title:
On independence of iterated Whitehead doubles in the knot concordance
  group

abstract:
  Let $D(K)$ be the positively-clasped untwisted Whitehead double of a knot
$K$, and $T_{p,q}$ be the $(p,q)$ torus knot. We show that $D(T_{2,2m+1})$ and
$D^2(T_{2,2m+1})$ are linearly independent in the smooth knot concordance group
$\mathcal{C}$ for each $m\geq 2$. Further, $D(T_{2,5})$ and $D^2(T_{2,5})$
generate a $\mathbb{Z}\oplus\mathbb{Z}$ summand in the subgroup of
$\mathcal{C}$ generated by topologically slice knots. We use the concordance
invariant $\delta$ of Manolescu and Owens, using Heegaard Floer correction
term. Interestingly, these results are not easily shown using other concordance
invariants such as the $\tau$-invariant of knot Floer theory and the
$s$-invariant of Khovanov homology. We also determine the infinity version of
the knot Floer complex of $D(T_{2,2m+1})$ for any $m\geq 1$ generalizing a
result for $T_{2,3}$ of Hedden, Kim and Livingston.


title:
Some results from algebraic geometry over complete discretely valued
  fields

abstract:
  This paper is concerned with algebraic geometry over complete discretely
valued fields $K$ of equicharacteristic zero. Several results are given
including: the canonical projection $K^{n} \times K\mathbb{P}^{m}
\longrightarrow K^{n}$ and blow-ups of the $K$-points of smooth $K$-varieties
are definably closed maps, a descent principle, a version of the Lojasiewicz
inequality for continuous rational functions, curve selection for semialgebraic
sets and the theorem on extending continuous hereditarily rational functions,
established for the real field in our joint paper with J. Kollar. Our approach
applies the quantifier elimination due to Pas. By the transfer principle of
Ax-Kochen-Ershov, all these results carry over to the case of Henselian
discretely valued fields. Using different arguments in our subsequent paper, we
establish them over Henselian real valued fields of equicharacteristic zero.


title:
Localization-like effect in two-dimensional alternate quantum walks with
  periodic coin operations

abstract:
  Exploiting multi-dimensional quantum walks as feasible platforms for quantum
computation and quantum simulation is attracting constantly growing attention
from a broad experimental physics community. Here, we propose a two-dimensional
quantum walk scheme with a single-qubit coin that presents, in the considered
regimes, a strong localization-like effect on the walker. The result could
provide new possible directions for the implementation of quantum algorithms or
from the point of view of quantum simulation. We characterize the
localization-like effect in terms of the parameters of a step-dependent qubit
operation that acts on the coin space after any standard coin operation,
showing that a proper choice can guarantee a non-negligible probability of
finding the walker in the origin even for large times. We finally discuss the
robustness to imperfections, a qualitative relation with coherences behavior,
and possible experimental realizations of this model with the current
state-of-the-art settings.


title:
Further stabilization results for voltage-actuated piezoelectric beams
  with magnetic effects

abstract:
  It is well known that magnetic energy of the piezoelectric beam is relatively
small, and it does not change the overall dynamics. Therefore, the models,
relying on electrostatic or quasi-static approaches, completely ignore the
magnetic energy stored/produced in the beam. A single piezoelectric beam model
without the magnetic effects is known to be exactly observable and
exponentially stabilizable in the energy space. However, the model with the
magnetic effects is proved to be not exactly observable / exponentially
stabilizable in the energy space for almost all choices of material parameters.
Moreover, even strong stability is not achievable for many values of the
material parameters. In this paper, it is shown that the uncontrolled system is
exactly observable in a space larger than the energy space. Then, by using a
$B^*-$type feedback controller, explicit polynomial decay estimates are
obtained for more regular initial data. Unlike the classical counterparts, this
choice of feedback corresponds to the current flowing through the electrodes,
and it matches better with the physics of the model. The results obtained in
this manuscript have direct implications on the controllability/stabilizability
of smart structures such as elastic beams/plates with piezoelectric patches and
the active constrained layer (ACL) damped beams/plates.


title:
Towards a better understanding of the distance scale from RR Lyrae
  variable stars: A case study for the inner halo globular cluster NGC 6723

abstract:
  We present BV photometry for 54 variables in the metal-rich inner halo
globular cluster NGC6723. With the discovery of new RR Lyrae variables (RRLs),
we obtain <P_ab> = 0.541 +/- 0.066 and <P_c> = 0.292 +/- 0.030 day,
n(c)/n(ab+c) = 0.167, and <V(RR)>_int = 15.459 +/- 0.055. We carry out the
Fourier decomposition analysis and obtain [Fe/H]_ZW = -1.23 +/- 0.11 and E(B-V)
= 0.063 +/- 0.015 for NGC 6723. By calibrating the zero-point from the recent
absolute trigonometric parallax measurements for RR Lyr, we derive the revised
M_V(RR)-[Fe/H] relation, providing M_V(RR)= 0.52 at [Fe/H] = -1.50 and (m-M)_0
= 18.54 for Large Magellanic Cloud (LMC), in excellent agreement with others.
We obtain (m-M)_0 = 14.65 +/- 0.05, equivalent to the distance from the Sun of
8.47 +/- 0.17 kpc, for NGC 6723 from various distance measurement methods using
RRLs. We find that RRLs in NGC 6723 do not have magnitude dependency on the
radial distance, due to a not severe degree of the apparent crowdedness.
Finally, we show that there exists a relation between the degree of photometric
contamination and the apparent crowdedness of the central region of globular
cluster systems. The use of this relation can play a significantly role on
mitigating the discrepancy to establish a cosmic distance scale using RRLs in
resolved stellar populations in the near-field cosmology.


title: Local logarithmic correlators as limits of Coulomb gas integrals

abstract:
  We will describe how logarithmic singularities arise as limits of Coulomb Gas
integrals. Our approach will combine analytic properties of the time-like
Liouville structure constants, together with the recursive formula of the
Virasoro conformal blocks. Although the Coulomb Gas formalism forces a diagonal
coupling between the chiral and antichiral sectors of the Conformal Field
Theory (CFT), we present new results for the multi-screening integrals which
are potentially interesting for applications to critical statistical systems
described by Logarithmic CFTs. In particular our findings extend and complement
previous results, derived with Coulomb Gas methods, at $c=0$ and $c=-2$.


title:
The structure and functions of an automated project management system
  for the centers of scientific and technical creativity of students

abstract:
  This article discusses the possibility of automating of the student's
projecting through the use of automated project management system. There are
described the purpose, structure and formalism of automated workplace of
student-designer (AWSD), and shown its structural-functional diagram.


title:
How serious can the stealth bias be in gravitational wave parameter
  estimation?

abstract:
  The upcoming direct detection of gravitational waves will open a window to
probing the strong-field regime of general relativity (GR). As a consequence,
waveforms that include the presence of deviations from GR have been developed
(e.g. in the parametrized post-Einsteinian approach). TIGER, a data analysis
pipeline which builds Bayesian evidence to support or question the validity of
GR, has been written and tested. In particular, it was shown recently that data
from the LIGO and Virgo detectors will allow to detect deviations from GR
smaller than can be probed with Solar System tests and pulsar timing
measurements or not accessible with conventional tests of GR. However, evidence
from several detections is required before a deviation from GR can be
confidently claimed. An interesting consequence is that, should GR not be the
correct theory of gravity in its strong field regime, using standard GR
templates for the matched filter analysis of interferometer data will introduce
biases in the gravitational wave measured parameters with potentially
disastrous consequences on the astrophysical inferences, such as the
coalescence rate or the mass distribution. We consider three heuristic possible
deviations from GR and show that the biases introduced by assuming GR's
validity manifest in various ways. The mass parameters are usually the most
affected, with biases that can be as large as $30$ standard deviations for the
symmetric mass ratio, and nearly one percent for the chirp mass, which is
usually estimated with sub-percent accuracy. We conclude that statements about
the nature of the observed sources, e.g. if both objects are neutron stars,
depend critically on the explicit assumption that GR it the right theory of
gravity in the strong field regime.


title: Exact results for Wilson loops in arbitrary representations

abstract:
  We compute the exact vacuum expectation value of 1/2 BPS circular Wilson
loops of ${\cal N}$=4 U(N) super Yang-Mills in arbitrary irreducible
representations. By localization arguments, the computation reduces to
evaluating certain integrals in a Gaussian matrix model, which we do using the
method of orthogonal polynomials. Our results are particularly simple for
Wilson loops in antisymmetric representations; in this case, we observe that
the final answers admit an expansion where the coefficients are positive
integers, and can be written in terms of sums over skew Young diagrams. As an
application of our results, we use them to discuss the exact Bremsstrahlung
functions associated to the corresponding heavy probes.


title: A Pair Production Telescope for Medium-Energy Gamma-Ray Polarimetry

abstract:
  We describe the science motivation and development of a pair production
telescope for medium-energy gamma-ray polarimetry. Our instrument concept, the
Advanced Energetic Pair Telescope (AdEPT), takes advantage of the
Three-Dimensional Track Imager, a low-density gaseous time projection chamber,
to achieve angular resolution within a factor of two of the pair production
kinematics limit (~0.6 deg at 70 MeV), continuum sensitivity comparable with
the Fermi-LAT front detector (<3x10-6 MeV cm-2 s-1 at 70 MeV), and minimum
detectable polarization less than 10% for a 10 millicrab source in 106 seconds.


title:
Integral expression for a topological charge in the Faddeev-Niemi
  non-linear sigma model

abstract:
  We have introduced Faddeev-Niemi type variables for static SU(3) Yang-Mills
theory. The variables suggest that a non-linear sigma model whose sigma fields
take values in SU(3)/(U(1)xU(1)) and SU(3)/(SU(2)xU(1)) may be relevant to
infrared limit of the theory. Shabanov showed that the energy functional of the
non-linear sigma model is bounded from below by certain functional. However,
the Shabanov's functional is not homotopy invariant, and its value can be an
arbitrary real number -- therefore it is not a topological charge. Since the
third homotopy group of SU(3)/(U(1)xU(1)) is isomorphic to the group of integer
numbers, there is a non-trivial topological charge (given by the isomorphism).
We apply Novikov's procedure to obtain integral expression for this charge. The
resulting formula is analogous to the Whitehead's realization of the Hopf
invariant.


title:
Analytic structure of the $n=7$ scattering amplitude in $\mathcal{N}=4$
  SYM theory at multi-Regge kinematics: Conformal Regge pole contribution

abstract:
  We investigate the analytic structure of the $2\to5$ scattering amplitude in
the planar limit of $\mathcal{N}=4$ SYM in multi-Regge kinematics in all
physical regions. We demonstrate the close connection between Regge pole and
Regge cut contributions: in a selected class of kinematic regions (Mandelstam
regions) the usual factorizing Regge pole formula develops unphysical
singularities which have to be absorbed and compensated by Regge cut
contributions. This leads, in the corrections to the BDS formula, to conformal
invariant 'renormalized' Regge pole expressions in the remainder function. We
compute these renormalized Regge poles for the $2\to5$ scattering amplitude.


title:
Bent waveguides for matter-waves: supersymmetric potentials and
  reflectionless geometries

abstract:
  Non-zero curvature in a waveguide leads to the appearance of an attractive
quantum potential which crucially affects the dynamics in matter-wave circuits.
Using methods of supersymmetric quantum mechanics, pairs of bent waveguides are
found whose geometry-induced potentials share the same scattering properties.
As a result, reflectionless waveguides, dual to the straight waveguide, are
identified. Strictly isospectral waveguides are also found by modulating the
depth of the trapping potential. Numerical simulations are used to demonstrate
the efficiency of these approaches in tailoring and controlling
curvature-induced quantum-mechanical effects.

categories: quant-ph cond-mat.quant-gas math-ph math.MP


title:
Negative-resistance models for parametrically flux-pumped
  superconducting quantum interference devices

abstract:
  A Superconducting QUantum Interference Device (SQUID) modulated by a fast
oscillating magnetic flux can be used as a parametric amplifier, providing gain
with very little added noise. Here, we develop linearized models to describe
the parametrically flux-pumped SQUID in terms of an impedance. An unpumped
SQUID acts as an inductance, the Josephson inductance, whereas a flux-pumped
SQUID develops an additional, parallel element which we have coined the
``pumpistor.'' Parametric gain can be understood as a result of a negative
resistance of the pumpistor. In the degenerate case, the gain is sensitive to
the relative phase between the pump and signal. In the nondegenerate case, gain
is independent of this phase.
  We develop our models first for degenerate parametric pumping in the
three-wave and four-wave cases, where the pump frequency is either twice or
equal to the signal frequency, respectively. We then derive expressions for the
nondegenerate case where the pump frequency is not a multiple of the signal
frequency, where it becomes necessary to consider idler tones which develop.
For the nondegenerate three-wave case, we present an intuitive picture for a
parametric amplifier containing a flux-pumped SQUID where current at the signal
frequency depends upon the load impedance at an idler frequency. This
understanding provides insight and readily testable predictions of circuits
containing flux-pumped SQUIDs.


title: Credible Autocoding of Fault Detection Observers

abstract:
  In this paper, we present a domain specific process to assist the
verification of observer-based fault detection software. Observer-based fault
detection systems, like control systems, yield invariant properties of
quadratic types. These quadratic invariants express both safety properties of
the software such as the boundedness of the states and correctness properties
such as the absence of false alarms from the fault detector. We seek to
leverage these quadratic invariants, in an automated fashion, for the formal
verification of the fault detection software. The approach, referred to as the
credible autocoding framework [1], can be characterized as autocoding with
proofs. The process starts with the fault detector model, along with its safety
and correctness properties, all expressed formally in a synchronous modeling
environment such as Simulink. The model is then transformed by a prototype
credible autocoder into both code and analyzable annotations for the code. We
demonstrate the credible autocoding process on a running example of an output
observer fault detector for a 3-degrees-of-freedom (3DOF) helicopter control
system.


title:
Trapping ultracold gases near cryogenic materials with rapid
  reconfigurability

abstract:
  We demonstrate a novel atom chip trapping system that allows the placement
and high-resolution imaging of ultracold atoms within microns from any <100
um-thin, UHV-compatible material, while also allowing sample exchange with
minimal experimental downtime. The sample is not connected to the atom chip,
allowing rapid exchange without perturbing the atom chip or laser cooling
apparatus. Exchange of the sample and retrapping of atoms has been performed
within a week turnaround, limited only by chamber baking. Moreover, the
decoupling of sample and atom chip provides the ability to independently tune
the sample temperature and its position with respect to the trapped ultracold
gas, which itself may remain in the focus of a high-resolution imaging system.
As a first demonstration of this new system, we have confined a 700-nK cloud of
8x10^4 87Rb atoms within 100 um of a gold-mirrored 100-um-thick silicon
substrate. The substrate was cooled to 35 K without use of a heat shield, while
the atom chip, 120 um away, remained at room temperature. Atoms may be imaged
and retrapped every 16 s, allowing rapid data collection.


title:
Spatial Wilson loops in the classical field of high-energy heavy-ion
  collisions

abstract:
  It has been previously shown numerically that the expectation value of the
magnetic Wilson loop at the initial time of a heavy-ion collision exhibits area
law scaling. This was obtained for a classical non-Abelian gauge field in the
forward light cone and for loops of area $A\gtrsim 2/Q_s^2$. Here, we present
an analytic calculation of the spatial Wilson loop in the classical field of a
collision within perturbation theory. It corresponds to a diagram with two
sources, for both projectile and target, whose field is evaluated at second
order in the gauge potential. The leading non-trivial contribution to the
magnetic loop in perturbation theory is proportional to the square of its area.


title:
On the backward Euler approximation of the stochastic Allen-Cahn
  equation

abstract:
  We consider the stochastic Allen-Cahn equation perturbed by smooth additive
Gaussian noise in a spatial domain with smooth boundary in dimension $d\le 3$,
and study the semidiscretization in time of the equation by an implicit Euler
method. We show that the method converges pathwise with a rate $O(\Delta
t^{\gamma}) $ for any $\gamma<\frac12$. We also prove that the scheme converges
uniformly in the strong $L^p$-sense but with no rate given.


title: The restrictions of the Maximum Entropy Production Principle

abstract:
  We tried to explain our point of view on this principle and answer a number
of critical questions in this comment. It is the first time we have clearly
presented all the existing restrictions of MEPP application and briefly
explained them; this will help to avoid misunderstandings connected with its
use.


title: The local standard of rest and the well in the velocity distribution

abstract:
  It is now recognised that the traditional method of calculating the LSR
fails. We find an improved estimate of the LSR by making use of the larger and
more accurate database provided by XHIP and repeating our preferred analysis
from Francis & Anderson (2009a). We confirm an unexpected high value of $U_0$
by calculating the mean for stars with orbits sufficiently inclined to the
Galactic plane that they do not participate in bulk streaming motions. Our best
estimate of the solar motion with respect to the LSR $(U_0, V_0, W_0) = (14.1
\pm 1.1, 14.6 \pm 0.4, 6.9 \pm 0.1)$ km\ s$^{-1}$.


title:
Characterization of a commercially available large area, high detection
  efficiency single-photon avalanche diode

abstract:
  We characterize a new commercial, back-illuminated reach-through silicon
single-photon avalanche photo diode (SPAD) SAP500 (Laser Components. Inc.),
operated in Geiger-mode for purpose of photon counting. We show that for this
sensor a significant interplay exists between dark counts, detection
efficiency, afterpulsing, excess voltage and operating temperature, sometimes
requiring a careful optimization tailored for a specific application. We find
that a large flat plateau of sensitive area of about 0.5 mm in diameter, a peak
quantum efficiency of 73% at 560 nm and timing precision down to 150 ps FWHM
are the main distinguishing characteristics of this SPAD.


title: Geometric constant term functor(s)

abstract:
  We study the Eisenstein series and constant term functors in the framework of
geometric theory of automorphic functions. Our main result says that for a
parabolic P in G with Levi quotient M, the !-constant term functor
CT_!:D-mod(Bun_G)-> D-mod(Bun_M) is canonically isomorphic to the *-constant
term functor CT^-_*:D-mod(Bun_G)\to D-mod(Bun_M), taken with respect to the
opposite parabolic P^-.


title: Light Non-degenerate Composite Partners at the LHC

abstract:
  We study the implications of a large degree of compositeness for the light
generation quarks in composite pseudo-Nambu-Goldstone-boson Higgs models. We
focus in particular on viable scenarios where the right-handed up-type quarks
have a sizable mixing with the strong dynamics. For concreteness we assume the
latter to be characterized by an SO(5)/SO(4) symmetry with fermionic resonances
in the SO(4) singlet and fourplet representations. Singlet partners dominantly
decay to a Higgs boson and jets. As no dedicated searches are currently looking
for these final states, singlet partners can still be rather light. Conversely,
some fourplet partners dominantly decay to an electroweak gauge boson and a
jet, a signature which has been analyzed at the LHC. To constrain the parameter
space of this scenario we have reinterpreted various LHC analyses. In the limit
of first two generation degeneracy, as in minimal flavor violation or
U(2)-symmetric flavor models, fourplet partners need to be relatively heavy,
with masses above 1.8 TeV, or the level of compositeness needs to be rather
small. The situation is rather different in models that deviate from the first
two generation degeneracy paradigm, as the charm parton distribution functions
are suppressed relative to the up quark ones. The right-handed charm quark can
be composite and its partners being as light as 600 GeV, while the right-handed
up quark needs either to be mostly elementary or to have its partners as heavy
as 2 TeV. Models with fully composite singlet fermions are also analyzed,
leading to similar conclusions. Finally, we consider the case where both the
fourplet and the singlet states are present. In this case the bounds could be
significantly weaken due to a combination of smaller production rates and the
opening of new channels including cascade processes.


title:
Galaxies on FIRE (Feedback In Realistic Environments): Stellar Feedback
  Explains Cosmologically Inefficient Star Formation

abstract:
  We present a series of high-resolution cosmological simulations of galaxy
formation to z=0, spanning halo masses ~10^8-10^13 M_sun, and stellar masses
~10^4-10^11. Our simulations include fully explicit treatment of both the
multi-phase ISM (molecular through hot) and stellar feedback. The stellar
feedback inputs (energy, momentum, mass, and metal fluxes) are taken directly
from stellar population models. These sources of stellar feedback, with zero
adjusted parameters, reproduce the observed relation between stellar and halo
mass up to M_halo~10^12 M_sun (including dwarfs, satellites, MW-mass disks, and
small groups). By extension, this leads to reasonable agreement with the
stellar mass function for M_star<10^11 M_sun. We predict weak redshift
evolution in the M_star-M_halo relation, consistent with current constraints to
z>6. We find that the M_star-M_halo relation is insensitive to numerical
details, but is sensitive to the feedback physics. Simulations with only
supernova feedback fail to reproduce the observed stellar masses, particularly
in dwarf and high-redshift galaxies: radiative feedback (photo-heating and
radiation pressure) is necessary to disrupt GMCs and enable efficient coupling
of later supernovae to the gas. Star formation rates agree well with the
observed Kennicutt relation at all redshifts. The galaxy-averaged Kennicutt
relation is very different from the numerically imposed law for converting gas
into stars in the simulation, and is instead determined by self-regulation via
stellar feedback. Feedback reduces star formation rates considerably and
produces a reservoir of gas that leads to rising late-time star formation
histories significantly different from the halo accretion history. Feedback
also produces large short-timescale variability in galactic SFRs, especially in
dwarfs. Many of these properties are not captured by common 'sub-grid' galactic
wind models.


title:
Thermal conduction by dark matter with velocity and momentum-dependent
  cross-sections

abstract:
  We use the formalism of Gould and Raffelt to compute the dimensionless
thermal conduction coefficients for scattering of dark matter particles with
standard model nucleons via cross-sections that depend on the relative velocity
or momentum exchanged between particles. Motivated by models invoked to
reconcile various recent results in direct detection, we explicitly compute the
conduction coefficients $\alpha$ and $\kappa$ for cross-sections that go as
$v_{\rm rel}^2$, $v_{\rm rel}^4$, $v_{\rm rel}^{-2}$, $q^2$, $q^4$ and
$q^{-2}$, where $v_{\rm rel}$ is the relative DM-nucleus velocity and $q$ is
the momentum transferred in the collision. We find that a $v_{\rm rel}^{-2}$
dependence can significantly enhance energy transport from the inner solar core
to the outer core. The same can true for any $q$-dependent coupling, if the
dark matter mass lies within some specific range for each coupling. This effect
can complement direct searches for dark matter; combining these results with
state-of-the-art Solar simulations should greatly increase sensitivity to
certain DM models. It also seems possible that the so-called Solar Abundance
Problem could be resolved by enhanced energy transport in the solar core due to
such velocity- or momentum-dependent scatterings.


title: Soft superconducting gap in semiconductor-based Majorana nanowires

abstract:
  We develop a theory for the proximity effect in
superconductor-semiconductor-normal metal tunneling structures, which have
recently been extensively studied experimentally, leading to the observation of
transport signatures consistent with the predicted zero-energy Majorana bound
states. We show that our model for the semiconductor nanowire having multiple
occupied subbands with different transmission probabilities through the barrier
reproduces the observed "soft-gap" behavior associated with substantial subgap
tunneling conductance. We study the manifestations of the soft gap phenomenon
both in the tunneling conductance and in local density of states measurements
and discuss the correlations between these two quantities. We emphasize that
the proximity effect associated with the hybridization between low-lying states
in the multiband semiconductor and the normal metal states in the lead is an
intrinsic effect leading to the soft gap problem. In addition to the intrinsic
contribution, there may be extrinsic effects, such as, for example, interface
disorder, exacerbating the soft gap problem. Our work establishes the generic
possibility of an ubiquitous presence of an intrinsic soft gap in the
superconductor-semiconductor-normal metal tunneling transport conductance
induced by the inverse proximity effect of the normal metal.


title:
On the formation and physical properties of the Intra-Cluster Light in
  hierarchical galaxy formation models

abstract:
  We study the formation of the Intra-Cluster Light (ICL) using a semi-analytic
model of galaxy formation, coupled to merger trees extracted from N-body
simulations of groups and clusters. We assume that the ICL forms by (1) stellar
stripping of satellite galaxies and (2) relaxation processes that take place
during galaxy mergers. The fraction of ICL in groups and clusters predicted by
our models ranges between 10 and 40 per cent, with a large halo-to-halo scatter
and no halo mass dependence. We note, however, that our predicted ICL fractions
depend on the resolution: for a set of simulations with particle mass one order
of magnitude larger than that adopted in the high resolution runs used in our
study, we find that the predicted ICL fractions are ~30-40 per cent larger than
those found in the high resolution runs. On cluster scale, large part of the
scatter is due to a range of dynamical histories, while on smaller scale it is
driven by individual accretion events and stripping of very massive satellites,
$M_{*} \gtrsim 10^{10.5} M_{\odot}$, that we find to be the major contributors
to the ICL. The ICL in our models forms very late (below $z\sim 1$), and a
fraction varying between 5 and 25 per cent of it has been accreted during the
hierarchical growth of haloes. In agreement with recent observational
measurements, we find the ICL to be made of stars covering a relatively large
range of metallicity, with the bulk of them being sub-solar.


title: Single production of an exotic bottom partner at LHC

abstract:
  We study single production and detection at the LHC run II of exotic partners
of the bottom quark. For masses larger than 1 TeV single production can
dominate over pair production that is suppressed due to phase space. The
presence of exotic partners of the bottom is motivated in models aiming to
solve the $A_{FB}^b$ anomaly measured at LEP and SLC. Minimal models of this
type with partial compositeness predict, as the lightest bottom partner, a new
fermion V of electric charge -4/3, also called mirror. The relevant coupling
for our study is a WVb vertex, which yields a signal that corresponds to a hard
W, a hard b-jet and a forward light jet. We design a search strategy for the
leptonic decay of the W, which avoids the large QCD multijet background and its
large uncertainties. We find that the main backgrounds are W+jets and ttbar,
and the key variables to enhance the signal over them are a hard b-jet and the
rapidity of the light jet. We determine the discovery reach for the LHC run II,
in particular we predict that, for couplings of order ~g/10, this signal could
be detected at a 95% confidence level with a mass up to 2.4 TeV using the first
100 fb-1.


title: Flavor Physics in Warped Space

abstract:
  We review constraints from quark and lepton flavor violation on extra
dimensional models with warped geometry, both in the minimal and the custodial
model. For both scenarios, KK masses that are large enough to suppress
constraints from electroweak precision tests also sufficiently suppress all
quark flavor and CP violation, with the exception of CP violation in $K\bar K$
mixing and (to a lesser extend) in $D\bar D$ mixing. In the lepton sector the
minimal scenario leads to excessively large contributions to $\mu\to e\gamma$
transitions, requiring KK masses of at least 20 TeV or larger.


title: Nonparametric Multi-group Membership Model for Dynamic Networks

abstract:
  Relational data-like graphs, networks, and matrices-is often dynamic, where
the relational structure evolves over time. A fundamental problem in the
analysis of time-varying network data is to extract a summary of the common
structure and the dynamics of the underlying relations between the entities.
Here we build on the intuition that changes in the network structure are driven
by the dynamics at the level of groups of nodes. We propose a nonparametric
multi-group membership model for dynamic networks. Our model contains three
main components: We model the birth and death of individual groups with respect
to the dynamics of the network structure via a distance dependent Indian Buffet
Process. We capture the evolution of individual node group memberships via a
Factorial Hidden Markov model. And, we explain the dynamics of the network
structure by explicitly modeling the connectivity structure of groups. We
demonstrate our model's capability of identifying the dynamics of latent groups
in a number of different types of network data. Experimental results show that
our model provides improved predictive performance over existing dynamic
network models on future network forecasting and missing link prediction.


title: Enhanced Photodetection in Graphene-Integrated Photonic Crystal Cavity

abstract:
  We demonstrate the controlled enhancement of photoresponsivity in a graphene
photodetector by coupling to slow light modes in a long photonic crystal linear
defect cavity. Near the Brillouin zone (BZ) boundary, spectral coupling of
multiple cavity modes results in broad-band photocurrent enhancement from 1530
nm to 1540 nm. Away from the BZ boundary, individual cavity resonances enhance
the photocurrent eight-fold in narrow resonant peaks. Optimization of the
photocurrent via critical coupling of the incident field with the
graphene-cavity system is discussed. The enhanced photocurrent demonstrates the
feasibility of a wavelength-scale graphene photodetector for efficient
photodetection with high spectral selectivity and broadband response.


title:
Numerical calculation of three-point branched covers of the projective
  line

abstract:
  We exhibit a numerical method to compute three-point branched covers of the
complex projective line. We develop algorithms for working explicitly with
Fuchsian triangle groups and their finite index subgroups, and we use these
algorithms to compute power series expansions of modular forms on these groups.


title: Light Dark Matter Anomalies After LUX

abstract:
  We examine the consistency of light dark matter (DM) elastic scattering in
CoGeNT, DAMA, and CDMS-Silicon in light of constraints from XENON, CDMS, LUX,
PICASSO and COUPP. We consider a variety of operators that have been employed
to reconcile anomalies with constraints, including anapole, magnetic dipole,
momentum-dependent, and isospin-violating DM. We find that elastic scattering
through these alternative operators does not substantially reduce the tension
between the signals and the null constraints for operators where at least two
of the three purported signals map onto a common space in the DM
mass--scattering cross-section plane. Taking a choice of the scintillation
efficiency that lies at the $-1 \sigma$ region of the Manzur et al measurement
relieves tension between signals and the LUX constraint---in particular for a
magnetic dipole interaction and a xenophobic interaction (though for the latter
the signal regions do not substantially overlap). We also find that modest
changes in the halo model does not alter this result. We conclude that, even
relaxing the assumption about the type of elastic scattering interaction and
taking a conservative choice for the scintillation efficiency, LUX and the
results from other null experiments remain in tension with a light DM elastic
scattering explanation of direct detection anomalies.


title:
The UM, a fully--compressible, non--hydrostatic, deep atmosphere GCM,
  applied to hot Jupiters

abstract:
  We are adapting the Global Circulation Model (GCM) of the UK Met Office, the
so--called Unified Model (UM), for the study of hot Jupiters. In this work we
demonstrate the successful adaptation of the most sophisticated dynamical core,
the component of the GCM which solves the equations of motion for the
atmosphere, available within the UM, ENDGame (Even Newer Dynamics for General
atmospheric modelling of the environment). Within the same numerical scheme
ENDGame supports solution to the dynamical equations under varying degrees of
simplification. We present results from a simple, shallow (in atmospheric
domain) hot Jupiter model (SHJ), and a more realistic (with a deeper
atmosphere) HD 209458b test case. For both test cases we find that the
large--scale, time--averaged (over the 1200 days prescribed test period),
dynamical state of the atmosphere is relatively insensitive to the level of
simplification of the dynamical equations. However, problems exist when
attempting to reproduce the results for these test cases derived from other
models. For the SHJ case the lower (and upper) boundary intersects the dominant
dynamical features of the atmosphere meaning the results are heavily dependent
on the boundary conditions. For the HD 209458b test case, when using the more
complete dynamical models, the atmosphere is still clearly evolving after 1200
days, and in a transient state. Solving the complete (deep atmosphere and
non--hydrostatic) dynamical equations allows exchange between the vertical and
horizontal momentum of the atmosphere, via Coriolis and metric terms.
Subsequently, interaction between the upper atmosphere and the deeper more
slowly evolving (radiatively inactive) atmosphere significantly alters the
results, and acts over timescales longer than 1200 days.


title: Cubulating hyperbolic free-by-cyclic groups: the irreducible case

abstract:
  Let $V$ be a finite graph and let $\phi:V\rightarrow V$ be an irreducible
train track map whose mapping torus has word-hyperbolic fundamental group $G$.
Then $G$ acts freely and cocompactly on a CAT(0) cube complex.


title: Directly Imaged L-T Transition Exoplanets in the Mid-Infrared

abstract:
  Gas-giant planets emit a large fraction of their light in the mid-infrared
($\gtrsim$3$\mu$m), where photometry and spectroscopy are critical to our
understanding of the bulk properties of extrasolar planets. Of particular
importance are the L and M-band atmospheric windows (3-5$\mu$m), which are the
longest wavelengths currently accessible to ground-based, high-contrast
imagers. We present binocular LBT AO images of the HR 8799 planetary system in
six narrow-band filters from 3-4$\mu$m, and a Magellan AO image of the 2M1207
planetary system in a broader 3.3$\mu$m band. These systems encompass the five
known exoplanets with luminosities consistent with L$\rightarrow$T transition
brown dwarfs. Our results show that the exoplanets are brighter and have
shallower spectral slopes than equivalent temperature brown dwarfs in a
wavelength range that contains the methane fundamental absorption feature
(spanned by the narrowband filters and encompassed by the broader 3.3$\mu$m
filter). For 2M1207 b, we find that thick clouds and non-equilibrium chemistry
caused by vertical mixing can explain the object's appearance. For the HR 8799
planets, we present new models that suggest the atmospheres must have patchy
clouds, along with non-equilibrium chemistry. Together, the presence of a
heterogeneous surface and vertical mixing presents a picture of dynamic
planetary atmospheres in which both horizontal and vertical motions influence
the chemical and condensate profiles.


title: Existence of Symmetric and Asymmetric Spikes for a Crime Hotspot Model

abstract:
  We study a crime hotspot model suggested by Short-Bertozzi-Brantingham. The
aim of this work is to establish rigorously the formation of hotspots in this
model representing concentrations of criminal activity. More precisely, for the
one-dimensional system, we rigorously prove the existence of steady states with
multiple spikes of the following types:
  (i) Multiple spikes of arbitrary number having the same amplitude (symmetric
spikes),
  (ii) Multiple spikes having different amplitude for the case of one large and
one small spike (asymmetric spikes).
  We use an approach based on Liapunov-Schmidt reduction and extend it to the
quasilinear crime hotspot model. Some novel results that allow us to carry out
the Liapunov-Schmidt reduction are: (i) approximation of the quasilinear crime
hotspot system on the large scale by the semilinear Schnakenberg model, (ii)
estimate of the spatial dependence of the second component on the small scale
which is dominated by the quasilinear part of the system.
  The paper concludes with an extension to the anisotropic case.


title:
Dark soliton in quasi-one-dimensional Bose-Einstein condensates with a
  Gaussian trap

abstract:
  In this paper we study dark solitons in quasi-one-dimensional Bose-Einstein
condensates (BECs) in presence of an anharmonic external potential. The
theoretical model is based on the Mu\~noz-Mateo and Delgado (MMD) equation that
describes cigar-shaped BECs with repulsive interatomic interactions. Since MMD
equation presents a nonpolynomial form, the soliton-sound recombination cannot
display the same pattern presented in the cubic model. We perform numerical
simulations to compare both cases.


title: Decay and Scattering for the Chern-Simons-Schr\"odinger Equations

abstract:
  We consider the Chern-Simons-Schr\"odinger model in 1+2 dimensions, and prove
scattering for small solutions of the Cauchy problem in the Coulomb gauge. This
model is a gauge covariant Schr\"odinger equation, with a potential decaying
like $r^{-1}$ at infinity. To overcome the difficulties due to this long range
decay we start by performing $L^2$-based estimates covariantly. This gives
favorable commutation identities so that only curvature terms, which decay
faster than $r^{-1}$, appear in our weighted energy estimates. We then select
the Coulomb gauge to reveal a genuinely cubic null structure, which allows us
to show sharp decay by Fourier methods.


title: Higher n-angulations from local rings

abstract:
  We show that the category of finitely generated free modules over certain
local rings is n-angulated for every n at least 3. In fact, we construct
several classes of n-angles, parametrized by equivalence classes of units in
the local rings. Finally, we show that for odd values of n some of these
n-angulated categories are not algebraic.


title:
Three-point current correlation functions as probes of Effective
  Conformal Theories

abstract:
  The three-point current correlation function in Euclidean spacetime for a
strongly coupled system with non-Abelian global symmetry, $\langle
J^a_i(x)J^b_j(y)J^c_k(z)\rangle$, is calculated from the weakly coupled AdS
dual. The contribution from the first non-renormalizable bulk operator,
$(F_{\mu\nu})^3$, is calculated and shown to lead to a polarization structure
different from the leading contribution, which comes from the renormalizable
$(F_{\mu\nu})^2$ operator. The non-renormalizable correction is suppressed by
powers of the cutoff scale $\Lambda$. This suggests a possible experimental
probe of the effective description through a measurement of the cutoff scale
$\Lambda$ in strongly coupled condensed matter systems.


title: Generalized master equation for modular exciton density transfer

abstract:
  A generalized master equation (GME) governing quantum evolution of modular
exciton density (MED) is derived for large scale light harvesting systems
composed of weakly interacting modules of multiple chromophores. The GME-MED
offers a practical framework to incorporate real time coherent quantum dynamics
calculations at small length scales into dynamics over large length scales,
without assumptions of time scale separation or specific forms of intra-module
quantum dynamics. A test of the GME-MED for four sites of the
Fenna-Matthews-Olson complex demonstrates how coherent dynamics of excitonic
populations over many coupled chromophores can be accurately described by
transitions between subgroups (modules) of delocalized excitons.


title: Relating and contrasting plain and prefix Kolmogorov complexity

abstract:
  In [3] a short proof is given that some strings have maximal plain Kolmogorov
complexity but not maximal prefix-free complexity. The proof uses Levin's
symmetry of information, Levin's formula relating plain and prefix complexity
and Gacs' theorem that complexity of complexity given the string can be high.
We argue that the proof technique and results mentioned above are useful to
simplify existing proofs and to solve open questions.
  We present a short proof of Solovay's result [21] relating plain and prefix
complexity: $K (x) = C (x) + CC (x) + O(CCC (x))$ and $C (x) = K (x) - KK (x) +
O(KKK (x))$, (here $CC(x)$ denotes $C(C(x))$, etc.).
  We show that there exist $\omega$ such that $\liminf C(\omega_1\dots
\omega_n) - C(n)$ is infinite and $\liminf K(\omega_1\dots \omega_n) - K(n)$ is
finite, i.e. the infinitely often C-trivial reals are not the same as the
infinitely often K-trivial reals (i.e. [1,Question 1]).
  Solovay showed that for infinitely many $x$ we have $|x| - C (x) \le O(1)$
and $|x| + K (|x|) - K (x) \ge \log^{(2)} |x| - O(\log^{(3)} |x|)$, (here $|x|$
denotes the length of $x$ and $\log^{(2)} = \log\log$, etc.). We show that this
result holds for prefixes of some 2-random sequences.
  Finally, we generalize our proof technique and show that no monotone relation
exists between expectation and probability bounded randomness deficiency (i.e.
[6, Question 1]).


title:
Chiral and deconfinement transitions in a magnetic background using the
  functional renormalization group with the Polyakov loop

abstract:
  We use the Polyakov loop coupled quark-meson model to approximate low energy
QCD and present results for the chiral and deconfinement transitions in the
presence of a constant magnetic background $B$ at finite temperature $T$ and
baryon chemical potential $\mu_B$. We investigate effects of various gluoni
potentials on the deconfinement transition with and without a fermionic
backreaction at finite $B$. Additionally we investigate the effect of the
Polyakov loop on the chiral phase transition, finding that magnetic catalysis
at low $\mu_B$ is present, but weakened by the Polyakov loop.


title: Invariant bilinear forms of algebras given by faithfully flat descent

abstract:
  The existence of nondegenerate invariant bilinear forms is one of the most
important tools in the study of Kac-Moody Lie algebras and extended affine Lie
algebras. In practice, these forms are created, or shown to exist, either by
assumption or in an ad hoc basis. The purpose of this work is to describe the
nature of the space of invariant bilinear forms of certain algebras given by
faithfully flat descent (which includes the affine Kac-Moody Lie algebras, as
well as Azumaya algebras and multiloop algebras) within a functorial framework.
This will allow us to conclude the existence, uniqueness and nature of
invariant bilinear forms for many important classes of algebras.


title: Wave-absorbing vehicular platoon controller

abstract:
  The paper tailors the so-called wave-based control popular in the field of
flexible mechanical structures to the field of distributed control of vehicular
platoons. The proposed solution augments the symmetric bidirectional control
algorithm with a wave-absorbing controller implemented on the leader, and/or on
the rear-end vehicle. The wave-absorbing controller actively absorbs an
incoming wave of positional changes in the platoon and thus prevents
oscillations of inter-vehicle distances. The proposed controller significantly
improves the performance of platoon manoeuvrers such as
acceleration/deceleration or changing the distances between vehicles without
making the platoon string unstable. Numerical simulations show that the
wave-absorbing controller performs efficiently even for platoons with a large
number of vehicles, for which other platooning algorithms are inefficient or
require wireless communication between vehicles.


title: New Results from ArgoNeuT

abstract:
  In this article, I discuss the latest results from ArgoNeuT, including
inclusive charged current cross sections and studies of final-state
interactions.


title: Risk-sensitive Reinforcement Learning

abstract:
  We derive a family of risk-sensitive reinforcement learning methods for
agents, who face sequential decision-making tasks in uncertain environments. By
applying a utility function to the temporal difference (TD) error, nonlinear
transformations are effectively applied not only to the received rewards but
also to the true transition probabilities of the underlying Markov decision
process. When appropriate utility functions are chosen, the agents' behaviors
express key features of human behavior as predicted by prospect theory
(Kahneman and Tversky, 1979), for example different risk-preferences for gains
and losses as well as the shape of subjective probability curves. We derive a
risk-sensitive Q-learning algorithm, which is necessary for modeling human
behavior when transition probabilities are unknown, and prove its convergence.
As a proof of principle for the applicability of the new framework we apply it
to quantify human behavior in a sequential investment task. We find, that the
risk-sensitive variant provides a significantly better fit to the behavioral
data and that it leads to an interpretation of the subject's responses which is
indeed consistent with prospect theory. The analysis of simultaneously measured
fMRI signals show a significant correlation of the risk-sensitive TD error with
BOLD signal change in the ventral striatum. In addition we find a significant
correlation of the risk-sensitive Q-values with neural activity in the
striatum, cingulate cortex and insula, which is not present if standard
Q-values are used.


title:
On the velocity space discretization for the Vlasov-Poisson system:
  comparison between Hermite spectral and Particle-in-Cell methods. Part 1:
  semi-implicit scheme

abstract:
  We discuss a spectral method for the numerical solution of the Vlasov-Poisson
system where the velocity space is decomposed by means of an Hermite basis. We
describe a semi-implicit time discretization that extends the range of
numerical stability relative to an explicit scheme. We also introduce and
discuss the effects of an artificial collisional operator, which is necessary
to take care of the velocity space filamentation problem, unavoidable in
collisionless plasmas. The computational efficiency and the cost-effectiveness
of this method are compared to a Particle-in-Cell (PIC) method in the case of a
two-dimensional phase space. The following examples are discussed: Langmuir
wave, Landau damping, ion-acoustic wave, two-stream instability, and plasma
echo. The Hermite spectral method can achieve solutions that are several orders
of magnitude more accurate (at a fraction of the cost) with respect to the PIC
method.


title:
Resonant time steps and instabilities in the numerical integration of
  Schr\"odinger equations

abstract:
  We consider the linear and non linear cubic Schr\"odinger equations with
periodic boundary conditions, and their approximations by splitting methods. We
prove that for a dense set of arbitrary small time steps, there exists
numerical solutions leading to strong numerical instabilities preventing the
energy conservation and regularity bounds obtained for the exact solution. We
analyze rigorously these instabilities in the semi-discrete and fully discrete
cases.


title: Querying Knowledge Graphs by Example Entity Tuples

abstract:
  We witness an unprecedented proliferation of knowledge graphs that record
millions of entities and their relationships. While knowledge graphs are
structure-flexible and content rich, they are difficult to use. The challenge
lies in the gap between their overwhelming complexity and the limited database
knowledge of non-professional users. If writing structured queries over simple
tables is difficult, complex graphs are only harder to query. As an initial
step toward improving the usability of knowledge graphs, we propose to query
such data by example entity tuples, without requiring users to form complex
graph queries. Our system, GQBE (Graph Query By Example), automatically derives
a weighted hidden maximal query graph based on input query tuples, to capture a
user's query intent. It efficiently finds and ranks the top approximate answer
tuples. For fast query processing, GQBE only partially evaluates query graphs.
We conducted experiments and user studies on the large Freebase and DBpedia
datasets and observed appealing accuracy and efficiency. Our system provides a
complementary approach to the existing keyword-based methods, facilitating
user-friendly graph querying. To the best of our knowledge, there was no such
proposal in the past in the context of graphs.


title:
Kurtoses and high order cumulants: Insights from resummed perturbation
  theory

abstract:
  Cumulants of conserved charges provide important information about the
physics of the quark-gluon plasma around the phase transition region, as they
are by construction sensitive to changes in the degrees of freedom of the
system. In this brief proceedings contribution, I report on recent results for
two such quantities from two different improved perturbative frameworks, as
well as discuss their relevance for heavy ion experiments.


title: An Experimental Comparison of Trust Region and Level Sets

abstract:
  High-order (non-linear) functionals have become very popular in segmentation,
stereo and other computer vision problems. Level sets is a well established
general gradient descent framework, which is directly applicable to
optimization of such functionals and widely used in practice. Recently, another
general optimization approach based on trust region methodology was proposed
for regional non-linear functionals. Our goal is a comprehensive experimental
comparison of these two frameworks in regard to practical efficiency,
robustness to parameters, and optimality. We experiment on a wide range of
problems with non-linear constraints on segment volume, appearance and shape.


title: Idea of a new Personality-Type based Recommendation Engine

abstract:
  Myers-Briggs Type Indicator (MBTI) types depict the psychological preferences
by which a person perceives the world and make decisions. There are 4 principal
functions through which the people see the world: sensation, intuition,
feeling, and thinking. These functions along with the Introverted\Extroverted
nature of the person, there are 16 personalities types, the humans are divided
into. Here an idea is presented where a user can get recommendations for books,
web media content, music and movies on the basis of the users' MBTI type. Only
things like books and other media content has been chosen because the
preferences in such things are mostly subjective. Apart from the recommended
content that is generally generated on the basis of the previous purchases,
searches can be enhanced by using the MBTI. A minimalist survey was designed
for collecting the data. This has a more than 100 features that show the
preference of a personality type. Those include preferences in book genres,
music genres, movie genres and even video games genres. After analyzing the
data that is collected from the survey, some inferences were drawn from it
which can be used to design a new recommendation engine for recommending the
content that coincides with the personality of the user.


title: Sets of constant distance from a Jordan curve

abstract:
  We study the $\epsilon$-level sets of the signed distance function to a
planar Jordan curve $\Gamma$, and ask what properties of $\Gamma$ ensure that
the $\epsilon$-level sets are Jordan curves, or uniform quasicircles, or
uniform chord-arc curves for all sufficiently small $\epsilon$. Sufficient
conditions are given in term of a scaled invariant parameter for measuring the
local deviation of subarcs from their chords. The chordal conditions given are
sharp.


title: Bayesian registration of functions and curves

abstract:
  Bayesian analysis of functions and curves is considered, where warping and
other geometrical transformations are often required for meaningful
comparisons. We focus on two applications involving the classification of mouse
vertebrae shape outlines and the alignment of mass spectrometry data in
proteomics. The functions and curves of interest are represented using the
recently introduced square root velocity function, which enables a warping
invariant elastic distance to be calculated in a straightforward manner. We
distinguish between various spaces of interest: the original space, the ambient
space after standardizing, and the quotient space after removing a group of
transformations. Using Gaussian process models in the ambient space and
Dirichlet priors for the warping functions, we explore Bayesian inference for
curves and functions. Markov chain Monte Carlo algorithms are introduced for
simulating from the posterior, including simulated tempering for multimodal
posteriors. We also compare ambient and quotient space estimators for mean
shape, and explain their frequent similarity in many practical problems using a
Laplace approximation. A simulation study is carried out, as well as shape
classification of the mouse vertebra outlines and practical alignment of the
mass spectrometry functions.


title:
Submodular Optimization with Submodular Cover and Submodular Knapsack
  Constraints

abstract:
  We investigate two new optimization problems -- minimizing a submodular
function subject to a submodular lower bound constraint (submodular cover) and
maximizing a submodular function subject to a submodular upper bound constraint
(submodular knapsack). We are motivated by a number of real-world applications
in machine learning including sensor placement and data subset selection, which
require maximizing a certain submodular function (like coverage or diversity)
while simultaneously minimizing another (like cooperative cost). These problems
are often posed as minimizing the difference between submodular functions [14,
35] which is in the worst case inapproximable. We show, however, that by
phrasing these problems as constrained optimization, which is more natural for
many applications, we achieve a number of bounded approximation guarantees. We
also show that both these problems are closely related and an approximation
algorithm solving one can be used to obtain an approximation guarantee for the
other. We provide hardness results for both problems thus showing that our
approximation factors are tight up to log-factors. Finally, we empirically
demonstrate the performance and good scalability properties of our algorithms.


title: Tunable Bound States in Continuum by Optical Frequency

abstract:
  We demonstrate the existence of tunable bound-states in continuum (BIC) in a
1-dimensional quantum wire with two impurities induced by an intense
monochromatic radiation field. We found that there is a new type of BIC due to
the Fano interference between two optical transition channels, in addition to
the ordinary BIC due to a geometrical interference between electron wave
functions emitted by impurities. In both cases the BIC can be achieved by
tuning the frequency of the radiation field.


title:
Resolved Spectroscopy of the T8.5 and Y0-0.5 Binary WISEPC
  J121756.91+162640.2AB

abstract:
  We present 0.9 - 2.5 um resolved spectra for the ultracool binary WISEPC
J121756.91+162640.2AB. The system consists of a pair of brown dwarfs that
straddles the currently defined T/Y spectral type boundary. We use synthetic
spectra generated by model atmospheres that include chloride and sulfide clouds
(Morley et al.), the distance to the system (Dupuy & Kraus), and the radius of
each component based on evolutionary models (Saumon & Marley) to determine a
probable range of physical properties for the binary. The effective temperature
of the T8.5 primary is 550 - 600 K, and that of the Y0 - Y0.5 secondary is 450
K. The atmospheres of both components are either free of clouds or have
extremely thin cloud layers. We find that the masses of the primary and
secondary are 30 and 22 M_Jup, respectively, and that the age of the system is
4 - 8 Gyr. This age is consistent with astrometric measurements (Dupuy & Kraus)
that show that the system has kinematics intermediate between those of the thin
and thick disks of the Galaxy. An older age is also consistent with an
indication by the H - K colors that the system is slightly metal-poor.


title: How to Gamble Against All Odds

abstract:
  A decision maker observes the evolving state of the world while constantly
trying to predict the next state given the history of past states. The ability
to benefit from such predictions depends not only on the ability to recognize
patters in history, but also on the range of actions available to the decision
maker.
  We assume there are two possible states of the world. The decision maker is a
gambler who has to bet a certain amount of money on the bits of an announced
binary sequence of states. If he makes a correct prediction he wins his wager,
otherwise he loses it.
  We compare the power of betting strategies (aka martingales) whose wagers
take values in different sets of reals. A martingale whose wagers take values
in a set $A$ is called an $A$-martingale. A set of reals $B$ anticipates a set
$A$, if for every $A$-martingale there is a countable set of $B$-martingales,
such that on every binary sequence on which the $A$-martingale gains an
infinite amount at least one of the $B$-martingales gains an infinite amount,
too.
  We show that for two important classes of pairs of sets $A$ and $B$, $B$
anticipates $A$ if and only if the closure of $B$ contains $rA$, for some
positive $r$. One class is when $A$ is bounded and $B$ is bounded away from
zero; the other class is when $B$ is well ordered (has no left-accumulation
points). Our results generalize several recent results in algorithmic
randomness and answer a question posed by Chalcraft et al. (2012).


title:
Curvature and Optimal Algorithms for Learning and Minimizing Submodular
  Functions

abstract:
  We investigate three related and important problems connected to machine
learning: approximating a submodular function everywhere, learning a submodular
function (in a PAC-like setting [53]), and constrained minimization of
submodular functions. We show that the complexity of all three problems depends
on the 'curvature' of the submodular function, and provide lower and upper
bounds that refine and improve previous results [3, 16, 18, 52]. Our proof
techniques are fairly generic. We either use a black-box transformation of the
function (for approximation and learning), or a transformation of algorithms to
use an appropriate surrogate function (for minimization). Curiously, curvature
has been known to influence approximations for submodular maximization [7, 55],
but its effect on minimization, approximation and learning has hitherto been
open. We complete this picture, and also support our theoretical claims by
empirical results.


title: The order of optimal control problems

abstract:
  The Pontryagin's Maximum Principle allows, in most cases, the design of
optimal controls of affine nonlinear control systems by considering the sign of
a smooth function. There are cases, although, where this function vanishes on a
whole time interval and the Pontryagin's Maximum Principle alone does not give
enough information to design the control. In these cases one considers the time
derivatives of this function until a k-order derivative that explicitly depends
on the control variable. The number q=k/2 is called problem order and it is the
same to all the extremals. The local order is a related concept used in
literature, but depending on each particular extremal. The confusion between
these two concepts led to misunderstandings in past works, where the problem
order was assumed to be an integer number. In this work we prove that this is
true if the control system has a single input but, in general, it is not true
if the control system has a multiple input.


title: Symplectic No-core Shell-model Approach to Intermediate-mass Nuclei

abstract:
  We present a microscopic description of nuclei in an intermediate-mass
region, including the proximity to the proton drip line, based on a no-core
shell model with a schematic many-nucleon long-range interaction with no
parameter adjustments. The outcome confirms the essential role played by the
symplectic symmetry to inform the interaction and the winnowing of shell-model
spaces. We show that it is imperative that model spaces be expanded well beyond
the current limits up through fifteen major shells to accommodate particle
excitations that appear critical to highly-deformed spatial structures and the
convergence of associated observables.


title:
A new proof of the $\mathfrak{sl}_{2}$ action on the triplet vertex
  algebra

abstract:
  Let $\mathcal {W}(p)$ be the triplet vertex algebra of central charge
$c_{p}=1-\frac{6(p-1)^{2}}{p}$, $p\geq2$. As a Virasoro module, we have
$$\mathcal {W}(p)=\bigoplus_{n=0} ^{\infty}(2n+1) L(c_{p}, n^{2}p+np-n).$$ It
was pointed out in \cite{am1} that $\mathcal {W}(p)$ admits an action of
$\mathfrak{sl}_{2}$. In this paper we give a combinatorics description of
$\mathcal {W}(p)$, from which the action of $\mathfrak{sl}_{2}$ follows quite
directly. In the end of this paper we give similar descriptions of the
invariant subalgebra $\mathcal {W}(p)^{\Gamma}$, these will be useful for the
characterizations of the exceptional vertex operator algebras of central charge
$1$ in forthcoming papers. We also hope to extend the method of this paper to
subalgebra of lattice vertex operator algebras of higher rank.


title:
Characterizations of the exceptional vertex operator algebras of central
  charge $1$: I

abstract:
  In this paper, we give a characterization of the rational vertex operator
algebra VTL, where L is the root lattice of type A1 and T is the tetrahedral
group.


title:
Fast large-scale optimization by unifying stochastic gradient and
  quasi-Newton methods

abstract:
  We present an algorithm for minimizing a sum of functions that combines the
computational efficiency of stochastic gradient descent (SGD) with the second
order curvature information leveraged by quasi-Newton methods. We unify these
disparate approaches by maintaining an independent Hessian approximation for
each contributing function in the sum. We maintain computational tractability
and limit memory requirements even for high dimensional optimization problems
by storing and manipulating these quadratic approximations in a shared, time
evolving, low dimensional subspace. Each update step requires only a single
contributing function or minibatch evaluation (as in SGD), and each step is
scaled using an approximate inverse Hessian and little to no adjustment of
hyperparameters is required (as is typical for quasi-Newton methods). This
algorithm contrasts with earlier stochastic second order techniques that treat
the Hessian of each contributing function as a noisy approximation to the full
Hessian, rather than as a target for direct estimation. We experimentally
demonstrate improved convergence on seven diverse optimization problems. The
algorithm is released as open source Python and MATLAB packages.


title:
Characterizations of the exceptional vertex operator algebras of central
  charge $1$: II

abstract:
  It is the second paper in a series devoted to the investigation of
characterizations of the exceptional vertex operator algebras of central charge
1. In this paper, we give a characterization of the rational vertex operator
algebra VOL, where L is the root lattice of type A1 and O is the octahedral
group.


title: A note on some special exponential sums

abstract:
  In this note, we presented a new decomposition of elements of finite fields
of even order and illustrated that it is an effective tool in evaluation of
some specific exponential sums over finite fields, the explicit value of some
exponential sums were obtained.


title: Whittaker Modules for the Schr\"{o}dinger Algebra

abstract:
  In this paper, the property and the classification the simple Whittaker
modules for the schr\"{o}dinger algebra are studied. A quasi-central element
plays an important role in the study of Whittaker modules of level zero. For
the Whittaker modules of nonzero level, our arguments use the Casimir element
of semisimple Lie algebra $sl_2$ and the description of simple modules over
conformal Galilei algebras by R. L\"{u}, V. Mazorchuk and K. Zhao.


title: Does Like Dissolves Like Rule Hold for Fullerene and Ionic Liquids?

abstract:
  Over 150 solvents have been probed to dissolve light fullerenes, but with a
quite moderate success. We uncover unusual mutual polarizability of C60
fullerene and selected room-temperature ionic liquids (RTILs), which can be
applied in numerous applications, e.g. to significantly promote
solubility/miscibility of highly hydrophobic C60 molecule. We report electron
density and molecular dynamics analysis supported by the state-of-the-art
hybrid density functional theory and empirical simulations with a specifically
refined potential. The analysis suggests a workability of the proposed scheme
and opens a new direction to obtain well-dispersed fullerene containing
systems. A range of common molecular solvents and novel ionic solvents are
compared to 1-butyl-3-methylimidazolium tetrafluoroborate.


title:
Gate-tunable nearly total terahertz absorption in graphene with resonant
  metal back reflector

abstract:
  The gate-tunable terahertz (THz) absorption of graphene layers with a
resonant metal back reflector (RMBF) is theoretically investigated. We
demonstrate that the THz absorption of graphene with RMBF can vary from nearly
negligible to nearly total by tuning the external gate voltage. This peculiar
nearly total THz absorption can be attributed to the Fabry-Perot cavity effect,
which enhances the absorption and reduces the reflection of graphene. The
absorption spectra of the graphene-RMBF structure can also be tailored in
bandwidth and center frequency by changing the thickness and dielectric
constant of the spacer layer.


title:
Asynchronous Systems and Binary Diagonal Random Matrices: A Proof and
  Convergence Rate

abstract:
  In a synchronized network of $n$ nodes, each node will update its parameter
based on the system state in a given iteration. It is well-known that the
updates can converge to a fixed point if the maximum absolute eigenvalue
(spectral radius) of the $n \times n$ iterative matrix ${\bf{F}}$ is less than
one (i.e. $\rho({\bf{F}})<1$). However, if only a subset of the nodes update
their parameter in an iteration (due to delays or stale feedback) then this
effectively renders the spectral radius of the iterative matrix as one. We
consider matrices of unit spectral radii generated from ${\bf{F}}$ due to
random delays in the updates. We show that if each node updates at least once
in every $T$ iterations, then the product of the random matrices (joint
spectral radius) corresponding to these iterations is less than one. We then
use this property to prove convergence of asynchronous iterative systems.
Finally, we show that the convergence rate of such a system is
$\rho({\bf{F}})\frac{(1-(1-\gamma)^T)^n}{T}$, where assuming ergodicity,
$\gamma$ is the lowest bound on the probability that a node will update in any
given iteration.


title:
An upper bound of the value of t of the support t-designs of extremal
  binary doubly even self-dual codes

abstract:
  Let C be an extremal binary doubly even self-dual code of length n and s(C)
denote the largest integer t such that the support design of C holds a t-design
for some weight. In this paper, we prove s(C) \leq 7.


title: Linear-Complexity Overhead-Optimized Random Linear Network Codes

abstract:
  Sparse random linear network coding (SRLNC) is an attractive technique
proposed in the literature to reduce the decoding complexity of random linear
network coding. Recognizing the fact that the existing SRLNC schemes are not
efficient in terms of the required reception overhead, we consider the problem
of designing overhead-optimized SRLNC schemes. To this end, we introduce a new
design of SRLNC scheme that enjoys very small reception overhead while
maintaining the main benefit of SRLNC, i.e., its linear encoding/decoding
complexity. We also provide a mathematical framework for the asymptotic
analysis and design of this class of codes based on density evolution (DE)
equations. To the best of our knowledge, this work introduces the first DE
analysis in the context of network coding. Our analysis method then enables us
to design network codes with reception overheads in the order of a few percent.
We also investigate the finite-length performance of the proposed codes and
through numerical examples we show that our proposed codes have significantly
lower reception overheads compared to all existing linear-complexity random
linear network coding schemes.


title: On the support designs of extremal binary doubly even self-dual codes

abstract:
  Let D be the support design of the minimum weight of an extremal binary
doubly even self-dual [24m,12m,4m+4] code. In this note, we consider the case
when D becomes a t-design with t \geq 6.


title: Exact solution of the area reactivity model of an isolated pair

abstract:
  We investigate the reversible diffusion-influenced reaction of an isolated
pair in two space dimensions in the context of the area reactivity model. We
compute the exact Green's function in the Laplace domain for the initially
unbound molecule. Furthermore, we calculate the exact expression for the
Green's function in the time domain by inverting the Laplace transform via the
Bromwich contour integral. The obtained results should be useful for comparing
the behavior of the area reactivity model with more conventional models based
on contact reactivity.


title: Euler-Poincar\'e equations for $G$-Strands

abstract:
  The $G$-strand equations for a map $\mathbb{R}\times \mathbb{R}$ into a Lie
group $G$ are associated to a $G$-invariant Lagrangian. The Lie group manifold
is also the configuration space for the Lagrangian. The $G$-strand itself is
the map $g(t,s): \mathbb{R}\times \mathbb{R}\to G$, where $t$ and $s$ are the
independent variables of the $G$-strand equations. The Euler-Poincar\'e
reduction of the variational principle leads to a formulation where the
dependent variables of the $G$-strand equations take values in the
corresponding Lie algebra $\mathfrak{g}$ and its co-algebra, $\mathfrak{g}^*$
with respect to the pairing provided by the variational derivatives of the
Lagrangian.
  We review examples of different $G$-strand constructions, including matrix
Lie groups and diffeomorphism group. In some cases the $G$-strand equations are
completely integrable 1+1 Hamiltonian systems that admit soliton solutions.


title: On the persistence properties of the cross-coupled Camassa-Holm system

abstract:
  In this paper we examine the evolution of solutions, that initially have
compact support, of a recently-derived system of cross-coupled Camassa-Holm
equations. The analytical methods which we employ provide a full picture for
the persistence of compact support for the momenta. For solutions of the system
itself, the answer is more convoluted, and we determine when the compactness of
the support is lost, replaced instead by an exponential decay rate.


title: Quantum Commuting Circuits and Complexity of Ising Partition Functions

abstract:
  Instantaneous quantum polynomial-time (IQP) computation is a class of quantum
computation consisting only of commuting two-qubit gates and is not universal
in the sense of standard quantum computation. Nevertheless, it has been shown
that if there is a classical algorithm that can simulate IQP efficiently, the
polynomial hierarchy (PH) collapses at the third level, which is highly
implausible. However, the origin of the classical intractability is still less
understood. Here we establish a relationship between IQP and computational
complexity of the partition functions of Ising models. We apply the established
relationship in two opposite directions. One direction is to find subclasses of
IQP that are classically efficiently simulatable in the strong sense, by using
exact solvability of certain types of Ising models. Another direction is
applying quantum computational complexity of IQP to investigate (im)possibility
of efficient classical approximations of Ising models with imaginary coupling
constants. Specifically, we show that there is no fully polynomial randomized
approximation scheme (FPRAS) for Ising models with almost all imaginary
coupling constants even on a planar graph of a bounded degree, unless the PH
collapses at the third level. Furthermore, we also show a multiplicative
approximation of such a class of Ising partition functions is at least as hard
as a multiplicative approximation for the output distribution of an arbitrary
quantum circuit.

categories: quant-ph cond-mat.dis-nn cond-mat.stat-mech cs.CC


title:
Pole expansion for solving a type of parametrized linear systems in
  electronic structure calculations

abstract:
  We present a new method for solving parametrized linear systems. Under
certain assumptions on the parametrization, solutions to the linear systems for
all parameters can be accurately approximated by linear combinations of
solutions to linear systems for a small set of fixed parameters. Combined with
either direct solvers or preconditioned iterative solvers for each linear
system with a fixed parameter, the method is particularly suitable for
situations when solutions to a large number of distinct parameters or a large
number of right hand sides are required. The method is also simple to
parallelize. We demonstrate the applicability of the method to the calculation
of the response functions in electronic structure theory. We demonstrate the
numerical performance of the method using a benzene molecule and a DNA
molecule.


title: A note on Sylvester-type equations

abstract:
  This work is to provide a comprehensive treatment of the relationship between
the theory of the generalized (palindromic) eigenvalue problem and the theory
of the Sylvester-type equations. Under a regularity assumption for a specific
matrix pencil, we show that the solution of the $\star$-Sylvester matrix
equation is uniquely determined and can be obtained by considering its
corresponding deflating subspace. We also propose an iterative method with
quadratic convergence to compute the stabilizing solution of the
$\star$-Sylvester matrix equation via the well-developed palindromic doubling
algorithm. We believe that our discussion is the first which implements the
tactic of the deflating subspace for solving Sylvester equations and could give
rise to the possibility of developing an advanced and effective solver for
different types of matrix equations.


title: New Limits on Coupled Dark Energy from Planck

abstract:
  Recently, the Planck collaboration has released the first cosmological papers
providing the high resolution, full sky, maps of the cosmic microwave
background (CMB) temperature anisotropies. It is crucial to understand that
whether the accelerating expansion of our universe at present is driven by an
unknown energy component (Dark Energy) or a modification to general relativity
(Modified Gravity). In this paper we study the coupled dark energy models, in
which the quintessence scalar field nontrivially couples to the cold dark
matter, with the strength parameter of interaction $beta$. Using the Planck
data alone, we obtain that the strength of interaction between dark sectors is
constrained as $beta < 0.102$ at $95%$ confidence level, which is tighter than
that from the WMAP9 data alone. Combining the Planck data with other probes,
like the Baryon Acoustic Oscillation (BAO), Type-Ia supernovae ``Union2.1
compilation'' and the CMB lensing data from Planck measurement, we find the
tight constraint on the strength of interaction $beta < 0.052$ ($95%$ C.L.).
Interestingly, we also find a non-zero coupling $beta = 0.078 pm 0.022$ ($68%$
C.L.) when we use the Planck, the ``SNLS'' supernovae samples, and the prior on
the Hubble constant from the Hubble Space Telescope (HST) together. This
evidence for the coupled dark energy models mainly comes from a tension between
constraints on the Hubble constant from the Planck measurement and the local
direct $H_0$ probes from HST.


title: Bhargava Integer Cubes and Weyl Group Multiple Dirichlet Series

abstract:
  We investigate the Shintani zeta functions associated to the prehomogeneous
spaces, the example under consideration is the set of $2 \times 2\times 2$
integer cubes. We show that there are three relative invariants under a certain
parabolic group action, they all have arithmetic nature and completely
determine the equivalence classes. We show that the associated Shintani zeta
function coincides with the $A_3$ Weyl group multiple Dirichlet series.
Finally, we show that the set of semi-stable integer orbits maps finitely and
surjectively to a certain moduli space.


title: Extremizers and Bellman function for martingale weak type inequality

abstract:
  We give an exact formula for the Bellman function of the weak type of
martingale transform. We also give the extremal functions (actually extremal
sequences of functions). We find them using the precise form of the Bellman
function. The extremal examples have a fractal nature as it often happens in
that kind of problems. This article is devoted to the unweighted weak type
estimate.


title:
Context-aware Dynamic Discovery and Configuration of 'Things' in Smart
  Environments

abstract:
  The Internet of Things (IoT) is a dynamic global information network
consisting of Internet-connected objects, such as RFIDs, sensors, actuators, as
well as other instruments and smart appliances that are becoming an integral
component of the future Internet. Currently, such Internet-connected objects or
`things' outnumber both people and computers connected to the Internet and
their population is expected to grow to 50 billion in the next 5 to 10 years.
To be able to develop IoT applications, such `things' must become dynamically
integrated into emerging information networks supported by architecturally
scalable and economically feasible Internet service delivery models, such as
cloud computing. Achieving such integration through discovery and configuration
of `things' is a challenging task. Towards this end, we propose a Context-Aware
Dynamic Discovery of {Things} (CADDOT) model. We have developed a tool
SmartLink, that is capable of discovering sensors deployed in a particular
location despite their heterogeneity. SmartLink helps to establish the direct
communication between sensor hardware and cloud-based IoT middleware platforms.
We address the challenge of heterogeneity using a plug in architecture. Our
prototype tool is developed on an Android platform. Further, we employ the
Global Sensor Network (GSN) as the IoT middleware for the proof of concept
validation. The significance of the proposed solution is validated using a
test-bed that comprises 52 Arduino-based Libelium sensors.


title: Novel magnetism of Ir5+ ions in the double perovskite Sr2YIrO6

abstract:
  We synthesize and study single crystals of a new double-perovskite Sr2YIrO6.
Despite two strongly unfavorable conditions for magnetic order, namely,
pentavalent Ir5+(5d4) ions which are anticipated to have Jeff=0 singlet ground
states in the strong spin-orbit coupling (SOC) limit, and geometric frustration
in a face centered cubic structure formed by the Ir5+ ions, we observe this
iridate to undergo a novel magnetic transition at temperatures below 1.3 K. We
provide compelling experimental and theoretical evidence that the origin of
magnetism is in an unusual interplay between strong non-cubic crystal fields
and intermediate-strength SOC. Sr2YIrO6 provides a rare example of the failed
dominance of SOC in the iridates.


title:
On the well-posedness and scattering for the Gross-Pitaevskii hierarchy
  via quantum de Finetti

abstract:
  We prove the existence of scattering states for the defocusing cubic
Gross-Pitaevskii (GP) hierarchy in ${\mathbb R}^3$. Moreover, we show that an
energy growth condition commonly used in the well-posedness theory of the GP
hierarchy is, in a specific sense, necessary. In fact, we prove that without
the latter, there exist initial data for the focusing cubic GP hierarchy for
which instantaneous blowup occurs.


title: A Structured Prediction Approach for Missing Value Imputation

abstract:
  Missing value imputation is an important practical problem. There is a large
body of work on it, but there does not exist any work that formulates the
problem in a structured output setting. Also, most applications have
constraints on the imputed data, for example on the distribution associated
with each variable. None of the existing imputation methods use these
constraints. In this paper we propose a structured output approach for missing
value imputation that also incorporates domain constraints. We focus on large
margin models, but it is easy to extend the ideas to probabilistic models. We
deal with the intractable inference step in learning via a piecewise training
technique that is simple, efficient, and effective. Comparison with existing
state-of-the-art and baseline imputation methods shows that our method gives
significantly improved performance on the Hamming loss measure.


title: The Complexity of Optimal Multidimensional Pricing

abstract:
  We resolve the complexity of revenue-optimal deterministic auctions in the
unit-demand single-buyer Bayesian setting, i.e., the optimal item pricing
problem, when the buyer's values for the items are independent. We show that
the problem of computing a revenue-optimal pricing can be solved in polynomial
time for distributions of support size 2, and its decision version is
NP-complete for distributions of support size 3. We also show that the problem
remains NP-complete for the case of identical distributions.


title: Large Margin Semi-supervised Structured Output Learning

abstract:
  In structured output learning, obtaining labelled data for real-world
applications is usually costly, while unlabelled examples are available in
abundance. Semi-supervised structured classification has been developed to
handle large amounts of unlabelled structured data. In this work, we consider
semi-supervised structural SVMs with domain constraints. The optimization
problem, which in general is not convex, contains the loss terms associated
with the labelled and unlabelled examples along with the domain constraints. We
propose a simple optimization approach, which alternates between solving a
supervised learning problem and a constraint matching problem. Solving the
constraint matching problem is difficult for structured prediction, and we
propose an efficient and effective hill-climbing method to solve it. The
alternating optimization is carried out within a deterministic annealing
framework, which helps in effective constraint matching, and avoiding local
minima which are not very useful. The algorithm is simple to implement and
achieves comparable generalization performance on benchmark datasets.


title:
A method for measuring the contact area in instrumented indentation
  testing by tip scanning probe microscopy imaging

abstract:
  The determination of the contact area is a key step to derive mechanical
properties such as hardness or an elastic modulus by instrumented indentation
testing. Two families of procedures are dedicated to extracting this area: on
the one hand, post mortem measurements that require residual imprint imaging,
and on the other hand, direct methods that only rely on the load vs. the
penetration depth curve. With the development of built-in scanning probe
microscopy imaging capabilities such as atomic force microscopy and indentation
tip scanning probe microscopy, last generation indentation devices have made
systematic residual imprint imaging much faster and more reliable. In this
paper, a new post mortem method is introduced and further compared to three
existing classical direct methods by means of a numerical and experimental
benchmark covering a large range of materials. It is shown that the new method
systematically leads to lower error levels regardless of the type of material.
Pros and cons of the new method vs. direct methods are also discussed,
demonstrating its efficiency in easily extracting mechanical properties with an
enhanced confidence.


title:
Coupling the Lorentz Integral Transform (LIT) and the Coupled Cluster
  (CC) Methods: A way towards continuum spectra of "not-so-few-body" systems

abstract:
  Here we summarize how the LIT and CC methods can be coupled, in order to
allow for ab initio calculations of reactions in medium mass nuclei. Results on
16O are reviewed and preliminary calculations on 40Ca are presented.


title: Predicting the chemical stability of monatomic chains

abstract:
  A simple model for evaluating the thermal atomic transfer rates in
nanosystems [EPL 94, 40002 (2011)] was developed to predict the chemical
reaction rates of nanosystems with small gas molecules. The accuracy of the
model was verified by MD simulations for molecular adsorption and desorption on
a monatomic chain. By the prediction, a monatomic carbon chain should survive
for 120 years in the ambient of 1 atm O2 at room temperature, and it is very
invulnerable to N2, H2O, NO2, CO and CO2, while a monatomic gold chain quickly
ruptures in vacuum. It is worth noting that since the model can be easily
applied via common ab initio calculations, it could be widely used in the
prediction of chemical stability of nanosystems.


title: A faster scaling in acceleration-sensitive atom interferometers

abstract:
  Atom interferometers have been used to measure acceleration with at best a
$T^2$ scaling in sensitivity as the interferometer time $T$ is increased. This
limits the sensitivity to acceleration which is theoretically achievable by
these configurations for a given frequency of acceleration. We predict and
experimentally measure the acceleration-sensitive phase shift of a
large-momentum-transfer atom interferometer based upon Bloch oscillations.
Using this novel interferometric scheme we demonstrate an improved scaling of
sensitivity which will scale as $T^3$. This enhanced scaling will allow an
increase in achievable sensitivity for any given frequency of an oscillatory
acceleration signal, which will be of particular use for inertial and
navigational sensors, and proposed gravitational wave detectors. A straight
forward extension should allow a $T^4$ scaling in acceleration sensitivity.


title: Single molecule capturer by doped monatomic carbon chain

abstract:
  The B-doped monatomic carbon chain has fine molecular capture ability to H2O
and especially to NO2, better than other doped monatomic carbon chains.At 300 K
and 1 atm, the capture probability of the B-doped monatomic carbon chain is
appreciable even in a NO2 concentration of 1 p.p.m., and the adsorbates'
influence on the quantum transport is notable for the detection. In contrast,
the pure monatomic carbon chain shows its invulnerability to N2, O2, H2O, NO2,
CO and CO2, and it is incapable for molecule capturing due to too low
adsorption ability and weak response on the quantum conductance. In the
investigation of these issues, a statistic mechanical model [EPL 94, 40002
(2011); Chin. Phys. Lett. 29, 2012 (080501)] was extended to predict the
adsorption and desorption rates of molecules on nanodevices. The theoretical
foundation of this model was further discussed and its accuracy was verified by
molecular dynamics simulations.


title:
Quantum tricriticality at the superfluid-insulator transition of binary
  Bose mixtures

abstract:
  Quantum criticality near a tricritical point (TCP) is studied in the
two-component Bose-Hubbard model on square lattices. The existence of quantum
TCP on a boundary of superfluid-insulator transition is confirmed by quantum
Monte Carlo simulations. Moreover, we analytically derive the quantum
tricritical behaviors on the basis of an effective field theory. We find two
significant features of the quantum tricriticality, that are the chemical
potential dependence of the superfluid transition temperature and a strong
density fluctuation. We suggest that these features are directly observable in
existing experimental setups of Bose-Bose mixtures in optical lattices.


title:
Coding based Data Broadcasting for Time Critical Applications with Rate
  Adaptation

abstract:
  In this paper, we dynamically select the transmission rate and design
wireless network coding to improve the quality of services such as delay for
time critical applications. In a network coded system, with low transmission
rate and hence longer transmission range, more packets may be encoded, which
increases the coding opportunity. However, low transmission rate may incur
extra transmission delay, which is intolerable for time critical applications.
We design a novel joint rate selection and wireless network coding (RSNC)
scheme with delay constraint, so as to maximize the total benefit (where we can
define the benefit based on the priority or importance of a packet for example)
of the packets that are successfully received at the destinations without
missing their deadlines. We prove that the proposed problem is NP-hard, and
propose a novel graph model to mathematically formulate the problem. For the
general case, we propose a transmission metric and design an efficient
algorithm to determine the transmission rate and coding strategy for each
transmission. For a special case when all delay constraints are the same, we
study the pairwise coding and present a polynomial time pairwise coding
algorithm that achieves an approximation ratio of 1 - 1/e to the optimal
pairwise coding solution, where e is the base of the natural logarithm.
Finally, simulation results demonstrate the superiority of the proposed RSNC
scheme.


title: Betweenness Centrality -- Incremental and Faster

abstract:
  We consider the incremental computation of the betweenness centrality of all
vertices in a large complex network modeled as a graph G = (V, E), directed or
undirected, with positive real edge-weights. The current widely used algorithm
to compute the betweenness centrality of all vertices in G is the Brandes
algorithm that runs in O(mn + n^2 log n) time, where n = |V| and m = |E|.
  We present an incremental algorithm that updates the betweenness centrality
score of all vertices in G when a new edge is added to G, or the weight of an
existing edge is reduced. Our incremental algorithm runs in O(m' n + n^2) time,
where m' is the size of a certain subset of E*, the set of edges in G that lie
on a shortest path. We achieve the same bound for the more general incremental
update of a vertex v, where the edge update can be performed on any subset of
edges incident to v.
  Our incremental algorithm is the first algorithm that is asymptotically
faster on sparse graphs than recomputing with the Brandes algorithm. Our
algorithm is also likely to be much faster than the Brandes algorithm on dense
graphs since m*, the size of E*, is often close to linear in n.
  Our incremental algorithm is very simple and the only data structures it uses
are arrays, lists, and stack. We give an efficient cache-oblivious
implementation that incurs O(scan(n^2) + n sort(m')) cache misses, where scan
and sort are well-known measures for efficient caching. We also give a static
algorithm for computing betweenness centrality of all vertices that runs in
time O(m* n + n^2 log n), which is faster than the Brandes algorithm on any
graph with n log n = o(m) and m* = o(m).


title: On the Axioms of Causal Set Theory

abstract:
  This paper offers suggested improvements to the causal sets program in
discrete gravity, which treats spacetime geometry as an emergent manifestation
of causal structure at the fundamental scale. This viewpoint, which I refer to
as the causal metric hypothesis, is summarized by Rafael Sorkin's phrase,
"order plus number equals geometry." Proposed improvements include recognition
of a generally nontransitive causal relation more fundamental than the causal
order, an improved local picture of causal structure, development and use of
relation space methods, and a new background-independent version of the
histories approach to quantum theory. Besides causal set theory, \`a la
Bombelli, Lee, Meyer, and Sorkin, this effort draws on Isham's topos-theoretic
framework for physics, Sorkin's quantum measure theory, Finkelstein's causal
nets, and Grothendieck's structural principles. This approach circumvents
undesirable structural features in causal set theory, such as the permeability
of maximal antichains, studied by Major, Rideout, and Surya, and the
configuration space pathology arising from the asymptotic enumeration of
Kleitman and Rothschild. The paper culminates in the theory of co-relative
histories and kinematic schemes, combining the causal metric hypothesis, the
histories approach to quantum theory, and Grothendieck's relative viewpoint.
This leads to the derivation of causal Schr\"odinger-type equations as
dynamical laws for discrete quantum spacetime.


title:
Crossover from Electromagnetically Induced Transparency to Autler-Townes
  Splitting in Open Ladder Systems with Doppler Broadening

abstract:
  We propose a general theoretical scheme to investigate the crossover from
electromagnetically induced transparency (EIT) to Autler-Townes splitting (ATS)
in open ladder-type atomic and molecular systems with Doppler broadening. We
show that when the wavenumber ratio $k_c/k_p\approx -1$, EIT, ATS, and EIT-ATS
crossover exist for both ladder-I and ladder-II systems, where $k_c$ ($k_p$) is
the wavenumber of control (probe) field. Furthermore, when $k_c/k_p$ is far
from $-1$ EIT can occur but ATS is destroyed if the upper state of the ladder-I
system is a Rydberg state. In addition, ATS exists but EIT is not possible if
the control field used to couple the two lower states of the ladder-II system
is a microwave field. The theoretical scheme developed here can be applied to
atoms, molecules, and other systems (including Na$_2$ molecules, and Rydberg
atoms), and the results obtained may have practical applications in optical
information processing and transformation.