title: Multifractality and long memory of a financial index

abstract:
  In this paper we will try to assess the multifractality displayed by the
high-frequency returns of Madrid's Stock Exchange IBEX35 index. A Multifractal
Detrended Fluctuation Analysis shows that this index has a wide singularity
spectrum which is most likely caused by its long memory. Our findings also show
that this long-memory can be considered as the superposition of a
high-frequency component (related to the daily cycles of arrival of information
to the market), over a slowly-varying component that reverberates for long
periods of time and which shows no apparent relation with human economic
cycles. This later component is therefore postulated to be endogenous to
market's dynamics and to be also the most probable source of some of the
stylized facts commonly associated with financial time series.


title:
A Three-Dimensional Model of Residential Energy Consumer Archetypes for
  Local Energy Policy Design in the UK

abstract:
  This paper reviews major studies in three traditional lines of research in
residential energy consumption in the UK, i.e. economic/infrastructure,
behaviour, and load profiling. Based on the review the paper proposes a
three-dimensional model for archetyping residential energy consumers in the UK
by considering property energy efficiency levels, the greenness of household
behaviour of using energy, and the duration of property daytime occupancy. With
the proposed model, eight archetypes of residential energy consumers in the UK
have been identified. They are: pioneer greens, follower greens, concerned
greens, home stayers, unconscientious wasters, regular wasters, daytime
wasters, and disengaged wasters. Using a case study, these archetypes of
residential energy consumers demonstrate the robustness of the 3-D model in
aiding local energy policy/intervention design in the UK.


title:
Thermodynamics of Charged Kalb Ramond AdS black hole in presence of
  Gauss-Bonnet coupling

abstract:
  We study the role of the Gauss-Bonnet corrections to the gravity action on
the charged AdS black hole in presence of rank 3 antisymmetric Kalb Ramond
tensor field strength. Analyzing the branch singularity and the killing
horizon, we explicitly derive various thermodynamic parameters and study their
behaviour in presence of five dimensional Gauss-Bonnet coupling in AdS
space-time. The possibility of a second order phase transition is explored in
the light of AdS/CMT correspondence and various critical exponents associated
with the discontinuities of the various thermodynamic parameters are
determined. We further comment on the universality of the well known Rushbrooke
Josephson scaling law and derive a relation between the degree of homogeneity
appearing in various free energies and the critical exponents by homogeneous
hypothesis test. By making use of the constraints appearing from Hawking
temperature and Gauss-Bonnet extended gravity version of Kubo formula we
introduce a bound on the five dimensional Gauss-Bonnet coupling and the
viscosity entropy ratio in the four dimensional holographic Conformal Field
Theory (CFT) dual. This yields a fractional deviation in viscosity entropy
ratio from the result obtained from Einstein gravity.

categories: hep-th cond-mat.stat-mech cond-mat.str-el gr-qc hep-ph


title: Graph Metrics for Temporal Networks

abstract:
  Temporal networks, i.e., networks in which the interactions among a set of
elementary units change over time, can be modelled in terms of time-varying
graphs, which are time-ordered sequences of graphs over a set of nodes. In such
graphs, the concepts of node adjacency and reachability crucially depend on the
exact temporal ordering of the links. Consequently, all the concepts and
metrics proposed and used for the characterisation of static complex networks
have to be redefined or appropriately extended to time-varying graphs, in order
to take into account the effects of time ordering on causality. In this chapter
we discuss how to represent temporal networks and we review the definitions of
walks, paths, connectedness and connected components valid for graphs in which
the links fluctuate over time. We then focus on temporal node-node distance,
and we discuss how to characterise link persistence and the temporal
small-world behaviour in this class of networks. Finally, we discuss the
extension of classic centrality measures, including closeness, betweenness and
spectral centrality, to the case of time-varying graphs, and we review the work
on temporal motifs analysis and the definition of modularity for temporal
graphs.


title:
Li-Yau and Harnack type inequalities in $RCD^*(K,N)$ metric measure
  spaces

abstract:
  Metric measure spaces satisfying the reduced curvature-dimension condition
$CD^*(K,N)$ and where the heat flow is linear are called $RCD^*(K,N)$-spaces.
This class of non smooth spaces contains Gromov-Hausdorff limits of Riemannian
manifolds with Ricci curvature bounded below by $K$ and dimension bounded above
by $N$. We prove that in $RCD^*(K,N)$-spaces the following properties of the
heat flow hold true: a Li-Yau type inequality, a Bakry-Qian inequality, the
Harnack inequality.


title: A universal set of qubit quantum channels

abstract:
  We investigate the set of quantum channels acting on a single qubit. We
provide an alternative, compact generalization of the Fujiwara-Algoet
conditions for complete positivity to non-unital qubit channels, which we then
use to characterize the possible geometric forms of the pure output of the
channel. We provide universal sets of quantum channels for all unital qubit
channels as well as for all extremal (not necessarily unital) qubit channels,
in the sense that all qubit channels in these sets can be obtained by
concatenation of channels in the corresponding universal set. We also show that
our universal sets are essentially minimal.


title:
Euler constant as a renormalized value of Riemann zeta function at its
  pole. Rationals related to Dirichlet L-functions

abstract:
  We believe that Euler constant is not just the "renormalized" value of the
Riemann zeta function in 1. In a sense that we shall clarify it is in fact the
normal and natural value of zeta of 1. In this paper we first propose a limit
definition of a function whose values coincide everywhere with those of the
Riemann zeta function, save in 1, where our limit definition yields the Euler
constant. Since in the literature one can find more than one way to regularize
the value of the zeta function at s=1, we give asymptotic expansions where, by
dint of some extended analogies, Euler constant appears to be the true
"renormalized" value. As a striking example of such analogies, we propose an
expansion of the logarithm function based on Euler constant and on all values
of the zeta function at odd positive integers, in which all these presumably
irrational numbers are accompanied by Harmonic numbers of corresponding orders.
The other aim of this paper is to show how sequences of rationals, often the
same, arise in computations related to Dirichlet L-functions. Here, a
connection with the Liouville lambda function appears to have been found. Thus
we raise the question about the possible usefulness of an extension of the
Liouville lambda function to rationals. .


title:
One Time Pad Password Protection: Using T.E.C. Steganography and Secure
  Password Transmission Protocols

abstract:
  A while ago, I developed what I called an encryption method. The most
favorable of reviews did not see a method but a collection of techniques. Be
that as it may, the process used, is described in the paper, Windtalking
Computers. This paper is about the steganographic method described, the
cryptanalysis efforts of that method and; a real world application of that
method as an answer to the increasing problem of password file hacking. The
premise is that the technique is a variant of one time pad, using a novel way
to produce one time pad output for digital input. There is no record in the
literature of such a method being used for encryption at all. Digital
encryption generally treats the letters of the plaintext as a binary number and
does some mathematical computation to produce ciphertext. The idea of inserting
bits with a random generated key is new. Therefore (because a uniquely random
generated key is used), the encryption is cryptanalytically unbreakable and/or
computationally secure and/or information theoretic. An academic version was
made. Challenges for decryption have not produced to-date a decryption.
Advantages and disadvantages of the method are discussed.
  Hackers are constantly penetrating networks and stealing password files.
Which, once in possession of a password file, hackers individually or
collectively with distributed processing over the Internet, decrypt the values
of the hash passwords. Thereby gaining access to systems. This problem has
become sufficiently significant for CAESAR (Competition for Authenticated
Encryption: Security, Applicability, and Robustness) to make calls for papers
for solutions. Herein is one proposed solution. While one time pad presents a
problem being computationally intensive, for the relatively short length of
passwords, the cost of computation may be cost effective for the security
provided.


title:
Syndrome Measurement Order for the [[7,1,3]] Quantum Error Correction
  Code

abstract:
  In this work we explore the accuracy of quantum error correction depending of
the order of the implemented syndrome measurements. CSS codes require bit-flip
and phase flip-syndromes be measured separately. To comply with fault tolerant
demands and to maximize accuracy this set of syndrome measurements should be
repeated allowing for flexibility in the order of their implementation. We
examine different possible orders of Shor state and Steane state syndrome
measurements for the [[7,1,3]] quantum error correction code. We find that the
best choice of syndrome order, determined by the fidelity of the state after
noisy error correction, will depend on the error environment. We also compare
the fidelity when syndrome measurements are done with Shor states versus Steane
states and find that Steane states generally, but not always, lead to final
states with higher fidelity. Together, these results allow a quantum computer
programmer to choose the optimal syndrome measurement scheme based on the
system's error environment.


title: Generalized Browder's and Weyl's Theorems for Generalized Derivations

abstract:
  Given Banach spaces $\X$ and $\Y$ and Banach space operators $A\in L(\X)$ and
$B\in L(\Y)$, let $\rho\colon L(\Y,\X)\to L(\Y,\X)$ denote the generalized
derivation defined by $A$ and $B$, i.e., $\rho (U)=AU-UB$ ($U\in L(\Y,\X)$).
The main objective of this article is to study Weyl and Browder type theorems
for $\rho\in L(L(\Y,\X))$. To this end, however, first the isolated points of
the spectrum and the Drazin spectrum of $\rho\in L(L(\Y,\X))$ need to be
characterized. In addition, it will be also proved that if $A$ and $B$ are
polaroid (respectively isoloid), then $\rho$ is polaroid (respectively
isoloid).


title: Viscous {\Lambda}CDM Universe Models

abstract:
  We explore flat {\Lambda}CDM models with bulk viscosity, and study the role
of the bulk viscosity in the evolution of these universe models. The dynamical
equations for these models are obtained and solved for some cases of bulk
viscosity. We obtain differential equations for the Hubble parameter H and the
energy density of dark matter {\rho}, for which we give analytical solutions
for some cases and for the general case we give a numerical solution. Also we
calculate the statefinder parameters for this model and display them in the
s-r-plane.


title: Bianchi Type-I Universe Models with Nonlinear Viscosity

abstract:
  In this paper we study the evolution of spatially homogeneous and anisotropic
Bianchi type-I Universe models with the cosmological constant, \Lambda, and
filled with nonlinear viscous fluid. The dynamical equations for these models
are obtained and solved for some special cases. We calculate the statefinder
parameters for the models and display them in the s-r-plane.


title:
Learning-Based Adaptive Transmission for Limited Feedback Multiuser
  MIMO-OFDM

abstract:
  Performing link adaptation in a multiantenna and multiuser system is
challenging because of the coupling between precoding, user selection, spatial
mode selection and use of limited feedback about the channel. The problem is
exacerbated by the difficulty of selecting the proper modulation and coding
scheme when using orthogonal frequency division multiplexing (OFDM). This paper
presents a data-driven approach to link adaptation for multiuser multiple input
mulitple output (MIMO) OFDM systems. A machine learning classifier is used to
select the modulation and coding scheme, taking as input the SNR values in the
different subcarriers and spatial streams. A new approximation is developed to
estimate the unknown interuser interference due to the use of limited feedback.
This approximation allows to obtain SNR information at the transmitter with a
minimum communication overhead. A greedy algorithm is used to perform spatial
mode and user selection with affordable complexity, without resorting to an
exhaustive search. The proposed adaptation is studied in the context of the
IEEE 802.11ac standard, and is shown to schedule users and adjust the
transmission parameters to the channel conditions as well as to the rate of the
feedback channel.


title:
Bonds, bands, and bandgaps in tetrahedrally bonded ternary compounds:
  the role of group V Lone Pairs

abstract:
  An interesting class of tetrahedrally coordinated ternary compounds have
attracted considerable interest because of their potential as good
thermoelectrics. These compounds, denoted as I$_3$-V-VI$_4$, contain three
monovalent-I (Cu, Ag), one nominally pentavalent-V (P, As, Sb, Bi), and four
hexavalent-VI (S, Se, Te) atoms; and can be visualized as ternary derivatives
of the II-VI zincblende or wurtzite semiconductors, obtained by starting from
four unit cells of (II-VI) and replacing four type II atoms by three type I and
one type V atoms. In trying to understand their electronic structures and
transport properties, some fundamental questions arise: whether V atoms are
indeed pentavalent and if not how do these compounds become semiconductors,
what is the role of V lone pair electrons in the origin of band gaps, and what
are the general characteristics of states near the valence band maxima and the
conduction band minima. We answer some of these questions using ab initio
calculations (density functional methods with both local and nonlocal
exchange-correlation potential).


title: Position Operators and Center of Mass: New Perspectives

abstract:
  After reviewing the work of Pryce on Center-of-Mass (CoM) definitions in
special relativity, and that of Jordan and Mukunda on position operators for
relativistic particles with spin, we propose two new criteria for a CoM
candidate: associativity, and compatibility with the Poisson bracket structure.
We find that they are not satisfied by all of Pryce's definitions, and they
also rule out Dixon's CoM generalization to the curved spacetime case. We also
emphasize that the various components of the CoM position do not commute among
themselves, in the general case, and thus provide a natural entry point to the
arena of noncommutative spacetime, without the ad-hoc assumptions of the
standard paradigm.


title:
Diagnosing Heterogeneous Dynamics in Single Molecule/Particle
  Trajectories with Multiscale Wavelets

abstract:
  We describe a simple automated method to extract and quantify transient
heterogeneous dynamical changes from large datasets generated in single
molecule/particle tracking experiments. Based on wavelet transform, the method
transforms raw data to locally match dynamics of interest. This is accomplished
using statistically adaptive universal thresholding, whose advantage is to
avoid a single arbitrary threshold that might conceal individual variability
across populations. How to implement this multiscale method is described,
focusing on local confined diffusion separated by transient transport periods
or hopping events, with 3 specific examples: in cell biology, biotechnology,
and glassy colloid dynamics. This computationally-efficient method can run
routinely on hundreds of millions of data points analyzed within an hour on a
desktop personal computer.


title: Measuring contact angle and meniscus shape with a reflected laser beam

abstract:
  Side-view imaging of the contact angle between an extended planar solid
surface and a liquid is problematic. Even when aligning the view perfectly
parallel to the contact line, focusing one point of the contact line is not
possible. We describe a new measurement technique for determining contact
angles with the reflection of a widened laser sheet on a moving contact line.
We verified this new technique measuring the contact angle on a cylinder,
rotating partially immersed in a liquid. A laser sheet is inclined under an
angle $\varphi$ to the unperturbed liquid surface and is reflected off the
meniscus. Collected on a screen, the reflection image contains information to
determine the contact angle. When dividing the laser sheet into an array of
laser rays by placing a mesh into the beam path, the shape of the meniscus can
be reconstructed from the reflection image. We verified the method by measuring
the receding contact angle versus speed for aqueous cetyltrimethyl ammonium
bromide solutions on a smooth hydrophobized as well as on a rough polystyrene
surface.


title:
Submillimeter ALMA Observations of the Dense Gas in the Low-Luminosity
  Type-1 Active Nucleus of NGC 1097

abstract:
  We present the first 100 pc scale view of the dense molecular gas in the
central ~ 1.3 kpc region of the type-1 Seyfert NGC 1097 traced by HCN (J=4-3)
and HCO+ (J=4-3) lines afforded with ALMA band 7. This galaxy shows significant
HCN enhancement with respect to HCO+ and CO in the low-J transitions, which
seems to be a common characteristic in AGN environments. Using the ALMA data,
we study the characteristics of the dense gas around this AGN and search for
the mechanism of HCN enhancement. We find a high HCN (J=4-3) to HCO+ (J=4-3)
line ratio in the nucleus. The upper limit of the brightness temperature ratio
of HCN (v2=1^{1f}, J=4-3) to HCN (J=4-3) is 0.08, which indicates that IR
pumping does not significantly affect the pure rotational population in this
nucleus. We also find a higher HCN (J=4-3) to CS (J=7-6) line ratio in NGC 1097
than in starburst galaxies, which is more than 12.7 on the brightness
temperature scale. Combined from similar observations from other galaxies, we
tentatively suggest that this ratio appears to be higher in AGN-host galaxies
than in pure starburst ones similar to the widely used HCN to HCO+ ratio. LTE
and non-LTE modeling of the observed HCN and HCO+ lines using J=4-3 and 1-0
data from ALMA, and J=3-2 data from SMA, reveals a high HCN to HCO+ abundance
ratio (5 < [HCN]/[HCO+] < 20: non-LTE analysis) in the nucleus, and that the
high-J lines (J=4-3 and 3-2) are emitted from dense (10^{4.5} < n_H2 [/cc] <
10^6), hot (70 < Tkin [K] < 550) regions. Finally we propose that the high
temperature chemistry is more plausible to explain the observed enhanced HCN
emission in NGC 1097 than the pure gas phase PDR/XDR chemistry.


title:
Witnessing negativity of Wigner function by estimating fidelities of
  cat-like states from homodyne measurements

abstract:
  We derive sampling functions for estimation of quantum state fidelity with
Schr\"odinger cat-like states, which are defined as superpositions of two
coherent states with opposite amplitudes. We also provide sampling functions
for fidelity with squeezed Fock states that can approximate the cat-like states
and can be generated from Gaussian squeezed states by conditional photon
subtraction. The fidelities can be determined by averaging the sampling
functions over quadrature statistics measured by homodyne detection. The
sampling functions are designed such that they can compensate for losses and
inefficient homodyning provided that the overall efficiency exceeds certain
threshold. The fidelity with an odd coherent state and the fidelity with a
squeezed odd Fock state provide convenient witnesses of negativity of Wigner
function of the measured state. The negativity of Wigner function at the origin
of phase space is certified if any of these fidelities exceeds 0.5. Finally, we
discuss the possibility of reducing the statistical uncertainty of the fidelity
estimates by a suitable choice of the dependence of the number of quadrature
samples on the relative phase shift between local oscillator and signal beam.


title:
Closed form solution for the surface area, the capacitance and the
  demagnetizing factors of the ellipsoid

abstract:
  We derive the closed form solutions for the surface area, the capacitance and
the demagnetizing factors of the ellipsoid immersed in the Euclidean space R^3.
The exact solutions for the above geometrical and physical properties of the
ellipsoid are expressed elegantly in terms of the generalized hypergeometric
functions of Appell of two variables. Various limiting cases of the theorems of
the exact solution for the surface area, the demagnetizing factors and the
capacitance of the ellipsoid are derived, which agree with known solutions for
the prolate and oblate spheroids and the sphere. Possible applications of the
results achieved, in various fields of science, such as in physics, biology and
space science are briefly discussed.


title: Embedding Quantum Simulators for Quantum Computation of Entanglement

abstract:
  We introduce the concept of embedding quantum simulators, a paradigm allowing
the efficient quantum computation of a class of bipartite and multipartite
entanglement monotones. It consists in the suitable encoding of a simulated
quantum dynamics in the enlarged Hilbert space of an embedding quantum
simulator. In this manner, entanglement monotones are conveniently mapped onto
physical observables, overcoming the necessity of full tomography and reducing
drastically the experimental requirements. Furthermore, this method is directly
applicable to pure states and, assisted by classical algorithms, to the
mixed-state case. Finally, we expect that the proposed embedding framework
paves the way for a general theory of enhanced one-to-one quantum simulators.

categories: quant-ph cond-mat.mes-hall cond-mat.quant-gas cond-mat.supr-con


title: Bounded prime gaps in short intervals

abstract:
  We generalise Zhang's and Pintz recent results on bounded prime gaps to give
a lower bound for the the number of prime pairs bounded by 6*10^7 in the short
interval $[x,x+x (\log x)^{-A}]$. Our result follows only by analysing Zhang's
proof of Theorem 1, but we also explain how a sharper variant of Zhang's
Theorem 2 would imply the same result for shorter intervals.


title:
Kepler Eclipsing Binary Stars. IV. Precise Eclipse Times for Close
  Binaries and Identification of Candidate Three-Body Systems

abstract:
  We present a catalog of precise eclipse times and analysis of third body
signals among 1279 close binaries in the latest Kepler Eclipsing Binary
Catalog. For these short period binaries, Kepler's 30 minute exposure time
causes significant smearing of light curves. In addition, common astrophysical
phenomena such as chromospheric activity, as well as imperfections in the light
curve detrending process, can create systematic artifacts that may produce
fictitious signals in the eclipse timings. We present a method to measure
precise eclipse times in the presence of distorted light curves, such as in
contact and near-contact binaries which exhibit continuously changing light
levels in and out of eclipse. 236 systems for which we find a timing variation
signal compatible with the presence of a third body are identified. These are
modeled for the light time travel effect and the basic properties of the third
body are derived. This study complements Orosz et al. (2013; in prep), which
focuses on eclipse timing variations of longer period binaries with flat
out-of-eclipse regions. Together, these two papers provide comprehensive
eclipse timings for all binaries in the Kepler Eclipsing Binary Catalog, as an
ongoing resource freely accessible online to the community.


title:
Dy-V magnetic interaction and local structure bias on the complex spin
  and orbital ordering in Dy$_{1-x}$Tb$_{x}$VO$_3$ (x\,=\,0 and 0.2)

abstract:
  The spin and orbital ordering in Dy$_{1-x}$Tb$_{x}$VO$_3$ (x\,=\,0 and 0.2)
was studied by measuring x-ray powder diffraction, magnetization, specific
heat, and neutron single crystal diffraction. The results show that G-OO/C-AF
and C-OO/G-AF phases coexist in Dy$_{0.8}$Tb$_{0.20}$VO$_3$ in the temperature
range 2\,K$\sim$60\,K and the volume fraction of each phase is temperature and
field dependent. The ordering of Dy moments at T*\,=\,12\,K induces a
transition from G-OO/C-AF to a C-OO/G-AF phase. Magnetic fields suppress the
long range order of Dy moments and thus the C-OO/G-AF phase below T*. The
polarized moments induced at the Dy sublattice by external magnetic fields
couple to the V 3d moments and this coupling favors the G-OO/C-AF state. Also
discussed is the effect of the Dy-V magnetic interaction and local structure
distortion on the spin and orbital ordering in Dy$_{1-x}$Tb$_{x}$VO$_3$.


title:
Riemannian metrics for neural networks II: recurrent networks and
  learning symbolic data sequences

abstract:
  Recurrent neural networks are powerful models for sequential data, able to
represent complex dependencies in the sequence that simpler models such as
hidden Markov models cannot handle. Yet they are notoriously hard to train.
Here we introduce a training procedure using a gradient ascent in a Riemannian
metric: this produces an algorithm independent from design choices such as the
encoding of parameters and unit activities. This metric gradient ascent is
designed to have an algorithmic cost close to backpropagation through time for
sparsely connected networks. We use this procedure on gated leaky neural
networks (GLNNs), a variant of recurrent neural networks with an architecture
inspired by finite automata and an evolution equation inspired by
continuous-time networks. GLNNs trained with a Riemannian gradient are
demonstrated to effectively capture a variety of structures in synthetic
problems: basic block nesting as in context-free grammars (an important feature
of natural languages, but difficult to learn), intersections of multiple
independent Markov-type relations, or long-distance relationships such as the
distant-XOR problem. This method does not require adjusting the network
structure or initial parameters: the network used is a sparse random graph and
the initialization is identical for all problems considered.


title: Passing through the Firewall

abstract:
  We propose that black hole information is encoded in non-local correlations
between microscopic interior and exterior degrees of freedom. We give a simple
qubit representation of this proposal, and show herein that for every black
hole state, the apparent firewall can be removed via a universal, state
independent unitary transformation. A central element in our discussion is the
distinction between virtual qubits, which are in a specified vacuum state, and
real qubits, that carry the free quantum information of the black hole. We
outline how our proposal may be realized in AdS/CFT


title: Black Hole Information as Topological Qubits

abstract:
  The principle of balanced holography, introduced in [1], posits that black
hole information is stored in non-local correlations between the interior and
exterior. Based on this concept, we propose that black hole information
decomposes into elementary units in the form of topological qubits, and is
protected from local sources of decoherence. The topological protection
mechanism ensures that the horizon of an evaporating black hole stays young and
smooth.


title:
Exact risk improvement of bandwidth selectors for kernel density
  estimation with directional data

abstract:
  New bandwidth selectors for kernel density estimation with directional data
are presented in this work. These selectors are based on asymptotic and exact
error expressions for the kernel density estimator combined with mixtures of
von Mises distributions. The performance of the proposed selectors is
investigated in a simulation study and compared with other existing rules for a
large variety of directional scenarios, sample sizes and dimensions. The
selector based on the exact error expression turns out to have the best
behaviour of the studied selectors for almost all the situations. This selector
is illustrated with real data for the circular and spherical cases.


title: The Casimir effect in a topologically closed Minkowski spacetime

abstract:
  Results concerning the Casimir effect in a topologically closed Minkowski
spacetime.


title: Random Walks on Multiplex Networks

abstract:
  Multiplex networks are receiving increasing interests because they allow to
model relationships between networked agents on several layers simultaneously.
In this supplementary material for the paper "Navigability of interconnected
networks under random failures", we extend well-known random walks to
multiplexes and we introduce a new type of walk that can exist only in
multiplexes. We derive exact expressions for vertex occupation time and the
coverage. Finally, we show how the efficiency in exploring the multiplex
critically depends on the underlying topology of layers, the weight of their
inter-connections and the strategy adopted to walk.


title: On coordinatization of mathematics

abstract:
  The problem of advancing coordinatization of mathematics is considered. The
need to develop a theory for measuring value and complexity of mathematical
implications and proofs is discussed including motivations, benefits and
implementation problems. Examples of mathematical considerations for such a
theory are given. Arguments supporting such an advance related to applications
in mathematical research guidance, publication standards and education are
given.


title:
Scaling between magnetic and lattice fluctuations in iron-pnictide
  superconductors

abstract:
  The phase diagram of the iron arsenides is dominated by a magnetic and a
structural phase transition, which need to be suppressed in order for
superconductivity to appear. The proximity between the two transition
temperature lines indicates correlation between these two phases, whose nature
remains unsettled. Here, we find a scaling relation between nuclear magnetic
resonance (NMR) and shear modulus data in the tetragonal phase of
electron-doped $\mathrm{Ba(Fe_{1-x}Co_{x})_{2}As_{2}}$ compounds. Because the
former probes the strength of magnetic fluctuations while the latter is
sensitive to orthorhombic fluctuations, our results provide strong evidence for
a magnetically-driven structural transition.


title: Spin flip of electron in static electric fields

abstract:
  The effects on the spin state of an electron in a time independent electric
field are examined. The probability of spin flipping is calculated, and other
effects are studied using the minimally coupled Dirac equation.


title: A new method for imaging nuclear threats using cosmic ray muons

abstract:
  Muon tomography is a technique that uses cosmic ray muons to generate three
dimensional images of volumes using information contained in the Coulomb
scattering of the muons. Advantages of this technique are the ability of cosmic
rays to penetrate significant overburden and the absence of any additional dose
delivered to subjects under study above the natural cosmic ray flux.
Disadvantages include the relatively long exposure times and poor position
resolution and complex algorithms needed for reconstruction. Here we
demonstrate a new method for obtaining improved position resolution and
statistical precision for objects with spherical symmetry.


title: Special Partial Graphs

abstract:
  The attempts to prove the Four Color Problem last for long years. A little
hope arises that the properties of the minimal partial triangulations will be
very useful for the solution of the Four Color Problem. That is why the
material of this paper is devoted to the examination of the specific partial
graphs and their properties. Such graphs will have all the elements of the
planar triangulation, but will have the minimal size. And it will be quite
interesting to found out their properties in order to search in the sequel for
the possibility to prove the Four Color Problem on the base of their
characteristics.


title: Entanglement in joint $\Lambda \bar{\Lambda}$ decay

abstract:
  We investigate the joint $\Lambda \bar{\Lambda}$ decay in the reaction $e^+
e^- \rightarrow \gamma \Lambda(\rightarrow p\pi^-) \bar{\Lambda}(\rightarrow
\bar{p}\pi^+)$. This reaction may provide information on the electromagnetic
form factors of the Lambda baryon, in the time-like region. We present a
conventional diagram-based calculation where production and decay steps are
coherent and summations over final-state proton and anti-proton spins are
performed. The resulting cross-section distribution is explictly covariant as
it is expressed in scalar products of the four-momentum vectors of the
participating particles. We compare this calculation with that of the folding
method which we extend and make explicitly covariant. In the folding method
production and decay distributions, not amplitudes, are folded together. Of
particular importance is then a correct counting of the number of possible
intermediate-hyperon-spin states.


title:
Modulation of localized solutions for the Schr\"odinger equation with
  logarithm nonlinearity

abstract:
  We investigate the presence of localized analytical solutions of the
Schr\"odinger equation with logarithm nonlinearity. After including
inhomogeneities in the linear and nonlinear coefficients, we use similarity
transformation to convert the nonautonomous nonlinear equation into an
autonomous one, which we solve analytically. In particular, we study stability
of the analytical solutions numerically.


title: Quantum Field Theory on Curved Backgrounds -- A Primer

abstract:
  Goal of this review is to introduce the algebraic approach to quantum field
theory on curved backgrounds. Based on a set of axioms, first written down by
Haag and Kastler, this method consists of a two-step procedure. In the first
one, a suitable algebra of observables is assigned to a physical system, which
is meant to encode all algebraic relations among observables, such as
commutation relations, while, in the second step, one must select an algebraic
state in order to recover the standard Hilbert space interpretation of a
quantum system. As quantum field theories possess infinitely many degrees of
freedom, many unitarily inequivalent Hilbert space representations exist and
the power of such approach is the ability to treat them all in a coherent
manner. We will discuss in detail the algebraic approach for free fields in
order to give to the reader all necessary information to deal with the recent
literature, which focuses on the applications to specific problems, mostly in
cosmology.


title:
The Hamiltonian structure of a coupled system derived from a
  supersymmetric breaking of Super KdV equations

abstract:
  A supersymmetric breaking procedure for $N=1$ Super KdV, using a Clifford
algebra, is implemented. Dirac's method for the determination of constraints is
used to obtain the Hamiltonian structure, via a Lagrangian, for the resulting
solitonic system of coupled Korteweg-de Vries type system. It is shown that the
Hamiltonian obtained by this procedure is bounded from below and in that sense
represents a model which is physically admissible.


title: Adapted pairs in type $A$ and regular nilpotent elements

abstract:
  Let $\mathfrak g$ be a simple Lie algebra over an algebraically closed field
$\bf k$ of characteristic zero and $\bf G$ its adjoint group. Let $\mathfrak q$
be a biparabolic subalgebra of $\mathfrak g$. The algebra $Sy(\mathfrak q)$ of
semi-invariants on $\mathfrak q^*$ is polynomial in most cases, in particular
when $\mathfrak g$ is simple of type $A$ or $C$. On the other hand $\mathfrak
q$ admits a canonical truncation $\mathfrak q_{\Lambda}$ such that
$Sy(\mathfrak q)=Sy(\mathfrak q_{\Lambda})=Y(\mathfrak q_{\Lambda})$ where
$Y(\mathfrak q_{\Lambda})$ denotes the algebra of invariant functions on
$\mathfrak q_{\Lambda}^*$. An adapted pair for $\mathfrak q_{\Lambda}$ is a
pair $(h,\,\eta)\in \mathfrak q_{\Lambda}\times\mathfrak q_{\Lambda}^*$ such
that $\eta$ is regular and $(ad\,h)\eta=-\eta$. In a previous paper of A.
Joseph (2008) adapted pairs for every truncated biparabolic subalgebra
$\mathfrak q_{\Lambda}$ of a simple Lie algebra $\mathfrak g$ of type $A$ were
constructed and then provide Weierstrass sections for $Y(\mathfrak
q_{\Lambda})$ in $\mathfrak q_{\Lambda}^*$. These latter are linear
subvarieties $\eta+V$ of $\mathfrak q_{\Lambda}^*$ such that the restriction
map induces an algebra isomorphism of $Y(\mathfrak q_{\Lambda})$ onto the
algebra of regular functions on $\eta+V$. Here we show that for each of the
adapted pairs $(h,\,\eta)$ constructed in the paper mentioned above one can
express $\eta$ as the image of a regular nilpotent element $y$ of $\mathfrak
g^*$ under the restriction to $\mathfrak q$. Since $y$ must be a $\bf G$
translate of the standard regular nilpotent element defined in terms of the
already chosen set $\pi$ of simple roots, one may attach to $y$ a unique
element of the Weyl group. Ultimately one can then hope to be able to describe
adapted pairs (in general) through the Weyl group.


title:
Hybrid Coding: An Interface for Joint Source-Channel Coding and Network
  Communication

abstract:
  A new approach to joint source-channel coding is presented in the context of
communicating correlated sources over multiple access channels. Similar to the
separation architecture, the joint source-channel coding system architecture in
this approach is modular, whereby the source encoding and channel decoding
operations are decoupled. However, unlike the separation architecture, the same
codeword is used for both source coding and channel coding, which allows the
resulting hybrid coding scheme to achieve the performance of the best known
joint source-channel coding schemes. Applications of the proposed architecture
to relay communication are also discussed.


title: The number of rank-$k$ flats in a matroid with no $U_{2,n}$-minor

abstract:
  We show that, if $k$ and $\ell$ are positive integers and $r$ is sufficiently
large, then the number of rank-$k$ flats in a rank-$r$ matroid $M$ with no
$U_{2,\ell+2}$-minor is less than or equal to number of rank-$k$ flats in a
rank-$r$ projective geometry over GF$(q)$, where $q$ is the largest prime power
not exceeding $\ell$.


title:
Fast Sweeping Methods for Hyperbolic Systems of Conservation Laws at
  Steady State

abstract:
  Fast sweeping methods have become a useful tool for computing the solutions
of static Hamilton-Jacobi equations. By adapting the main idea behind these
methods, we describe a new approach for computing steady state solutions to
systems of conservation laws. By exploiting the flow of information along
characteristics, these fast sweeping methods can compute solutions very
efficiently. Furthermore, the methods capture shocks sharply by directly
imposing the Rankine-Hugoniot shock conditions. We present convergence analysis
and numerics for several one- and two-dimensional examples to illustrate the
use and advantages of this approach.


title: Cool horizons for entangled black holes

abstract:
  General relativity contains solutions in which two distant black holes are
connected through the interior via a wormhole, or Einstein-Rosen bridge. These
solutions can be interpreted as maximally entangled states of two black holes
that form a complex EPR pair. We suggest that similar bridges might be present
for more general entangled states.
  In the case of entangled black holes one can formulate versions of the
AMPS(S) paradoxes and resolve them. This suggests possible resolutions of the
firewall paradoxes for more general situations.


title:
Using Cross-Correlations to Calibrate Lensing Source Redshift
  Distributions: Improving Cosmological Constraints from Upcoming Weak Lensing
  Surveys

abstract:
  Cross-correlations between the galaxy number density in a lensing source
sample and that in an overlapping spectroscopic sample can in principle be used
to calibrate the lensing source redshift distribution. In this paper, we study
in detail to what extent this cross-correlation method can mitigate loss of
cosmological information in upcoming weak lensing surveys (combined with a CMB
prior) due to lack of knowledge of the source distribution. We consider a
scenario where photometric redshifts are available, and find that, unless the
photometric redshift distribution p(z_{ph}|z) is calibrated very accurately a
priori (bias and scatter known to ~0.002 for, e.g., EUCLID), the additional
constraint on p(z_{ph}|z) from the cross correlation technique to a large
extent restores the cosmological information originally lost due to the
uncertainty in dn/dz(z). Considering only the gain in photo-z accuracy and not
the additional cosmological information, enhancements of the dark energy figure
of merit of up to a factor of 4 (40) can be achieved for a SuMIRe (Subaru
Measurement of Images and Redshifts, the combination of the Hyper Suprime Cam
lensing survey and the Prime Focus Spectrograph redshift survey)-like
(EUCLID-like) combination of lensing and redshift surveys. However, the success
of the method is strongly sensitive to our knowledge of the galaxy bias
evolution in the source sample. If this bias is modeled by a free parameter in
each of a large number of redshift bins, we find that a prior of order 0.01 is
needed on b_i \sqrt{\Delta z} in each redshift slice (where \Delta z is the bin
width and b_i the value of the galaxy bias in the i-th source bin) to optimize
the gains from the cross-correlation method (i.e. to approach the cosmology
constraints attainable if the bias were known exactly).[abridged]


title: D-branes and $K$-homology

abstract:
  In this thesis the close relationship between the topological $K$-homology
group of the spacetime manifold $X$ of string theory and D-branes in string
theory is examined. An element of the $K$-homology group is given by an
equivalence class of $K$-cycles $[M,E,\phi]$, where $M$ is a closed spin$^c$
manifold, $E$ is a complex vector bundle over $M$, and $\phi: M\rightarrow X$
is a continuous map. It is proposed that a $K$-cycle $[M,E,\phi]$ represents a
D-brane configuration wrapping the subspace $\phi(M)$. As a consequence, the
$K$-homology element defined by $[M,E,\phi]$ represents a class of D-brane
configurations that have the same physical charge. Furthermore, the $K$-cycle
representation of D-branes resembles the modern way of characterizing
fundamental strings, in which the strings are represented as two-dimensional
surfaces with maps into the spacetime manifold. This classification of D-branes
also suggests the possibility of physically interpreting D-branes wrapping
singular subspaces of spacetime, enlarging the known types of singularities
that string theory can cope with.


title: An extended finite element method with smooth nodal stress

abstract:
  The enrichment formulation of double-interpolation finite element method
(DFEM) is developed in this paper. DFEM is first proposed by Zheng \emph{et al}
(2011) and it requires two stages of interpolation to construct the trial
function. The first stage of interpolation is the same as the standard finite
element interpolation. Then the interpolation is reproduced by an additional
procedure using the nodal values and nodal gradients which are derived from the
first stage as interpolants. The re-constructed trial functions are now able to
produce continuous nodal gradients, smooth nodal stress without post-processing
and higher order basis without increasing the total degrees of freedom. Several
benchmark numerical examples are performed to investigate accuracy and
efficiency of DFEM and enriched DFEM. When compared with standard FEM,
super-convergence rate and better accuracy are obtained by DFEM. For the
numerical simulation of crack propagation, better accuracy is obtained in the
evaluation of displacement norm, energy norm and the stress intensity factor.


title: Variations on a theorem of Davenport concerning abundant numbers

abstract:
  Let \sigma(n) = \sum_{d \mid n}d be the usual sum-of-divisors function. In
1933, Davenport showed that that n/\sigma(n) possesses a continuous
distribution function. In other words, the limit D(u):= \lim_{x\to\infty}
\frac{1}{x}\sum_{n \leq x,~n/\sigma(n) \leq u} 1 exists for all u \in [0,1] and
varies continuously with u. We study the behavior of the sums \sum_{n \leq
x,~n/\sigma(n) \leq u} f(n) for certain complex-valued multiplicative functions
f. Our results cover many of the more frequently encountered functions,
including \varphi(n), \tau(n), and \mu(n). They also apply to the
representation function for sums of two squares, yielding the following
analogue of Davenport's result: For all u \in [0,1], the limit \[
\tilde{D}(u):= \lim_{R\to\infty} \frac{1}{\pi R}\#\{(x,y) \in \Z^2: 0<x^2+y^2
\leq R \text{ and } \frac{x^2+y^2}{\sigma(x^2+y^2)} \leq u\} \] exists, and
\tilde{D}(u) is both continuous and strictly increasing on [0,1].


title: Natural exit of fresh inflation to a radiation dominated universe

abstract:
  We examine the transition from a fresh inflationary scenario to a radiation
dominated universe when the inflaton field is coupled to gravity. We show that
this transition is very natural when this coupling is $\xi=1/4$ at the end of
fresh inflation. This is a very important result that shows as fresh inflation
has a natural exit to the radiation dominated epoch.


title:
On the Performance Bounds of some Policy Search Dynamic Programming
  Algorithms

abstract:
  We consider the infinite-horizon discounted optimal control problem
formalized by Markov Decision Processes. We focus on Policy Search algorithms,
that compute an approximately optimal policy by following the standard Policy
Iteration (PI) scheme via an -approximate greedy operator (Kakade and Langford,
2002; Lazaric et al., 2010). We describe existing and a few new performance
bounds for Direct Policy Iteration (DPI) (Lagoudakis and Parr, 2003; Fern et
al., 2006; Lazaric et al., 2010) and Conservative Policy Iteration (CPI)
(Kakade and Langford, 2002). By paying a particular attention to the
concentrability constants involved in such guarantees, we notably argue that
the guarantee of CPI is much better than that of DPI, but this comes at the
cost of a relative--exponential in $\frac{1}{\epsilon}$-- increase of time
complexity. We then describe an algorithm, Non-Stationary Direct Policy
Iteration (NSDPI), that can either be seen as 1) a variation of Policy Search
by Dynamic Programming by Bagnell et al. (2003) to the infinite horizon
situation or 2) a simplified version of the Non-Stationary PI with growing
period of Scherrer and Lesner (2012). We provide an analysis of this algorithm,
that shows in particular that it enjoys the best of both worlds: its
performance guarantee is similar to that of CPI, but within a time complexity
similar to that of DPI.


title:
Stability of topologically-protected quantum computing proposals as seen
  through spin glasses

abstract:
  Sensitivity to noise makes most of the current quantum computing schemes
prone to error and nonscalable, allowing only for small proof-of-principle
devices. Topologically-protected quantum computing aims at solving this problem
by encoding quantum bits and gates in topological properties of the hardware
medium that are immune to noise that does not impact the entire system at once.
There are different approaches to achieve topological stability or active error
correction, ranging from quasiparticle braidings to spin models and topological
color codes. The stability of these proposals against noise can be quantified
by their error threshold. This figure of merit can be computed by mapping the
problem onto complex statistical-mechanical spin-glass models with local
disorder on nontrival lattices that can have many-body interactions and are
sometimes described by lattice gauge theories. The error threshold for a given
source of error then represents the point in the temperature-disorder phase
diagram where a stable symmetry-broken phase vanishes. An overview of the
techniques used to estimate the error thresholds is given, as well as a summary
of recent results on the stability of different topologically-protected quantum
computing schemes to different error sources.


title: Identifying Pairs in Simulated Bio-Medical Time-Series

abstract:
  The paper presents a time-series-based classification approach to identify
similarities in pairs of simulated human-generated patterns. An example for a
pattern is a time-series representing a heart rate during a specific
time-range, wherein the time-series is a sequence of data points that represent
the changes in the heart rate values. A bio-medical simulator system was
developed to acquire a collection of 7,871 price patterns of financial
instruments. The financial instruments traded in real-time on three American
stock exchanges, NASDAQ, NYSE, and AMEX, simulate bio-medical measurements. The
system simulates a human in which each price pattern represents one bio-medical
sensor. Data provided during trading hours from the stock exchanges allowed
real-time classification. Classification is based on new machine learning
techniques: self-labeling, which allows the application of supervised learning
methods on unlabeled time-series and similarity ranking, which applied on a
decision tree learning algorithm to classify time-series regardless of type and
quantity.


title: Stanley depth and symbolic powers of monomial ideals

abstract:
  The aim of this paper is to study the Stanley depth of symbolic powers of a
squarefree monomial ideal. We prove that for every squarefree monomial ideal
$I$ and every pair of integers $k, s\geq 1$, the inequalities ${\rm sdepth}
(S/I^{(ks)}) \leq {\rm sdepth} (S/I^{(s)})$ and ${\rm sdepth} (I^{(ks)}) \leq
{\rm sdepth} (I^{(s)})$ hold. If moreover $I$ is unmixed of height $d$, then we
show that for every integer $k\geq1$, ${\rm sdepth}(I^{(k+d)})\leq {\rm
sdepth}(I^{{(k)}})$ and ${\rm sdepth}(S/I^{(k+d)})\leq {\rm
sdepth}(S/I^{{(k)}})$. Finally, we consider the limit behavior of the Stanley
depth of symbolic powers of a squarefree monomial ideal. We also introduce a
method for comparing the Stanley depth of factors of monomial ideals.


title: Predicting Parameters in Deep Learning

abstract:
  We demonstrate that there is significant redundancy in the parameterization
of several deep learning models. Given only a few weight values for each
feature it is possible to accurately predict the remaining values. Moreover, we
show that not only can the parameter values be predicted, but many of them need
not be learned at all. We train several different architectures by learning
only a small number of weights and predicting the rest. In the best case we are
able to predict more than 95% of the weights of a network without any drop in
accuracy.


title:
The central limit theorem for monotone convolution with applications to
  free Levy processes and infinite ergodic theory

abstract:
  In this paper free harmonic analysis tools are used to study parabolic
iteration in the complex upper half-plane. The main result here is a complete
characterization for the norming constants in the monotonic central limit
theorem. This allows us to construct a new class of conservative and ergodic
measure-preserving transformations on the real line with Lebesgue measure.
Among all, we mention that the generalized Boole transformation with infinitely
many poles is shown to be conservative, as long as its residues are summable.


title: Where the "it from bit" come from?

abstract:
  In his 1989 essay, John Archibald Wheeler has tried to answer the eternal
question of existence. He did it by searching for links between information,
physics, and quanta. The main concept emerging from his essay is that "every
physical quantity, every it, derives its ultimate significance from bits,
binary yes-or-no indications". This concept has been summarized in the
catchphrase "it from bit". In the Wheeler's essay, it is possible to read
several times the echoes of the philosophy of Niels Bohr. The Danish physicist
has pointed out how the quantum and relativistic physics - forcing us to
abandon the anchor of the visual reference of common sense - have imposed a
greater attention to the language. Bohr did not deny the physical reality, but
recognizes that there is always need of a language no matter what a person
wants to do. To put it as Carlo Sini, language is the first toolbox that man
has at hands to analyze the experience. It is not a thought translated into
words, because to think is to operate with signs as reminded us by various
philosophers from Leonardo da Vinci to Ludwig Wittgenstein. [...]


title: A Gaussian refinement of the Lieb-Robinson bound

abstract:
  This paper has been withdrawn by the authors because of an error in the
proof. We can, however, prove a weaker spatial fall-off that is still
superlinear, namely exp[-x log x].

categories: math-ph cond-mat.stat-mech math.MP quant-ph


title:
Low-velocity shocks traced by extended SiO emission along the W43
  ridges: witnessing the formation of young massive clusters

abstract:
  The formation of high-mass stars is tightly linked to that of their parental
clouds. We here focus on the high-density parts of W43, a molecular cloud
undergoing an efficient event of formation. The cloud structure is studied with
a column density image derived from Herschel continuum maps obtained at 70,
160, 250, 350, and 500 micron. We identify two high-column density filamentary
clouds, quoted as the W43-MM1 and W43-MM2 ridges, which both account for
1.5x10^4 Msun gas mass above 10^23 cm-2 and within areas of 5 and 14pc^2,
respectively. We used the N_2H^+ 1--0 line to confirm that the W43-MM1 and
W43-MM2 ridges are structures coherent in velocity and gravitationally bound,
despite their large velocity dispersion and ~5 kms line widths. The most
intriguing result of the W43 large program is the bright wide-spread SiO 2--1
emission: 1--11 K kms$ stretching an area of ~28 pc^2. Concentrated toward the
W43-MM1 and W43-MM2 ridges and their immediate surroundings, it leads to a
total luminosity of L_SiO 2-1 ~4 10^4 K kms kpc^2pc^2. We measured a steep
relation between the luminosity and velocity extent of the SiO~2--1 lines and
propose to use it to distinguish the low-velocity shocks observed here from the
more classical high-velocity ones associated with outflows of high-mass young
stellar objects. We used state-of-the-art shock models to demonstrate that
low-velocity (<10 kms^-1) shocks with a small amount (10%) of Si atoms
initially in gas phase or in grain mantles can explain the observed SiO column
density in W43. The spatial and velocity overlaps between the ridges
high-density gas (n_H2>10^4-10^5 cm^-3) and the shocked SiO gas suggests that
ridges could be forming via colliding flows driven by gravity and accompanied
by low-velocity shocks. This mechanism may be the initial conditions for the
formation of young massive clusters in these ridges.


title: Analysis and simulation of the operation of a Kelvin probe

abstract:
  Experiments that measure extremely small gravitational forces are often
hampered by the presence of non-gravitational forces that can neither be
calculated nor separately measured. Among these spurious forces is
electrostatic attraction between a test mass and its surroundings due to the
presence of spatially varying surface potential known as the "patch effect." In
order to make surfaces with small surface potential variation, it is necessary
to be able to measure it. A Kelvin probe (KP) measures contact potential
difference (CPD), using the time-varying capacitance between the sample and a
vibrating tip that is biased with a backing potential. Assuming that the tip
remains constant, this measures the sample's surface potential variation. We
examine the operation of the KP from the perspective of parameter estimation in
the presence of noise. We show that, when the CPD is estimated from
measurements at two separate backing potentials, the standard deviation of the
optimal estimate depends on the total observing time. Further, the observing
time may be unevenly divided between the two backing potentials, provided the
values of those potentials are correspondingly set. We simulate a two-stage KP
data analysis, including a sub-optimal estimator with advantages for real-time
operation. Based on the real-time version, we present a novel approach to
stabilizing the average distance of the tip from the sample. We also present
the results of a series of covariance analyses that validate and bound the
applicability of the suboptimal estimator, make a comparison with the results
of an optimal estimator and guide the user. We discuss the application of the
KP to the LISA and to a test of the weak equivalence principle.


title: Waveform Design for Secure SISO Transmissions and Multicasting

abstract:
  Wireless physical-layer security is an emerging field of research aiming at
preventing eavesdropping in an open wireless medium. In this paper, we propose
a novel waveform design approach to minimize the likelihood that a message
transmitted between trusted single-antenna nodes is intercepted by an
eavesdropper. In particular, with knowledge first of the eavesdropper's channel
state information (CSI), we find the optimum waveform and transmit energy that
minimize the signal-to-interference-plus-noise ratio (SINR) at the output of
the eavesdropper's maximum-SINR linear filter, while at the same time provide
the intended receiver with a required pre-specified SINR at the output of its
own max-SINR filter. Next, if prior knowledge of the eavesdropper's CSI is
unavailable, we design a waveform that maximizes the amount of energy available
for generating disturbance to eavesdroppers, termed artificial noise (AN),
while the SINR of the intended receiver is maintained at the pre-specified
level. The extensions of the secure waveform design problem to multiple
intended receivers are also investigated and semidefinite relaxation (SDR) -an
approximation technique based on convex optimization- is utilized to solve the
arising NP-hard design problems. Extensive simulation studies confirm our
analytical performance predictions and illustrate the benefits of the designed
waveforms on securing single-input single-output (SISO) transmissions and
multicasting.


title: Creating Infinitesimal Generators And Robust Messages With Adinkras

abstract:
  Adinkras are graphs that can describe off-shell supermultiplets in 1
dimension with a Lie superalgebra known as Garden algebra. In this paper, I
show that the degrees of freedom of the adinkra can be represented by a
subgraph called a baobab. Because the structure of adinkras and baobabs are
very general, I will show that all finite-dimensional Lie superalgebras can be
similarly described by more general Lie adinkras and Lie baobabs. Furthermore,
it will be shown that adinkras can represent forward error correction block
codes, and bit erasures in Garden algebra adinkras can be corrected using logic
circuits derived from baobabs.


title: The importance of stepping up in the excursion set approach

abstract:
  Recently, we provided a simple but accurate formula which closely
approximates the first crossing distribution associated with random walks
having correlated steps. The approximation is accurate for the wide range of
barrier shapes of current interest and is based on the requirement that, in
addition to having the right height, the walk must cross the barrier going
upwards. Therefore, it only requires knowledge of the bivariate distribution of
the walk height and slope, and is particularly useful for excursion set models
of the massive end of the halo mass function. However, it diverges at lower
masses. We show how to cure this divergence by using a formulation which
requires knowledge of just one other variable. While our analysis is general,
we use examples based on Gaussian initial conditions to illustrate our results.
Our formulation, which is simple and fast, yields excellent agreement with the
considerably more computationally expensive Monte-Carlo solution of the first
crossing distribution, for a wide variety of moving barriers, even at very low
masses.


title:
Multiple integral formulae for the scalar product of on-shell and
  off-shell Bethe vectors in SU(3)-invariant models

abstract:
  We study the scalar product S_{l,m} between an on-shell and an off-shell
Bethe state in models with SU(3)-invariance, where l and m denote the
cardinalities of the two sets of Bethe roots. We construct recursion relations
relating S_{l,m} to scalar products of smaller dimension, namely S_{l-1,m} and
S_{l,m-1}. Solving these recursion relations we obtain new multiple integral
expressions for S_{l,m}, whose integrands are (l+m) \times (l+m) determinants,
and closely related to the Slavnov determinant expression for the SU(2) scalar
product.


title:
Scientific Objectives for UV/Visible Astrophysics Investigations: A
  Summary of Responses by the Community (2012)

abstract:
  Following several recommendations presented by the Astrophysics Decadal
Survey 2010 centered around the need to define "a future ultraviolet-optical
space capability," on 2012 May 25, NASA issued a Request for Information (RFI)
seeking persuasive ultraviolet (UV) and visible wavelength astrophysics science
investigations. The goal was to develop a cohesive and compelling set of
science objectives that motivate and support the development of the next
generation of ultraviolet/visible space astrophysics missions. Responses were
due on 10 August 2012 when 34 submissions were received addressing a number of
potential science drivers. A UV/visible Mission RFI Workshop was held on 2012
September 20 where each of these submissions was summarized and discussed in
the context of each other. We present a scientific analysis of these
submissions and presentations and the pursuant measurement capability needs,
which could influence ultraviolet/visible technology development plans for the
rest of this decade. We also describe the process and requirements leading to
the inception of this community RFI, subsequent workshop and the expected
evolution of these ideas and concepts for the remainder of this decade.


title:
A multi-fidelity stochastic collocation method for parabolic PDEs with
  random input data

abstract:
  Over the last few years there have been dramatic advances in our
understanding of mathematical and computational models of complex systems in
the presence of uncertainty. This has led to a growth in the area of
uncertainty quantification as well as the need to develop efficient, scalable,
stable and convergent computational methods for solving differential equations
with random inputs. Stochastic Galerkin methods based on polynomial chaos
expansions have shown superiority to other non-sampling and many sampling
techniques. However, for complicated governing equations numerical
implementations of stochastic Galerkin methods can become non-trivial. On the
other hand, Monte Carlo and other traditional sampling methods, are
straightforward to implement. However, they do not offer as fast convergence
rates as stochastic Galerkin. Other numerical approaches are the stochastic
collocation (SC) methods, which inherit both, the ease of implementation of
Monte Carlo and the robustness of stochastic Galerkin to a great deal. In this
work we propose a novel enhancement to stochastic collocation methods using
deterministic model reduction techniques. Linear parabolic partial differential
equations with random forcing terms are analysed. The input data are assumed to
be represented by a finite number of random variables. A rigorous convergence
analysis, supported by numerical results, shows that the proposed technique is
not only reliable and robust but also efficient.


title: Details of an Automotive Sub-System: Saab Instrument Cluster Module

abstract:
  The goal of this technical report is to give the details of a real world
existing sub-system in the automotive industry. It is produced to be used for
reproduction of the same experiment if other researchers are interested in.
Hence, it would be possible to compare the results of our published studies
with the results of similar tools. The data is collected for the purpose of
applying metaheuristic optimization approaches. The case study based on these
data shows that metaheuristic optimization approaches can find efficient
solutions for multiple quality attributes while fulfilling given constraints.
  The case study was conducted at Saab Automobile AB in order to evaluate the
AQOSA framework in an industrial context. AQOSA (Automated Quality-driven
Optimization of Software Architecture) is our architecture optimization
framework that supports multiple quality attributes including response time,
processor utilization, bus utilization, safety and cost.
  To enable validation of the results we selected an existing realization for
the Saab 9-5 Instrument Cluster Module ECU (Electronic Control Unit) and the
surrounding sub-systems. The goal of the case study is to find a better
solution than the current realization while fulfilling the requirements and
constraints. The results of the case study and the details of AQOSA framework
is reported in a paper from the authors in Journal of Systems and Software,
Special Issue on Quality Optimization of Software Architecture and Design
Specifications.


title:
Optimal Lyapunov quantum control on two-level systems: convergence and
  extended techniques

abstract:
  Taking a two-level system as an example, we show that a strong control field
may enhance the efficiency of optimal Lyapunov quantum control in [Hou et al.,
Phys. Rev. A \textbf{86}, 022321 (2012)] but could decrease its control
fidelity. A relationship between the strength of the control field and the
control fidelity is established. An extended technique, which combines free
evolution and external control, is proposed to improve the control fidelity. We
analytically demonstrate that the extended technique can be used to design a
control law for steering a two-level system exactly to the target state. In
such a way, the convergence of the extended optimal Lyapunov quantum control
can be guaranteed.


title: Five lectures on DPG methods

abstract:
  This is a set of lecture notes introducing graduate students to the topic of
Discontinuous Petrov-Galerkin (DPG) methods.


title: Reconstructing the Population Genetic History of the Caribbean

abstract:
  The Caribbean basin is home to some of the most complex interactions in
recent history among previously diverged human populations. Here, by making use
of genome-wide SNP array data, we characterize ancestral components of
Caribbean populations on a sub-continental level and unveil fine-scale patterns
of population structure distinguishing insular from mainland Caribbean
populations as well as from other Hispanic/Latino groups. We provide genetic
evidence for an inland South American origin of the Native American component
in island populations and for extensive pre-Columbian gene flow across the
Caribbean basin. The Caribbean-derived European component shows significant
differentiation from parental Iberian populations, presumably as a result of
founder effects during the colonization of the New World. Based on demographic
models, we reconstruct the complex population history of the Caribbean since
the onset of continental admixture. We find that insular populations are best
modeled as mixtures absorbing two pulses of African migrants, coinciding with
early and maximum activity stages of the transatlantic slave trade. These two
pulses appear to have originated in different regions within West Africa,
imprinting two distinguishable signatures in present day Afro-Caribbean genomes
and shedding light on the genetic impact of the dynamics occurring during the
slave trade in the Caribbean.


title: Observing the Next Galactic Supernova

abstract:
  We model the distance, extinction, and magnitude probability distributions of
a successful Galactic core-collapse supernova (ccSN), its shock breakout
radiation, and its massive star progenitor. We find, at very high probability
(~100%), that the next Galactic SN will easily be detectable in the near-IR and
that near-IR photometry of the progenitor star very likely (~92%) already
exists in the 2MASS survey. Most ccSNe (~98%) will be easily observed in the
optical, but a significant fraction (~43%) will lack observations of the
progenitor due to a combination of survey sensitivity and confusion. If
neutrino detection experiments can quickly disseminate a likely position (~3
deg), we show that a modestly priced IR camera system can probably detect the
shock breakout radiation pulse even in daytime (~64% for the cheapest design).
Neutrino experiments should seriously consider adding such systems, both for
their scientific return and as an added and internal layer of protection
against false triggers. We find that shock breakouts from failed ccSNe of red
supergiants may be more observable than those of successful SNe. We review the
process by which neutrinos from a Galactic ccSN would be detected and
announced. We provide new information on the EGADS system and its potential for
providing instant neutrino alerts. We also discuss the distance, extinction,
and magnitude probability distributions for the next Galactic Type Ia SN. Based
on our modeled observability, we find a Galactic ccSN rate of 3.2 (+7.3/-2.6)
per century and a Galactic Type Ia SN rate of 1.4 (+1.4/-0.8) per century for a
total Galactic SN rate of 4.6 (+7.4/-2.7) per century is needed to account for
the SNe observed over the last millennium.


title: Characterization of the MALT90 Survey and the Mopra Telescope at 90 GHz

abstract:
  We characterize the Millimeter Astronomy Legacy Team 90 GHz (MALT90) Survey
and the Mopra telescope at 90 GHz. We combine repeated position-switched
observations of the source G300.968+01.145 with a map of the same source in
order to estimate the pointing reliability of the position-switched
observations and, by extension, the MALT90 survey; we estimate our pointing
uncertainty to be 8 arcseconds. We model the two strongest sources of
systematic gain variability as functions of elevation and time-of-day and
quantify the remaining absolute flux uncertainty. Corrections based on these
two variables reduce the scatter in repeated observations from 12-25% down to
10-17%. We find no evidence for intrinsic source variability in
G300.968+01.145. For certain applications, the corrections described herein
will be integral for improving the absolute flux calibration of MALT90 maps and
other observations using the Mopra telescope at 90 GHz.


title:
Did massive black holes in globular clusters initially satisfy galactic
  scaling relations?

abstract:
  The masses of supermassive black holes (SMBHs, M_BH=10^6-10^11 Msun) in the
centres of galaxies are related to the host stellar spheroid mass and velocity
dispersion. A key question is how these relations originate, and over which
range of black hole masses they hold. It has been speculated that
intermediate-mass black holes (IMBHs, M_BH=10^2-10^5 Msun) could play a
fundamental role in the growth of SMBHs. A handful of IMBHs has recently been
detected in Galactic globular clusters (GCs), but their masses are inconsistent
with the galactic scaling relations of SMBHs. In this Letter, we derive the
initial properties of the GCs using a standard analytical evolutionary model,
of which the free parameters are fixed by independent constraints. We find that
the observed IMBH masses initially followed the galactic SMBH scaling
relations, and subsequently moved off these relations due to the dynamical
evolution of their host GCs. This work is concluded with a brief discussion of
the uncertainties and the implications of our results for the possible
universality of massive black hole growth.


title: Excluding Black Hole Firewalls with Extreme Cosmic Censorship

abstract:
  The AMPS argument for black hole firewalls seems to arise not only from the
assumption of local effective field theory outside the stretched horizon but
also from an overcounting of internal black hole states that include states
that are singular in the past. Here I propose to exclude such singular states
by Extreme Cosmic Censorship (the conjectured principle that the universe is
entirely nonsingular, except for transient singularities inside black and/or
white holes). I argue that the remaining set of nonsingular realistic states do
not have firewalls but yet preserve information in Hawking radiation from black
holes that form from nonsingular initial states.


title:
Systematic Uncertainties In Constraining Dark Matter Annihilation From
  The Cosmic Microwave Background

abstract:
  Anisotropies of the cosmic microwave background (CMB) have proven to be a
very powerful tool to constrain dark matter annihilation at the epoch of
recombination. However, CMB constraints are currently derived using a number of
reasonable but yet un-tested assumptions that could potentially lead to a
misestimation of the true bounds. In this paper we examine the potential impact
of these systematic effects. In particular, we separately study the propagation
of the secondary particles produced by annihilation in two energy regimes;
first following the shower from the initial particle energy to the keV scale,
and then tracking the resulting secondary particles from this scale to the
absorption of their energy as heat, ionization, or excitation of the medium. We
improve both the high and low energy parts of the calculation, in particular
finding that our more accurate treatment of losses to sub-10.2 eV photons
produced by scattering of high-energy electrons weakens the constraints on
particular DM annihilation models by up to a factor of two. On the other hand,
we find that the uncertainties we examine for the low energy propagation do not
significantly affect the results for current and upcoming CMB data. We include
the evaluation of the precise amount of excitation energy, in the form of
Lyman-alpha photons, produced by the propagation of the shower, and examine the
effects of varying the Helium fraction and Helium ionization fraction. In the
recent literature, simple approximations for the fraction of energy absorbed in
different channels have often been used to derive CMB constraints: we assess
the impact of using accurate versus approximate energy fractions. Finally we
check that the choice of recombination code (between RECFAST v1.5 and
COSMOREC), to calculate the evolution of the free electron fraction in the
presence of dark matter annihilation, introduces negligible differences.


title:
Heavy quark energy loss far from equilibrium in a strongly coupled
  collision

abstract:
  We compute and study the drag force acting on a heavy quark propagating
through the matter produced in the collision of two sheets of energy in a
strongly coupled gauge theory that can be analyzed holographically. Although
this matter is initially far from equilibrium, we find that the equilibrium
expression for heavy quark energy loss in a homogeneous strongly coupled plasma
with the same instantaneous energy density or pressure as that at the location
of the quark describes many qualitative features of our results. One
interesting exception is that there is a time delay after the initial collision
before the heavy quark energy loss becomes significant. At later times, once a
liquid plasma described by viscous hydrodynamics has formed, expressions based
upon assuming instantaneous homogeneity and equilibrium provide a
semi-quantitative description of our results - as long as the rapidity of the
heavy quark is not too large. For a heavy quark with large rapidity, the
gradients in the velocity of the hydrodynamic fluid result in qualitative
consequences for the 'drag' force acting on the quark. In certain
circumstances, the force required to drag the quark through the plasma can
point opposite to the velocity of the quark, meaning that the force that the
plasma exerts on a quark moving through it acts in the same direction as its
velocity. And, generically, the force includes a component perpendicular to the
direction of motion of the quark. Our results support a straightforward
approach to modeling the drag on, and energy loss of, heavy quarks with modest
rapidity in heavy ion collisions, both before and after the quark-gluon plasma
hydrodynamizes, and provide cautionary lessons at higher rapidity.


title: A gradient estimate for harmonic functions sharing the same zeros

abstract:
  Let u, v be two harmonic functions in the disk of radius two which have
exactly the same set Z of zeros. We observe that the gradient of \log |u/v| is
bounded in the unit disk by a constant which depends on Z only. In case Z is
empty this goes back to Li-Yau's gradient estimate for positive harmonic
functions. The general boundary Harnack principle gives H\"older estimates on
\log |u/v|.


title:
The Formation of Systems with Tightly-packed Inner Planets (STIPs) via
  Aerodynamic Drift

abstract:
  The NASA Kepler mission has revealed an abundant class of Systems with
Tightly-packed Inner Planets (STIPs). The current paradigm for planet formation
suggests that small planetesimals will quickly spiral into the host star due to
aerodynamic drag, preventing rocky planet formation. In contrast, we find that
aerodynamic drift, when acting on an ensemble of solids, can concentrate mass
at short orbital periods in gaseous disks. Sublimation fronts may further aid
this process. Kepler data suggest that the innermost known planets are found
near the silicate sublimation zone. STIP planets should have a wide range of
volatile fractions due to aerodynamic drift and H2 dissociation-driven gas
accretion. We further propose that the low mass of Mars is evidence that the
Solar System was once a proto-STIP.


title: Evidence for the Tidal Destruction of Hot Jupiters by Subgiant Stars

abstract:
  Tidal transfer of angular momentum is expected to cause hot Jupiters to
spiral into their host stars. Although the timescale for orbital decay is very
uncertain, it should be faster for systems with larger and more evolved stars.
Indeed, it is well established that hot Jupiters are found less frequently
around subgiant stars than around main-sequence stars. However, the
interpretation of this finding has been ambiguous, because the subgiants are
also thought to be more massive than the F- and G-type stars that dominate the
main-sequence sample. Consequently it has been unclear whether the absence of
hot Jupiters is due to tidal destruction, or inhibited formation of those
planets around massive stars. Here we show that the Galactic space motions of
the planet-hosting subgiant stars demand that on average they be similar in
mass to the planet-hosting main-sequence F- and G-type stars. Therefore the two
samples are likely to differ only in age, and provide a glimpse of the same
exoplanet population both before and after tidal evolution. As a result, the
lack of hot Jupiters orbiting subgiants is clear evidence for their tidal
destruction. Questions remain, though, about the interpretation of other
reported differences between the planet populations around subgiants and
main-sequence stars, such as their period and eccentricity distributions and
overall occurrence rates.


title: Left-Right Symmetric Theory with Light Sterile Neutrinos

abstract:
  A simple theoretical framework for the spontaneous breaking of parity, baryon
and lepton numbers is proposed. In this context, the baryon and lepton numbers
are independent local gauge symmetries, while parity is defined making use of
the left-right symmetry. We show that in the minimal model the new leptoquark
fields needed to define an anomaly-free theory also generate neutrino masses
through the type III seesaw mechanism. The spectrum of neutrinos and some
phenomenological aspects are discussed. This theory predicts the possible
existence of two light sterile neutrinos.


title:
Relations Between Neutron-Star Parameters in the Hartle-Thorne
  Approximation

abstract:
  Using stellar structure calculations in the Hartle-Thorne approximation, we
derive analytic expressions connecting the ellipticity of the stellar surface
to the compactness, the spin angular momentum, and the quadrupole moment of the
spacetime. We also obtain empirical relations between the compactness, the spin
angular momentum, and the spacetime quadrupole. Our formulae reproduce the
results of numerical calculations to within a few percent and help reduce the
number of parameters necessary to model the observational appearance of
moderately spinning neutron stars. This is sufficient for comparing theoretical
spectroscopic and timing models to observations that aim to measure the masses
and radii of neutron stars and to determine the equation of state prevailing in
their interiors.


title: Density-Independent Model of Self-Propelled Particles

abstract:
  We examine a density-independent modification of the Vicsek model in which a
particle interacts with neighbors defined by Delaunay triangulation. To
feasibly simulate the model, an algorithm for repairing the triangulation over
time was developed. This algorithm may also be applied to any time-varying
two-dimensional Delaunay triangulation. This model exhibits a continuous phase
transition with noise, and a distinct set of critical exponents were measured
which satisfy a hyperscaling relationship. The critical exponents are found to
vary between a low and high velocity regime, but they are robust under the
inclusion of a repulsive interaction. We present evidence that the correlation
length approximately scales with the size of the system even in the ordered
phase.


title: The global electroweak Standard Model fit after the Higgs discovery

abstract:
  We present an update of the global Standard Model (SM) fit to electroweak
precision data under the assumption that the new particle discovered at the LHC
is the SM Higgs boson. In this scenario all parameters entering the
calculations of electroweak precision observalbes are known, allowing, for the
first time, to over-constrain the SM at the electroweak scale and assert its
validity. Within the SM the W boson mass and the effective weak mixing angle
can be accurately predicted from the global fit. The results are compatible
with, and exceed in precision, the direct measurements. An updated
determination of the S, T and U parameters, which parametrize the oblique
vacuum corrections, is given. The obtained values show good consistency with
the SM expectation and no direct signs of new physics are seen. We conclude
with an outlook to the global electroweak fit for a future e+e- collider.


title: A handbook of vector-like quarks: mixing and single production

abstract:
  We obtain constraints on the mixing of vector-like quarks coupling
predominantly to the third generation. We consider all (seven) relevant types
of vector-like quarks, individually. The constraints are derived from oblique
corrections and Z -> b bbar measurements at LEP and SLC. We investigate the
implications of these constraints on LHC phenomenology, concerning the decays
of the heavy quarks and their single production. We also explore indirect
effects of heavy quark mixing in top and bottom couplings. A remarkable effect
is the possibility of explaining the anomalous forward-backward asymmetry in Z
-> b bbar at LEP, with a hypercharge -5/6 doublet. We also study the impact of
the new quarks on single Higgs production at the LHC and Higgs decay.


title:
Parallel Astronomical Data Processing with Python: Recipes for multicore
  machines

abstract:
  High performance computing has been used in various fields of astrophysical
research. But most of it is implemented on massively parallel systems
(supercomputers) or graphical processing unit clusters. With the advent of
multicore processors in the last decade, many serial software codes have been
re-implemented in parallel mode to utilize the full potential of these
processors. In this paper, we propose parallel processing recipes for multicore
machines for astronomical data processing. The target audience are astronomers
who are using Python as their preferred scripting language and who may be using
PyRAF/IRAF for data processing. Three problems of varied complexity were
benchmarked on three different types of multicore processors to demonstrate the
benefits, in terms of execution time, of parallelizing data processing tasks.
The native multiprocessing module available in Python makes it a relatively
trivial task to implement the parallel code. We have also compared the three
multiprocessing approaches - Pool/Map, Process/Queue, and Parallel Python. Our
test codes are freely available and can be downloaded from our website.


title: Hidden SUSY from precision gauge unification

abstract:
  We revisit the implications of naturalness and gauge unification in the MSSM.
We find that precision unification of the couplings in connection with a small
mu parameter requires a highly compressed gaugino pattern as it is realized in
mirage mediation. Due to the small mass difference between gluino and LSP,
collider limits on the gluino mass are drastically relaxed. Without further
assumptions, the relic density of the LSP is very close to the observed dark
matter density due to coannihilation effects.


title: Proper Motions in Globular Clusters using Deconvolution of HST Images

abstract:
  A sub-sampled deconvolution technique for crowded field photometry with the
HST WFPC2 instrument was proposed by Butler (2000) and applied to search for
optical counterparts to pulsars in globular clusters (Golden et al. 2001).
Simulations showed that the method, which takes account of the point-spread
function (PSF) spatial variation, can provide better star detection and
recovers the resolution lost to aberrations and poor sampling. The original
emphasis was on precision photometry in crowded fields. In the present work, we
have extended this technique to determine proper motions of stars in globular
clusters. Actual HST images of the globular clusters, along with realistic
simulations of the globular clusters, were used to benchmark the technique for
astrometric accuracy. The ultimate aim is to use this dynamical data to search
for intermediate-mass black holes in globular cluster cores.


title: Inside-Out Planet Formation

abstract:
  The compact multi-transiting planet systems discovered by Kepler challenge
planet formation theories. Formation in situ from disks with radial mass
surface density, $\Sigma$, profiles similar to the minimum mass solar nebula
(MMSN) but boosted in normalization by factors $\gtrsim 10$ has been suggested.
We propose that a more natural way to create these planets in the inner disk is
formation sequentially from the inside-out via creation of successive
gravitationally unstable rings fed from a continuous stream of small (~cm--m
size) "pebbles", drifting inwards via gas drag. Pebbles collect at the pressure
maximum associated with the transition from a magneto-rotational instability
(MRI)-inactive ("dead zone") region to an inner MRI-active zone. A pebble ring
builds up until it either becomes gravitationally unstable to form an $\sim 1\
M_\oplus$ planet directly or induces gradual planet formation via core
accretion. The planet may undergo Type I migration into the active region,
allowing a new pebble ring and planet to form behind it. Alternatively if
migration is inefficient, the planet may continue to accrete from the disk
until it becomes massive enough to isolate itself from the accretion flow. A
variety of densities may result depending on the relative importance of
residual gas accretion as the planet approaches its isolation mass. The process
can repeat with a new pebble ring gathering at the new pressure maximum
associated with the retreating dead zone boundary. Our simple analytical model
for this scenario of inside-out planet formation yields planetary masses,
relative mass scalings with orbital radius, and minimum orbital separations
consistent with those seen by Kepler. It provides an explanation of how massive
planets can form with tightly-packed and well-aligned system architectures,
starting from typical protoplanetary disk properties.


title: Geometric Engineering in Toric F-Theory and GUTs with U(1) Gauge Factors

abstract:
  An algorithm to systematically construct all Calabi-Yau elliptic fibrations
realized as hypersurfaces in a toric ambient space for a given base and gauge
group is described. This general method is applied to the particular question
of constructing SU(5) GUTs with multiple U(1) gauge factors. The basic data
consists of a top over each toric divisor in the base together with
compactification data giving the embedding into a reflexive polytope. The
allowed choices of compactification data are integral points in an auxiliary
polytope. In order to ensure the existence of a low-energy gauge theory, the
elliptic fibration must be flat, which is reformulated into conditions on the
top and its embedding. In particular, flatness of SU(5) fourfolds imposes
additional linear constraints on the auxiliary polytope of compactifications,
and is therefore non-generic. Abelian gauge symmetries arising in toric
F-theory compactifications are studied systematically. Associated to each top,
the toric Mordell-Weil group determining the minimal number of U(1) factors is
computed. Furthermore, all SU(5)-tops and their splitting types are determined
and used to infer the pattern of U(1) matter charges.


title: CoRoT: harvest of the exoplanet program

abstract:
  One of the objectives of the CoRoT mission is the search for transiting
extrasolar planets using high-precision photometry, and the accurate
characterization of their fundamental parameters. The CoRoT satellite
consecutively observes crowded stellar fields since February 2007, in
high-cadence precise photometry; periodic eclipses are detected and analysed in
the stellar light curves. Then complementary observations using ground-based
facilities allows establishing the nature of the transiting body and its mass.
CoRoT has acquired more than 163,000 light curves and detected about 500 planet
candidates. A fraction of them (5%) are confirmed planets whose masses are
independently measured. Main highlights of the CoRoT discoveries are: i) the
variety of internal structures in close-in giant planets, ii) the
characterisation of the first known transiting rocky planet, CoRoT-7 b, iii)
multiple constraints on the formation, evolution, role of tides in planetary
systems.


title: Elementary cycles of time

abstract:
  Elementary particles, i.e. the basic constituents of nature, are
characterized by quantum recurrences in time. The flow of time of every
physical system can be therefore decomposed in elementary cycles of time. This
allows us to enforce the local nature of relativistic time, yielding
interesting unified descriptions of fundamental aspects of modern physics, as
shown in recent publications and reviewed in [arXiv:1305.2802]. Every particle
can be regarded as a reference clock with time resolution of the order of its
Compton time, typically many orders of magnitude more accurate than the atomic
clocks. Here we summarize basic conceptual aspects of the resulting relational
interpretation of the relativistic time flow.


title: Neutrinoless Quadruple Beta Decay

abstract:
  We point out that lepton number violation is possible even if neutrinos are
Dirac particles. We illustrate this by constructing a simple model that allows
for lepton number violation by four units only. As a consequence, neutrinoless
double beta decay is forbidden, but neutrinoless quadruple beta decay is
possible: $(A,Z) \to (A,Z+4) + 4 e^-$. We identify three candidate isotopes for
this decay, the most promising one being Nd-150 due to its high $Q_{0\nu
4\beta}$-value of 2 MeV. Analogous processes, such as neutrinoless quadruple
electron capture, are also possible. The expected lifetimes are extremely long,
and experimental searches are challenging.


title:
The SEEDS Direct Imaging Survey for Planets and Scattered Dust Emission
  in Debris Disk Systems

abstract:
  Debris disks around young main-sequence stars often have gaps and cavities
which for a long time have been interpreted as possibly being caused by
planets. In recent years, several giant planet discoveries have been made in
systems hosting disks of precisely this nature, further implying that
interactions with planets could be a common cause of such disk structures. As
part of the SEEDS high-contrast imaging survey, we are surveying a population
of debris disk-hosting stars with gaps and cavities implied by their spectral
energy distributions, in order to attempt to spatially resolve the disk as well
as to detect any planets that may be responsible for the disk structure. Here
we report on intermediate results from this survey. Five debris disks have been
spatially resolved, and a number of faint point sources have been discovered,
most of which have been tested for common proper motion, which in each case has
excluded physical companionship with the target stars. From the detection
limits of the 50 targets that have been observed, we find that beta Pic b-like
planets (~10 Mjup planets around G--A-type stars) near the gap edges are less
frequent than 15--30%, implying that if giant planets are the dominant cause of
these wide (27 AU on average) gaps, they are generally less massive than beta
Pic b.


title: Higher-spin realization of a dS static patch/cut-off CFT correspondence

abstract:
  We derive a holographic relation for the dS static patch with the dual field
theory defined on the observer horizon. The starting point is the duality of
higher-spin theory on AdS_4 and the O(N) vector model. We build on a similar
analytic continuation as used recently to obtain a realization of dS/CFT, and
adapt it to the static patch. The resulting duality relates higher-spin theory
on the dS_4 static patch to a cut-off CFT on the cylinder RxS^2. The
construction permits a derivation of the finite thermodynamic entropy
associated to the horizon of the static patch from the dual field theory. As a
further brick we recover the spectrum of quasinormal frequencies from the
correlation functions of the boundary theory. In the last part we incorporate
the dS/dS correspondence as an independent proposal for holography on dS and
show that a concrete realization can be obtained by similar reasoning.


title:
Photonic circuits for iterative decoding of a class of low-density
  parity-check codes

abstract:
  Photonic circuits in which stateful components are coupled via guided
electromagnetic fields are natural candidates for native implementation of
iterative stochastic algorithms based on propagation of information around a
graph. Conversely, such message passing algorithms suggest novel circuit
architectures for signal processing and computation that are well matched to
nanophotonic device physics. Here we construct and analyze a quantum optical
model of a photonic circuit for iterative decoding of a class of low-density
parity-check (LDPC) codes called expander codes. Our circuit can be understood
as an open quantum system whose autonomous dynamics map straightforwardly onto
the subroutines of an LDPC decoding scheme, with several attractive features:
it can operate in the ultra-low power regime of photonics in which quantum
fluctuations become significant, is robust to noise and component
imperfections, achieves comparable performance to known iterative algorithms
for this class of codes, and provides an instructive example of how
nanophotonic cavity quantum electrodynamic components can enable useful new
information technology even if the solid-state qubits on which they are based
are heavily dephased and cannot support large-scale entanglement.


title: Exciton Condensation in Bilayer Quantum Hall Systems

abstract:
  The condensation of excitons, bound electron-hole pairs in a solid, into a
coherent collective electronic state was predicted over 50 years ago. Perhaps
surprisingly, the phenomenon was first observed in a system consisting of two
closely-spaced parallel two-dimensional electron gases in a semiconductor
double quantum well. At an appropriate high magnetic field and low temperature,
the bilayer electron system condenses into a state resembling a superconductor,
only with the Cooper pairs replaced by excitons comprised of electrons in one
layer bound to holes in the other. In spite of being charge neutral, the
transport of excitons within the condensate gives rise to several spectacular
electrical effects. This article describes these phenomena and examines how
they inform our understanding of this unique phase of quantum electronic
matter.


title: Iterative Decoding and Turbo Equalization: The Z-Crease Phenomenon

abstract:
  Iterative probabilistic inference, popularly dubbed the soft-iterative
paradigm, has found great use in a wide range of communication applications,
including turbo decoding and turbo equalization. The classic approach of
analyzing the iterative approach inevitably use the statistical and
information-theoretical tools that bear ensemble-average flavors. This paper
consider the per-block error rate performance, and analyzes it using nonlinear
dynamical theory. By modeling the iterative processor as a nonlinear dynamical
system, we report a universal "Z-crease phenomenon:" the zig-zag or up-and-down
fluctuation -- rather than the monotonic decrease -- of the per-block errors,
as the number of iteration increases. Using the turbo decoder as an example, we
also report several interesting motion phenomenons which were not previously
reported, and which appear to correspond well with the notion of "pseudo
codewords" and "stopping/trapping sets." We further propose a heuristic
stopping criterion to control Z-crease and identify the best iteration. Our
stopping criterion is most useful for controlling the worst-case per-block
errors, and helps to significantly reduce the average-iteration numbers.