
generate qubits operation for quantum logic ports. A realistic implementation
in silicon and the coupling of the qubit with a detector are discussed.


title:
The PdBI Arcsecond Whirlpool Survey (PAWS). I. A
  Cloud-Scale/Multi-Wavelength View of the Interstellar Medium in a
  Grand-Design Spiral Galaxy

abstract:
  The PdBI (Plateau de Bure Interferometer) Arcsecond Whirlpool Survey (PAWS)
has mapped the molecular gas in the central ~9kpc of M51 in its 12CO(1-0) line
emission at cloud-scale resolution of ~40pc using both IRAM telescopes. We
utilize this dataset to quantitatively characterize the relation of molecular
gas (or CO emission) to other tracers of the interstellar medium (ISM), star
formation and stellar populations of varying ages. Using 2-dimensional maps, a
polar cross-correlation technique and pixel-by-pixel diagrams, we find: (a)
that (as expected) the distribution of the molecular gas can be linked to
different components of the gravitational potential, (b) evidence for a
physical link between CO line emission and radio continuum that seems not to be
caused by massive stars, but rather depend on the gas density, (c) a close
spatial relation between the PAH and molecular gas emission, but no predictive
power of PAH emission for the molecular gas mass,(d) that the I-H color map is
an excellent predictor of the distribution (and to a lesser degree the
brightness) of CO emission, and (e) that the impact of massive (UV-intense)
young star-forming regions on the bulk of the molecular gas in central ~9kpc
can not be significant due to a complex spatial relation between molecular gas
and star-forming regions that ranges from co-spatial to spatially offset to
absent. The last point, in particular, highlights the importance of galactic
environment -- and thus the underlying gravitational potential -- for the
distribution of molecular gas and star formation.


title: Cosmic Chronometers in the R_h=ct Universe

abstract:
  The use of luminous red galaxies as cosmic chronometers provides us with an
indispensable method of measuring the universal expansion rate H(z) in a
model-independent way. Unlike many probes of the cosmological history, this
approach does not rely on integrated quantities, such as the luminosity
distance, and therefore does not require the pre-assumption of any particular
model, which may bias subsequent interpretations of the data. We employ three
statistical tools -- the Akaike, Kullback, and Bayes Information Criteria (AIC,
KIC and BIC) -- to compare the LCDM model and the R_h=ct Universe with the
currently available measurements of H(z), and show that the R_h=ct Universe is
favored by these model selection criteria. The parameters in each model are
individually optimized by maximum likelihood estimation. The R_h=ct Universe
fits the data with a reduced chi^2_dof=0.745 for a Hubble constant
H_0=63.2+/-2.5 km/s/Mpc, and H_0 is the sole parameter in this model. By
comparison, the optimal LCDM model, which has three free parameters (including
H_0=68.9+/-2.4 km/s/Mpc, Omega_m=0.32, and a dark-energy equation of state
p_de=-rho_de), fits the H(z) data with a reduced chi^2_dof=0.777. With these
chi^2_dof values, the AIC yields a likelihood of about 82 per cent that the
distance--redshift relation of the R_h=ct Universe is closer to the correct
cosmology, than is the case for LCDM. If the alternative BIC criterion is used,
the respective Bayesian posterior probabilities are 91.2 per cent (R_h=ct)
versus 8.8 per cent (LCDM). Using the concordance LCDM parameter values, rather
than those obtained by fitting LCDM to the cosmic chronometer data, would
further disfavor LCDM.


title: The N=4 Superconformal Bootstrap

abstract:
  We implement the conformal bootstrap for N=4 superconformal field theories in
four dimensions. Consistency of the four-point function of the stress-energy
tensor multiplet imposes significant upper bounds for the scaling dimensions of
unprotected local operators as functions of the central charge of the theory.
At the threshold of exclusion, a particular operator spectrum appears to be
singled out by the bootstrap constraints. For large values of the central
charge, this extremal spectrum is compatible with that of supergravity in AdS_5
x S^5. For finite central charge, we conjecture that the extremal spectrum is
that of N=4 SYM at an S-duality invariant value of the complexified gauge
coupling.


title: The Cosmophenomenology of Axionic Dark Radiation

abstract:
  Relativistic axions are good candidates for the dark radiation for which
there are mounting observational hints. The primordial decays of heavy fields
produce axions which are ultra-energetic compared to thermalised matter and
inelastic axion-matter scattering can occur with $E_{CoM} \gg T_{\gamma}$, thus
accessing many interesting processes which are otherwise kinematically
forbidden in standard cosmology. Axion-photon scattering into quarks and
leptons during BBN affects the light element abundances, and bounds on
overproduction of $^4$He constrain a combination of the axion decay constant
and the reheating temperature. For supersymmetric models, axion scattering into
visible sector superpartners can give direct non-thermal production of dark
matter at $T_{\gamma} \ll T_{freezeout}$. Most axions --- or any other dark
radiation candidate from modulus decay --- still linger today as a Cosmic Axion
Background with $E_{axion} \sim \mathcal{O}(100) eV$, and a flux of $\sim 10^6
cm^{-2} s^{-1}$.


title:
General relativistic simulations of binary black hole-neutron stars:
  Precursor electromagnetic signals

abstract:
  We perform the first general relativistic force-free simulations of neutron
star (NS) magnetospheres in orbit about spinning and non-spinning black holes.
We find promising precursor electromagnetic emission: typical Poynting
luminosities at, e.g., an orbital separation of 6.6 times the NS radius are L ~
6 x 10^{42} erg/s for a 1.4 solar-mass NS with a 10^{13}G polar magnetic field.
The Poynting flux peaks within a broad beam of ~40 degrees in the azimuthal
direction and within ~60 degrees from the orbital plane, establishing a
possible lighthouse effect. Our calculations, though preliminary, preview more
detailed simulations of these systems that we plan to perform in the future.


title: Multiloop integrals in dimensional regularization made simple

abstract:
  Scattering amplitudes at loop level can be expressed in terms of Feynman
integrals. The latter satisfy partial differential equations in the kinematical
variables. We argue that a good choice of basis for (multi-)loop integrals can
lead to significant simplifications of the differential equations, and propose
criteria for finding an optimal basis. This builds on experience obtained in
supersymmetric field theories that can be applied successfully to generic
quantum field theory integrals. It involves studying leading singularities and
explicit integral representations. When the differential equations are cast
into canonical form, their solution becomes elementary. The class of functions
involved is easily identified, and the solution can be written down to any
desired order in epsilon within dimensional regularization. Results obtained in
this way are particularly simple and compact. In this letter, we outline the
general ideas of the method and apply them to a two-loop example.


title:
Entropy production in classical Yang-Mills theory from Glasma initial
  conditions

abstract:
  We study the thermalization process in classical Yang-Mills (CYM) field
theory starting from noisy glasma-like initial conditions by investigating the
initial-value sensitivity of trajectories. Kunihiro et al. linked entropy
generation to the Kolmogorov-Sinai entropy, which gives the entropy production
rate in classical chaotic systems, calculated numerically for CYM fields
starting from purely random initial field configurations. In contrast, we here
study glasma-like initial conditions. For small random fluctuations we obtain
qualitatively similar results while no entropy increase is observed when such
fluctuations are absent. We analyze the intermediate time Lyapunov spectrum for
several time windows and calculate the Kolmogorov-Sinai entropy. We find a
large number of positive Lyapunov exponents at the early stages of time
evolution. Also for later times their number is a sizeable fraction of the
total number of degrees of freedom. The spectrum of positive Lyapunov exponents
at first changes rapidly, but then stabilizes, indicating that the dynamics of
the gauge fields approaches a steady state. Thus we conclude that also for
glasma-like initial conditions a significant amount of entropy is produced by
classical gluon field dynamics.

categories: hep-ph cond-mat.stat-mech nlin.CD nucl-th


title: The not-so-massive black hole in the microquasar GRS1915+105

abstract:
  We present a new dynamical study of the black hole X-ray transient
GRS1915+105 making use of near-infrared spectroscopy obtained with X-shooter at
the VLT. We detect a large number of donor star absorption features across a
wide range of wavelengths spanning the H and K bands. Our 24 epochs covering a
baseline of over 1 year permit us to determine a new binary ephemeris including
a refined orbital period of P=33.85 +/- 0.16 d. The donor star radial velocity
curves deliver a significantly improved determination of the donor
semi-amplitude which is both accurate (K_2=126 +/- 1 km/s) and robust against
choice of donor star template and spectral features used. We furthermore
constrain the donor star's rotational broadening to vsini=21 +/-4 km/s,
delivering a binary mass ratio of q=0.042 +/- 0.024. If we combine these new
constraints with distance and inclination estimates derived from modelling the
radio emission, a black hole mass of M_BH=10.1 +/- 0.6 M_sun is inferred,
paired with an evolved mass donor of M_2=0.47 +/- 0.27 M_sun. Our analysis
suggests a more typical black hole mass for GRS1915+105 rather than the
unusually high values derived in the pioneering dynamical study by Greiner et
al. (2001). Our data demonstrate that high-resolution infrared spectroscopy of
obscured accreting binaries can deliver dynamical mass determinations with a
precision on par with optical studies.


title: Heterotic Moduli Stabilisation

abstract:
  We perform a systematic analysis of moduli stabilisation for weakly coupled
heterotic string theory compactified on manifolds which are Calabi-Yau up to
alpha' effects. We review how to fix all geometric and bundle moduli in a
supersymmetric way by fractional fluxes, the requirement of a holomorphic gauge
bundle, D-terms, higher order perturbative contributions to W, non-perturbative
and threshold effects. We then show that alpha' corrections to K lead to new
stable Minkowski (or dS) vacua where the complex structure moduli Z and the
dilaton are fixed supersymmetrically, while the fixing of the Kahler moduli at
a lower scale leads to spontaneous SUSY breaking. The minimum lies at
moderately large volumes of all geometric moduli, at a perturbative string
coupling and at the right value of the GUT coupling. We also give a dynamical
derivation of anisotropic compactifications which allow for gauge coupling
unification around 10^16 GeV. The gravitino mass can be anywhere between the
GUT and TeV scale depending on the fixing of the Z-moduli. In general, these
are fixed by turning on background fluxes, leading to a gravitino mass around
the GUT scale since the heterotic 3-form flux does not contain enough freedom
to tune W to small values. Moreover accommodating the observed value of the
cosmological constant (CC) is a challenge. Low-energy SUSY could instead be
obtained in particular situations where the gauge bundle is holomorphic only at
a point-like sub-locus of Z-moduli space, or where the number of Z-moduli is
small (like orbifold models), since in these cases one may fix all moduli
without turning on any quantised flux. However tuning the CC is even more of a
challenge in these cases. Another option is to focus on non-complex manifolds
since these allow for new geometric fluxes which can be used to tune W and the
CC, even if their moduli space is presently only poorly understood.


title:
A near-optimal approximation algorithm for Asymmetric TSP on embedded
  graphs

abstract:
  We present a near-optimal polynomial-time approximation algorithm for the
asymmetric traveling salesman problem for graphs of bounded orientable or
non-orientable genus. Our algorithm achieves an approximation factor of O(f(g))
on graphs with genus g, where f(n) is the best approximation factor achievable
in polynomial time on arbitrary n-vertex graphs. In particular, the
O(log(n)/loglog(n))-approximation algorithm for general graphs by Asadpour et
al. [SODA 2010] immediately implies an O(log(g)/loglog(g))-approximation
algorithm for genus-g graphs. Our result improves the
O(sqrt(g)*log(g))-approximation algorithm of Oveis Gharan and Saberi [SODA
2011], which applies only to graphs with orientable genus g; ours is the first
approximation algorithm for graphs with bounded non-orientable genus.
  Moreover, using recent progress on approximating the genus of a graph, our
O(log(g) / loglog(g))-approximation can be implemented even without an
embedding when the input graph has bounded degree. In contrast, the
O(sqrt(g)*log(g))-approximation algorithm of Oveis Gharan and Saberi requires a
genus-g embedding as part of the input.
  Finally, our techniques lead to a O(1)-approximation algorithm for ATSP on
graphs of genus g, with running time 2^O(g)*n^O(1).


title:
The Topology and Size of the Universe from CMB Temperature and
  Polarization Data

abstract:
  We analyze seven year and nine year WMAP temperature maps for signatures of
three finite flat topologies M_0=T^3, M_1=T^2 x R^1, and M_2=S^1 x R^2. We use
Monte-Carlo simulations with the Feldman-Cousins method to obtain confidence
intervals for the size of the topologies considered. We analyze the V, W, and Q
frequency bands along with the ILC map and find no significant difference in
the results. The 95.5% confidence level lower bound on the size of the topology
is 1.5L_0 for M_0, 1.4L_0 for M_1, and 1.1L_0 for M_2, where L_0 is the radius
of the last scattering surface. Our results agree very well with the recently
released results from the Planck temperature data. We show that the likelihood
function is not Gaussian in the size, and therefore simulations are important
for obtaining accurate bounds on the size. We then introduce the formalism for
including polarization data in the analysis. The improvement that we find from
WMAP polarization maps is small because of the high level of instrumental
noise, but our forecast for Planck maps shows a much better improvement on the
lower bound for L. For the M_0 topology we expect an improvement on the lower
bound of L from 1.7L_0 to 1.9L_0 at 95.5% confidence level. Using both
polarization and temperature data is important because it tests the hypothesis
that deviations in the TT spectrum at small l originate in the primordial
perturbation spectrum.


title: Tripartite quantum state violating the hidden influence constraints

abstract:
  The possibility to explain quantum correlations via (possibly) unknown causal
influences propagating gradually and continuously at a finite speed v > c has
attracted a lot of attention recently. In particular, it could be shown that
this assumption leads to correlations that can be exploited for superluminal
communication. This was achieved studying the set of possible correlations that
are allowed within such a model and comparing them to correlations produced by
local measurements on a four-party entangled quantum state. Here, we report on
a quantum state that allows for the same conclusion involving only three
parties.


title:
Characterization of projectively flat Finsler manifolds of constant
  curvature with finite dimensional holonomy group

abstract:
  In this paper we prove that the holonomy group of a simply connected locally
projectively flat Finsler manifold of constant curvature is a finite
dimensional Lie group if and only if it is flat or it is Riemannian.


title: Dynamics of Large Fragments in the Tail of Active Asteroid P/2010 A2

abstract:
  We examine the motions of large fragments at the head of the dust tail of
active asteroid P/2010 A2. In previous work we showed that these fragments were
ejected from the primary nucleus in early 2009, either following a
hypervelocity impact or by rotationally induced break-up. Here, we follow their
positions through a series of Hubble Space Telescope images taken during the
first half of 2010. The orbital evolution of each fragment allows us to
constrain its velocity relative to the main nucleus after leaving its sphere of
gravitational influence. We find that the fragments constituting a prominent
X-shaped tail feature were emitted in a direction opposite to the motion of the
asteroid and towards the south of its orbital plane. Derived emission
velocities of these primary fragments range between 0.02 and 0.3 m/s,
comparable to the ~0.08 m/s gravitational escape speed from the nucleus. Their
sizes are on the order of decimeters or larger. We obtain the best fits to our
data with ejection velocity vectors lying in a plane that includes the nucleus.
This may suggest that the cause of the disruption of P/2010 A2 is rotational
break-up.


title: On the S-Euclidean minimum of an ideal class

abstract:
  We show that the S-Euclidean minimum of an ideal class is a rational number,
generalizing a result of Cerri. We also give some corollaries which explain the
relationship of our results with Lenstra's notion of a norm-Euclidean ideal
class and the conjecture of Barnes and Swinnerton-Dyer on quadratic forms. The
proof is self-contained but uses ideas from ergodic theory and topological
dynamics, particularly those of Berend.


title:
Asymptotically inspired moment-closure approximation for adaptive
  networks

abstract:
  Adaptive social networks, in which nodes and network structure co-evolve, are
often described using a mean-field system of equations for the density of node
and link types. These equations constitute an open system due to dependence on
higher order topological structures. We propose a new approach to moment
closure based on the analytical description of the system in an asymptotic
regime. We apply the proposed approach to two examples of adaptive networks:
recruitment to a cause model and adaptive epidemic model. We show a good
agreement between the improved mean-field prediction and simulations of the
full network system.


title: Non-Gaussian Halo Bias Beyond the Squeezed Limit

abstract:
  Primordial non-Gaussianity, in particular the coupling of modes with widely
different wavelengths, can have a strong impact on the large-scale clustering
of tracers through a scale-dependent bias with respect to matter. We
demonstrate that the standard derivation of this non-Gaussian scale-dependent
bias is in general valid only in the extreme squeezed limit of the primordial
bispectrum, i.e. for clustering over very large scales. We further show how the
treatment can be generalized to describe the scale-dependent bias on smaller
scales, without making any assumptions on the nature of tracers apart from a
dependence on the small-scale fluctuations within a finite region. If the
leading scale-dependent bias \Delta b \propto k^{\alpha}, then the first
subleading term will scale as k^{\alpha+2}. This correction typically becomes
relevant as one considers clustering over scales k >~ 0.01 h Mpc^{-1}.


title: Analytic Comparison between X-ray Fluorescence CT and K-edge CT

abstract:
  X-ray fluorescence computed tomography (XFCT) and K-edge computed tomography
(CT) are two important modalities to quantify a distribution of gold
nanoparticles (GNPs) in a small animal for preclinical studies. It is valuable
to determine which modality is more efficient for a given application. In this
paper, we report a theoretical analysis in terms of signal-to-noise ratio (SNR)
for the two modalities, showing that there is a threshold for the GNPs
concentration and XFCT has a better SNR than K-edge CT if GNPs concentration is
less than this threshold. Numerical simulations are performed and two kinds of
phantoms are used to represent multiple concentration levels and feature sizes.
Experimental results illustrate that XFCT is superior to K-edge CT when
contrast concentration is lower than 0.4% which coincides with the theoretical
analysis.


title: Model-based Bayesian Reinforcement Learning for Dialogue Management

abstract:
  Reinforcement learning methods are increasingly used to optimise dialogue
policies from experience. Most current techniques are model-free: they directly
estimate the utility of various actions, without explicit model of the
interaction dynamics. In this paper, we investigate an alternative strategy
grounded in model-based Bayesian reinforcement learning. Bayesian inference is
used to maintain a posterior distribution over the model parameters, reflecting
the model uncertainty. This parameter distribution is gradually refined as more
data is collected and simultaneously used to plan the agent's actions. Within
this learning framework, we carried out experiments with two alternative
formalisations of the transition model, one encoded with standard multinomial
distributions, and one structured with probabilistic rules. We demonstrate the
potential of our approach with empirical results on a user simulator
constructed from Wizard-of-Oz data in a human-robot interaction scenario. The
results illustrate in particular the benefits of capturing prior domain
knowledge with high-level rules.


title: Gromov-Hausdorff collapsing of Calabi-Yau manifolds

abstract:
  This paper is a sequel to arXiv:1108.0967. We further study Gromov-Hausdorff
collapsing limits of Ricci-flat K\"ahler metrics on abelian fibered Calabi-Yau
manifolds. Firstly, we show that in the same setup as arXiv:1108.0967, if the
dimension of the base manifold is one, the limit metric space is homeomorphic
to the base manifold. Secondly, if the fibered Calabi-Yau manifolds are
Lagrangian fibrations of holomorphic symplectic manifolds, the metrics on the
regular parts of the limits are special K\"ahler metrics. By combining these
two results, we extend arXiv:math/0008018 to any fibered projective K3 surface
without any assumption on the type of singular fibers.


title:
Optimal initiation of a GLWB in a variable annuity: no arbitrage
  approach

abstract:
  This paper offers a financial economic perspective on the optimal time (and
age) at which the owner of a Variable Annuity (VA) policy with a Guaranteed
Living Withdrawal Benefit (GLWB) rider should initiate guaranteed lifetime
income payments. We abstract from utility, bequest and consumption preference
issues by treating the VA as liquid and tradable. This allows us to use an
American option pricing framework to derive a so-called optimal initiation
region. Our main practical finding is that given current design parameters in
which volatility (asset allocation) is restricted to less than 20%, while
guaranteed payout rates (GPR) as well as bonus (roll-up) rates are less than
5%, GLWBs that are in-the-money should be turned on by the late 50s and
certainly the early 60s. The exception to the rule is when a non-constant GPR
is about to increase (soon) to a higher age band, in which case the optimal
policy is to wait until the new GPR is hit and then initiate immediately. Also,
to offer a different perspective, we invert the model and solve for the bonus
(roll-up) rate that is required to justify delaying initiation at any age. We
find that the required bonus is quite high and more than what is currently
promised by existing products. Our methodology and results should be of
interest to researchers as well as to the individuals that collectively have
over \$1 USD trillion in aggregate invested in these products. We conclude by
suggesting that much of the non-initiation at older age is irrational (which
obviously benefits the insurance industry.)


title: Direct constraints on the top-Higgs coupling from the 8 TeV LHC data

abstract:
  The LHC experiments have analyzed the 7 and 8 TeV LHC data in the main Higgs
production and decay modes. Current analyses only loosely constrain an
anomalous top-Higgs coupling in a direct way. In order to strongly constrain
this coupling, the Higgs-top associated production is reanalyzed. Thanks to the
strong destructive interference in the t-channel for standard model couplings,
this process can be very sensitive to both the magnitude and the sign of a
non-standard top-Higgs coupling. We project the sensitivity to anomalous
couplings to the integrated luminosity of 50 fb^{-1}, corresponding to the data
collected by the ATLAS and CMS experiments in 7 and 8 TeV collisions, as of
2012. We show that the combination of di-photon and multi-lepton signatures,
originating from different combinations of the top and Higgs decay modes, can
be a potential probe to constrain a large portion of the negative top-Higgs
coupling space presently allowed by the ATLAS and CMS global fits.


title: A scaling approach to Caffarelli-Kohn-Nirenberg inequality

abstract:
  We mainly consider the general Caffarelli-Kohn-Nirenberg inequality in the
Euclidean and Riemannian setting. In both cases, our proof relies mostly on a
new parameter s conveniently introduced, see (2.7).


title: Backbone structure of the Edwards-Anderson spin-glass model

abstract:
  We study the ground-state spatial heterogeneities of the Edwards-Anderson
spin-glass model with both bimodal and Gaussian bond distributions. We
characterize these heterogeneities by using a general definition of bond
rigidity, which allows us to classify the bonds of the system into two sets,
the backbone and its complement, with very different properties. This
generalizes to continuous distributions of bonds the well known definition of a
backbone for discrete bond distributions. By extensive numerical simulations we
find that the topological structure of the backbone for a given lattice
dimensionality is very similar for both discrete and continuous bond
distributions. We then analyze how these heterogeneities influence the
equilibrium properties at finite temperature and we discuss the possibility
that a suitable backbone picture can be relevant to describe spin-glass
phenomena.


title:
Three years of Fermi GBM Earth Occultation Monitoring: Observations of
  Hard X-ray/Soft Gamma-Ray Sources

abstract:
  The Gamma ray Burst Monitor (GBM) on board Fermi Gamma-ray Space Telescope
has been providing continuous data to the astronomical community since 2008
August 12. We will present the results of the analysis of the first three years
of these continuous data using the Earth occultation technique to monitor a
catalog of 209 sources. Although the occultation technique is in principle
quite simple, in practice there are many complications including the dynamic
instrument response, source confusion, and scattering in the Earth's
atmosphere, which will be described. We detect 99 sources, including 40
low-mass X-ray binary/neutron star systems, 31 high-mass X-ray binary/neutron
star systems, 12 black hole binaries, 12 active galaxies, 2 other sources, plus
the Crab Nebula and the Sun. Nine of these sources are detected in the 100-300
keV band, including seven black-hole binaries, the active galaxy Cen A, and the
Crab. The Crab and Cyg X-1 are also detected in the 300-500 keV band. GBM
provides complementary data to other sky monitors below 100 keV and is the only
all-sky monitor above 100 keV. In our fourth year of monitoring, we have
already increased the number of transient sources detected and expect several
of the weaker persistent sources to cross the detection threshold. I will
briefly discuss these new sources and what to expect from our five year
occultation catalog.


title:
Concentration inequalities for non-Lipschitz functions with bounded
  derivatives of higher order

abstract:
  Building on the inequalities for homogeneous tetrahedral polynomials in
independent Gaussian variables due to R. Lata{\l}a we provide a concentration
inequality for non-necessarily Lipschitz functions $f\colon \R^n \to \R$ with
bounded derivatives of higher orders, which hold when the underlying measure
satisfies a family of Sobolev type inequalities $\|g- \E g\|_p \le C(p)\|\nabla
g\|_p.$
  Such Sobolev type inequalities hold, e.g., if the underlying measure
satisfies the log-Sobolev inequality (in which case $C(p) \le C\sqrt{p}$) or
the Poincar\'e inequality (then $C(p) \le Cp$). Our concentration estimates are
expressed in terms of tensor-product norms of the derivatives of $f$.
  When the underlying measure is Gaussian and $f$ is a polynomial
(non-necessarily tetrahedral or homogeneous), our estimates can be reversed (up
to a constant depending only on the degree of the polynomial). We also show
that for polynomial functions, analogous estimates hold for arbitrary random
vectors with independent sub-Gaussian coordinates.
  We apply our inequalities to general additive functionals of random vectors
(in particular linear eigenvalue statistics of random matrices) and the problem
of counting cycles of fixed length in Erd\H{o}s-R{\'e}nyi random graphs,
obtaining new estimates, optimal in a certain range of parameters.


title: Fuzzy Aggregates in Fuzzy Answer Set Programming

abstract:
  Fuzzy answer set programming is a declarative framework for representing and
reasoning about knowledge in fuzzy environments. However, the unavailability of
fuzzy aggregates in disjunctive fuzzy logic programs, DFLP, with fuzzy answer
set semantics prohibits the natural and concise representation of many
interesting problems. In this paper, we extend DFLP to allow arbitrary fuzzy
aggregates. We define fuzzy answer set semantics for DFLP with arbitrary fuzzy
aggregates including monotone, antimonotone, and nonmonotone fuzzy aggregates.
We show that the proposed fuzzy answer set semantics subsumes both the original
fuzzy answer set semantics of DFLP and the classical answer set semantics of
classical disjunctive logic programs with classical aggregates, and
consequently subsumes the classical answer set semantics of classical
disjunctive logic programs. We show that the proposed fuzzy answer sets of DFLP
with fuzzy aggregates are minimal fuzzy models and hence incomparable, which is
an important property for nonmonotonic fuzzy reasoning.


title: Network Compression: Worst-Case Analysis

abstract:
  We study the problem of communicating a distributed correlated memoryless
source over a memoryless network, from source nodes to destination nodes, under
quadratic distortion constraints. We establish the following two complementary
results: (a) for an arbitrary memoryless network, among all distributed
memoryless sources of a given correlation, Gaussian sources are least
compressible, that is, they admit the smallest set of achievable distortion
tuples, and (b) for any memoryless source to be communicated over a memoryless
additive-noise network, among all noise processes of a given correlation,
Gaussian noise admits the smallest achievable set of distortion tuples. We
establish these results constructively by showing how schemes for the
corresponding Gaussian problems can be applied to achieve similar performance
for (source or noise) distributions that are not necessarily Gaussian but have
the same covariance.


title: On Double 3-Term Arithmetic Progressions

abstract:
  In this note we are interested in the problem of whether or not every
increasing sequence of positive integers $x_1x_2x_3...$ with bounded gaps must
contain a double 3-term arithmetic progression, i.e., three terms $x_i$, $x_j$,
and $x_k$ such that $i + k = 2j$ and $x_i + x_k = 2x_j$. We consider a few
variations of the problem, discuss some related properties of double arithmetic
progressions, and present several results obtained by using RamseyScript, a
high-level scripting language.


title: Linear magnetoresistance from Dirac-like fermions in graphite

abstract:
  We show that magnetoresistance of Bernal-stacked graphite (with the magnetic
field ${\bf B}$ parallel to the c-axis and the current in the ab plane) scales
linearly with the magnetic field over an interval of classically weak fields.
The linearity is related to the presence of extremely light, Dirac-like
carriers near the $H$ ($H^{\prime}$)- points of the Brillouin zone. The Hall
resistivity in this interval also shows a non-analytic, $B\ln |B|$ behavior,
and is dominated by holes.


title: Limits of local algorithms over sparse random graphs

abstract:
  Local algorithms on graphs are algorithms that run in parallel on the nodes
of a graph to compute some global structural feature of the graph. Such
algorithms use only local information available at nodes to determine local
aspects of the global structure, while also potentially using some randomness.
Recent research has shown that such algorithms show significant promise in
computing structures like large independent sets in graphs locally. Indeed the
promise led to a conjecture by Hatami, \Lovasz and Szegedy
\cite{HatamiLovaszSzegedy} that local algorithms may be able to compute maximum
independent sets in (sparse) random $d$-regular graphs. In this paper we refute
this conjecture and show that every independent set produced by local
algorithms is multiplicative factor $1/2+1/(2\sqrt{2})$ smaller than the
largest, asymptotically as $d\rightarrow\infty$.
  Our result is based on an important clustering phenomena predicted first in
the literature on spin glasses, and recently proved rigorously for a variety of
constraint satisfaction problems on random graphs. Such properties suggest that
the geometry of the solution space can be quite intricate. The specific
clustering property, that we prove and apply in this paper shows that typically
every two large independent sets in a random graph either have a significant
intersection, or have a nearly empty intersection. As a result, large
independent sets are clustered according to the proximity to each other. While
the clustering property was postulated earlier as an obstruction for the
success of local algorithms, such as for example, the Belief Propagation
algorithm, our result is the first one where the clustering property is used to
formally prove limits on local algorithms.


title: Distinguishing eigenforms modulo a prime ideal

abstract:
  Consider the Fourier expansions of two elements of a given space of modular
forms. How many leading coefficients must agree in order to guarantee that the
two expansions are the same? Sturm gave an upper bound for modular forms of a
given weight and level. This was adapted by Ram Murty, Kohnen and Ghitza to the
case of two eigenforms of the same level but having potentially different
weights. We consider their expansions modulo a prime ideal, presenting a new
bound. In the process of analysing this bound, we generalise a result of Bach
and Sorenson, who provide a practical upper bound for the least prime in an
arithmetic progression.


title:
Fermi surface topology and de Hass-van Alphen orbits in PuIn$_{\rm 3}$
  and PuSn$_{\rm 3}$ compounds

abstract:
  Since the recent discovery of plutonium-based superconductors such as
PuCoIn$_{\rm 5}$, systematic studies of the electronic properties for plutonium
compounds are providing insight into the itinerancy-localization crossover of
Pu 5$f$ electrons. We are particularly interested in understanding the Fermi
surface properties of PuIn$_{3}$ compound, which serves as the building block
for the PuCoIn$_{\rm 5}$ superconductor. Motivated by the first observation of
quantum oscillation and renewed interest in the de-Hass van-Alphen (dHvA)
measurements on PuIn$_{\rm 3}$, we study the Fermi surface (FS) topology and
the band dispersion in both paramagnetic and antiferromagnetic state of
PuIn$_{\rm 3}$, based on density functional theory with generalized gradient
approximation. We compare the results with its isostructural paramagnetic
compound PuSn$_{\rm 3}$. We show the detailed Fermi surfaces of compounds
PuIn$_{\rm 3}$ and PuSn$_{\rm 3}$ and conclude that the FS topology of an
antiferromagnetic PuIn$_3$ agrees better with dHvA measurements. In addition,
we show the magnetization of the antiferromagnetic order can alter the angle
dependence and values of the effective mass for the dHvA orbits. We point out
the accurate determination of the magnetic order orientation with respect to
the crystal orientation is crucial to advance the understanding of the
electronic structures of the PuIn$_{\rm 3}$ compound.


title:
Detecting the structure of haplotypes, local ancestry and excessive
  local European ancestry in Mexicans

abstract:
  We present a two-layer hidden Markov model to detect structure of haplotypes
for unrelated individuals. This allows modeling two scales of linkage
disequilibrium (one within a group of haplotypes and one between groups),
thereby taking advantage of rich haplotype information to infer local ancestry
for admixed individuals. Our method outperforms competing state-of-art methods,
particularly for regions of small ancestral track lengths. Applying our method
to Mexican samples in HapMap3, we found five coding regions, ranging from $0.3
-1.3$ megabase (Mb) in lengths, that exhibit excessive European ancestry
(average dosage > 1.6). A particular interesting region of 1.1Mb (with average
dosage 1.95) locates on Chromosome 2p23 that harbors two genes, PXDN and MYT1L,
both of which are associated with autism and schizophrenia. In light of the low
prevalence of autism in Hispanics, this region warrants special attention. We
confirmed our findings using Mexican samples from the 1000 genomes project. A
software package implementing methods described in the paper is freely
available at \url{http://bcm.edu/cnrc/mcmcmc}


title: Locality Optimization for Data Parallel Programs

abstract:
  Productivity languages such as NumPy and Matlab make it much easier to
implement data-intensive numerical algorithms. However, these languages can be
intolerably slow for programs that don't map well to their built-in primitives.
In this paper, we discuss locality optimizations for our system Parakeet, a
just-in-time compiler and runtime system for an array-oriented subset of
Python. Parakeet dynamically compiles whole user functions to high performance
multi-threaded native code. Parakeet makes extensive use of the classic data
parallel operators Map, Reduce, and Scan. We introduce a new set of data
parallel operators,TiledMap, TiledReduce, and TiledScan, that break up their
computations into local pieces of bounded size so as better to make use of
small fast memories. We introduce a novel tiling transformation to generate
tiled operators automatically. Applying this transformation once tiles the
program for cache, and applying it again enables tiling for registers. The
sizes for cache tiles are left unspecified until runtime, when an autotuning
search is performed. Finally, we evaluate our optimizations on benchmarks and
show significant speedups on programs that exhibit data locality.


title: A Simulation and Modeling of Access Points with Definition Language

abstract:
  This submission has been withdrawn by arXiv administrators because it
contains fictitious content and was submitted under a pseudonym, which is
against arXiv policy.


title: Data enriched linear regression

abstract:
  We present a linear regression method for predictions on a small data set
making use of a second possibly biased data set that may be much larger. Our
method fits linear regressions to the two data sets while penalizing the
difference between predictions made by those two models. The resulting
algorithm is a shrinkage method similar to those used in small area estimation.
We find a Stein-type finding for Gaussian responses: when the model has 5 or
more coefficients and 10 or more error degrees of freedom, it becomes
inadmissible to use only the small data set, no matter how large the bias is.
We also present both plug-in and AICc-based methods to tune our penalty
parameter. Most of our results use an $L_2$ penalty, but we obtain formulas for
$L_1$ penalized estimates when the model is specialized to the location
setting. Ordinary Stein shrinkage provides an inadmissibility result for only 3
or more coefficients, but we find that our shrinkage method typically produces
much lower squared errors in as few as 5 or 10 dimensions when the bias is
small and essentially equivalent squared errors when the bias is large.


title: Towards a Workload for Evolutionary Analytics

abstract:
  Emerging data analysis involves the ingestion and exploration of new data
sets, application of complex functions, and frequent query revisions based on
observing prior query answers. We call this new type of analysis evolutionary
analytics and identify its properties. This type of analysis is not well
represented by current benchmark workloads. In this paper, we present a
workload and identify several metrics to test system support for evolutionary
analytics. Along with our metrics, we present methodologies for running the
workload that capture this analytical scenario.


title:
Reconstruction of Signals from Magnitudes of Redundant Representations:
  The Complex Case

abstract:
  This paper is concerned with the question of reconstructing a vector in a
finite-dimensional complex Hilbert space when only the magnitudes of the
coefficients of the vector under a redundant linear map are known. We present
new invertibility results as well an iterative algorithm that finds the
least-square solution and is robust in the presence of noise. We analyze its
numerical performance by comparing it to the Cramer-Rao lower bound.


title:
Dark Matter and Pulsar Origins of the Rising Cosmic Ray Positron
  Fraction in Light of New Data From AMS

abstract:
  The rise of the cosmic ray positron fraction with energy, as first observed
with high confidence by PAMELA, implies that a large flux of high energy
positrons has been recently (or is being currently) injected into the local
volume of the Milky Way. With the new and much more precise measurement of the
positron fraction recently provided by AMS, we revisit the question of the
origin of these high energy positrons. We find that while some dark matter
models (annihilating directly to electrons or muons) no longer appear to be
capable of accommodating these data, other models in which ~1-3 TeV dark matter
particles annihilate to unstable intermediate states could still be responsible
for the observed signal. Nearby pulsars also remain capable of explaining the
observed positron fraction. Future measurements of the positron fraction by AMS
(using a larger data set), combined with their anticipated measurements of
various cosmic ray secondary-to-primary ratios, may enable us to further
discriminate between these remaining scenarios.


title: Quadratic Hyperbolicity Preservers & Multiplier Sequences

abstract:
  It is known (see \cite[Br\"and\'en, Lemma 2.7]{B10}) that a necessary
condition for $T:=\sum Q_k(x) D^k$ to be hyperbolicity preserving is that
$Q_k(x)$ and $Q_{k-1}(x)$ have interlacing zeros. We characterize all quadratic
linear operators, as a consequence we find several classes of $P_n$-multiplier
sequence.


title:
Information Measures of Complexity, Emergence, Self-organization,
  Homeostasis, and Autopoiesis

abstract:
  This chapter reviews measures of emergence, self-organization, complexity,
homeostasis, and autopoiesis based on information theory. These measures are
derived from proposed axioms and tested in two case studies: random Boolean
networks and an Arctic lake ecosystem.
  Emergence is defined as the information a system or process produces.
Self-organization is defined as the opposite of emergence, while complexity is
defined as the balance between emergence and self-organization. Homeostasis
reflects the stability of a system. Autopoiesis is defined as the ratio between
the complexity of a system and the complexity of its environment. The proposed
measures can be applied at different scales, which can be studied with
multi-scale profiles.


title: Bayesian Lensing Shear Measurement

abstract:
  We derive an estimator of weak gravitational lensing shear from background
galaxy images that avoids noise-induced biases through a rigorous Bayesian
treatment of the measurement. The derived shear estimator disposes with the
assignment of ellipticities to individual galaxies that is typical of previous
approaches to galaxy lensing. Shear estimates from the mean of the Bayesian
posterior are unbiased in the limit of large number of background galaxies,
regardless of the noise level on individual galaxies. The Bayesian formalism
requires a prior describing the (noiseless) distribution of the target galaxy
population over some parameter space; this prior can be constructed from
low-noise images of a subsample of the target population, attainable from long
integrations of a fraction of the survey field. We find two ways to combine
this exact treatment of noise with rigorous treatment of the effects of the
instrumental point-spread function and sampling. The Bayesian model fitting
(BMF) method assigns a likelihood of the pixel data to galaxy models (e.g.
Sersic ellipses). The Bayesian Fourier domain (BFD) method compresses the pixel
data to a small set of weighted moments calculated after PSF correction in
Fourier space. A numerical test using a simplified model of a biased galaxy
measurement process demonstrates that the Bayesian formalism recovers applied
shears to $<1$ part in $10^3$ accuracy and provides accurate uncertainty
estimates. BFD is the first shear measurement algorithm that is model-free and
requires no approximations or ad hoc assumptions in correcting for the effects
of PSF, noise, or sampling on the galaxy images. These algorithms are good
candidates for attaining the part-per-thousand shear inference required for
hemisphere-scale weak gravitational lensing surveys. (abridged)


title: The causal meaning of Fisher's average effect

abstract:
  In order to formulate the Fundamental Theorem of Natural Selection, Fisher
defined the average excess and average effect of a gene substitution. Finding
these notions to be somewhat opaque, some authors have recommended
reformulating Fisher's ideas in terms of covariance and regression, which are
classical concepts of statistics. We argue that Fisher intended his two
averages to express a distinction between correlation and causation. On this
view the average effect is a specific weighted average of the actual phenotypic
changes that result from physically changing the allelic states of homologous
genes. We show that the statistical and causal conceptions of the average
effect, perceived as inconsistent by Falconer, can be reconciled if certain
relationships between the genotype frequencies and non-additive residuals are
conserved. There are certain theory-internal considerations favoring Fisher's
original formulation in terms of causality; for example, the frequency-weighted
mean of the average effects equaling zero at each locus becomes a derivable
consequence rather than an arbitrary constraint. More broadly, Fisher's
distinction between correlation and causation is of critical importance to
gene-trait mapping studies and the foundations of evolutionary biology.


title:
Potential Networks, Contagious Communities, and Understanding Social
  Network Structure

abstract:
  In this paper we study how the network of agents adopting a particular
technology relates to the structure of the underlying network over which the
technology adoption spreads. We develop a model and show that the network of
agents adopting a particular technology may have characteristics that differ
significantly from the social network of agents over which the technology
spreads. For example, the network induced by a cascade may have a heavy-tailed
degree distribution even if the original network does not.
  This provides evidence that online social networks created by technology
adoption over an underlying social network may look fundamentally different
from social networks and indicates that using data from many online social
networks may mislead us if we try to use it to directly infer the structure of
social networks. Our results provide an alternate explanation for certain
properties repeatedly observed in data sets, for example: heavy-tailed degree
distribution, network densification, shrinking diameter, and network community
profile. These properties could be caused by a sort of `sampling bias' rather
than by attributes of the underlying social structure. By generating networks
using cascades over traditional network models that do not themselves contain
these properties, we can nevertheless reliably produce networks that contain
all these properties.
  An opportunity for interesting future research is developing new methods that
correctly infer underlying network structure from data about a network that is
generated via a cascade spread over the underlying network.


title:
Trapping hot quasi-particles in a high-power superconducting electronic
  cooler

abstract:
  The performance of hybrid superconducting electronic coolers is usually
limited by the accumulation of hot quasi-particles in the superconducting
leads. This issue is all the more stringent in large-scale and high-power
devices, as required by applications. Introducing a metallic drain connected to
the superconducting electrodes via a fine-tuned tunnel barrier, we efficiently
remove quasi-particles and obtain electronic cooling from 300 mK down to 130 mK
with a 400 pW cooling power. A simple thermal model accounts for the
experimental observations.


title: Vertex Arboricity of Toroidal Graphs with a Forbidden Cycle

abstract:
  The vertex arboricity $a(G)$ of a graph $G$ is the minimum $k$ such that
$V(G)$ can be partitioned into $k$ sets where each set induces a forest. For a
planar graph $G$, it is known that $a(G)\leq 3$. In two recent papers, it was
proved that planar graphs without $k$-cycles for some $k\in\{3, 4, 5, 6, 7\}$
have vertex arboricity at most 2. For a toroidal graph $G$, it is known that
$a(G)\leq 4$. Let us consider the following question: do toroidal graphs
without $k$-cycles have vertex arboricity at most 2? It was known that the
question is true for k=3, and recently, Zhang proved the question is true for
$k=5$. Since a complete graph on 5 vertices is a toroidal graph without any
$k$-cycles for $k\geq 6$ and has vertex arboricity at least three, the only
unknown case was k=4. We solve this case in the affirmative; namely, we show
that toroidal graphs without 4-cycles have vertex arboricity at most 2.


title: A carpet cloak for heat flux and temperature field

abstract:
  Based on transformation optics theory, we present a new carpet device that
can be used to thermally protect a region from the invasion of external heat
flux. The designed device is termed 'thermal carpet', which provides
considerable cloaking effect. The cloaking performance for heat flux
originating from different directions are analyzed. Unlike most thermal cloak
designs reported in the literature, the material parameters are constant with
position throughout the cloak, indicating that only one type of metamaterial
composite to fabricate such a carpet is required.


title:
Pricing approximations and error estimates for local L\'evy-type models
  with default

abstract:
  We find approximate solutions of partial integro-differential equations,
which arise in financial models when defaultable assets are described by
general scalar L\'evy-type stochastic processes. We derive rigorous error
bounds for the approximate solutions. We also provide numerical examples
illustrating the usefulness and versatility of our methods in a variety of
financial settings.


title:
Could $Z_{c}(3900)$ be a $I^{G}J^{P}=1^{+}1^{+}$ $D^{*}\bar{D}$
  molecular state?

abstract:
  We investigate the nature of the recently observed narrow resonance
$Z_{c}(3900)$, which is assumed to be a $D^{*}\bar{D}$ molecular state with
quantum numbers $I^{G}J^{P}=1^{+}1^{+}$. Using QCD sum rules, we consider
contributions up to dimension eight in the operator product expansion and work
at the leading order in $\alpha_{s}$. The mass we arrived at is $(3.88 \pm
0.17) \mbox{GeV}$, which coincides with the mass of $Z_{c}(3900)$.


title: Managing Interference Correlation Through Random Medium Access

abstract:
  The capacity of wireless networks is fundamentally limited by interference.
However, little research has focused on the interference correlation, which may
greatly increase the local delay (namely the number of time slots required for
a node to successfully transmit a packet). This paper focuses on the question
that whether increasing randomness in the MAC, such as frequency-hopping
multiple access (FHMA) and ALOHA, helps to reduce the effect of interference
correlation. We derive closed-form results for the mean and variance of the
local delay for the two MAC protocols and evaluate the optimal parameters that
minimize the mean local delay. Based on the optimal parameters, we propose the
definitions of two operation regimes: correlation-limited regime and
bandwidth-limited regime. Our results reveal that while the mean local delays
for FHMA with N sub-bands and for ALOHA with transmit probability p are the
same when p=1/N with thermal noise ignored, significant difference exists
between the variances. At last, we evaluate the mean delay-jitter tradeoff and
the bounds on the tail probability of the local delay, which shed key insights
into the system design.


title: Random Matrix Theory approach to Mesoscopic Fluctuations of Heat Current

abstract:
  We consider an ensemble of fully connected networks of N oscillators coupled
harmonically with random springs and show, using Random Matrix Theory
considerations, that both the average phonon heat current and its variance are
scale-invariant and take universal values in the large N-limit. These anomalous
mesoscopic uctuations is the hallmark of strong correlations between normal
modes.


title:
Angular Distribution of Bremsstrahlung Produced by 10-keV and 20-keV
  Electrons Incident on a Thick Au Target

abstract:
  The relative intensities of the thick-target bremsstrahlung produced by
10-keV and 20-keV electrons incident on Au at forward angles ranging from 0
degrees to 25 degrees are compared. Following corrections for photon absorption
within the target, the detected radiation appears to be distributed
anisotropically only for photon energies, k, that are approximately equal to
the initial energy of the incident electrons, E. The results are compared to
the theoretical angular distributions of Kissel et al. [At. Data Nucl. Data
Tables 28, 381 (1983)]. The comparison suggests that when k/E is approximately
equal to 1, the angular distribution of bremsstrahlung emitted by electrons
incident on thick targets is similar to the theoretical angular distribution of
bremsstrahlung emitted by electrons incident on free-atom targets.


title:
Theoretical study on copper's energetics and magnetism in TiO2
  polymorphs

abstract:
  We carried out density functional theory calculations to model the electronic
structure and the magnetic interactions in copper doped anatase and rutile
titanium dioxide in order to shed light on the potential of these systems as
magnetic oxides using different density functional schemes. In both polymorphs
copper dopant was found to be most stable in substitutional lattice positions.
Ferromagnetism is predicted to be stable well above room temperature with long
range interactions prevailing in the anatase phase while the rutile phase
exhibits only short range superexchange interaction among nearest neighbouring
Cu ions. Additionally, energetic evaluation of dopants in scattered and compact
configurations reveals a dopant clustering tendency in anatase TiO2.


title:
Multi-Color Photometry of the Outburst of the New WZ Sge-type Dwarf
  Nova, OT J012059.6+325545

abstract:
  We present our photometric studies of the newly discovered optical transient,
OT J012059.6+325545, which underwent a large outburst between 2010 November and
2011 January. The amplitude of the outburst was about 8 mag. We performed
simultaneous multi-color photometry by using g', Rc, and i'-band filters from
the early stage of the outburst. The time resolved photometry during the early
stage revealed periodic variations with double-peaked profiles, which are
referred to as early superhumps, with amplitudes of about 0.08 mag. After the
rapid fading from the main outburst, we found rebrightening phenomena, which
occurred at least nine times. The large amplitude of the outburst, early
superhumps, and rebrightening phenomena are typical features of WZ Sge-type
dwarf novae. We detected color variations within the early superhump
modulations making this only the second system, after V445 And, for which this
has been established. We carried out numerical calculations of the accretion
disk to explain both of the modulations and the color variations of the early
superhump. This modeling of the disk height supports the idea that height
variations within the outer disk can produce the early superhump modulations,
though we cannot rule out that temperature asymmetries may also play a role.


title:
The existence of free non-cyclic subgroups in weakly locally finite
  division rings

abstract:
  In this paper we prove that every non-central subnormal subgroup of the
multiplicative group of a weakly locally finite division ring contains free
non-cyclic subgroups.


title:
Suppression of local heat flux in a turbulent magnetized intracluster
  medium

abstract:
  X-ray observations of hot gas in galaxy clusters often show steeper
temperature gradients across cold fronts -- contact discontinuities, driven by
the differential gas motions. These sharp (a few kpc wide) surface
brightness/temperature discontinuities would be quickly smeared out by the
electron thermal conduction in unmagnetized plasma, suggesting significant
suppression of the heat flow across the discontinuities. In fact, the character
of the gas flow near cold fronts is favorable for suppression of conduction by
aligning magnetic field lines along the discontinuities. We argue that a
similar mechanism is operating in the bulk of the gas. Generic 3D random
isotropic and incompressible motions increase the temperature gradients (in
some places) and at the same time suppress the local conduction by aligning the
magnetic field lines perpendicular to the local temperature gradient. We show
that the suppression of the effective conductivity in the bulk of the gas can
be linked to the increase of the frozen magnetic field energy density. On
average the rate of decay of the temperature fluctuations $\mathrm{d}\langle
\delta T^2 \rangle /\mathrm{d}t$ decreases as $\langle B^2 \rangle ^{-1/5}$.


title: Multi-Resolution Video Streaming in Peer-to-peer Networks

abstract:
  We consider multi-resolution streaming in fully-connected peer-to-peer
networks, where transmission rates are constrained by arbitrarily specified
upload capacities of the source and peers. We fully characterize the capacity
region of rate vectors achievable with arbitrary coding, where an achievable
rate vector describes a vector of throughputs of the different resolutions that
can be supported by the network. We then prove that all rate vectors in the
capacity region can be achieved using pure routing strategies. This shows that
coding has no capacity advantage over routing in this scenario.


title:
Solving Heat Conduction Problems by the Direct Meshless Local
  Petrov-Galerkin (DMLPG) method

abstract:
  As an improvement of the Meshless Local Petrov-Galerkin (MLPG), the Direct
Meshless Local Petrov-Galerkin (DMLPG) method is applied here to the numerical
solution of transient heat conduction problem. The new technique is based on
direct recoveries of test functionals (local weak forms) from values at nodes
without any detour via classical moving least squares (MLS) shape functions.
This leads to an absolutely cheaper scheme where the numerical integrations
will be done over low-degree polynomials rather than complicated MLS shape
functions. This eliminates the main disadvantage of MLS based methods in
comparison with finite element methods (FEM), namely the costs of numerical
integration.


title: Reflection relations and fermionic basis

abstract:
  There are two approaches to computing the one-point functions for sine-Gordon
model in infinite volume. One is a bootstrap type procedure based on the
reflection relations. Another uses the fermionic basis which was originally
found for the lattice six-vertex model. In this paper we show that the two
approaches are deeply interrelated.


title:
A Common Generalization of the Theorems of Erd\H{o}s-Ko-Rado and
  Hilton-Milner

abstract:
  Let $m$, $n$, and $k$ be integers satisfying $0 < k \leq n < 2k \leq m$. A
family of sets $\mathcal{F}$ is called an $(m,n,k)$-intersecting family if
$\binom{[n]}{k} \subseteq \mathcal{F} \subseteq \binom{[m]}{k}$ and any pair of
members of $\mathcal{F}$ have nonempty intersection. Maximum $(m,k,k)$- and
$(m,k+1,k)$-intersecting families are determined by the theorems of
Erd\H{o}s-Ko-Rado and Hilton-Milner, respectively. We determine the maximum
families for the cases $n = 2k-1, 2k-2, 2k-3$, and $m$ sufficiently large.


title:
Persistence in fluctuating environments for interacting structured
  populations

abstract:
  Individuals within any species exhibit differences in size, developmental
state, or spatial location. These differences coupled with environmental
fluctuations in demographic rates can have subtle effects on population
persistence and species coexistence. To understand these effects, we provide a
general theory for coexistence of structured, interacting species living in a
stochastic environment. The theory is applicable to nonlinear, multi species
matrix models with stochastically varying parameters. The theory relies on
long-term growth rates of species corresponding to the dominant Lyapunov
exponents of random matrix products. Our coexistence criterion requires that a
convex combination of these long-term growth rates is positive with probability
one whenever one or more species are at low density. When this condition holds,
the community is stochastically persistent: the fraction of time that a species
density goes below $\delta>0$ approaches zero as $\delta$ approaches zero.
Applications to predator-prey interactions in an autocorrelated environment, a
stochastic LPA model, and spatial lottery models are provided. These
applications demonstrate that positive autocorrelations in temporal
fluctuations can disrupt predator-prey coexistence, fluctuations in
log-fecundity can facilitate persistence in structured populations, and
long-lived, relatively sedentary competing populations are likely to coexist in
spatially and temporally heterogenous environments.


title: Stochastic Analysis on RAID Reliability for Solid-State Drives

abstract:
  Solid-state drives (SSDs) have been widely deployed in desktops and data
centers. However, SSDs suffer from bit errors, and the bit error rate is time
dependent since it increases as an SSD wears down. Traditional storage systems
mainly use parity-based RAID to provide reliability guarantees by striping
redundancy across multiple devices, but the effectiveness of RAID in SSDs
remains debatable as parity updates aggravate the wearing and bit error rates
of SSDs. In particular, an open problem is that how different parity
distributions over multiple devices, such as the even distribution suggested by
conventional wisdom, or uneven distributions proposed in recent RAID schemes
for SSDs, may influence the reliability of an SSD RAID array. To address this
fundamental problem, we propose the first analytical model to quantify the
reliability dynamics of an SSD RAID array. Specifically, we develop a
"non-homogeneous" continuous time Markov chain model, and derive the transient
reliability solution. We validate our model via trace-driven simulations and
conduct numerical analysis to provide insights into the reliability dynamics of
SSD RAID arrays under different parity distributions and subject to different
bit error rates and array configurations. Designers can use our model to decide
the appropriate parity distribution based on their reliability requirements.


title:
Improved Accuracy and Parallelism for MRRR-based Eigensolvers -- A Mixed
  Precision Approach

abstract:
  The real symmetric tridiagonal eigenproblem is of outstanding importance in
numerical computations; it arises frequently as part of eigensolvers for
standard and generalized dense Hermitian eigenproblems that are based on a
reduction to tridiagonal form. For its solution, the algorithm of Multiple
Relatively Robust Representations (MRRR) is among the fastest methods. Although
fast, the solvers based on MRRR do not deliver the same accuracy as competing
methods like Divide & Conquer or the QR algorithm. In this paper, we
demonstrate that the use of mixed precisions leads to improved accuracy of
MRRR-based eigensolvers with limited or no performance penalty. As a result, we
obtain eigensolvers that are not only equally or more accurate than the best
available methods, but also -in most circumstances- faster and more scalable
than the competition.


title:
Emergence of slow collective oscillations in neural networks with spike
  timing dependent plasticity

abstract:
  The collective dynamics of excitatory pulse coupled neurons with spike timing
dependent plasticity (STDP) is studied. The introduction of STDP induces
persistent irregular oscillations between strongly and weakly synchronized
states, reminiscent of brain activity during slow-wave sleep. We explain the
oscillations by a mechanism, the Sisyphus Effect, caused by a continuous
feedback between the synaptic adjustments and the coherence in the neural
firing. Due to this effect, the synaptic weights have oscillating equilibrium
values, and this prevents the system from relaxing into a stationary
macroscopic state.


title: Coarse-grained quantum state estimation for noisy measurements

abstract:
  We introduce a straightforward numerical coarse-graining scheme to estimate
quantum states for a set of noisy measurement outcomes, which are difficult to
calibrate, that is based solely on the measurement data collected from these
outcomes. This scheme involves the maximization of a weighted entropy function
that is simple to implement and can readily be extended to any number of
ill-calibrated noisy outcomes in a measurement set-up, thus offering practical
applicability for general tomography experiments without additional knowledge
or assumptions about the structures of the noisy outcomes. Simulation results
for two-qubit quantum states show that coarse-graining can improve the
tomographic efficiencies for noise levels ranging from low to moderately high
values.


title: Geometrical scaling in high energy collisions and its breaking

abstract:
  We analyze geometrical scaling (GS) in Deep Inelstic Scattering at HERA and
in pp collisions at the LHC energies and in NA61/SHINE experiment. We argue
that GS is working up to relatively large Bjorken $x \sim 0.1$. This allows to
study GS in negative pion multiplicity $p_{\rm T}$ distributions at NA61/SHINE
energies where clear sign of scaling violations is seen with growing rapidity
when one of the colliding partons has Bjorekn $x \ge 0.1$.


title: Flexoelectric deformation of a homogeneously polarized ball

abstract:
  The problem of finding the elastic strains arising due to the converse
flexoelectric effect is solved for a case of uniformly polarized ball of
isotropic dielectric material. The strains occurs due to the fact that, as
shown in a previous paper, in presence of flexoelectricity elastic boundary
condition has non-classical form.


title: Projective Compactifications and Einstein metrics

abstract:
  For complete affine manifolds we introduce a definition of compactification
based on the projective differential geometry (i.e.\ geodesic path data) of the
given connection. The definition of projective compactness involves a real
parameter $\alpha$ called the order of projective compactness. For volume
preserving connections, this order is captured by a notion of volume
asymptotics that we define. These ideas apply to complete pseudo-Riemannian
spaces, via the Levi-Civita connection, and thus provide a notion of
compactification alternative to conformal compactification. For each order
$\alpha$, we provide an asymptotic form of a metric which is sufficient for
projective compactness of the given order, thus also providing many local
examples.
  Distinguished classes of projectively compactified geometries of orders one
and two are associated with Ricci-flat connections and non--Ricci--flat
Einstein metrics, respectively. Conversely, these geometric conditions are
shown to force the indicated order of projective compactness. These special
compactifications are shown to correspond to normal solutions of classes of
natural linear PDE (so-called first BGG equations), or equivalently holonomy
reductions of projective Cartan/tractor connections. This enables the
application of tools already available to reveal considerable information about
the geometry of the boundary at infinity. Finally, we show that metrics
admitting such special compactifications always have an asymptotic form as
mentioned above.


title:
Milnor invariants of length $2k+2$ for links with vanishing Milnor
  invariants of length $\leq k$

abstract:
  J.-B. Meilhan and the second author showed that any Milnor
$\bar{\mu}$-invariant of length between 3 and $2k+1$ can be represented as a
combination of HOMFLYPT polynomial of knots obtained by certain band sum of the
link components, if all $\bar{\mu}$-invariants of length $\leq k$ vanish. They
also showed that their formula does not hold for length $2k+2$. In this paper,
we improve their formula to give the $\bar{\mu}$-invariants of length $2k+2$ by
adding correction terms. The correction terms can be given by a combination of
HOMFLYPT polynomial of knots determined by $\bar{\mu}$-invariants of length
$k+1$. In particular, for any 4-component link the $\bar{\mu}$-invariants of
length 4 are given by our formula, since all $\bar{\mu}$-invariants of length 1
vanish.


title:
Neutron stars in a perturbative $f(R)$ gravity model with strong
  magnetic fields

abstract:
  We investigate the effect of a strong magnetic field on the structure of
neutron stars in a model with perturbative $f(R)$ gravity. The effect of an
interior strong magnetic field of about $10^{17 \sim 18}$ G on the equation of
state is derived in the context of a quantum hadrodynamics (QHD) model. We
solve the modified spherically symmetric hydrostatic equilibrium equations
derived for a gravity model with $f(R)=R+\alpha R^2$. Effects of both the
finite magnetic field and the modified gravity are detailed for various values
of the magnetic field and the perturbation parameter $\alpha$ along with a
discussion of their physical implications. We show that there exists a
parameter space of the modified gravity and the magnetic field strength, in
which even a soft equation of state can accommodate a large ($> 2$ M$_\odot$)
maximum neutron star mass through the modified mass-radius relation.


title: Homogeneous spaces of Hilbert type

abstract:
  Let k be a global field. Let G be a connected linear algebraic k-group,
assumed reductive when k is a function field. It follows from a result of a
preprint by Bary-Soroker, Fehm and Petersen that when H is a smooth connected
k-subgroup of G, the quotient space G/H is of Hilbert type. We prove a similar
result for certain non-connected k-subgroups H of G. In particular, we prove
that if G is a simply connected k-group over a number field k, and H is an
abelian k-subgroup of G, not necessarily connected, then G/H is of Hilbert
type.


title: Fluctuations in Relativistic Causal Hydrodynamics

abstract:
  Formalism to calculate the hydrodynamic fluctuations by applying the Onsager
theory to the relativistic Navier-Stokes equation is already known. In this
work, we calculate hydrodynamic-fluctuations within the framework of the second
order hydrodynamics of M\"{u}ller, Israel and Stewart and its generalization to
the third order. We have also calculated the fluctuations for several other
causal hydrodynamical equations. We show that the form for the
Onsager-coefficients and form of the correlation-functions remains same as
those obtained by the relativistic Navier-Stokes equation and it does not
depend on any specific model of hydrodynamics. Further we numerically
investigate evolution of the correlation function using the one dimensional
boost-invariant (Bjorken) flow. We compare the correlation functions obtained
using the causal hydrodynamics with the correlation-function for the
relativistic Navier-Stokes equation. We find that the qualitative behavior of
the correlation-functions remain same for all the models of the causal
hydrodynamics.

categories: hep-ph nucl-th physics.flu-dyn physics.plasm-ph


title:
Exact solutions and particle creation for nonconformal scalar fields in
  homogeneous isotropic cosmological models

abstract:
  The problem is solved of describing scale factors of a homogeneous isotropic
spaces-time such that the exact solution for the scalar field with a
nonconformal coupling to curvature can be obtained from solutions for the
conformally coupled field by redefining the mass and momentum. Explicit
expressions for dependence of time from the large-scale factor are presented in
the form of Abelian integrals in these cases. The exact solution for a scalar
field with Gauss-Bonnet type coupling with curvature is received and it is
shown that the corresponding nonconformal additions can dominate at the
particles creation by gravitational field.


title: Nonlinear unmixing of hyperspectral images: models and algorithms

abstract:
  When considering the problem of unmixing hyperspectral images, most of the
literature in the geoscience and image processing areas relies on the widely
used linear mixing model (LMM). However, the LMM may be not valid and other
nonlinear models need to be considered, for instance, when there are
multi-scattering effects or intimate interactions. Consequently, over the last
few years, several significant contributions have been proposed to overcome the
limitations inherent in the LMM. In this paper, we present an overview of
recent advances in nonlinear unmixing modeling.


title:
Proceedings of the 37th Annual Workshop of the Austrian Association for
  Pattern Recognition (\"OAGM/AAPR), 2013

abstract:
  This volume represents the proceedings of the 37th Annual Workshop of the
Austrian Association for Pattern Recognition (\"OAGM/AAPR), held May 23-24,
2013, in Innsbruck, Austria.


title: Privacy-preserving Data Mining, Sharing and Publishing

abstract:
  The goal of the paper is to present different approaches to
privacy-preserving data sharing and publishing in the context of e-health care
systems. In particular, the literature review on technical issues in privacy
assurance and current real-life high complexity implementation of medical
system that assumes proper data sharing mechanisms are presented in the paper.


title: Einstein gravity with Gauss-Bonnet entropic corrections

abstract:
  A toy model of Einstein gravity with a Gauss-Bonnet classically "entropic"
term mimicking a quantum correction is considered. The static black hole
solution due to Tomozawa is found and generalized with the inclusion of non
trivial horizon topology, and its entropy evaluated deriving the first law by
equations of motion. As a result the Bekenstein-Hawking area law turns to be
corrected by a logarithmic area term. A Misner-Sharp expression for the mass of
black hole is found. Within a Friedmann-Lema\^itre-Robertson-Walker (FLRW)
cosmological setting, the model is used in order to derive modified Friedmann
equations. Such new equations are shown to reproduce the first law with the
same formal entropy and quasi local energy of the static case, but here within
a FLRW space-time interpreted as a dynamical cosmological black hole. A
detailed analysis of cosmological solutions is presented, and it is shown that
the presence of the correction term provides regular solutions and interesting
phases of acceleration and decelerations, as well as, with negligible matter,
exact de Sitter solutions.


title: Morphotropic interfaces in PMN-PT single crystals

abstract:
  The paper describes heterostructures spontaneously formed in PMN-PT single
crystals cooled under bias electric field applied along [001]pc and then
zero-field-heated in the vicinity of the so-called depoling temperature. In
particular, formation of lamellar structures composed of tetragonal-like and
rhombohedral-like layers extending over macroscopic (mm) lengths is
demonstrated by optical observations and polarized Raman investigations.


title:
Kinetic proofreading at single molecular level: Aminoacylation of
  tRNA^{Ile} and the role of water as an editor

abstract:
  Proofreading/editing in protein synthesis is essential for accurate
translation of information from the genetic code. In this article we present a
theoretical investigation of efficiency of a kinetic proofreading mechanism
that employs hydrolysis of the wrong substrate as the discriminatory step in
enzyme catalytic reactions. We consider aminoacylation of tRNA^{Ile} which is a
crucial step in protein synthesis and for which experimental results are now
available. We present an augmented kinetic scheme and then employ methods of
stochastic simulation algorithm to obtain time dependent concentrations of
different substances involved in the reaction and their rates of formation. We
obtain the rates of product formation and ATP hydrolysis for both correct and
wrong substrates (isoleucine and valine in our case), in single molecular
enzyme as well as ensemble enzyme kinetics. The present theoretical scheme
correctly reproduces (i) the amplitude of the discrimination factor in the
overall rates between isoleucine and valine which is obtained as (1.8 \times
10^2).(4.33 \times 10^2) = 7.8 \times 10^4, (ii) the rates of ATP hydrolysis
for both Ile and Val at different substrate concentrations in the
aminoacylation of tRNA^{Ile}. The present study shows a non-michaelis type
dependence of rate of reaction on tRNA^{Ile} concentration in case of valine.
The editing in steady state is found to be independent of amino acid
concentration. Interestingly, the computed ATP hydrolysis rate for valine at
high substrate concentration is same as the rate of formation of Ile-tRNA^{Ile}
whereas at intermediate substrate concentration the ATP hydrolysis rate is
relatively low.


title: Analytic Samplers and the Combinatorial Rejection Method

abstract:
  Boltzmann samplers, introduced by Duchon et al. in 2001, make it possible to
uniformly draw approximate size objects from any class which can be specified
through the symbolic method. This, through by evaluating the associated
generating functions to obtain the correct branching probabilities.
  But these samplers require generating functions, in particular in the
neighborhood of their sunglarity, which is a complex problem; they also require
picking an appropriate tuning value to best control the size of generated
objects. Although Pivoteau~\etal have brought a sweeping question to the first
question, with the introduction of their Newton oracle, questions remain.
  By adapting the rejection method, a classical tool from the random, we show
how to obtain a variant of the Boltzmann sampler framework, which is tolerant
of approximation, even large ones. Our goal for this is twofold: this allows
for exact sampling with approximate values; but this also allows much more
flexibility in tuning samplers. For the class of simple trees, we will try to
show how this could be used to more easily calibrate samplers.


title: Neutrinos and rare isotopes

abstract:
  The close connection between neutrino physics and the physics explored at
rare isotope facilities is explored. The duality between the Hamiltonian
describing the self-interacting neutrino gas near the proto-neutron star in a
core-collapse supernova and the BCS theory of pairing is elucidated. This many
neutrino system is unique as it is the only many-body system driven by weak
interactions. Its symmetries are discussed.


title:
Mechanical and Optical Characterization of a Suspended Core Fiber
  Exhibiting Fundamental-Mode Cutoff Wavelength in Presence of Nanoscale Air
  Holes in the Core Region

abstract:
  In this work, mechanical and optical characterization of a new type of
suspended core fiber (SCF) has been performed. The proposed SCF along with
additional central air holes exhibits an unusual property of fundamental mode
cutoff at short wavelengths. Two variants (single hole and double hole) of
design under two different fiber platforms (SiO2 and As2Se3) have been
considered to develop better insight into the mechanical and optical properties
of the structure deploying plane strain and full vector eigen analysis,
respectively. Dependence of thermal stress likely to be present in such
nanostructured fibers on fiber materials and geometries are thoroughly studied.
A relation between the cutoff condition and geometrical parameters of the
design has been obtained with reference to characteristic decay length which
nullifies the possibility of any numerical artifact. In addition, improvement
of fiber birefringence and evanescence sensing capability due to the presence
of such air holes in the guided region has been theoretically demonstrated.
Effects of such air holes on fiber properties like GVD and mode mismatch are
also studied with a relation to power confinement inside such nano scale
regions.