title:
Operational Optimal Ship Routing Using a Hybrid Parallel Genetic
  Algorithm

abstract:
  Optimization of ship routing depends on several parameters, like ship and
cargo characteristics, environmental factors, topography, international
navigation rules, crew comfort etc. The complex nature of the problem leads to
oversimplifications in analytical techniques, while stochastic methods like
simulated annealing can be both time consuming and sensitive to local minima.
In this work, a hybrid parallel genetic algorithm - estimation of distribution
algorithm is developed in the island model, to operationally calculate the
optimal ship routing. The technique, which is applicable not only to clusters
but to grids as well, is very fast and has been applied to very difficult
environments, like the Greek seas with thousands of islands and extreme
micro-climate conditions.


title:
Magnetostriction-driven multiferroicity of MnTe and MnTe/ZnTe epitaxial
  films

abstract:
  Here we demonstrate that MnTe epitaxial films with zinc-blend structure and
MnTe/ZnTe multilayers should show ferroelectric polarization in
antiferromagnetically (AFM) ordered state and thus belong to multiferroics.
Spontaneous ferroelectric polarization results from the bending of highly ionic
Mn-Te-Mn bonds induced by magnetostrictive shear strain. Orientation of
ferroelectric polarization is coupled with orientation of AFM vector and thus
can be controlled by application of the external magnetic field. Due to the
clamping of electric and magnetic order parameters, domain structure in MnTe is
governed by two mechanisms: depolarizing field produced by electric dipoles and
destressing field produced by magnetoelastic dipoles. The values of
monodomainization electric and magnetic fields depend upon the sample shape and
diminish with the film thickness. Magnetoelectric nature of the domains make it
possible to visualize the domain structure by linear and nonlinear optical
methods (Kerr effect, second harmonic generation technique).


title:
Existence and Uniqueness of Strong Solutions for a Compressible
  Multiphase Navier-Stokes Miscible Fluid-Flow Problem in Dimension n = 1

abstract:
  We prove the global existence and uniqueness of strong solutions for a
compressible multifluid described by the barotropic Navier-Stokes equations in
dim = 1. The result holds when the diffusion coefficient depends on the
pressure. It relies on a global control in time of the L2 norm of the space
derivative of the density, via a new kind of entropy.


title:
Anomalous Scaling Behavior in Polymer Thin Film Growth by Vapor
  Deposition

abstract:
  As a first step to understand anomalous kinetic roughening with
multifractality in recent experiments of the vapor deposition polymerization
(VDP) growth, we study a simple toy model of the VDP growth in a
(1+1)-dimensional lattice, along with monomer diffusion, polymer nucleation,
limited active end bonding, and shadowing effects. Using extensive numerical
simulations, we observe that the global roughness exponent is different from
the local one. It is argued that such anomalies in VDP growth are attributed to
the instability induced by the nonlocal shadowing effects on active ends of
polymers. As varying the ratio of diffusion coefficient to the deposition rate
by cosine flux, we also discuss the role of diffusion in kinetic roughening of
the polymer thin film growth, which is quite different from that of the metal
or semiconductor film growth. Finally, we suggest its (2+1)-dimensional
version, which can be directly compared with experimental results.


title:
The solution classical and quantum feedback optimal control problem
  without the Bellman Equation

abstract:
  A new approach, which is proposed in this paper allows one to construct the
Bellman function V(t,x) and optimal control u(t) directly,i.e.,without any
reference to the Bellman equation, by way of using strong large deviations
principle for the solutions Colombeau-Ito's SDE.


title: Spin-orbit coupling in ballistic carbon nanotubes

abstract: This paper has been withdrawn.


title:
Magnetism in a TiO2/LaAlO3 heterostructure: an ab initio study about the
  role of oxygen vacancies

abstract:
  In this work we study the electronic structure and magnetism of a TiO2 film
grown on another non-magnetic oxide such as a LaAlO3 (001) substrate,
concentrating on the role played by structural relaxation and oxygen vacancies.
Using Density Functional Theory ab-initio methods, we study the free-standing
anatase film as well as the interfaces with either the LaO or AlO2 planes of
LaAlO3, focusing on the possibility of magnetic solutions. Our results show
that the interface LaO/TiO2 is favored against the AlO2/TiO2 one if no oxygen
vacancies are present in the interface whereas the contrary happens when there
are oxygen vacancies. In both cases, the cohesive energy is of the same order
of magnitude but only the AlO2/TiO2 interface presents an stable magnetic
solution.


title:
Evidence for the decay B_s^0 --> D_s^(*)D_s^(*) and a measurement of
  Delta_Gamma_s^CP/Gamma_s

abstract:
  We search for the semi-inclusive process B_s^0 --> D_s^(*)D_s^(*) using 2.8
fb^-1 of ppbar collisions at s^(1/2) = 1.96 TeV recorded by the D0 detector
operating at the Fermilab Tevatron Collider. We observe 26.6 +/- 8.4 signal
events with a significance above background of 3.2 standard deviations yielding
a branching ratio of Br(B_s^0 --> D_s^(*)D_s^(*)) = 0.035 +/- 0.010(stat) +/-
0.011(syst). Under certain theoretical assumptions, these double-charm final
states saturate CP-even eigenstates in the B_s^0 decays resulting in a width
difference of Delta_Gamma_s^CP/Gamma_s = 0.072 +/- 0.021(stat) +/- 0.022(syst).


title: Optimized single-qubit gates for Josephson phase qubits

abstract:
  In a Josephson phase qubit the coherent manipulations of the computational
states are achieved by modulating an applied ac current, typically in the
microwave range. In this work we show that it is possible to find optimal
modulations of the bias current to achieve high-fidelity gates. We apply
quantum optimal control theory to determine the form of the pulses and study in
details the case of a NOT-gate. To test the efficiency of the optimized pulses
in an experimental setup, we also address the effect of possible imperfections
in the pulses shapes, the role of off-resonance elements in the Hamiltonian,
and the effect of capacitive interaction with a second qubit.


title:
Concept of a veritable osp(1$|$2) super-triangle sum rule with 6-$j^S$
  symbols from intrinsic operator techniques: an open problem

abstract:
  Efficiency of intrinsic operator techniques (using only products and ranks of
tensor operators) is first evidenced by condensed proofs of already known
$\bigtriangledown$-triangle sum rules of su(2)/su$_q$(2). {\em A new compact}
su$_q$(2)-{\em expression} is found, using a $q$-series $\Phi$, with
$\Phi(n)_{| q=1}=1$. This success comes from an ultimate identification process
over monomials like $(c_0)^p$. For osp(1$|$2), analogous principles of
calculation are transposed, involving a second parameter $d_0$. Ultimate
identification process then must be done over binomials like
${(c_{0}+{d_{0}}^{2})}^{\Omega -m} ({d_{0}}^{2})^{m}$. {\em Unknown}
polynomials ${\cal P}$ are introduced as well as their expansion coefficients,
$x$, over the binomials. It is clearly shown that a hypothetical super-triangle
sum rule requires super-triangles $\bigtriangleup^{S}$, instead of
$\bigtriangledown$ for su(2)/su$_q$(2). Coefficients $x$ are integers ({\em
conjecture 1}). Massive unknown advances are done for intermediate steps of
calculation. Among other, are proved {\em two theorems} on tensor operators,
"zero" by construction. However, the ultimate identification seems to lead to a
dead end, due to analytical apparent complexities. Up today, except for a few
of coefficients $x$, no general formula is really available.


title: Non-Gaussian Signatures from the Postinflationary Early Universe

abstract:
  We consider contributions to non-Gaussianity of the Cosmic Microwave
Background (CMB) from remnants of post-inflationary phase transitions in the
very early universe. Such signatures can optimistically be used to discover
evidence of new particle physics through cosmological observations. More
conservatively they provide a potential obstacle to extracting information
about the non-Gaussian nature of primordial density fluctuations from any
detection in the CMB. We demonstrate this explicitly by computing the
bispectrum from global textures, which may be generated from a wide class of
particle physics models.


title: P-values for high-dimensional regression

abstract:
  Assigning significance in high-dimensional regression is challenging. Most
computationally efficient selection algorithms cannot guard against inclusion
of noise variables. Asymptotically valid p-values are not available. An
exception is a recent proposal by Wasserman and Roeder (2008) which splits the
data into two parts. The number of variables is then reduced to a manageable
size using the first split, while classical variable selection techniques can
be applied to the remaining variables, using the data from the second split.
This yields asymptotic error control under minimal conditions. It involves,
however, a one-time random split of the data. Results are sensitive to this
arbitrary choice: it amounts to a `p-value lottery' and makes it difficult to
reproduce results. Here, we show that inference across multiple random splits
can be aggregated, while keeping asymptotic control over the inclusion of noise
variables. We show that the resulting p-values can be used for control of both
family-wise error (FWER) and false discovery rate (FDR). In addition, the
proposed aggregation is shown to improve power while reducing the number of
falsely selected variables substantially.


title:
Kosterlitz-Thouless transition in thin films: A Monte Carlo study of
  three-dimensional lattice models

abstract:
  We study the phase transition of thin films in the three-dimensional XY
universality class. To this end, we perform a Monte Carlo study of the improved
two-component \phi^4 model, the improved dynamically diluted XY model and the
standard XY model on the simple cubic lattice. We study films of a thickness up
to L_0=32 lattice spacings. In the short direction of the lattice free boundary
conditions are employed. Using a finite size scaling (FSS) method, proposed
recently, we determine the transition temperature with high accuracy. The
effectively two-dimensional finite size scaling behaviour of the Binder
cumulant U_4, the second moment correlation length over the lattice size
\xi_{2nd}/L, the ratio of the partition functions with anti-periodic and
periodic boundary conditions Z_a/Z_p and the helicity modulus \Upsilon clearly
confirm the Kosterlitz-Thouless nature of the transition. We analyse the
scaling of the transition temperature with the thickness L_0 of the film. The
predictions of the renormalization group (RG) theory are confirmed. We compute
the universal ratio of the thickness of the film L_0 and the transversal
correlation length \xi_T in the three-dimensional thermodynamic limit at the
Kosterlitz-Thouless transition temperature of a film of thickness L_0:
[L_{0,KT}/\xi_T]^* = 1.595(7). This results can be compared with experimental
results on thin films of 4He near the \lambda-transition.


title: Variation and Rough Path Properties of Local Times of L\'evy Processes

abstract:
  In this paper, we will prove that the local time of a L\'evy process is of
finite $p$-variation in the space variable in the classical sense, a.s. for any
$p>2$, $t\geq 0$, if the L\'evy measure satisfies $\int_{R\setminus
\{0\}}(|y|^{3\over 2}\wedge 1)n(dy)<\infty$, and is a rough path of roughness
$p$ a.s. for any $2<p<3$ under a slightly stronger condition for the L\'evy
measure. Then for any function $g$ of finite $q$-variation ($1\leq q <3$), we
establish the integral $\int_{-\infty}^{\infty}g(x)dL_t^x$ as a Young integral
when $1\leq q<2$ and a Lyons' rough path integral when $2\leq q<3$. We
therefore apply these path integrals to extend the Tanaka-Meyer formula for a
continuous function $f$ if $\nabla ^-f$ exists and is of finite $q$-variation
when $1\leq q<3$, for both continuous semi-martingales and a class of L\'evy
processes.


title: On the long time behavior of the TCP window size process

abstract:
  The TCP window size process appears in the modeling of the famous
Transmission Control Protocol used for data transmission over the Internet.
This continuous time Markov process takes its values in $[0,\infty)$, is
ergodic and irreversible. It belongs to the Additive Increase Multiplicative
Decrease class of processes. The sample paths are piecewise linear
deterministic and the whole randomness of the dynamics comes from the jump
mechanism. Several aspects of this process have already been investigated in
the literature. In the present paper, we mainly get quantitative estimates for
the convergence to equilibrium, in terms of the $W_1$ Wasserstein coupling
distance, for the process and also for its embedded chain.


title: Master Equation and Perturbative Chern-Simons theory

abstract:
  We extend the Chern-Simons perturbative invariant of Axelrod and Singer to
non-acyclic connections. We construct a solution of the quantum master equation
on the space of functions on the cohomology of the connection. We prove that
this solution is well defined up to master homotopy. We discuss also invariants
of links.


title: Reducing the Heterotic Supergravity on nearly-Kahler coset spaces

abstract:
  We study the dimensional reduction of the ${\cal N}=1$, ten-dimensional
Heterotic Supergravity to four dimensions, at leading order in $\alpha'$, when
the internal space is a nearly-K\"{a}hler manifold. Nearly-K\"{a}hler manifolds
in six dimensions are all the non-symmetric coset spaces and a group manifold.
Here we reduce the theory using as internal manifolds the three six-dimensional
non-symmetric coset spaces, omitting the case of the group manifold in the
prospect of obtaining chiral fermions when the gauge fields will be included.
We determine the effective actions for these cases, which turn out to describe
${\cal N}=1$ four-dimensional supergravities of the no-scale type and we study
the various possibilities concerning their vacuum.


title:
Laser frequency stabilization to highly excited state transitions using
  electromagnetically induced transparency in a cascade system

abstract:
  We demonstrate laser frequency stabilization to excited state transitions
using cascade electromagnetically induced transparency (EIT). Using a room
temperature Rb vapor cell as a reference, we stabilize a first diode laser to
the D2 transition and a second laser to a transition from the intermediate
state to a Rydberg state with principal quantum number n=19 - 70. A combined
laser linewidth of 280 kHz over a 0.1 ms time period is achieved. This method
may be applied generally to any cascade system and allows laser stabilization
to an atomic reference in the absence of strong optical transitions.


title: Heavy baryon spectroscopy in the QCD string model

abstract:
  QCD string model formulated in the framework of the Field Correlator Method
(FCM) in QCD is employed to calculate the masses of $\Sigma_c$, $\Xi_c$ and
recently observed at Tevatron $\Sigma_b$, $\Xi_b$ baryons and their orbital
excitations.
  The auxiliary field formalism allows one to write a simple local form of the
effective Hamiltonian for the three quark system, which comprises both
confinement and relativistic effects, and contains only universal parameters:
the string tension $\sigma$, the strong coupling constant $\alpha_s$, and the
bare (current) quark masses $m_i$. We calculate the hyperfine splitting with
account of the both perturbative and non--perturbative spin-spin forces between
quarks in a baryon. For the orbital excitations we estimate the string
correction for the confinement potential - the leading correction to the
contribution of the proper inertia of the rotating string. This correction
lowers the masses of the P-states by 50 MeV. We find our numerical results to
be in good agreement with experimental data.


title:
Random phase approximation with exchange for the photoionization of
  confined atoms: Xe in C_{60} fullerene

abstract:
  Photoionization of a Xe atom confined inside C$_{60}$ has been studied using
the random phase approximation with exchange (RPAE) method. The C$_{60}$
fullerene has been descr ibed by an attractive short range spherical well with
potential $V(r)$, given by $V(r)=-V_ 0$ for $r_i<r<r_0$, otherwise $V(r)=0$
where $r_i$ and $r_0$ are respectively, the inner and outer radii of the
spherical shell. The radial parts of the wave funct ion in the three regions
$r<r_i$, $r_i<r<r_0$ and $r>r_0$ have been obtained by solving the
Schr\"{o}dinger equation using both regular and irregular solutions and the
continuous boundary conditions at $r_i$ and $r_0$. The photoionization cross
sections for the Xe 4d, $5s$ and $5p$ ele ctrons in the Xe@C$_{60}$ endohedral
molecule have been evaluated and compared with those of the photoionization for
the free Xe atom and other previo us calculations for the Xe@C$_{60}$
fullerene. Our method surmounted the weaknesses of the previous model potential
calculation s and demonstrated significantly stronger correlated confinement
resonances for the Xe@C$_{60}$ photoionization.


title:
Algebraic mechanics as an accessible toy model demonstrating entropy
  generation from reversible microscopic dynamics

abstract:
  One observes that a considerable level of confusion remains about some of
those aspects of irreversibility, entropy generation and `the arrow of time'
which actually are well understood. This demands that great care must be taken
in any discussion of irreversibility to use clear-cut notions and precise
language in order to be definite about which property follows from which
assumption. In this work, a novel toy model of `algebraic mechanics' is
presented that elucidates specific key aspects of entropy generation in a
system with extremely simple reversible fundamental dynamics. It is argued why
insights gained through a detailed quantitative study of this toy model also
have to be taken into account for any realistic model of microscopic dynamics,
classical or quantum alike. As irreversibility also touches upon the quantum
mechanical measurement process (through the `proof' of the `H-Theorem'), a
simple way to address the tenacious question `when (and how) the wave function
collapses' is offered.


title: Geometry of canonical self-similar tilings

abstract:
  We give several different geometric characterizations of the situation in
which the parallel set $F_\epsilon$ of a self-similar set $F$ can be described
by the inner $\epsilon$-parallel set $T_{-\epsilon}$ of the associated
canonical tiling $\mathcal T$, in the sense of \cite{SST}. For example,
$F_\epsilon=T_{-\epsilon} \cup C_\epsilon$ if and only if the boundary of the
convex hull $C$ of $F$ is a subset of $F$, or if the boundary of $E$, the
unbounded portion of the complement of $F$, is the boundary of a convex set. In
the characterized situation, the tiling allows one to obtain a tube formula for
$F$, i.e., an expression for the volume of $F_\epsilon$ as a function of
$\epsilon$. On the way, we clarify some geometric properties of canonical
tilings.
  Motivated by the search for tube formulas, we give a generalization of the
tiling construction which applies to all self-affine sets $F$ having empty
interior and satisfying the open set condition. We also characterize the
relation between the parallel sets of $F$ and these tilings.


title: Entanglement entropy of integer Quantum Hall states

abstract:
  We compute the entanglement entropy, in real space, of the ground state of
the integer Quantum Hall states for three different domains embedded in the
torus, the disk and the sphere. We establish the validity of the area law with
a vanishing value of the topological entanglement entropy. The entropy per unit
length of the perimeter depends on the filling fraction, but it is independent
of the geometry.


title:
100 Years of Deuterostomia (Grobben, 1908): Cladogenetic and Anagenetic
  Relations within the Notoneuralia Domain

abstract:
  Results from molecular systematics and comparative developmental genetics
changed the picture of metazoan and especially bilaterian radiation. According
to this new animal phylogeny (introduced by Adoutte et al. 1999/2000), Grobbens
(1908) widely favoured protostome-deuterostome division of the Bilateria can be
upheld, but only with major rearrangements within these superphyla. On the
cladogenetic level, the Protostomia are split into two unexpected subgroups,
the Lophotrochozoa and Ecdysozoa. The deuterostomes are split into the
subgroups Chordata and Ambulacraria, which is not novel since Grobben (1908)
introduced the Deuterostomia in this way (together with the Chaetognatha as a
third line). However, many details of the new deuterostome phylogeny do not fit
traditional, morphology-based reconstructions. As a consequence, three
relatively unexpected proposals for early deuterostome evolution are favoured
today: An ambulacraria-scenario, a xenoturbellid-scenario, and a
chordate-scenario. The first two proposals are often discussed in the
literature, while the chordate-scenario is almost completely neglected.
Therefore, the paper presented focuses on the chordate scenario, i.e. the
hypothesis of an acrania-like ur-deuterostomian. It is argued that the
acrania-hypothesis is clearly preferable when biomechanic options of a
polysegmented, hydroskeletal body plan are taken into account. The so called
hydroskeleton hypothesis, rooted in the work of W. F. Gutmann, is the most
detailed anagenetic scenario which depicts an acrania-like ur-deuterostome.


title: Non-geometric flux vacua, S-duality and algebraic geometry

abstract:
  The four dimensional gauged supergravities descending from non-geometric
string compactifications involve a wide class of flux objects which are needed
to make the theory invariant under duality transformations at the effective
level. Additionally, complex algebraic conditions involving these fluxes arise
from Bianchi identities and tadpole cancellations in the effective theory. In
this work we study a simple T and S-duality invariant gauged supergravity, that
of a type IIB string compactified on a $T^6/(Z_2 x Z_2)$ orientifold with
O3/O7-planes. We build upon the results of recent works and develop a
systematic method for solving all the flux constraints based on the algebra
structure underlying the fluxes. Starting with the T-duality invariant
supergravity, we find that the fluxes needed to restore S-duality can be simply
implemented as linear deformations of the gauge subalgebra by an element of its
second cohomology class. Algebraic geometry techniques are extensively used to
solve these constraints and supersymmetric vacua, centering our attention on
Minkowski solutions, become systematically computable and are also provided to
clarify the methods.


title: Test Functions in Constrained Interpolation

abstract:
  We give a set of test functions for the interpolation problem on $H_1^\infty$
, the constrained interpolation problem studied by Davidson, Paulsen,
Raghupathi and Singh. We show that this set of test functions is minimal.


title:
Divergence-Free Reconstruction of Magnetic Fields and WENO Schemes for
  Magnetohydrodynamics

abstract:
  Balsara (2001, J. Comput. Phys., 174, 614) showed the importance of
divergence-free reconstruction in adaptive mesh refinement problems for
magnetohydrodynamics (MHD) and the importance of the same for designing robust
second order schemes for MHD was shown in Balsara (2004, ApJS, 151, 149).
Second order accurate divergence-free schemes for MHD have shown themselves to
be very useful in several areas of science and engineering. However, certain
computational MHD problems would be much benefited if the schemes had third and
higher orders of accuracy. In this paper we show that the reconstruction of
divergence-free vector fields can be carried out with better than second order
accuracy. As a result, we design divergence-free weighted essentially
non-oscillatory (WENO) schemes for MHD that have order of accuracy better than
second. A multistage Runge-Kutta time integration is used to ensure that the
temporal accuracy matches the spatial accuracy. Accuracy analysis is carried
out and it is shown that the schemes meet their design accuracy for smooth
problems. Stringent tests are also presented showing that the schemes perform
well on those tests.


title: Nematic Films and Radially Anisotropic Delaunay Surfaces

abstract:
  We develop a theory of axisymmetric surfaces minimizing a combination of
surface tension and nematic elastic energies which may be suitable for
describing simple film and bubble shapes. As a function of the elastic constant
and the applied tension on the bubbles, we find the analogues of the unduloid,
sphere, and nodoid in addition to other new surfaces.


title:
Role of Coulomb interaction in the superconducting properties of CaC6
  and H under pressure

abstract:
  Superconductivity in intercalated graphite CaC6 and H under extreme pressure,
in the framework of superconducting density functional theory, is discussed. A
detailed analysis on how the electron-phonon and electron-electron interactions
combine together to determine the superconducting gap and critical temperature
of these systems is presented. In particular, we discuss the effect on the
calculated Tc of the anisotropy of the electron-phonon interaction and of the
different approximations for screening the Coulomb repulsion. These results
contribute to the understanding of multigap and anisotropic superconductivity,
which has received a lot of attention since the discovery of MgB2, and show how
it is possible to describe the superconducting properties of real materials on
a fully ab-initio basis.


title: Charge dynamics of the spin-density-wave state in BaFe$_2$As$_2$

abstract:
  We report on a thorough optical investigation of BaFe$_2$As$_2$ over a broad
spectral range and as a function of temperature, focusing our attention on its
spin-density-wave (SDW) phase transition at $T_{SDW}=135$ K. While
BaFe$_2$As$_2$ remains metallic at all temperatures, we observe a depletion in
the far infrared energy interval of the optical conductivity below $T_{SDW}$,
ascribed to the formation of a pseudogap-like feature in the excitation
spectrum. This is accompanied by the narrowing of the Drude term consistent
with the $dc$ transport results and suggestive of suppression of scattering
channels in the SDW state. About 20% of the spectral weight in the far infrared
energy interval is affected by the SDW phase transition.


title: Space-Time Structure of Loop Quantum Black Hole

abstract:
  In this paper we have improved the semiclassical analysis of loop quantum
black hole (LQBH) in the conservative approach of constant polymeric parameter.
In particular we have focused our attention on the space-time structure. We
have introduced a very simple modification of the spherically symmetric
Hamiltonian constraint in its holonomic version. The new quantum constraint
reduces to the classical constraint when the polymeric parameter goes to
zero.Using this modification we have obtained a large class of semiclassical
solutions parametrized by a generic function of the polymeric parameter. We
have found that only a particular choice of this function reproduces the black
hole solution with the correct asymptotic flat limit. In r=0 the semiclassical
metric is regular and the Kretschmann invariant has a maximum peaked in
L-Planck. The radial position of the pick does not depend on the black hole
mass and the polymeric parameter. The semiclassical solution is very similar to
the Reissner-Nordstrom metric. We have constructed the Carter-Penrose diagrams
explicitly, giving a causal description of the space-time and its maximal
extension. The LQBH metric interpolates between two asymptotically flat
regions, the r to infinity region and the r to 0 region. We have studied the
thermodynamics of the semiclassical solution. The temperature, entropy and the
evaporation process are regular and could be defined independently from the
polymeric parameter. We have studied the particular metric when the polymeric
parameter goes towards to zero. This metric is regular in r=0 and has only one
event horizon in r = 2m. The Kretschmann invariant maximum depends only on
L-Planck. The polymeric parameter does not play any role in the black hole
singularity resolution. The thermodynamics is the same.


title: The galileon as a local modification of gravity

abstract:
  In the DGP model, the ``self-accelerating'' solution is plagued by a ghost
instability, which makes the solution untenable. This fact as well as all
interesting departures from GR are fully captured by a four-dimensional
effective Lagrangian, valid at distances smaller than the present Hubble scale.
The 4D effective theory involves a relativistic scalar \pi, universally coupled
to matter and with peculiar derivative self-interactions. In this paper, we
study the connection between self-acceleration and the presence of ghosts for a
quite generic class of theories that modify gravity in the infrared. These
theories are defined as those that at distances shorter than cosmological,
reduce to a certain generalization of the DGP 4D effective theory. We argue
that for infrared modifications of GR locally due to a universally coupled
scalar, our generalization is the only one that allows for a robust
implementation of the Vainshtein effect--the decoupling of the scalar from
matter in gravitationally bound systems--necessary to recover agreement with
solar system tests. Our generalization involves an internal ``galilean''
invariance, under which \pi's gradient shifts by a constant. This symmetry
constrains the structure of the \pi Lagrangian so much so that in 4D there
exist only five terms that can yield sizable non-linearities without
introducing ghosts. We show that for such theories in fact there are
``self-accelerating'' deSitter solutions with no ghost-like instabilities. In
the presence of compact sources, these solutions can support spherically
symmetric, Vainshtein-like non-linear perturbations that are also stable
against small fluctuations. [Short version for arxiv]


title: The Church Problem for Countable Ordinals

abstract:
  A fundamental theorem of Buchi and Landweber shows that the Church synthesis
problem is computable. Buchi and Landweber reduced the Church Problem to
problems about ω-games and used the determinacy of such games as one of
the main tools to show its computability. We consider a natural generalization
of the Church problem to countable ordinals and investigate games of arbitrary
countable length. We prove that determinacy and decidability parts of the
Bu}chi and Landweber theorem hold for all countable ordinals and that its full
extension holds for all ordinals < \omega\^\omega.


title:
Reconstructing mass profiles of simulated galaxy clusters by combining
  Sunyaev-Zeldovich and X-ray images

abstract:
  We present a method to recover mass profiles of galaxy clusters by combining
data on thermal Sunyaev-Zeldovich (tSZ) and X-ray imaging, thereby avoiding to
use any information on X-ray spectroscopy. This method, which represents a
development of the geometrical deprojection technique presented in Ameglio et
al. (2007), implements the solution of the hydrostatic equilibrium equation. In
order to quantify the efficiency of our mass reconstructions, we apply our
technique to a set of hydrodynamical simulations of galaxy clusters. We propose
two versions of our method of mass reconstruction. Method 1 is completely
model-independent, while Method 2 assumes instead the analytic mass profile
proposed by Navarro et al. (1997) (NFW). We find that the main source of bias
in recovering the mass profiles is due to deviations from hydrostatic
equilibrium, which cause an underestimate of the mass of about 10 per cent at
r_500 and up to 20 per cent at the virial radius. Method 1 provides a
reconstructed mass which is biased low by about 10 per cent, with a 20 per cent
scatter, with respect to the true mass profiles. Method 2 proves to be more
stable, reducing the scatter to 10 per cent, but with a larger bias of 20 per
cent, mainly induced by the deviations from equilibrium in the outskirts. To
better understand the results of Method 2, we check how well it allows to
recover the relation between mass and concentration parameter. When analyzing
the 3D mass profiles we find that including in the fit the inner 5 per cent of
the virial radius biases high the halo concentration. Also, at a fixed mass,
hotter clusters tend to have larger concentration. Our procedure recovers the
concentration parameter essentially unbiased but with a scatter of about 50 per
cent.


title:
Efficient, High Accuracy ADER-WENO Schemes for Hydrodynamics and
  Divergence-Free Magnetohydrodynamics

abstract:
  The present paper introduces a class of finite volume schemes of increasing
order of accuracy in space and time for hyperbolic systems that are in
conservation form. This paper specifically focuses on Euler system that is used
for modeling the flow of neutral fluids and the divergence-free, ideal
magnetohydrodynamics (MHD) system that is used for large scale modeling of
ionized plasmas.
  Efficient techniques for weighted essentially non-oscillatory (WENO)
interpolation have been developed for finite volume reconstruction on
structured meshes. We also present a new formulation of the ADER (for Arbitrary
Derivative Riemann Problem) schemes that relies on a local continuous
space-time Galerkin formulation instead of the usual Cauchy-Kovalewski
procedure.
  The schemes reported here have all been implemented in the RIEMANN framework
for computational astrophysics. We demonstrate that the ADER-WENO meet their
design accuracies. Several stringent test problems of Euler flows and MHD flows
are presented in one, two and three dimensions. Many of our test problems
involve near infinite shocks in multiple dimensions and the higher order
schemes are shown to perform very robustly and accurately under all conditions.


title: Fast Maximum-Likelihood Decoding of the Golden Code

abstract:
  The golden code is a full-rate full-diversity space-time code for two
transmit antennas that has a maximal coding gain. Because each codeword conveys
four information symbols from an M-ary quadrature-amplitude modulation
alphabet, the complexity of an exhaustive search decoder is proportional to
M^2. In this paper we present a new fast algorithm for maximum-likelihood
decoding of the golden code that has a worst-case complexity of only O(2M^2.5).
We also present an efficient implementation of the fast decoder that exhibits a
low average complexity. Finally, in contrast to the overlaid Alamouti codes,
which lose their fast decodability property on time-varying channels, we show
that the golden code is fast decodable on both quasistatic and rapid
time-varying channels.


title:
An ab initio Calculation of the Universal Equation of State for the O(N)
  Model

abstract:
  Using an Environmentally Friendly Renormalization Group we derive an ab
initio universal scaling form for the equation of state for the O(N) model,
y=f(x), that exhibits all required analyticity properties in the limits $x\to
0$, $x\to\infty$ and $x\to -1$. Unlike current methodologies based on a
phenomenological scaling ansatz the scaling function is derived solely from the
underlying Landau-Ginzburg-Wilson Hamiltonian and depends only on the three
Wilson functions $\gamma_\lambda$, $\gamma_\phi$ and $\gamma_{\phi^2}$ which
exhibit a non-trivial crossover between the Wilson-Fisher fixed point and the
strong coupling fixed point associated with the Goldstone modes on the
coexistence curve. We give explicit results for N=2, 3 and 4 to one-loop order
and compare with known results.


title: Persistent Homology of Complex Networks

abstract:
  Long lived topological features are distinguished from short lived ones
(considered as topological noise) in simplicial complexes constructed from
complex networks. A new topological invariant, persistent homology, is
determined and presented as a parametrized version of a Betti number. Complex
networks with distinct degree distributions exhibit distinct persistent
topological features. Persistent toplogical attributes, shown to be related to
robust quality of networks, also reflect defficiency in certain connectivity
properites of networks. Random networks, networks with exponential conectivity
distribution and scale-free networks were considered for homological
persistency analysis.


title: Neutralino Dark Matter in the USSM

abstract:
  This paper provides a comprehensive discussion of neutralino dark matter
within classes of extended supersymmetric models referred to as the USSM
containing one additional SM singlet Higgs plus an extra $Z'$, together with
their superpartners the singlino and bino'. These extra states of the USSM can
significantly modify the nature and properties of neutralino dark matter
relative to that of the minimal (or even next-to-minimal) supersymmetric
standard models. We derive the Feynman rules for the USSM and calculate the
dark matter relic abundance and direct detection rates for elastic scattering
in the USSM for interesting regions of parameter space where the largest
differences are expected.


title:
(Sr_3Sc_2O_5)Fe_2As_2 as a possible parent compound for FeAs-based
  superconductors

abstract:
  A new compound with the FeAs-layers, namely (Sr_3Sc_2O_5)Fe_2As_2
(abbreviated as FeAs-32522), was successfully fabricated. It has a layered
structure with the space group of I4/mmm, and with the lattice constants a =
4.069 $\AA$ and c = 26.876 $\AA$. The in-plane Fe ions construct a square
lattice which is close to that of other FeAs-based superconductors, such as
REFeAsO (RE = rare earth elements) and (Ba,Sr)Fe_2As_2. However the inter
FeAs-layer spacing in the new compound is greatly enlarged. The temperature
dependence of resistivity exhibits a weak upturn in the low temperature region,
but a metallic behavior was observed above about 60 K. The magnetic
susceptibility shows also a non-monotonic behavior. Interestingly, the
well-known resistivity anomaly which was discovered in all other parent
compounds, such as REFeAsO, (Ba,Sr)Fe_2As_2 and (Sr,Ca,Eu)FeAsF and associated
with the Spin-Density-Wave (SDW)/structural transition has not been found in
the new system either on the resistivity data or the magnetization data. This
could be induced by the large spacing distance between the FeAs-planes,
therefore the antiferromagnetic correlation between the moments of Fe ions in
neighboring FeAs-layers cannot be established. Alternatively it can also be
attributed to the self-doping effect between Fe and Sc ions. The Hall
coefficient R_H is negative but strongly temperature dependent in wide
temperature region, which indicates the dominance of electrical conduction by
electron-like charge carriers and probably a multi-band effect or a spin
related scattering effect. It is found that the magnetoresistance cannot be
described by the Kohler's rule, which gives further support to above arguments.


title:
Signature of persistent metallic domains in FORC measurements of the
  VO$_2$ metal-insulator transition

abstract:
  We have performed first order reversal curve measurements of the
temperature-driven metal-insulator transition in VO$_2$ thin films, which
enable quantitative analysis of the hysteresis behavior. An unexpected
tail-like feature in the contour plot of the reversal curve distribution
indicates the existence of metallic domains, even at temperatures below the
closing of the hysteresis. These domains interact with the surrounding medium
and change the reversal path relative to a path from a \emph{fully} insulating
state. With this in mind, and assuming that such interaction persist through
the entire phase transition, we develop a model where the driving force (or
energy barrier) in charge of opening a hysteresis in VO$_2$ are inter-domain
interactions. This model is intrinsically different from the Preisach model
usually used to describe hysteresis; given that it looks for the microscopic
origin of the hysteresis, and provides physical parameters to characterize it.


title: The N=2 cascade revisited and the enhancon bearings

abstract:
  Supergravity backgrounds with varying fluxes generated by fractional branes
at non-isolated Calabi-Yau singularities had escaped a precise dual field
theory interpretation so far. In the present work, considering the prototypical
example of such models, the C*C^2/Z_2 orbifold, we propose a solution for this
problem, and show that the known cascading solution corresponds to a vacuum on
the Coulomb branch of the corresponding quiver gauge theory involving a
sequence of strong coupling transitions reminiscent of the baryonic root of N=2
SQCD. We also find a slight modification of this cascading vacuum which upon
mass deformation is expected to flow to the Klebanov-Strassler cascade.
Finally, we discuss an infinite class of vacua on the Coulomb branch whose RG
flows include infinitely coupled conformal regimes, and explain their
gravitational manifestation in terms of new geometric structures that we dub
enhancon bearings. Repulson-free backgrounds dual to all the vacua we analyse
are explicitly provided.


title: Origin of the long-wavelength magnetic modulation in Ca3Co2O6

abstract:
  The origin of the long-wavelength incommensurate magnetic structure of
Ca3Co2O6 is discussed considering possible inter-chains super-superexchange
paths. The experimental value of the propagation vector k=(0,0,$\Delta$) with
$\Delta$ $>$ 1 can be reproduced only if one considers the next nearest
super-superexchange interaction. A spin-dimer analysis using the
Extended-Huckel Tight-Binding method confirms that, despite longer interatomic
Co-Co distances, the latter interaction is indeed much stronger. The stability
of the observed structure with respect to certain commensurate states is
discussed.


title: Boolean modeling of collective effects in complex networks

abstract:
  Complex systems are often modeled as Boolean networks in attempts to capture
their logical structure and reveal its dynamical consequences. Approximating
the dynamics of continuous variables by discrete values and Boolean logic gates
may, however, introduce dynamical possibilities that are not accessible to the
original system. We show that large random networks of variables coupled
through continuous transfer functions often fail to exhibit the complex
dynamics of corresponding Boolean models in the disordered (chaotic) regime,
even when each individual function appears to be a good candidate for Boolean
idealization. A suitably modified Boolean theory explains the behavior of
systems in which information does not propagate faithfully down certain chains
of nodes. Model networks incorporating calculated or directly measured transfer
functions reported in the literature on transcriptional regulation of genes are
described by the modified theory.


title: Unitarity bound for gluon shadowing

abstract:
  Although at small Bjorken x gluons originated from different nucleons in a
nucleus overlap in the longitudinal direction, most of them are still well
separated in the transverse plane, therefore cannot fuse. For this reason the
gluon density in nuclei cannot drop at small x below a certain bottom bound,
which we evaluated in a model independent manner assuming the maximal strength
of gluon fusion. We also calculated gluon shadowing in the saturated regime
using on the Balitsky-Kovchegov equation, and found the nuclear ratio to be
well above the unitarity bound. The recently updated analysis of parton
distributions in nuclei \cite{eps08} including RHIC data on high-pT hadron
production at forward rapidities, led to astonishingly strong gluon shadowing,
which is far beyond the unitarity bound. This indicates a misconception in the
interpretation of the nuclear suppression observed at HRIC.


title: Nucleon Form Factors from 5D Skyrmions

abstract:
  Several aspects of hadron physics are well described by a simple 5D effective
field theory. Baryons arise in this scenario as "large" (and therefore
calculable) 5D skyrmions. We extend and refine the existing analysis of this 5D
soliton, which is fairly non-trivial due to the need of numerical methods. We
perform the complete quantization of those collective coordinates which are
relevant for computing the static observables like the nucleon form factors. We
compare the result with simple expectations about large-N_c QCD and with the
experimental data. An agreement within 30% is found.


title: Wave functions of the nucleon and its parity partner from lattice QCD

abstract:
  We compute moments of distribution amplitudes using gauge configurations with
two flavors of clover fermions from QCDSF/DIK and operators which are optimized
with respect to their behavior under the lattice symmetries. The knowledge of
these quantities helps in understanding the internal structure of hadrons and
in the analysis of (semi-)exclusive processes. We present results for the
nucleon distribution amplitude which suggest that the asymmetries (the
deviations from the asymptotic form) are smaller than indicated by sum rule
calculations. Using the same approach we were also able to calculate the same
quantities for the $N^\star(1535)$, the parity partner of the nucleon. These
results show a stronger deviation from the asymptotic form.


title:
Splice diagram determining singularity links and universal abelian
  covers

abstract:
  To a rational homology sphere graph manifold one can associate a weighted
tree invariant called splice diagram. In this article we prove a sufficient
numerical condition on the splice diagram for a graph manifold to be a
singularity link. We also show that if two manifolds have the same splice
diagram, then their universal abelian covers are homeomorphic. To prove the
last theorem we have to generalize our notions to orbifolds.


title:
The local FIR Galaxy Colour-Luminosity distribution: A reference for
  BLAST, and Herschel/SPIRE sub-mm surveys

abstract:
  We measure the local galaxy far-infrared (FIR) 60-to-100 um colour-luminosity
distribution using an all-sky IRAS survey. This distribution is an important
reference for the next generation of FIR--submillimetre surveys that have and
will conduct deep extra-galactic surveys at 250--500 um. With the peak in
dust-obscured star-forming activity leading to present-day giant ellipticals
now believed to occur in sub-mm galaxies near z~2.5, these new
FIR--submillimetre surveys will directly sample the SEDs of these distant
objects at rest-frame FIR wavelengths similar to those at which local galaxies
were observed by IRAS. We have taken care to correct for temperature bias and
evolution effects in our IRAS 60 um-selected sample. We verify that our
colour-luminosity distribution is consistent with measurements of the local FIR
luminosity function, before applying it to the higher-redshift Universe. We
compare our colour-luminosity correlation with recent dust-temperature
measurements of sub-mm galaxies and find evidence for pure luminosity evolution
of the form (1+z)^3. This distribution will be useful for the development of
evolutionary models for BLAST and SPIRE surveys as it provides a statistical
distribution of rest-frame dust temperatures for galaxies as a function of
luminosity.


title: Plumbers' knots

abstract:
  We construct a new type of geometric knot theory, plumbers' knots, and solve
the problems of distinguishing and enumerating such knots at a fixed level of
complexity. (v2) Minor edits, added theorem 3.18. (v3) Substantial revisions,
essentially completely rewritten in places.


title:
Phenomenology of the three-flavor PNJL model and thermal strange quark
  production

abstract:
  We study the temperature dependence of the adjoint Polyakov loop and its
implication for the momentum spectrum of gluons in the mean-field
approximation. This allows us to calculate the contribution of the thermal
(transverse) gluons to the thermodynamic pressure. As an application, we
evaluate the rates for the strange quark pair-production processes $q\bar{q}
\to s\bar{s}$ and $gg \to s\bar{s}$ as functions of temperature including
thermal effects on quark deconfinement and chiral symmetry breaking.


title: Quantum Criticality and Yang-Mills Gauge Theory

abstract:
  We present a family of nonrelativistic Yang-Mills gauge theories in D+1
dimensions whose free-field limit exhibits quantum critical behavior with
gapless excitations and dynamical critical exponent z=2. The ground state
wavefunction is intimately related to the partition function of relativistic
Yang-Mills in D dimensions. The gauge couplings exhibit logarithmic scaling and
asymptotic freedom in the upper critical spacetime dimension, equal to 4+1. The
theories can be deformed in the infrared by a relevant operator that restores
Poincare invariance as an accidental symmetry. In the large-N limit, our
nonrelativistic gauge theories can be expected to have weakly curved gravity
duals.

categories: hep-th cond-mat.mes-hall cond-mat.str-el hep-ph


title:
Mott transition between a spin-liquid insulator and a metal in three
  dimensions

abstract:
  We study a bandwidth controlled Mott metal-insulator transition (MIT) between
a Fermi liquid metal and a quantum spin-liquid insulator at half-filling in
three dimensions (3D). Using a slave rotor approach, and incorporating gauge
field fluctuations, we find a continuous MIT and discuss the finite temperature
crossovers around this critical point. We show that the specific heat C=T ln ln
(1/T) at the MIT and argue that the electrical transport on the metallic side
near the transition should exhibit a `conductivity minimum' as a function of
temperature. A possible candidate to test these predictions is the 3D spin
liquid insulator Na4Ir3O8 which exhibits a pressure-tuned transition into a
metallic phase. We also present the electron spectral function of Na4Ir3O8 at
the transition.


title: State diagrams for harmonically trapped bosons in optical lattices

abstract:
  We use quantum Monte Carlo simulations to obtain zero-temperature state
diagrams for strongly correlated lattice bosons in one and two dimensions under
the influence of a harmonic confining potential. Since harmonic traps generate
a coexistence of superfluid and Mott insulating domains, we use local
quantities such as the quantum fluctuations of the density and a local
compressibility to identify the phases present in the inhomogeneous density
profiles. We emphasize the use of the "characteristic density" to produce a
state diagram that is relevant to experimental optical lattice systems,
regardless of the number of bosons or trap curvature and of the validity of the
local-density approximation. We show that the critical value of U/t at which
Mott insulating domains appear in the trap depends on the filling in the
system, and it is in general greater than the value in the homogeneous system.
Recent experimental results by Spielman et al. [Phys. Rev. Lett. 100, 120402
(2008)] are analyzed in the context of our two-dimensional state diagram, and
shown to exhibit a value for the critical point in good agreement with
simulations. We also study the effects of finite, but low (T<t/2),
temperatures. We find that in two dimensions they have little influence on our
zero-temperature results, while their effect is more pronounced in one
dimension.


title:
Spatially Resolved 3 micron Spectroscopy of Elias 1: Origin of Diamonds
  in Protoplanetary Disks

abstract:
  We present spatially resolved 3 um spectra of Elias 1 obtained with an
adaptive optics system. The central part of the disk is almost devoid of PAH
emission at 3.3 um; it shows up only at 30 AU and beyond. The PAH emission
extends up to 100 AU, at least to the outer boundary of our observation. The
diamond emission, in contrast, is more centrally concentrated, with the column
density peaked around 30 AU from the star. There are only three Herbig Ae/Be
stars known to date that show diamond emission at 3.53 um. Two of them have
low-mass companions likely responsible for the large X-ray flares observed
toward the Herbig Ae/Be stars. We speculate on the origin of diamonds in
circumstellar disks in terms of the graphitic material being transformed into
diamond under the irradiation of highly energetic particles.


title: Constraints on the Primordial Magnetic Field from $\sigma_8$

abstract:
  A primordial magnetic field (PMF) can affect the evolution of density field
fluctuations in the early universe.In this paper we constrain the PMF amplitude
$B_\lambda$ and power spectral index $n_\mathrm{B}$ by comparing calculated
density field fluctuations with observational data, i.e. the number density
fluctuation of galaxies.We show that the observational constraints on
cosmological density fluctuations, as parameterized by $\sigma_8$, lead to
strong constraints on the amplitude and spectral index of the PMF.


title: The Race Between Stars and Quasars in Reionizing Cosmic Hydrogen

abstract:
  The cosmological background of ionizing radiation has been dominated by
quasars once the Universe aged by ~2 billion years. At earlier times (redshifts
z>3), the observed abundance of bright quasars declined sharply, implying that
cosmic hydrogen was reionized by stars instead. Here, we explain the physical
origin of the transition between the dominance of stars and quasars as a
generic feature of structure formation in the concordance LCDM cosmology. At
early times, the fraction of baryons in galaxies grows faster than the maximum
(Eddington-limited) growth rate possible for quasars. As a result, quasars were
not able to catch up with the rapid early growth of stellar mass in their host
galaxies.


title: Primordial non-Gaussianities in the Intergalactic Medium

abstract:
  We present results from the first high-resolution hydrodynamical simulations
of non-Gaussian cosmological models. We focus on the statistical properties of
the transmitted Lyman-alpha flux in the high redshift intergalactic medium.
Imprints of non-Gaussianity are present and are larger at high redshifts.
Differences larger than 20 % at z>3 in the flux probability distribution
function for high transmissivity regions (voids) are expected for values of the
non linearity parameter f_NL=\pm 100 when compared to a standard LCDM cosmology
with f_NL=0. We investigate also the one-dimensional flux bispectrum: at the
largest scales (corresponding to tens of Mpc) we expect deviations in the flux
bispectrum up to 20% at z~4 (for f_NL=\pm 100), significantly larger than
deviations of ~ 3% in the flux power spectrum. We briefly discuss possible
systematic errors that can contaminate the signal. Although challenging, a
detection of non-Gaussianities in the interesting regime of scales and
redshifts probed by the Lyman-alpha forest, could be possible with future data
sets.


title:
Electronic phase separation in the slightly underdoped iron pnictide
  superconductor Ba(1-x)K(x)Fe(2)As(2)

abstract:
  Here we present a combined study of the slightly underdoped novel pnictide
superconductor Ba(1-x)K(x)Fe(2)As(2) by means of X-ray powder diffraction,
neutron scattering, muon spin rotation (muSR), and magnetic force microscopy
(MFM). Commensurate static magnetic order sets in below Tm ~ 70 K as inferred
from the emergence of the magnetic (1 0 -3) reflection in the neutron
scattering data and from the observation of damped oscillations in the
zero-field-muSR asymmetry. Transverse-field muSR below Tc shows a coexistence
of magnetically ordered and non-magnetic states, which is also confirmed by MFM
imaging. We explain such coexistence by electronic phase separation into
antiferromagnetic and superconducting/normal state regions on a lateral scale
of several tens of nanometers. Our findings indicate that such mesoscopic phase
separation can be considered an intrinsic property of some iron pnictide
superconductors.


title: Kerr-AdS/CFT Correspondence in Diverse Dimensions

abstract:
  It was proposed recently that the near-horizon states of an extremal
four-dimensional Kerr black hole could be identified with a certain chiral
conformal field theory whose Virasoro algebra arises as an asymptotic symmetry
algebra of the near-horizon Kerr geometry. Supportive evidence for the proposed
duality came from the equality of the microscopic entropy of the CFT,
calculated by means of the Cardy formula, and the Bekenstein-Hawking entropy of
the extremal Kerr black hole. In this paper we examine the proposed Kerr/CFT
correspondence in a broader context. In particular, we show that the
microscopic entropy and the Bekenstein-Hawking entropy agree also for the
extremal Kerr-AdS metric in four dimensions, and also for the extremal Kerr-AdS
metrics in dimensions 5, 6 and 7. General formulae for all higher dimensions
are also presented.


title: Quasi-degenerate neutrinos and tri-bi-maximal mixing

abstract:
  We consider how, for quasi-degenerate neutrinos with tri-bi-maximal mixing at
a high-energy scale, the mixing angles are affected by radiative running from
high to low-energy scales in a supersymmetric theory. The limits on the
high-energy scale that follow from consistency with the observed mixing are
determined. We construct a model in which a non-Abelian discrete family
symmetry leads both to a quasi-degenerate neutrino mass spectrum and to near
tri-bi-maximal mixing.


title: Phase diagram of Hertzian spheres

abstract:
  We report the phase diagram of interpenetrating Hertzian spheres. The Hertz
potential is purely repulsive, bounded at zero separation, and decreases
monotonically as a power law with exponent 5/2, vanishing at the overlapping
threshold. This simple functional describes the elastic interaction of weakly
deformable bodies and, therefore, it is a reliable physical model of soft
macromolecules, like star polymers and globular micelles. Using thermodynamic
integration and extensive Monte Carlo simulations, we computed accurate free
energies of the fluid phase and a large number of crystal structures. For this,
we defined a general primitive unit cell that allows for the simulation of any
lattice. We found multiple re-entrant melting and first-order transitions
between crystals with cubic, trigonal, tetragonal, and hexagonal symmetries.


title: On the Origin of Dwarf Elliptical Galaxies: The Fundamental Plane

abstract:
  Early-type dwarf galaxies are the most common type of galaxies observed in
the Universe. The origin of this kind of systems is still not well understood.
The aim of this paper is to investigate whether the different locations of
dwarf galaxies with respect to ellipticals in the face-on view of the
fundamental plane could be due to the transformation of bright disc galaxies in
low-mass systems by harassment. We have run high-resolution N-body numerical
simulations to test the tidal stripping scenario of the dE galaxies. The
present simulations modelled several individual tidal stripping events on
initial disc-like galaxy models with different bulge-to-disc mass ratios. Tidal
stripping is a very efficient mechanism for removing stars and dark matter
particles from galaxies. The particles of the disc and halo components were
easily stripped, while the bulge not. Thus, the scale length of the discs were
40-50% shorter than the initial ones. Prograde tidal interactions create tidal
features like stable bars in the discs of the galaxies. After several tidal
interactions the galaxy remnants looks like a dwarf spheroidal system.
Simulated galaxies with initial large B/D ratios are closer to the face-on view
of the fundamental plane defined by bright E and bulges of early-type galaxies.
Nevertheless, galaxies with initial small B/D ratio are located, after four
fast tidal encounters, at the position of dE galaxies in the face-on view of
the fundamental plane. We conclude that fast galaxy-galaxy interactions are
efficient mechanisms for transforming bright galaxies in dwarf ones. Indeed,
the different location observed between Es and dEs in the face-on view of the
fundamental plane can be explained by the formation of dwarf galaxies by
harassment of late-type bright ones.


title:
Asymptotics of solutions of the wave equation on de Sitter-Schwarzschild
  space

abstract:
  Solutions to the wave equation on de Sitter-Schwarzschild space with smooth
initial data on a Cauchy surface are shown to decay exponentially to a constant
at temporal infinity, with corresponding uniform decay on the appropriately
compactified space.


title:
Lorentz Invariance Violation and the Observed Spectrum of Ultrahigh
  Energy Cosmic Rays

abstract:
  There has been much interest in possible violations of Lorentz invariance,
particularly motivated by quantum gravity theories. It has been suggested that
a small amount of Lorentz invariance violation (LIV) could turn off photomeson
interactions of ultrahigh energy cosmic rays (UHECRs) with photons of the
cosmic background radiation and thereby eliminate the resulting sharp
steepening in the spectrum of the highest energy CRs predicted by Greisen
Zatsepin and Kuzmin (GZK). Recent measurements of the UHECR spectrum reported
by the HiRes and Auger collaborations, however, indicate the presence of the
GZK effect. We present the results of a detailed calculation of the
modification of the UHECR spectrum caused by LIV using the formalism of Coleman
and Glashow. We then compare these results with the experimental UHECR data
from Auger and HiRes. Based on these data, we find a best fit amount of LIV of
$4.5^{+1.5}_{-4.5} \times 10^{-23}$,consistent with an upper limit of $6 \times
10^{-23}$. This possible amount of LIV can lead to a recovery of the cosmic ray
spectrum at higher energies than presently observed. Such an LIV recovery
effect can be tested observationally using future detectors.


title: Spin-charge separation in strongly interacting finite ladder rings

abstract:
  We study the conductance through Aharonov-Bohm finite ladder rings with
strongly interacting electrons, modelled by the prototypical t-J model. For a
wide range of parameters we observe characteristic dips in the conductance as a
function of magnetic flux, predicted so far only in chains which are a
signature of spin and charge separation. These results open the possibility of
observing this peculiar many-body phenomenon in anisotropic ladder systems and
in real nanoscopic devices.


title:
Extinction of Populations and the Schr\"{o}dinger Equation: Analytic
  Calculations for Abrupt Transitions

abstract:
  We study bifurcations in a spatially extended nonlinear system representing
population dynamics with the help of analytic calculations based on the
time-independent Schr\"{o}dinger equation for a quantum particle subjected to a
uniform gravitational field. Despite the linear character of the
Schr\"{o}dinger equation, the result we obtain helps in the understanding of
the onset of abrupt transitions leading to extinction of biological
populations. The result is expressed in terms of Airy functions and sheds light
on the behavior of bacteria in a Petri dish as well as of large animals such as
rodents moving over a landscape.


title: Complete intersection points on general surfaces in $\PP^3$

abstract:
  In this paper we consider the existence of complete intersection points of
type $(a,b,c)$, on the generic degree $d$ surface of $\PP^3$. For any choice of
$a, b, c$ we resolve the existence question asymptotically, i.e. for all $d \gg
0$. For small values of $a, b, c$ we resolve the existence problem completely.


title: Covariant Balance Laws in Continua with Microstructure

abstract:
  The purpose of this paper is to extend the Green-Naghdi-Rivlin balance of
energy method to continua with microstructure. The key idea is to replace the
group of Galilean transformations with the group of diffeomorphisms of the
ambient space. A key advantage is that one obtains in a natural way all the
needed balance laws on both the macro and micro levels along with two
Doyle-Erickson formulas.


title: Intrinsic Coupling between Current and Domain Wall Motion in (Ga,Mn)As

abstract:
  We consider current-induced domain wall motion and, the reciprocal process,
moving domain wall-induced current. The associated Onsager coefficients are
expressed in terms of scattering matrices. Uncommonly, in (Ga,Mn)As, the
effective Gilbert damping coefficient $\alpha_w$ and the effective out-of-plane
spin transfer torque parameter $\beta_w$ are dominated by spin-orbit
interaction in combination with scattering off the domain wall, and not
scattering off extrinsic impurities. Numerical calculations give $\alpha_w \sim
0.01$ and $\beta_w \sim 1$ in dirty (Ga,Mn)As. The extraordinary large
$\beta_w$ parameter allows experimental detection of current or voltage induced
by domain wall motion in (Ga,Mn)As.


title:
Apollonian circle packings and closed horospheres on hyperbolic
  3-manifolds

abstract:
  We obtain an asymptotic formula for the number of circles of curvature at
most T in any given bounded Apollonian circle packing. For an integral packing,
we obtain the upper bounds for the number of circles with prime curvature as
well as of pairs of circles with prime curvatures, which are sharp up constant
multiples. The main ingredient of our proof is the effective equidistribution
of expanding horospheres on geometrically finite hyperbolic 3-manifolds under
the assumption that the critical exponent of its fundamental group exceeds one.


title: Newtonian Aspects of General Relativistic Galaxy Models

abstract:
  Many cosmological observations call for the existence of dark matter. The
most direct evidence for dark matter is inferred from the measured flatness of
galactic rotation curves. The latter is based on Newtonian gravity. Alternative
approaches to the rotation curve problem by means of general relativity have
recently been put forward. The class of models of interest is a subset of the
axially symmetric and stationary solutions of Einstein's equations with
rotating dust. As a step toward the understanding of general relativistic
galaxy models, we analyse rigidly as well as non-rigidly rotating
(Post-)Newtonian spacetimes. We find that the Newtonian limit of the considered
general relativistic galaxy model leads to Post-Newtonian terms in the metric.


title:
The matching property of infinitesimal isometries on elliptic surfaces
  and elasticity of thin shells

abstract:
  Using the notion of Gamma-convergence, we discuss the limiting behavior of
the 3d nonlinear elastic energy for thin elliptic shells, as their thickness h
converges to zero, under the assumption that the elastic energy of deformations
scales like $h^\beta$ with $2<\beta<4$. We establish that, for the given
scaling regime, the limiting theory reduces to the linear pure bending. Two
major ingredients of the proofs are: the density of smooth infinitesimal
isometries in the space of $W^{2,2}$ first order infinitesimal isometries, and
a result on matching smooth infinitesimal isometries with exact isometric
immersions on smooth elliptic surfaces.


title:
CARS: the CFHTLS-Archive-Research Survey; I. Five-band multi-colour data
  from 37 sq. deg. CFHTLS-Wide observations

abstract:
  We present the CFHTLS-Archive-Research Survey (CARS). It is a virtual
multi-colour survey based on public archive images from the CFHT-Legacy-Survey.
Our main scientific interests in CARS are optical searches for galaxy clusters
from low to high redshift and their subsequent study with photometric and
weak-gravitational lensing techniques. As a first step of the project we
present multi-colour catalogues from 37 sq. degrees of the CFHTLS-Wide
component. Our aims are to create astrometrically and photometrically well
calibrated co-added images. Second goal are five-band (u*, g', r', i', z')
multi-band catalogues with an emphasis on reliable estimates for object
colours. These are subsequently used for photometric redshift estimates. The
article explains in detail data processing, multi-colour catalogue creation and
photometric redshift estimation. Furthermore we apply a novel technique, based
on studies of the angular galaxy cross-correlation function, to quantify the
reliability of photo-z's. The accuracy of our high-confidence photo-z sample
(10-15 galaxies per sq. arcmin) is estimated to $\sigma_{\Delta_z/(1+z)}\approx
0.04-0.05$ up to i'<24 with typically only 1-3% outliers. Interested users can
obtain access to our data by request to the authors.


title:
On the importance of satellite lines to the He-like K ALPHA complex and
  the G ratio for calcium, iron, and nickel

abstract:
  New, more detailed calculations of the emission spectra of the He-like K
ALPHA complex of calcium, iron and nickel have been carried out using data from
both distorted-wave and R-matrix calculations. The value of the GD ratio (an
extended definition of the G ratio that accounts for the effect of resolved and
unresolved satellite lines) is significantly enhanced at temperatures below the
temperature of He-like maximum abundance. Furthermore it is shown that
satellite lines are important contributors to the GD ratio such that GD/G>1 at
temperatures well above the temperature of maximum abundance. These new
calculations demonstrate, with an improved treatment of the KLn (n>=3)
satellite lines, that K ALPHA satellite lines need to be included in models of
He like spectra even at relatively high temperatures. The excellent agreement
between spectra and line ratios calculated from R-matrix and distorted-wave
data also confirms the validity of models based on distorted-wave data for
highly charged systems, provided the effect of resonances are taken into
account as independent processes.


title:
Template nanowires for spintronics applications: nanomagnet microwave
  resonators functioning in zero applied magnetic field

abstract:
  Low-cost spintronic devices functioning in zero applied magnetic field are
required for bringing the idea of spin-based electronics into the real-world
industrial applications. Here we present first microwave measurements performed
on nanomagnet devices fabricated by electrodeposition inside porous membranes.
In the paper, we discuss in details a microwave resonator consisting of three
nanomagnets, which functions in zero external magnetic field. By applying a
microwave signal at a particular frequency, the magnetization of the middle
nanomagnet experiences the ferromagnetic resonance (FMR), and the device
outputs a measurable direct current (spin-torque diode effect). Alternatively,
the nanodevice can be used as a microwave oscillator functioning in zero field.
In order to test the resonators at microwave frequencies, we developed a simple
measurement set-up.


title:
Interference of nematic quantum critical quasiparticles: a route to the
  octet model

abstract:
  Repeated observations of inhomogeneity in cuperate superconductors[1-5] make
one immediately question the existance of coherent quasiparticles(qp's) and the
applicability of a momentum space picture. Yet, obversations of interference
effects[6-9] suggest that the qp's maintain a remarkable coherence under
special circumstances. In particular, quasi-particle interference (QPI) imaging
using scanning tunneling spectroscopy revealed a highly unusual form of
coherence: accumulation of coherence only at special points in momentum space
with a particular energy dispersion[5-7]. Here we show that nematic quantum
critical fluctuations[10], combined with the known extreme velocity
anisotropy[11] provide a natural mechanism for the accumulation of coherence at
those special points. Our results raise the intriguing question of whether the
nematic fluctuations provide the unique mechanism for such a phenomenon.


title:
Asymptotic analysis of a family of polynomials associated with the
  inverse error function

abstract:
  We analyze the sequence of polynomials defined by the differential-difference
equation $P_{n+1}(x)=P_{n}^{\prime}(x)+x(n+1)P_{n}(x)$ asymptotically as
$n\to\infty$. The polynomials $P_{n}(x)$ arise in the computation of higher
derivatives of the inverse error function $\operatorname{inverf}(x)$. We use
singularity analysis and discrete versions of the WKB and ray methods and give
numerical results showing the accuracy of our formulas.


title: Supergravity Solutions Without Tri-holomorphic U(1) Isometries

abstract:
  We investigate the construction of five-dimensional supergravity solutions
that don't have any tri-holomorphic U(1) isometries. We construct a class of
solutions that in various limits of parameters reduces to many of previously
constructed five-dimensional supergravity solutions based on both hyper-Kahler
base spaces that can be put into a Gibbons-Hawking form and hyper-Kahler base
spaces that can't be put into a Gibbons-Hawking form. We find a new solution
which is over triaxial Bianchi type IX Einstein-hyperkahler base space with no
tri-holomorphic U(1) symmetry. One special case of this solution corresponds to
five-dimensional solution based on Eguchi-Hanson type II geometry.


title:
A continuous model for microtubule dynamics with catastrophe, rescue and
  nucleation processes

abstract:
  Microtubules are a major component of the cytoskeleton distinguished by
highly dynamic behavior both in vitro and in vivo. We propose a general
mathematical model that accounts for the growth, catastrophe, rescue and
nucleation processes in the polymerization of microtubules from tubulin dimers.
Our model is an extension of various mathematical models developed earlier
formulated in order to capture and unify the various aspects of tubulin
polymerization including the dynamic instability, growth of microtubules to
saturation, time-localized periods of nucleation and depolymerization as well
as synchronized oscillations exhibited by microtubules under various
experimental conditions. Our model, while attempting to use a minimal number of
adjustable parameters, covers a broad range of behaviors and has predictive
features discussed in the paper. We have analyzed the resultant behaviors of
the microtubules changing each of the parameter values at a time and observing
the emergence of various dynamical regimes.


title: On the cohomology of a simple normal crossings divisor

abstract:
  We establish a formula which decomposes the cohomologies of various sheaves
on a simple normal crossings divisor (SNC) $D$ in terms of the simplicial
cohomologies of the dual complex $\Delta(D)$ with coefficients in a presheaf of
vector spaces. This presheaf consists precisely of the corresponding cohomology
data on the components of $D$ and on their intersections. We use this formula
to give a Hodge decomposition for SNC divisors and investigate the toric
setting. We also conjecture the existence of such a formula for effective
non-reduced divisors with SNC support, and show that this would imply the
vanishing of the higher simplicial cohomologies of the dual complex associated
to a resolution of an isolated rational singularity.


title: Superfocusing by Nano-Shells

abstract:
  Recently Merlin and co-workers demonstrated, both theoretically and in the
microwave range experimentally, subwavelength focusing of evanescent waves by
patterned plates. The present paper extends these ideas and the design
procedure to scatterers of arbitrary shapes and to the optical range of
wavelengths. The analytical study is supported by numerical results. The most
intriguing feature of the proposed design is that, in the framework of
classical electrodynamics of continuous media, focusing can in principle be
arbitrarily sharp, subject to the constraints of fabrication.


title: Dissipation and the Relaxation to Equilibrium

abstract:
  Using the recently derived Dissipation Theorem and a corollary of the
Transient Fluctuation Theorem (TFT), namely the Second Law Inequality, we
derive the unique time independent, equilibrium phase space distribution
function for an ergodic Hamiltonian system in contact with a remote heat bath.
We prove under very general conditions that any deviation from this equilibrium
distribution breaks the time independence of the distribution. Provided
temporal correlations decay, and the system is ergodic, we show that any
nonequilibrium distribution that is an even function of the momenta, eventually
relaxes (not necessarily monotonically) to the equilibrium distribution.
Finally we prove that the negative logarithm of the microscopic partition
function is equal to the thermodynamic Helmholtz free energy divided by the
thermodynamic temperature and Boltzmann's constant. Our results complement and
extend the findings of modern ergodic theory and show the importance of
dissipation in the process of relaxation towards equilibrium.


title:
Solutions of Polynomial Systems Derived from the Steady Cavity Flow
  Problem

abstract:
  We propose a general algorithm to enumerate all solutions of a
zero-dimensional polynomial system with respect to a given cost function. The
algorithm is developed and is used to study a polynomial system obtained by
discretizing the steady cavity flow problem in two dimensions. The key
technique on which our algorithm is based is to solve polynomial optimization
problems via sparse semidefinite programming relaxations (SDPR), which has been
adopted successfully to solve reaction-diffusion boundary value problems
recently. The cost function to be minimized is derived from discretizing the
fluid's kinetic energy. The enumeration algorithm's solutions are shown to
converge to the minimal kinetic energy solutions for SDPR of increasing order.
We demonstrate the algorithm with SDPR of first and second order on polynomial
systems for different scenarios of the cavity flow problem and succeed in
deriving the $k$ smallest kinetic energy solutions. The question whether these
solutions converge to solutions of the steady cavity flow problem is discussed,
and we pose a conjecture for the minimal energy solution for increasing
Reynolds number.


title: Semantics and Evaluation of Top-k Queries in Probabilistic Databases

abstract:
  We study here fundamental issues involved in top-k query evaluation in
probabilistic databases. We consider simple probabilistic databases in which
probabilities are associated with individual tuples, and general probabilistic
databases in which, additionally, exclusivity relationships between tuples can
be represented. In contrast to other recent research in this area, we do not
limit ourselves to injective scoring functions. We formulate three intuitive
postulates that the semantics of top-k queries in probabilistic databases
should satisfy, and introduce a new semantics, Global-Topk, that satisfies
those postulates to a large degree. We also show how to evaluate queries under
the Global-Topk semantics. For simple databases we design dynamic-programming
based algorithms, and for general databases we show polynomial-time reductions
to the simple cases. For example, we demonstrate that for a fixed k the time
complexity of top-k query evaluation is as low as linear, under the assumption
that probabilistic databases are simple and scoring functions are injective.


title:
The endpoint case of the Bennett-Carbery-Tao multilinear Kakeya
  conjecture

abstract:
  Bennett, Carbery, and Tao formulated an n-linear analogue of the Kakeya
conjecture in R^n. They proved the conjecture except for the endpoint case. We
prove the endpoint case.


title: Physical properties of noncentrosymmetric superconductor Ru$_7$B$_3$

abstract:
  Transition metal boride Ru$_7$B$_3$ was found to be a noncentrosymmetric
superconductor with $T_{C}$ equal to 3.3 K. Superconducting and normal state
properties of Ru$_7$B$_3$ were determined by a self-consistent analysis through
resistivity($\rho_{xx}$ and $\rho_{xy}$), specific heat, lower critical field
measurement and electronic band structure calculation. It is found that
Ru$_7$B$_3$ belongs to an s-wave dominated single band superconductor with
energy gap 0.5 meV and could be categorized into type II superconductor with
weak electron-phonon coupling. Unusual 'kink' feature is clearly observed in
field-broadening resistivity curves, suggesting the possible mixture of spin
triplet induced by the lattice without inversion symmetry.


title:
Exploring Parameter Constraints on Quintessential Dark Energy: the
  Inverse Power Law Model

abstract:
  We report on the results of a Markov Chain Monte Carlo (MCMC) analysis of an
inverse power law (IPL) quintessence model using the Dark Energy Task Force
(DETF) simulated data sets as a representation of future dark energy
experiments. We generate simulated data sets for a Lambda-CDM background
cosmology as well as a case where the dark energy is provided by a specific IPL
fiducial model and present our results in the form of likelihood contours
generated by these two background cosmologies. We find that the relative
constraining power of the various DETF data sets on the IPL model parameters is
broadly equivalent to the DETF results for the w_{0}-w_{a} parameterization of
dark energy. Finally, we gauge the power of DETF "Stage 4" data by
demonstrating a specific IPL model which, if realized in the universe, would
allow Stage 4 data to exclude a cosmological constant at better than the
3-sigma level.


title: On the tunnel number and the Morse-Novikov number of knots

abstract:
  We prove that the Morse-Novikov number of a link L in a 3-sphere is less than
or equal to twice the tunnel number of L.


title: Non-universal non-equilibrium critical dynamics with disorder

abstract:
  We investigate finite size scaling aspects of disorder reaction-diffusion
processes in one dimension utilizing both numerical and analytical approaches.
The former averages the spectrum gap of the associated evolution operators by
doubling their degrees of freedom, while the latter uses various techniques to
map the equations of motion to a first passage time process. Both approaches
are consistent with nonuniversal dynamic exponents, and with stretched
exponential scaling forms for particular disorder realizations.


title: Solving a characteristic Cauchy problem

abstract:
  In this paper we give a meaning to the nonlinear characteristic Cauchy
problem for the Wave Equation in base form by replacing it by a family of
non-characteristic problems in an appropriate algebra of generalized functions.
We prove existence of a solution and we precise how it depends on the choice
made. We also check that in the classical case (non-characteristic) our new
solution coincides with the classical one.


title: Scaling properties in deep inelastic scattering

abstract:
  Using the "Quality Factor" (QF) method, we analyse the scaling properties of
deep-inelastic processes at HERA and fixed target experiments for x<10^{-2}.


title: The timescales of chemical enrichment in the Galaxy

abstract:
  The time-scales of chemical enrichment are fundamental to understand the
evolution of abundances and abundance ratios in galaxies. In particular, the
time-scales for the enrichment by SNe II and SNe Ia are crucial in interpreting
the evolution of abundance ratios such as [alpha/Fe]. In fact, the
alpha-elements are produced mainly by SNe II on time-scales of the order of 3
to 30 Myr, whereas the Fe is mainly produced by SNe Ia on a larger range of
time-scales, going from 30 Myr to a Hubble time. This produces differences in
the [alpha/Fe] ratios at high and low redshift and it is known as "time-delay"
model. In this talk we review the most common progenitor models for SNe Ia and
the derived rates together with the effect of the star formation history on the
[alpha/Fe] versus [Fe/H] diagram in the Galaxy. From these diagrams we can
derive the timescale for the formation of the inner halo (roughly 2 Gyr), the
timescale for the formation of the local disk (roughly 7-8 Gyr) as well the
time-scales for the formation of the whole disk. These are functions of the
galactocentric distance and vary from 2-3 Gyr in the inner disk up to a Hubble
time in the outer disk (inside-out formation). Finally, the timescale for the
formation of the bulge is found to be no longer than 0.3 Gyr, similar to the
timescale for the formation of larger spheroids such as elliptical galaxies. We
show the time-delay model applied to galaxies of different morphological type,
identified by different star formation histories, and how it constrains
differing galaxy formation models.


title: Modular Forms of weight 8 for $\Gamma_g(1,2)$

abstract:
  We complete the program indicated by the Ansatz of D'Hoker and Phong in genus
~4 by proving the uniqueness of the restriction to Jacobians of the weight 8
Siegel cusp forms satisfying the Anstaz. We prove $\dim [\Gamma_4(1,2),8]_0=2$
and $\dim [\Gamma_4(1,2),8]=7$. In each genus, we classify the linear relations
among the self-dual lattices of rank {16}. We extend the program to genus ~5 by
constructing the unique linear combination of theta series that satisfies the
Ansatz.


title:
Minoration du rang des courbes elliptiques sur les corps de classes de
  Hilbert

abstract:
  Soit $E/\BmQ$ une courbe elliptique. Soit $D<0$ un discriminant fondamental
suffisamment grand. Si $E(\bar{\BmQ})$ contient des points de Heegner de
discriminant $D$, ces points engendrent un sous-groupe dont le rang est
sup\'erieur \`a $\pabs{D}^{0.0009}$. Ce r\'esultat est en accord avec la
conjecture de Birch et Swinnerton-Dyer.
  ---
  Let $E/\BmQ$ be an elliptic curve. Let $D<0$ be a sufficiently large
fundamental discriminant. If $E(\bar{\BmQ})$ contains Heegner points of
discriminant $D$, these points generate a subgroup of rank greater than
$\pabs{D}^{0.0009}$. This result is in agreement with the conjecture of Birch
and Swinnerton-Dyer.


title: Oriented bivariant theories, I

abstract:
  In 1981 W. Fulton and R. MacPherson introduced the notion of bivariant theory
(BT), which is a sophisticated unification of covariant theories and
contravariant theories. This is for the study of singular spaces. In 2001 M.
Levine and F. Morel introduced the notion of algebraic cobordism, which is a
universal oriented Borel-Moore functor with products (OBMF) of geometric type,
in an attempt to understand better V. Voevodsky's (higher) algebraic cobordism.
In this paper we introduce a notion of oriented bivariant theory (OBT), a
special case of which is nothing but the oriented Borel-Moore functor with
products. The present paper is a first one of the series to try to understand
Levine-Morel's algebraic cobordism from a bivariant-theoretical viewpoint, and
its first step is to introduce OBT as a unification of BT and OBMF.


title: Holographic Responses of Fermion Matter

abstract:
  We consider the $D4-D8-\bar{D8}$ brane system which serves as ultraviolet
completion of the Nambu-Jona-Lasinio model, where the only degrees of freedom
carrying baryon charge are fermions. By turning on chemical potential for this
charge one may expect the formation of the Fermi liquid ground state. At strong
coupling we use the dual holographic description to investigate the responses
of the system to small perturbations. In the chirally symmetric phase we find
that the density dependent part of the heat capacity vanishes linearly with
temperature. We also observe a zero sound excitation in the collisionless
regime, whose speed is equal to that of normal sound in the hydrodynamic
regime. Both the linear dependence of the heat capacity and the existence of
zero sound are properties of the Fermi liquid ground state. We also compute the
two-point function of the currents at vanishing frequency but do not find any
singularities at finite values of the momentum.


title: Hall Effect of Spin Waves in Frustrated Magnets

abstract:
  We examine a possible spin Hall effect for localized spin systems with no
charge degrees of freedom. In this scenario, a longitudinal magnetic field
gradient induces a transverse spin current carried by spin wave excitations
with an anomalous velocity which is associated with the Berry curvature raised
by spin chirality, in analogy with anomalous Hall effects in itinerant electron
systems. Our argument is based on a semiclassical equations of motion
applicable to general spin systems. Also, a microscopic model of frustrated
magnets which exhibits the anamalous spin Hall effect is presented.


title:
Astrometry with the Keck-Interferometer: the ASTRA project and its
  science

abstract:
  The sensitivity and astrometry upgrade ASTRA of the Keck Interferometer is
introduced. After a brief overview of the underlying interferometric
principles, the technology and concepts of the upgrade are presented. The
interferometric dual-field technology of ASTRA will provide the KI with the
means to observe two objects simultaneously, and measure the distance between
them with a precision eventually better than 100 uas. This astrometric
functionality of ASTRA will add a unique observing tool to fields of
astrophysical research as diverse as exo-planetary kinematics, binary
astrometry, and the investigation of stars accelerated by the massive black
hole in the center of the Milky Way as discussed in this contribution.


title: Six Hot Topics in Planetary Astronomy

abstract:
  Six hot topics in modern planetary astronomy are described: 1) lightcurves
and densities of small bodies 2) colors of Kuiper belt objects and the
distribution of the ultrared matter 3) spectroscopy and the crystallinity of
ice in the outer Solar system 4) irregular satellites of the giant planets 5)
the Main Belt Comets and 6) comets and meteor stream parents.


title:
Pressure-Induced Reentrant Oblique Antiferromagnetic Phase in Spin Dimer
  System TlCuCl_3

abstract:
  Magnetization measurements under a hydrostatic pressure of P = 1.4 GPa were
performed on the coupled spin dimer system TlCuCl_3, which exhibits a
pressure-induced quantum phase transition from a gapped singlet state to an
antiferromagnetic state at P_c = 0.042 GPa. Antiferromagnetic ordering with
ordered moments parallel to the ac plane was observed at T_N = 16.7 K at 1.4
GPa. The spin reorientation phase transition was observed at T_R ~ 9.2 K for
zero magnetic field, at which the ordered moments start to incline towards the
b axis. With increasing external field parallel to th b axis, a second-order
phase transition from the oblique antiferromagnetic (OAF) phase to the
spin-flop (SF) phase occurs below T_R. We argue that the OAF phase arises from
the competition between the anisotropic energies of the conventional second
order and the fourth order, that increases with increasing pressure. We discuss
the OAF-SF transition within the framework of the mean field approximation.


title: Supersymmetric field theories and cohomology

abstract:
  This is the Ph.D. dissertation of the author. The project has been motivated
by the conjecture that the Hopkins-Miller tmf spectrum can be described in
terms of `spaces' of conformal field theories. In this dissertation, spaces of
field theories are constructed as classifying spaces of categories whose
objects are certain types of field theories. If such a category has a symmetric
monoidal structure and its components form a group, by work of Segal, its
classifying space is an infinite loop space and defines a cohomology theory.
This has been carried out for two classes of field theories: (i) For each
integer n, there is a category SEFT_n whose objects are the Stolz-Teichner
(1|1)-dimensional super Euclidean field theories of degree n. It is proved that
the classifying space |SEFT_n| represents degree-n K or KO cohomology,
depending on the coefficients of the field theories. (ii) For each integer n,
there is a category AFT_n whose objects are a kind of (2|1)-dimensional field
theories called `annular field theories,' defined using supergeometric versions
of circles and annuli only. It is proved that the classifying space |AFT_n|
represents the degree-n elliptic cohomology associated with the Tate curve. To
the author's knowledge, this is the first time the definitions of
low-dimensional supersymmetric field theories are given in full detail.


title: Decoherence in rf SQUID Qubits

abstract:
  We report measurements of coherence times of an rf SQUID qubit using pulsed
microwaves and rapid flux pulses. The modified rf SQUID, described by an
double-well potential, has independent, in situ, controls for the tilt and
barrier height of the potential. The decay of coherent oscillations is
dominated by the lifetime of the excited state and low frequency flux noise and
is consistent with independent measurement of these quantities obtained by
microwave spectroscopy, resonant tunneling between fluxoid wells and decay of
the excited state. The oscillation's waveform is compared to analytical results
obtained for finite decay rates and detuning and averaged over low frequency
flux noise.


title: Reexamination of Finite-Lattice Extrapolation of Haldane Gaps

abstract:
  We propose two methods of estimating a systematic error in extrapolation to
the infinite-size limit in the study of measuring the Haldane gaps of the
one-dimensional Heisenberg antiferromagnet with the integer spin up to S=5. The
finite-size gaps obtained by numerical diagonalizations based on Lanczos
algorithm are presented for sizes that have not previously been reported. The
changes of boundary conditions are also examined. We successfully demonstrate
that our methods of extrapolation work well. The Haldane gap for S=1 is
stimated to be $0.4104789 \pm 0.0000013$. We successfully obtain the gaps up to
S=5, which make us confirm the asymptotic formula of the Haldane gap in
$S\to\infty$.


title: Robust quantum repeater with atomic ensembles and single-photon sources

abstract:
  We present a quantum repeater protocol using atomic ensembles, linear optics
and single-photon sources. Two local 'polarization' entangled states of atomic
ensembles $u$ and $d$ are generated by absorbing a single photon emitted by an
on-demand single-photon sources, based on which high-fidelity local
entanglement between four ensembles can be established efficiently through
Bell-state measurement. Entanglement in basic links and entanglement connection
between links are carried out by the use of two-photon interference. In
addition to being robust against phase fluctuations in the quantum channels,
this scheme may speed up quantum communication with higher fidelity by about 2
orders of magnitude for 1280 km compared with the partial read (PR) protocol
(Sangouard {\it et al.}, Phys. Rev. A {\bf77}, 062301 (2008)) which may
generate entanglement most quickly among the previous schemes with the same
ingredients.


title: Flaring variability of Microquasars

abstract:
  We discuss flaring variability of radio emission of microquasars, measured in
monitoring programs with the RATAN-600 radio telescope. We carried out a
multi-frequency (1-30 GHz) daily monitoring of the radio flux variability of
the microquasars SS433, GRS1915+105, and Cyg X-3 during the recent sets in
2005-2007. A lot of bright short-time flares were detected from GRS 1915+105
and they could be associated with active X-ray events. In January 2006 we
detected a drop down of the quiescent fluxes from Cyg X-3 (from 100 to $\sim$20
mJy), then the 1 Jy-flare was detected on 2 February 2006 after 18 days of
quenched radio emission. The daily spectra of the flare in the maximum were
flat from 2 to 110 GHz, using the quasi-simultaneous observations at 110 GHz
with the RT45m telescope and the NMA millimeter array of NRO in Japan. Several
bright radio flaring events (1-15 Jy) followed during the continuing state of
very variable and intensive 1-12 keV X-ray emission ($\sim$0.5 Crab), which was
monitored in the RXTE ASM program. Swift/BAT ASM hard X-ray fluxes correlated
strongly with flaring radio data. The various spectral and temporal
characteristics of the light curves from the microquasars could be determined
from such comparison. We conclude that monitoring of the flaring radio emission
is a good tracer of jet activity X-ray binaries.


title:
Prediction of Solar Flares from a Statistical Analysis of Events during
  Solar Cycle 23

abstract:
  Ways to give medium- and short-term predictions of solar flares are proposed
according to the statistical analysis of events during solar cycle 23. On one
hand, the time distribution of both C and M class flares shows two main periods
of 13.2 and 26.4 months in this cycle by wavelet analysis. On the other hand,
active regions of specific magnetic configurations and their evolutions give
high productivity of C class flares but relatively low productivity of
energetic (M and X class) flares. Furthermore, by considering the measurable
kinetic features of active regions, i.e., the rotation of the sunspots, some
active regions of specified types are observed to have high energetic flare
productivity, above 66%. The periodicity of the activity revealed can be used
for medium-term C and M class flare forecasting and the high productivity of
active regions forms the basis for short-term prediction of individual
energetic flares.


title: Products of longitudinal pseudodifferential operators on flag varieties

abstract:
  Associated to each set $S$ of simple roots for $SL(n,\mathbb{C})$ is an
equivariant fibration $X\to X_S$ of the space $X$ of complete flags of
$\mathbb{C}^n$. To each such fibration we associate an algebra $J_S$ of
operators on $L^2(X)$ which contains, in particular, the longitudinal
pseudodifferential operators of negative order tangent to the fibres. These
form a lattice of operator ideals whose common intersection is the compact
operators. As a consequence, the product of fibrewise smoothing operators (for
instance) along the fibres of two such fibrations, $X\to X_S$ and $X\to X_T$,
is a compact operator if $S\cup T$ is the full set of simple roots.
  The construction uses noncommutative harmonic analysis, and hinges upon a
representation theoretic property of subgroups of SU(n), which may be described
as `essential orthogonality of subrepresentations'.


title:
Homological Stability among Moduli Spaces of Holomorphic Curves in
  Complex Projective Space

abstract:
  The primary goal of this paper is to find a homotopy theoretic approximation
to moduli spaces of holomorphic maps Riemann surfaces into complex projective
space. There is a similar treatment of a partial compactification of these
moduli spaces of consisting of irreducible stable maps in the sense of
Gromov-Witten theory. The arguments follow those from a paper of G. Segal on
the topology of the space of rational functions.