title:
High-harmonic generation in diatomic molecules: a quantum-orbit analysis
  of the interference patterns

abstract:
  We perform a detailed analysis of high-order harmonic generation in diatomic
molecules within the strong-field approximation, with emphasis on
quantum-interference effects. Specifically, we investigate how the different
types of electron orbits, involving one or two centers, affect the interference
patterns in the spectra. We also briefly address the influence of the choice of
gauge, and of the initial and final electronic bound states on such patterns.
For the length-gauge SFA and undressed bound states, there exist additional
terms, which can be interpreted as potential energy shifts. If, on the one
hand, such shifts alter the potential barriers through which the electron
initially tunnels, and may lead to a questionable physical interpretation of
the features encountered, on the other hand they seem to be necessary in order
to reproduce the overall maxima and minima in the spectra. Indeed, for dressed
electronic bound states in the length gauge, or undressed bound states in the
velocity gauge, for which such shifts are absent, there is a breakdown of the
interference patterns. In order to avoid such a problem, we provide an
alternative pathway for the electron to reach the continuum, by means of an
additional attosecond-pulse train. A comparison of the purely monochromatic
case with the situation for which the attosecond pulses are present suggests
that the patterns are due to the interference between the electron orbits which
finish at different centers, regardless of whether one or two centers are
involved.


title:
A New Comment on "Experimental Observation of Optical Rotation Generated
  in Vacuum by a Magnetic Field"

abstract:
  One of the magneto-optical properties of the mirrors of the Fabry-Perot
cavity used for the experiment is considered as a possible origin of the PVLAS
measurement result.


title: The polar ring galaxy AM1934-563 revisited

abstract:
  We report long-slit spectroscopic observations of the dust-lane polar-ring
galaxy AM1934-563 obtained with the Southern African Large Telescope (SALT)
during its performance-verification phase. The observations target the spectral
region of the Ha, [NII] and [SII] emission-lines, but show also deep NaI
stellar absorption lines that we interpret as produced by stars in the galaxy.
We derive rotation curves along the major axis of the galaxy that extend out to
about 8 kpc from the center for both the gaseous and the stellar components,
using the emission and absorption lines. We derive similar rotation curves
along the major axis of the polar ring and point out differences between these
and the ones of the main galaxy. We identify a small diffuse object visible
only in Ha emission and with a low velocity dispersion as a dwarf HII galaxy
and argue that it is probably metal-poor. Its velocity indicates that it is a
fourth member of the galaxy group in which AM1934-563 belongs. We discuss the
observations in the context of the proposal that the object is the result of a
major merger and point out some observational discrepancies from this
explanation. We argue that an alternative scenario that could better fit the
observations may be the slow accretion of cold intergalactic gas, focused by a
dense filament of galaxies in which this object is embedded (abridged).


title: Nonlocal Cosmology

abstract:
  We explore nonlocally modified models of gravity, inspired by quantum loop
corrections, as a mechanism for explaining current cosmic acceleration. These
theories enjoy two major advantages: they allow a delayed response to cosmic
events, here the transition from radiation to matter dominance, and they avoid
the usual level of fine tuning; instead, emulating Dirac's dictum, the required
large numbers come from the large time scales involved. Their solar system
effects are safely negligible, and they may even prove useful to the black hole
information problem.


title: On elliptic Dunkl operators

abstract:
  We attach elliptic Dunkl operators to an abelian variety with a finite group
action. This generalizes elliptic Dunkl operators for Weyl groups, defined by
Buchstaber, Felder, and Veselov in 1994. We show that these operators commute,
and use them to define representations from category O of elliptic Cherednik
algebras. We also consider the monodromy representations of differential
equations defined by elliptic Dunkl operators, and show that they yield finite
dimensional rrepresentations of generalized double affine Hecke algebras.


title: Stability of boundary measures

abstract:
  We introduce the boundary measure at scale r of a compact subset of the
n-dimensional Euclidean space. We show how it can be computed for point clouds
and suggest these measures can be used for feature detection. The main
contribution of this work is the proof a quantitative stability theorem for
boundary measures using tools of convex analysis and geometric measure theory.
As a corollary we obtain a stability result for Federer's curvature measures of
a compact, allowing to compute them from point-cloud approximations of the
compact.


title:
Vector invariants of a class of pseudo-reflection groups and
  multisymmetric syzygies

abstract:
  First and second fundamental theorems are given for polynomial invariants of
a class of pseudo-reflection groups (including the Weyl groups of type $B_n$),
under the assumption that the order of the group is invertible in the base
field. Special case of the result is a finite presentation of the algebra of
multisymmetric polynomials. Reducedness of the invariant commuting scheme is
proved as a by-product. The algebra of multisymmetric polynomials over an
arbitrary base ring is revisited.


title:
Dualheap Selection Algorithm: Efficient, Inherently Parallel and
  Somewhat Mysterious

abstract:
  An inherently parallel algorithm is proposed that efficiently performs
selection: finding the K-th largest member of a set of N members. Selection is
a common component of many more complex algorithms and therefore is a widely
studied problem.
  Not much is new in the proposed dualheap selection algorithm: the heap data
structure is from J.W.J.Williams, the bottom-up heap construction is from R.W.
Floyd, and the concept of a two heap data structure is from J.W.J. Williams and
D.E. Knuth. The algorithm's novelty is limited to a few relatively minor
implementation twists: 1) the two heaps are oriented with their roots at the
partition values rather than at the minimum and maximum values, 2)the coding of
one of the heaps (the heap of smaller values) employs negative indexing, and 3)
the exchange phase of the algorithm is similar to a bottom-up heap
construction, but navigates the heap with a post-order tree traversal.
  When run on a single processor, the dualheap selection algorithm's
performance is competitive with quickselect with median estimation, a common
variant of C.A.R. Hoare's quicksort algorithm. When run on parallel processors,
the dualheap selection algorithm is superior due to its subtasks that are
easily partitioned and innately balanced.


title: Direct CP Violation in B Decays

abstract:
  We discuss several aspects of direct CP asymmetries in B decays, which are
very useful in spite of hadronic uncertainties in asymmetry calculations. 1)
Asymmetries in decays to $D^{(*)}K^{(*)}$, $\pi^+\pi^-, \rho^+\rho^-$,
providing precision tests for the CKM phase $\gamma$. 2) Null tests in $B^+\to
J/\psi K^+, \pi^+\pi^0$, where a nonzero asymmetry provides evidence for New
Physics. 3) Isospin and broken flavor SU(3) relations among CP asymmetries in
$B\to K\pi, \pi\pi$ predicting $A_{CP}(B^0\to K^0\pi^0)$ and $A_{CP}(B^0\to
\pi^0\pi^0)$. 4) The significance of $A_{CP}(B^0\to K^+\pi^-)\ne A_{CP}(B^+\to
K^+\pi^0)$. 5) A potentially stringent constraint on $\gamma$ from
$A_{CP}(B^+\to K^+\pi^0)$ and $R_c\equiv 2\Gamma(B^+\to K^+\pi^0)/\Gamma(B^+\to
K^0\pi^+)$. 6) The role of direct CP asymmetries in $b\to s\bar qq$ decays for
studying the origin of potential New Physics.


title:
Viscous spin exchange torque on precessional magnetization in
  $(\mathrm{LaMnO}_3)_{2n}/(\mathrm{SrMnO}_3)_{n}$ superlattices

abstract:
  Photoinduced magnetization dynamics is investigated in chemically ordered
$(\mathrm{LaMnO}_3)_{2n}/(\mathrm{SrMnO}_3)_n$ superlattices using the
time-resolved magneto-optic Kerr effect. A monotonic frequency-field dependence
is observed for the $n=1$ superlattice, indicating a single spin population
consistent with a homogeneous hole distribution. In contrast, for $n\geq2$
superlattices, a large precession frequency is observed at low fields
indicating the presence of an exchange torque in the dynamic regime. We propose
a model that ascribes the emergence of exchange torque to the coupling between
two spin populations -- viscous and fast spins.


title: Ultra High Energy Cosmic Rays Diffusion in an Expanding Universe

abstract:
  We study the solution of the diffusion equation for Ultra-High Energy Cosmic
Rays in the general case of an expanding universe, comparing it with the well
known Syrovatsky solution obtained in the more restrictive case of a static
universe. The formal comparison of the two solutions with all parameters being
fixed identically reveals an appreciable discrepancy. This discrepancy is less
important if in both models a different set of best-fit parameters is used.


title: Continuous input nonlocal games

abstract:
  We present a family of nonlocal games in which the inputs the players receive
are continuous. We study three representative members of the family. For the
first two a team sharing quantum correlations (entanglement) has an advantage
over any team restricted to classical correlations. We conjecture that this is
true for the third member of the family as well.


title: Minimality in topological groups and Heisenberg type groups

abstract:
  We study relatively minimal subgroups in topological groups. We find, in
particular, some natural relatively minimal subgroups in unipotent groups which
are defined over "good" rings. By "good" rings we mean archimedean absolute
valued (not necessarily associative) division rings. Some of the classical
rings which we consider besides the field of reals are the ring of quaternions
and the ring of octonions. This way we generalize in part a previous result
which was obtained by Dikranjan and Megrelishvili and involved the Heisenberg
group.


title:
General Hubbard model for strongly interacting fermions in an optical
  lattice and its phase detection

abstract:
  Based on consideration of the system symmetry and its Hilbert space, we show
that strongly interacting fermions in an optical lattice or superlattice can be
generically described by a lattice resonance Hamiltonian. The latter can be
mapped to a general Hubbard model with particle assisted tunneling rates. We
investigate the model under population imbalance and show the attractive and
the repulsive models have the same complexity in phase diagram under the
particle-hole mapping. Using this mapping, we propose an experimental method to
detect possible exotic superfluid/magnetic phases for this system.


title:
The competition of hydrogen-like and isotropic interactions on polymer
  collapse

abstract:
  We investigate a lattice model of polymers where the nearest-neighbour
monomer-monomer interaction strengths differ according to whether the local
configurations have so-called ``hydrogen-like'' formations or not. If the
interaction strengths are all the same then the classical $\theta$-point
collapse transition occurs on lowering the temperature, and the polymer enters
the isotropic liquid-drop phase known as the collapsed globule. On the other
hand, strongly favouring the hydrogen-like interactions give rise to an
anisotropic folded (solid-like) phase on lowering the temperature. We use Monte
Carlo simulations up to a length of 256 to map out the phase diagram in the
plane of parameters and determine the order of the associated phase
transitions. We discuss the connections to semi-flexible polymers and other
polymer models. Importantly, we demonstrate that for a range of energy
parameters two phase transitions occur on lowering the temperature, the second
being a transition from the globule state to the crystal state. We argue from
our data that this globule-to-crystal transition is continuous in two
dimensions in accord with field-theory arguments concerning Hamiltonian walks,
but is first order in three dimensions.


title: Predictions for masses of Xi_b baryons

abstract:
  The recent observation by CDF of Sigma_b^{+-} (uub and ddb) baryons within 2
MeV of the predicted Sigma_b - Lambda_b splitting has provided strong
confirmation for the theoretical approach based on modeling the color hyperfine
interaction. We now apply this approach to predict the masses of the Xi_b
family of baryons with quark content usb and dsb - the ground state Xi_b at
5790 to 5800 MeV, and the excited states Xi_b^' and Xi_b^*. The main source of
uncertainty is the method used to estimate the mass difference m_b - m_c from
known hadrons. We verify that corrections due to the details of the interquark
potential and to Xi_b-Xi_b^' mixing are small.


title: Spitzer Mid-to-Far-Infrared Flux Densities of Distant Galaxies

abstract:
  We study the infrared (IR) properties of high-redshift galaxies using deep
Spitzer 24, 70, and 160 micron data. Our primary interest is to improve the
constraints on the total IR luminosities, L(IR), of these galaxies. We combine
the Spitzer data in the southern Extended Chandra Deep Field with a
K-band-selected galaxy sample and photometric redshifts from the
Multiwavelength Survey by Yale-Chile. We used a stacking analysis to measure
the average 70 and 160 micron flux densities of 1.5 < z < 2.5 galaxies as a
function of 24 micron flux density, X-ray activity, and rest-frame near-IR
color. Galaxies with 1.5 < z < 2.5 and S(24)=53-250 micro-Jy have L(IR) derived
from their average 24-160 micron flux densities within factors of 2-3 of those
derived from the 24 micron flux densities only. However, L(IR) derived from the
average 24-160 micron flux densities for galaxies with S(24) > 250 micro-Jy and
1.5 < z < 2.5 are lower than those derived using only the 24 micron flux
density by factors of 2-10. Galaxies with S(24) > 250 micro-Jy have S(70)/S(24)
flux ratios comparable to sources with X-ray detections or red rest-frame IR
colors, suggesting that warm dust possibly heated by AGN may contribute to the
high 24 micron emission. Based on the average 24-160 micron flux densities,
nearly all 24 micron-selected galaxies at 1.5 < z < 2.5 have L(IR) < 6 x 10^12
solar luminosities, which if attributed to star formation corresponds to < 1000
solar masses per year. This suggests that high redshift galaxies may have
similar star formation efficiencies and feedback processes as local analogs.
Objects with L(IR) > 6 x 10^12 solar luminosities are quite rare, with a
surface density ~ 30 +/- 10 per sq. deg, corresponding to ~ 2 +/- 1 x 10^-6
Mpc^-3 over 1.5 < z < 2.5.


title: A Research-Based Curriculum for Teaching the Photoelectric Effect

abstract:
  Physics faculty consider the photoelectric effect important, but many
erroneously believe it is easy for students to understand. We have developed
curriculum on this topic including an interactive computer simulation,
interactive lectures with peer instruction, and conceptual and mathematical
homework problems. Our curriculum addresses established student difficulties
and is designed to achieve two learning goals, for students to be able to (1)
correctly predict the results of photoelectric effect experiments, and (2)
describe how these results lead to the photon model of light. We designed two
exam questions to test these learning goals. Our instruction leads to better
student mastery of the first goal than either traditional instruction or
previous reformed instruction, with approximately 85% of students correctly
predicting the results of changes to the experimental conditions. On the
question designed to test the second goal, most students are able to correctly
state both the observations made in the photoelectric effect experiment and the
inferences that can be made from these observations, but are less successful in
drawing a clear logical connection between the observations and inferences.
This is likely a symptom of a more general lack of the reasoning skills to
logically draw inferences from observations.


title:
Canonical heights and the arithmetic complexity of morphisms on
  projective space

abstract:
  Let F and G be morphisms of degree at least 2 from P^N to P^N that are
defined over the algebraic closure of Q. We define the arithmetic distance
d(F,G) between F and G to be the supremum over all algebraic points P of
|h_F(P)-h_G(P)|, where h_F and h_G are the canonical heights associated to the
morphisms F and G, respectively. We prove comparison theorems relating d(F,G)
to more naive height functions and show that for a fixed G, the set of F
satisfying d(F,G) < B is a set of bounded height. In particular, there are only
finitely many such F defined over any given number field.


title: Renormalization and Induced Gauge Action on a Noncommutative Space

abstract:
  Field theories on deformed spaces suffer from the IR/UV mxing and
renormalization is generically spoiled. In work with R. Wulkenhaar, one of us
realized a way to cure this desease by adding one more marginal operator. We
review these ideas, show the application to $\phi^3$ models and use heat kernel
expansion methods for a scalar field theory coupled to an external gauge field
on a $\theta$-deformed space and derive noncommutative gauge actions.


title: Models of Neutrino Masses and Mixing

abstract:
  Neutrino physics has entered an era of precision measurements. With these
precise measurements, we may be able to distinguish different models that have
been constructed to explain the small neutrino masses and the large mixing
among them. In this talk, I review some of the existing theoretical models and
their predictions for neutrino oscillations.


title: Nonarchimedean Green functions and dynamics on projective space

abstract:
  Let F: P^N_K --> P^N_K be a morphism of degree d > 1 defined over a field K
that is algebraically closed and complete with respect to a nonarchimedean
absolute value. We prove that a modified Green function G_F associated to F is
Holder continuous on P^N(K) and that the Fatou set F is equal to the set of
points at which G_F is locally constant. Further, G_F vanishes precisely on the
set of points P such that F has good reduction at every point in the forward
orbit of P. We also prove that the iterates of F are locally uniformly
Lipschitz on the Fatou set of F.


title: Transient jets in V617 Sagittarii

abstract:
  Some of the luminous Compact Binary Supersoft X-Ray sources (CBSS) have shown
indications of jets, also called satellites due to their appearance in the
spectra. In V Sagittae (V Sge) stars, the galactic counterparts of the CBSS,
such features have been reported only for WX Cen. If V Sge stars are indeed the
analogs of CBSS, one may expect transient jet emission in other objects of this
class. Spectroscopic observations of the V Sge star V617 Sgr have been made,
both at high photometric state and at decline. We show that V617 Sgr presents
Halpha satellites at high photometric state with velocities of +/-780 km/s.
This feature confirms, once more, the CBSS nature of the V Sge stars, however
the details of the spectral characteristics also suggest that the two groups of
stars display some intrinsic spectroscopic differences, which are likely to be
due to a selection effect related to chemical abundance.


title:
A multiwavelength study of young massive star forming regions: II. The
  dust environment

abstract:
  We present observations of 1.2-mm dust continuum emission, made with the
Swedish ESO Submillimeter Telescope, towards eighteen luminous IRAS point
sources, all with colors typical of compact HII regions and associated with
CS(2-1) emission, thought to be representative of young massive star forming
regions. Emission was detected toward all the IRAS objects. We find that the
1.2-mm sources associated with them have distinct physical parameters, namely
sizes of 0.4 pc, dust temperatures of 30 K, masses of 2x10^3 Msun, column
densities of 3x10^23 cm^-2, and densities of 4x10^5 cm^-3. We refer to these
dust structures as massive and dense cores. Most of the 1.2-mm sources show
single-peaked structures, several of which exhibit a bright compact peak
surrounded by a weaker extended envelope. The observed radial intensity
profiles of sources with this type of morphology are well fitted with power-law
intensity profiles with power-law indices in the range 1.0-1.7. This result
indicates that massive and dense cores are centrally condensed, having radial
density profiles with power-law indices in the range 1.5-2.2. We also find that
the UC HII regions detected with ATCA towards the IRAS sources investigated
here (Paper I) are usually projected at the peak position of the 1.2-mm dust
continuum emission, suggesting that massive stars are formed at the center of
the centrally condensed massive and dense cores.


title: Dijet Azimuthal Correlations in QCD Hard Processes

abstract:
  We study the azimuthal correlation distribution for dijet production in QCD
hard processes. This observable is sensitive to soft and/or collinear emissions
in the back-to-back region, giving rise to single and double logarithms. We
provide resummed predictions to NLL accuracy for both DIS at HERA and hadronic
collisions at Tevatron and perform a NLO matching to NLOJET++ results in the
DIS case.


title: Theoretical Resolution of Magnetic Reconnection in High Energy Plasmas

abstract:
  The formation of macroscopic reconnected magnetic structures (islands) have
been observed in advanced experiments on weakly collisional, well confined
plasmas while established theories of the drift-tearing modes, which depend
strongly on the electron temperature gradient and can describe the formation of
these structures, had predicted practically inaccessible excitation thresholds
for them in these regimes. The relevant theoretical dilemma is resolved as
mesoscopic modes that depend critically on the ratio of the transverse (to the
magnetic field) to the longitudinal thermal
conductivity${D^e_{\perp}/D^e_{\|}$, can produce large scale magnetic
reconnection. These modes are envisioned to emerge from a background, which can
be coherent, of collisionless microscopic reconnecting modes driven by the
electron temperature gradient, that create a sequence of adjacent strings of
magnetic islands and increase considerably the ratio ${D^e_{\perp}/D^e_{\|}$
over its classical value. The mesoscopic reconnecting mode is treated by a
singular perturbation analysis involving three asymptotic regions and the small
parameters ${(D^e_{\perp}/D^e_{\|})}^{1/4}$ and ${\epsilon}^{1/4}_{*}$, where
${\epsilon}_{*} {\equiv}D_m/D_A$, $D_m$ is the magnetic diffusion coefficient,
$D_A\sim\texttt{v}^{2}_{A}r_{Te}/(D_Bk_{\perp})$,
$r_{Te}\equiv(-d\texttt{ln}T_e/dr)^{-1}$, $k_{\perp}$ is the transverse mode
number, $\texttt{v}^{2}_{A}=B^{2}/(4\pi{nm}_{i})}$ and $D_B=cT_e/(eB)$.


title:
Planets around evolved intermediate-mass stars. I. Two substellar
  companions in the open clusters NGC 2423 and NGC 4349

abstract:
  Context. Many efforts are being made to characterize extrasolar planetary
systems and unveil the fundamental mechanisms of planet formation. An important
aspect of the problem, which remains largely unknown, is to understand how the
planet formation process depends on the mass of the parent star. In particular,
as most planets discovered to date orbit a solar-mass primary, little is known
about planet formation around more massive stars. Aims. To investigate this
point, we present first results from a radial velocity planet search around red
giants in the clump of intermediate-age open clusters. We choose clusters
harbouring red giants with masses between 1.5 and 4 M_sun, using the well-known
cluster parameters to accurately determine the stellar masses. We are therefore
exploring a poorly-known domain of primary masses, which will bring new
insights into the properties of extrasolar planetary systems. Methods. We are
following a sample of about 115 red giants with the Coralie and HARPS
spectrographs to obtain high-precision radial velocity (RV) measurements and
detect giant planets around these stars. We use bisector and activity index
diagnostics to distinguish between planetary-induced RV variations and stellar
photospheric jitter. Results. We present the discoveries of a giant planet and
a brown dwarf in the open clusters NGC 2423 and NGC 4349, orbiting the 2.4
M_sun-star NGC2423 No3 (TYC 5409-2156-1) and the 3.9 M_sun-star NGC4349 No127
(TYC 8975-2606-1). These low-mass companions have orbital periods of 714 and
678 days and minimum masses of 10.6 and 19.8 M_jup, respectively. Combined with
the other known planetary systems, these detections indicate that the frequency
of massive planets is higher around intermediate-mass stars, and therefore
probably scales with the mass of the protoplanetary disk.


title: A resolution of the K(2)-local sphere at the prime 3

abstract:
  We develop a framework for displaying the stable homotopy theory of the
sphere, at least after localization at the second Morava K-theory K(2). At the
prime 3, we write the spectrum L_{K(2)S^0 as the inverse limit of a tower of
fibrations with four layers. The successive fibers are of the form E_2^hF where
F is a finite subgroup of the Morava stabilizer group and E_2 is the second
Morava or Lubin-Tate homology theory. We give explicit calculation of the
homotopy groups of these fibers. The case n=2 at p=3 represents the edge of our
current knowledge: n=1 is classical and at n=2, the prime 3 is the largest
prime where the Morava stabilizer group has a p-torsion subgroup, so that the
homotopy theory is not entirely algebraic.


title:
Comments on the breakdown of the Landauer bound for information erasure
  in the quantum regime

abstract:
  Upon reviewing the article by Allahverdyan and Nieuwenhuizen in PRE, we
conclude that neither the Landauer principle nor the counterexamples presented
by the authors have any relation (i) to thermodynamics, and (ii) to the
interdependence of nonstatistical quantum physics and thermodynamics.


title:
Physical properties of the noncentrosymmetric superconductor
  Mg_10Ir_19B_16

abstract:
  Specific heat, electrical resistivity, and magnetic susceptibility
measurements on a high quality sample of Mg10Ir19B16 provide a self-consistent
determination of its superconducting properties. They indicate that Mg10Ir19B16
is a type-II superconductor (Tc=4.45K, k(0)=20), with an electron-phonon
coupling constant l_ep=0.66. An analysis of the T-dependent specific heat shows
that superconducting properties are dominated by an s-wave gap (D=0.7 meV).
Point contact tunneling data provide evidence for multiple superconducting
gaps, as expected from strong asymmetric spin-orbit coupling.


title: Exactly solvable interacting vertex models

abstract:
  We introduce and solvev a special family of integrable interacting vertex
models that generalizes the well known six-vertex model. In addition to the
usual nearest-neighbor interactions among the vertices, there exist extra
hard-core interactions among pair of vertices at larger distances.The
associated row-to-row transfer matrices are diagonalized by using the recently
introduced matrix product {\it ansatz}. Similarly as the relation of the
six-vertex model with the XXZ quantum chain, the row-to-row transfer matrices
of these new models are also the generating functions of an infinite set of
commuting conserved charges. Among these charges we identify the integrable
generalization of the XXZ chain that contains hard-core exclusion interactions
among the spins. These quantum chains already appeared in the literature. The
present paper explains their integrability.


title:
Backreaction in trans-Planckian cosmology: renormalization, trace
  anomaly and selfconsistent solutions

abstract:
  We analyze the semiclassical Einstein equations for quantum scalar fields
satisfying modified dispersion relations. We first discuss in detail the
renormalization procedure based on adiabatic subtraction and dimensional
regularization. We show that, contrary to what expected from power counting
arguments, in 3+1 dimensions the subtraction involves up to the fourth
adiabatic order even for dispersion relations containing higher powers of the
momentum. Then we analyze the dependence of the trace of the renormalized
energy momentum tensor with the scale of new physics, and we recover the usual
trace anomaly in the appropriate limit. We also find selfconsistent de Sitter
solutions for dispersion relations that contain up to the fourth power of the
momentum. Using this particular example, we also discuss the possibility that
the modified dispersion relation can be mimicked at lower energies by an
effective initial state in a theory with the usual dispersion relation.


title:
The effect of Fe and Ru substitution for Ni on the thermopower in
  MgCNi_3

abstract:
  The intermetallic perovskite MgCNi3 is a superconductor with a Tc=7 K.
Substitution of Fe and Ru for Ni decreases Tc monotonically as the doping
concentration is increased. Here we report thermopower measurements, S(T), on
MgCNi3, MgCNi3-xFex and MgCNi3-xRux. For MgCNi3, the thermopower is negative, -
12.5 mikroV/K, at 300 K. The absolute value of S decreases as x increases in
MgCNi3-xFex and MgCNi3-xRux. The sign of S changes from negative to positive at
low temperatures for values of x > 0.01. These data show that the carriers in
MgCNi3 are electrons, and by increasing x and decreasing temperature, the
participation of hole carriers clearly increases. The influence of the magnetic
moments of the Fe atoms on the thermopower is not visible.


title: GZK Photons Above 10 EeV

abstract:
  We calculate the flux of "GZK-photons", namely the flux of photons produced
by extragalactic nucleons through the resonant photoproduction of pions, the so
called GZK effect. This flux depends on the UHECR spectrum on Earth, of the
spectrum of nucleons emitted at the sources, which we characterize by its slope
and maximum energy, on the distribution of sources and on the intervening
cosmological backgrounds, in particular the magnetic field and radio
backgrounds. For the first time we calculate the GZK photons produced by
nuclei. We calculate the possible range of the GZK photon fraction of the total
UHECR flux for the AGASA and the HiRes spectra. We find that for nucleons
produced at the sources it could be as large as a few % and as low as 10^{-4}
above 10 EeV. For nuclei produced at the sources the maximum photon fraction is
a factor of 2 to 3 times smaller above 10 EeV but the minimum could be much
smaller than for nucleons. We also comment on cosmogenic neutrino fluxes.


title: New AB-Thermonuclear Reactor for Aerospace

abstract:
  There are two main methods of nulcear fusion: inertial confinement fusion
(ICF) and magnetic confinement fusion (MCF). Existing thermonuclear reactors
are very complex, expensive, large, and heavy. They cannot achieve the Lawson
creterion.
  The author offers an innovation. ICF has on the inside surface of the
shell-shaped combustion chamber a covering of small Prism Reflectors (PR) and
plasma reflector. These prism reflectors have a noteworthy advantage, in
comparison with conventional mirror and especially with conventional shell:
they multi-reflect the heat and laser radiation exactly back into collision
with the fuel target capsule (pellet). The plasma reflector reflects the
Bremsstrahlung radiation.
  The offered innovation decreases radiation losses, creates significant
radiation pressure and increases the reaction time. The Lawson criterion
increases by hundreds of times. The size, cost, and weight of a typical
installation will decrease by tens of times.
  The author is researching the efficiency of these innovations. Keywords:
Thermonuclear reactor, Multi-reflex AB-thermonuclear reactor, aerospace
thermonuclear engine.
  This work is presented as paper AIAA-2006-7225 to Space-2006 Conference,
19-21 September, 2006, San Jose, CA, USA.


title: Color Screening Melts Quarkonium

abstract:
  We calculate quarkonium spectral functions in a quark-gluon plasma using a
potential model based on full QCD lattice calculations of the free energy of
static quark-antiquark pair. We estimate the binding energy and the thermal
width of different quarkonium states. The estimated upper limit for the
dissociation temperatures is considerably lower than the ones suggested in the
recent literature.


title: Mapping Class Groups do not have Kazhdan's Property (T)

abstract:
  We prove that the mapping class group of a closed oriented surface of genus
at least two does not have Kazhdan's property (T).


title: Electron-Electron Interactions in the Vacuum Polarization of Graphene

abstract:
  We discuss the effect of electron-electron interactions on the static
polarization properties of graphene beyond RPA. Divergent self-energy
corrections are naturally absorbed into the renormalized coupling constant
$\alpha$. We find that the lowest order vertex correction, which is the first
non-trivial correlation contribution, is finite, and about 30% of the RPA
result at strong coupling $\alpha \sim 1$. The vertex correction leads to
further reduction of the effective charge. Finite contributions to dielectric
screening are expected in all orders of perturbation theory.


title: Cosmic Acceleration, Dark Energy and Fundamental Physics

abstract:
  A web of interlocking observations has established that the expansion of the
Universe is speeding up and not slowing, revealing the presence of some form of
repulsive gravity. Within the context of general relativity the cause of cosmic
acceleration is a highly elastic (p\sim -rho), very smooth form of energy
called ``dark energy'' accounting for about 75% of the Universe. The
``simplest'' explanation for dark energy is the zero-point energy density
associated with the quantum vacuum; however, all estimates for its value are
many orders-of-magnitude too large. Other ideas for dark energy include a very
light scalar field or a tangled network of topological defects. An alternate
explanation invokes gravitational physics beyond general relativity.
Observations and experiments underway and more precise cosmological
measurements and laboratory experiments planned for the next decade will test
whether or not dark energy is the quantum energy of the vacuum or something
more exotic, and whether or not general relativity can self consistently
explain cosmic acceleration. Dark energy is the most conspicuous example of
physics beyond the standard model and perhaps the most profound mystery in all
of science.


title: Algebraic charge liquids

abstract:
  High temperature superconductivity emerges in the cuprate compounds upon
changing the electron density of an insulator in which the electron spins are
antiferromagnetically ordered. A key characteristic of the superconductor is
that electrons can be extracted from them at zero energy only if their momenta
take one of four specific values (the `nodal points'). A central enigma has
been the evolution of the zero energy electrons in the metallic state between
the antiferromagnet and the superconductor, and recent experiments yield
apparently contradictory results. The oscillation of the resistance in this
metal as a function of magnetic field indicate that the zero energy electrons
carry momenta which lie on elliptical `Fermi pockets', while ejection of
electrons by high intensity light indicates that the zero energy electrons have
momenta only along arc-like regions. We present a theory of new states of
matter, which we call `algebraic charge liquids', which arise naturally between
the antiferromagnet and the superconductor, and reconcile these observations.
Our theory also explains a puzzling dependence of the density of
superconducting electrons on the total electron density, and makes a number of
unique predictions for future experiments.


title: Black Hole Constraints on Varying Fundamental Constants

abstract:
  Here we apply the Generalized Second Law of Thermodynamics and derive upper
limits on the variation in the fundamental constants. The maximum variation in
the electronic charge permitted for black holes accreting and emitting in the
present cosmic microwave background corresponds to a variation in the fine
structure constant of ((Delta alpha) / alpha) ~ 2 x 10^-23 per second. This
value matches the variation measured by Webb et al. using absorption lines in
the spectra of distant quasars and suggests the variation mechanism may be a
coupling between the electron and the cosmic photon background.


title:
Effects of Selection and Covariance on X-ray Scaling Relations of Galaxy
  Clusters

abstract:
  We explore how the behavior of galaxy cluster scaling relations are affected
by flux-limited selection biases and intrinsic covariance among observable
properties. Our models presume log-normal covariance between luminosity (L) and
temperature (T) at fixed mass (M), centered on evolving, power-law mean
relations as a function of host halo mass. Selection can mimic evolution; the
\lm and \lt relations from shallow X-ray flux-limited samples will deviate from
mass-limited expectations at nearly all scales while the relations from deep
surveys ($10^{-14} \cgsflux$) become complete, and therefore unbiased, at
masses above $\sims 2 \times 10^{14} \hinv \msol$. We derive expressions for
low-order moments of the luminosity distribution at fixed temperature, and show
that the slope and scatter of the \lt relation observed in flux-limited samples
is sensitive to the assumed \lt correlation coefficient. In addition, \lt
covariance affects the redshift behavior of halo counts and mean luminosity in
a manner that is nearly degenerate with intrinsic population evolution.


title: Bipolar spintronics: From spin injection to spin-controlled logic

abstract:
  An impressive success of spintronic applications has been typically realized
in metal-based structures which utilize magnetoresistive effects for
substantial improvements in the performance of computer hard drives and
magnetic random access memories. Correspondingly, the theoretical understanding
of spin-polarized transport is usually limited to a metallic regime in a linear
response, which, while providing a good description for data storage and
magnetic memory devices, is not sufficient for signal processing and digital
logic. In contrast, much less is known about possible applications of
semiconductor-based spintronics and spin-polarized transport in related
structures which could utilize strong intrinsic nonlinearities in
current-voltage characteristics to implement spin-based logic. Here we discuss
the challenges for realizing a particular class of structures in semiconductor
spintronics: our proposal for bipolar spintronic devices in which carriers of
both polarities (electrons and holes) contribute to spin-charge coupling. We
formulate the theoretical framework for bipolar spin-polarized transport, and
describe several novel effects in two- and three-terminal structures which
arise from the interplay between nonequilibrium spin and equilibrium
magnetization.


title: Phases of Dense Quarks at Large N_c

abstract:
  In the limit of a large number of colors, N_c, we suggest that gauge theories
can exhibit several distinct phases at nonzero temperature and quark density.
Two are familiar: a cold, dilute phase of confined hadrons, where the pressure
is ~ 1, and a hot phase of deconfined quarks and gluons, with pressure ~ N_c^2.
When the quark chemical potential mu ~ 1, the deconfining transition
temperature, T_d, is independent of mu. For T < T_d, as mu increases above the
mass threshold, baryons quickly form a dense phase where the pressure is ~ N_c.
As illustrated by a Skyrme crystal, chiral symmetry can be both spontaneously
broken, and then restored, in the dense phase. While the pressure is ~ N_c,
like that of (non-ideal) quarks, the dense phase is still confined, with
interactions near the Fermi surface those of baryons, and not of quarks. Thus
in the chirally symmetric region, baryons near the Fermi surface are parity
doubled. We suggest possible implications for the phase diagram of QCD.


title:
Analysis and packaging of radiochemical solar neutrino data. 1. Bayesian
  approach

abstract:
  According to current practice, the results of each run of a radiochemical
solar neutrino experiment comprise an estimate of the flux and upper and lower
error estimates. These estimates are derived by a maximum-likelihood procedure
from the times of decay events in the analysis chamber. This procedure has the
following shortcomings: (a) Published results sometimes include negative flux
estimates. (b) Even if the flux estimate is non-negative, the probability
distribution function implied by the flux and error estimates will extend into
negative territory; and (c) The overall flux estimate derived from the results
of a sequence of runs may differ substantially from an estimate made by a
global analysis of all of the timing data taken together. These defects
indicate that the usual packaging of data in radiochemical solar neutrino
experiments provides an inadequate summary of the data, which implies a loss of
information. This article reviews this problem from a Bayesian perspective, and
suggests an alternative scheme for the packaging of radiochemical solar
neutrino data, which is we believe free from the above objections.


title: Linear pre-metric electrodynamics and deduction of the light cone

abstract:
  We formulate a general framework for describing the electromagnetic
properties of spacetime. These properties are encoded in the `constitutive
tensor of the vacuum', a quantity analogous to that used in the description of
material media. We give a generally covariant derivation of the Fresnel
equation describing the local properties of the propagation of electromagnetic
waves for the case of the most general possible linear constitutive tensor. We
also study the particular case in which a light cone structure is induced and
the circumstances under which such a structure emerges. In particular, we will
study the relationship between the dual operators defined by the constitutive
tensor under certain conditions and the existence of a conformal metric.
Closure and symmetry of the constitutive tensor will be found as conditions
which ensure the existence of a conformal metric. We will also see how the
metric components can be explicitly deduced from the constitutive tensor if
these two conditions are met. Finally, we will apply the same method to explore
the consequences of relaxing the condition of symmetry and how this affects the
emergence of the light cone.


title:
Nonlinear wave-wave interactions in stratified flows: Direct numerical
  simulations

abstract:
  To investigate the formation mechanism of energy spectra of internal waves in
the oceans, direct numerical simulations are performed. The simulations are
based on the reduced dynamical equations of rotating stratified turbulence. In
the reduced dynamical equations only wave modes are retained, and vortices and
horizontally uniform vertical shears are excluded. Despite the simplifications,
our simulations reproduce some key features of oceanic internal-wave spectra:
accumulation of energy at near-inertial waves and realistic frequency and
horizontal wavenumber dependencies. Furthermore, we provide evidence that
formation of the energy spectra in the inertial subrange is dominated by
scale-separated interactions with the near-inertial waves. These findings
support oceanographers' intuition that spectral energy density of internal
waves is the result of predominantly wave-wave interactions.


title: Updated analysis of NN elastic scattering to 3 GeV

abstract:
  A partial-wave analysis of NN elastic scattering data has been updated to
include a number of recent measurements. Experiments carried out at the Cooler
Synchrotron (COSY) by the EDDA Collaboration have had a significant impact
above 1 GeV. Results are discussed in terms of the partial-wave and
direct-reconstruction amplitudes.


title: Operads of compatible structures and weighted partitions

abstract:
  In this paper we describe operads encoding two different kinds of
compatibility of algebraic structures. We show that there exist decompositions
of these in terms of black and white products and we prove that they are Koszul
for a large class of algebraic structures by using the poset method of B.
Vallette. In particular we show that this is true for the operads of compatible
Lie, associative and pre-Lie algebras.


title:
The cycle of interstellar dust in galaxies of different morphological
  types

abstract:
  By means of chemical evolution models for galaxies of different morphological
type, we have performed a detailed study of the evolution of the cosmic dust
properties in different environments: the solar neighbourhood, elliptical
galaxies and dwarf irregular galaxies. Starting from the same formalism as
developed by Dwek (1998), We have taken into account dust production from low
and intermediate mass stars, supernovae II and Ia as well as dust destruction
and dust accretion processes in a detailed model of chemical evolution for the
solar vicinity. Then, by means of the same dust prescriptions but adopting
different galactic models (different star formation histories and presence of
galactic winds), we have extended our study to ellipticals and dwarf irregular
galaxies. We have investigated how the assumption of different star formation
histories affects the dust production rates, the dust depletion, the dust
accretion and destruction rates. We have shown how the inclusion of the dust
treatment is helpful in solving the so-called Fe discrepancy, observed in the
hot gaseous halos of local ellipticals, and in reproducing the chemical
abundances observed in the Lyman Break Galaxies. Finally, our new models can be
very useful in future detailed spectro-photometric studies of galaxies.


title: The effect of curvature and topology on membrane hydrodynamics

abstract:
  We study the mobility of extended objects (rods) on a spherical liquid-liquid
interface to show how this quantity is modified in a striking manner by both
the curvature and the topology of the interface. We present theoretical
calculations and experimental measurements of the interfacial fluid velocity
field around a moving rod bound to the crowded interface of a water-in-oil
droplet. By using different droplet sizes, membrane viscosities, and rod
lengths, we show that the viscosity mismatch between the interior and exterior
fluids leads to a suppression of the fluid flow on small droplets that cannot
be captured by the flat interface predictions.


title: Carrier-mediated magnetoelectricity in complex oxide heterostructures

abstract:
  While tremendous success has been achieved to date in creating both single
phase and composite magnetoelectric materials, the quintessential
electric-field control of magnetism remains elusive. In this work, we
demonstrate a linear magnetoelectric effect which arises from a novel
carrier-mediated mechanism, and is a universal feature of the interface between
a dielectric and a spin-polarized metal. Using first-principles density
functional calculations, we illustrate this effect at the SrRuO$_3$/SrTiO$_3$
interface and describe its origin. To formally quantify the magnetic response
of such an interface to an applied electric field, we introduce and define the
concept of spin capacitance. In addition to its magnetoelectric and spin
capacitive behavior, the interface displays a spatial coexistence of magnetism
and dielectric polarization suggesting a route to a new type of interfacial
multiferroic.


title: Searching for H->WW(*) and Other Diboson Final States at CDF

abstract:
  We report searches for standard model (SM) Higgs production decaying to WW(*)
and continuum ZZ production in the two charged lepton and two neutrino final
states. The data were collected with the CDF II detector at the Fermilab
Tevatron and correspond to an integrated luminosity of 1.1^fb-1. In order to
separate the processes contributing to the final state, event probabilities
calculated using the leading order differential cross-sections were used to
construct a likelihood ratio discriminant. The observed (median expected) 95%
C.L. upper limit for sigma(H->WW^(*)) with 160 GeV/c^2 mass hypothesis is 1.3
(1.8) pb which corresponds to 3.4 (4.8) times the SM prediction at
next-to-next-to-leading logarithmic level (NNLL) calculation. The significance
of the observed ZZ signal is 1.9 sigma and the 95% C.L. upper limit is 3.4 pb
which is consistent with the next-to-leading order (NLO) calculation of
1.4+/-0.1 pb.


title: Spin-waves in a complex magnetic system: nonextensive approach

abstract:
  In this paper we analyze the spin-wave excitations (magnons) of an
inhomogeneous spin system within the Boltzmann-Gibbs framework and then connect
the results with the nonextensive approach (in the sense of Tsallis
statistics). Considering an equivalence between those two frameworks, we could
connect the entropic parameter q with moments of the distribution of exchange
integrals of the inhomogenous system. It ratifies the idea that the entropic
parameter is connected to the microscopic properties of the system.


title:
New metamaterials with macroscopic behavior outside that of continuum
  elastodynamics

abstract:
  Metamaterials are constructed such that, for a narrow range of frequencies,
the momentum density depends on the local displacement gradient, and the stress
depends on the local velocity. In these models the momentum density generally
depends not only on the strain, but also on the local rotation, and the stress
is generally not symmetric. A variant is constructed for which, at a fixed
frequency, the momentum density is independent of the local rotation (but still
depends on the strain) and the stress is symmetric (but still depends on the
velocity). Generalizations of these metamaterials may be useful in the design
of elastic cloaking devices.


title:
Entropy production in high-energy heavy-ion collisions and the
  correlation of shear viscosity and thermalization time

abstract:
  We study entropy production in the early stage of high-energy heavy-ion
collisions due to shear viscosity. We employ the second-order theory of
Israel-Stewart with two different stress relaxation times, as appropriate for
strong coupling or for a Boltzmann gas, respectively, and compare the
hydrodynamic evolution. Based on present knowledge of initial particle
production, we argue that entropy production is tightly constrained. We derive
new limits on the shear viscosity to entropy density ratio $\eta/s$,
independent from elliptic flow effects, and determine the corresponding
Reynolds number. Furthermore, we show that for a given entropy production
bound, that the initial time $\tau_0$ for hydrodynamics is correlated to the
viscosity. The conjectured lower bound for $\eta/s$ provides a lower limit for
$\tau_0$.


title: Gorenstein Multiple Structures on Smooth Algebraic Varieties

abstract:
  We characterize the Gorenstein nilpotent scheme structures on a smooth
algebraic variety as support, in terms of a duality property of the graded
objects associated to two canonical filtrations.


title: Role of resonances in rho^0 -> pi^+ pi^- gamma

abstract:
  We study the effect of the sigma(600) and a_1(1260) resonances in the rho^0
-> pi^+ pi^- gamma decay, within the meson dominance model. Major effects are
driven by the mass and width parameters of the sigma(600), and the usually
neglected contribution of the a_1(1260), although small by itself, may become
sizable through its interference with pion bremsstrahlung, and the proper
relative sign can favor the central value of the experimental branching ratio.
We present a procedure, using the gauge invariant structure of the resonant
amplitudes, to kinematically enhance the resonant effects in the angular and
energy distribution of the photon. We also elaborate on the coupling constants
involved.


title: A Case Study of Low-Mass Star Formation

abstract:
  This article synthesizes observational data from an extensive program aimed
toward a comprehensive understanding of star formation in a low-mass
star-forming molecular cloud. New observations and published data spanning from
the centimeter wave band to the near infrared reveal the high and low density
molecular gas, dust, and pre-main sequence stars in L1551.


title:
Relationship between Hawking radiation from black holes and spontaneous
  excitation of atoms

abstract:
  Using the formalism that separates the contributions of vacuum fluctuations
and radiation reaction to the rate of change of the mean atomic energy, we show
that a two-level atom in interaction with a quantum massless scalar field both
in the Hartle-Hawking and Unruh vacuum in a 1+1 dimensional black hole
background spontaneously excites as if there is thermal radiation at the
Hawking temperature emanating from the black hole. Our calculation, therefore,
ties the existence of Hawking radiation to the spontaneous excitation of a
two-level atom placed in vacuum in the exterior of a black hole and shows
pleasing consistence of two different physical phenomena, the Hawking radiation
and the spontaneous excitation of atoms, which are quite prominent in their own
right.


title: Contractions, deformations and curvature

abstract:
  The role of curvature in relation with Lie algebra contractions of the
pseudo-ortogonal algebras so(p,q) is fully described by considering some
associated symmetrical homogeneous spaces of constant curvature within a
Cayley-Klein framework. We show that a given Lie algebra contraction can be
interpreted geometrically as the zero-curvature limit of some underlying
homogeneous space with constant curvature. In particular, we study in detail
the contraction process for the three classical Riemannian spaces (spherical,
Euclidean, hyperbolic), three non-relativistic (Newtonian) spacetimes and three
relativistic ((anti-)de Sitter and Minkowskian) spacetimes. Next, from a
different perspective, we make use of quantum deformations of Lie algebras in
order to construct a family of spaces of non-constant curvature that can be
interpreted as deformations of the above nine spaces. In this framework, the
quantum deformation parameter is identified as the parameter that controls the
curvature of such "quantum" spaces.


title: SU(3) Ghosts with Spin

abstract:
  A new Lorentz-covariant gauge is presented for SU(3). In this gauge, both the
ghosts and the gauge fields in the (4, 5, 6, 7) gauge directions acquire
half-integral spin. As a result, the ghosts in these directions have the
correct relationship between spin and statistics, while the gauge fields have
the incorrect relationship. Consequently, asymptotic ghost states are not
forbidden in this gauge and can possibly form new matter states. Conversely,
asymptotic gauge fields in the (4, 5, 6, 7) directions are forbidden in this
gauge, so the SU(3) symmetry is broken down to an SU(2)xU(1) symmetry
asymptotically.


title:
A Mathematica script for harmonic oscillator nuclear matrix elements
  arising in semileptonic electroweak interactions

abstract:
  Semi-leptonic electroweak interactions in nuclei - such as \beta decay, \mu
capture, charged- and neutral-current neutrino reactions, and electron
scattering - are described by a set of multipole operators carrying definite
parity and angular momentum, obtained by projection from the underlying nuclear
charge and three-current operators. If these nuclear operators are approximated
by their one-body forms and expanded in the nucleon velocity through order
|\vec{p}|/M, where \vec{p} and M are the nucleon momentum and mass, a set of
seven multipole operators is obtained. Nuclear structure calculations are often
performed in a basis of Slater determinants formed from harmonic oscillator
orbitals, a choice that allows translational invariance to be preserved.
Harmonic-oscillator single-particle matrix elements of the multipole operators
can be evaluated analytically and expressed in terms of finite polynomials in
q^2, where q is the magnitude of the three-momentum transfer. While results for
such matrix elements are available in tabular form, with certain restriction on
quantum numbers, the task of determining the analytic form of a response
function can still be quite tedious, requiring the folding of the tabulated
matrix elements with the nuclear density matrix, and subsequent algebra to
evaluate products of operators. Here we provide a Mathematica script for
generating these matrix elements, which will allow users to carry out all such
calculations by symbolic manipulation. This will eliminate the errors that may
accompany hand calculations and speed the calculation of electroweak nuclear
cross sections and rates. We illustrate the use of the new script by
calculating the cross sections for charged- and neutral-current neutrino
scattering in ^{12}C.


title: Holographic hessence models

abstract:
  We discuss the evolution of holographic hessence model, which satisfies the
holographic principle and can naturally realizes the equation of state crossing
-1. By discussing the evolution of the models in the $w w'$ plane, we find
that, if $c\geq1$, $w_{he}\geq-1$ and $\dot{V}<0$ keep for all time, which are
quintessence-like. However, if $c<-1$, which mildly favors the current
observations, $w_{he}$ evolves from $w_{he}>-1$ to $w_{he}<-1$, and the
potential is a nonmonotonic function. In the earlier time, the potential must
be rolled down, and then be climbed up. Considered the current constraint on
the parameter $c$, we reconstruct the potential of the holographic hessence
model.


title:
Predicting the progress of diffusively limited chemical reactions in the
  presence of chaotic advection

abstract:
  The effects of chaotic advection and diffusion on fast chemical reactions in
two-dimensional fluid flows are investigated using experimentally measured
stretching fields and fluorescent monitoring of the local concentration. Flow
symmetry, Reynolds number, and mean path length affect the spatial distribution
and time dependence of the reaction product. A single parameter \lambda*N,
where \lambda is the mean Lyapunov exponent and N is the number of mixing
cycles, can be used to predict the time-dependent total product for flows
having different dynamical features.


title: Non-abelian Reidemeister torsion for twist knots

abstract:
  This paper gives an explicit formula for the SL_2(C)-non-abelian Reidemeister
torsion as defined in [Dub06] in the case of twist knots. For hyperbolic twist
knots, we also prove that the non-abelian Reidemeister torsion at the holonomy
representation can be expressed as a rational function evaluated at the cusp
shape of the knot.


title: Nanorheology of viscoelastic shells: Applications to viral capsids

abstract:
  We study the microrheology of nanoparticle shells [Dinsmore et al. Science
298, 1006 (2002)] and viral capsids [Ivanovska et al. PNAS 101, 7600 (2004)] by
computing the mechanical response function and thermal fluctuation spectrum of
a viscoelastic spherical shell that is permeable to the surrounding solvent. We
determine analytically the damped dynamics of the shear, bend, and compression
modes of the shell coupled to the solvent both inside and outside the sphere in
the zero Reynolds number limit. We identify fundamental length and time scales
in the system, and compute the thermal correlation function of displacements of
antipodal points on the sphere and the mechanical response to pinching forces
applied at these points. We describe how such a frequency-dependent antipodal
correlation and/or response function, which should be measurable in new
AFM-based microrheology experiments, can probe the viscoelasticity of these
synthetic and biological shells constructed of nanoparticles.


title:
Constraints on the spectral index for the inflation models in string
  landscape

abstract:
  We conjecture that the inflation models with trans-Planckian excursions in
the field space should be in the swampland. We check this conjecture in a few
examples and investigate the constraints on the spectral index for the
slow-roll inflation model in string landscape where the variation of inflaton
during the period of inflation is less than the Planck scale $M_p$. A red
primordial power spectrum with a lower bound on the spectral index is
preferred. Both the tensor-scalar ratio and the running can be ignored.


title: Schwinger Pair Production at Finite Temperature in Scalar QED

abstract:
  In scalar QED we study the Schwinger pair production from an initial ensemble
of charged bosons when an electric field is turned on for a finite period
together with or without a constant magnetic field. The scalar QED Hamiltonian
depends on time through the electric field, which causes the initial ensemble
of bosons to evolve out of equilibrium. Using the Liouville-von Neumann method
for the density operator and quantum states for each momentum mode, we
calculate the Schwinger pair-production rate at finite temperature, which is
the pair-production rate from the vacuum times a thermal factor of the
Bose-Einstein distribution.


title:
Unusual superexchange pathways in a Ni triangular lattice of
  NiGa$_2$S$_4$ with negative charge-transfer energy

abstract:
  We have studied the electronic structure of the Ni triangular lattice in
NiGa$_2$S$_4$ using photoemission spectroscopy and subsequent model
calculations. The cluster-model analysis of the Ni 2$p$ core-level spectrum
shows that the S 3$p$ to Ni 3$d$ charge-transfer energy is $\sim$ -1 eV and the
ground state is dominated by the $d^9L$ configuration ($L$ is a S 3$p$ hole).
Cell perturbation analysis for the NiS$_2$ triangular lattice indicates that
the strong S 3$p$ hole character of the ground state provides the enhanced
superexchange interaction between the third nearest neighbor sites.


abstract:
  The analog of the Schauder inequality for closed surfaces in Euclidean spaces
is obtained in this article.


title: On the derivative of the Minkowski question mark function $?(x)$

abstract:
  Let $ x = [0;a_1,a_2,...]$ be the decomposition of the irrational number $x
\in [0,1]$ into regular continued fraction. Then for the derivative of the
Minkowski function $?(x)$ we prove that $?'(x) = +\infty$ provided $
\limsup_{t\to \infty}\frac{a_1+...+a_t}{t} <\kappa_1 =\frac{2\log
\lambda_1}{\log 2} = 1.388^+$, and $?'(x) = 0$ provided $ \liminf_{t\to
\infty}\frac{a_1+...+a_t}{t} >\kappa_2 = \frac{4L_5-5L_4}{L_5-L_4}= 4.401^+$
(here $ L_j = \log (\frac{j+\sqrt{j^2+4}}{2}) - j\cdot\frac{\log 2}{2}$).
Constants $\kappa_1,\kappa_2$ are the best possible. Also we prove that $?'(x)
= +\infty$ holds for all $x$ with partial quotients bounded by 4.


title:
Observation of photoinduced phase transition in phase-separated
  Pr$_{0.55}$(Ca$_{1-y}$Sr$_{y}$)$_{0.45}$MnO$_3$ thin films via x-ray
  photoemission spectroscopy

abstract:
  Perovskite manganite thin films, $Pr_{0.55}(Ca_{1-y}Sr_y)_{0.45}MnO_3$, have
been studied using x-ray photoemission spectroscopy in order to clarify the
consequence of the competition between ferromagnetic metal (FM) and
charge-orbital ordered insulator (COOI). Films with $y$ = 0.40 undergo uniform
paramagnetic insulator to FM transition. On the other hand, in films with $y$ =
0.25, the composition near the bicritical point, phase separation of COOI and
FM domains is indicated by the spectral change below 125 K. Interestingly,
between 50 K and 70 K, the visible laser illumination transfers the COOI-like
spectra obtained in cooling process to the FM-like spectra obtained in warming
process. This indicates that the photoinduced IMT is governed by the increase
of the FM volume fraction and is deeply related to the phase separation between
the FM and COOI states.


title:
Generalized pseudo-Newtonian potential for studying accretion disk
  dynamics in off-equatorial planes around rotating black holes: Description of
  a vector potential

abstract:
  We prescribe a pseudo-Newtonian vector potential for studying accretion disks
around Kerr black holes. The potential is useful to study the inner properties
of disk not confined to the equatorial plane where general relativistic effect
is indispensable. Therefore, we incorporate the essential properties of the
metric at the inner radii through the pseudo-Newtonian potential derived from
the general Kerr spacetime. The potential, reproducing most of the salient
features of the general-relativity, is valid for entire regime of Kerr
parameter. It reproduces the last stable circular orbit exactly as that in the
Kerr geometry. It also reproduces last bound orbit and energy at last stable
circular orbit with a maximum error ~7% and ~15% respectively upto an orbital
inclination 30 degree.


title: LHC Signatures of MSSM Higgs-sector CP Violation

abstract:
  We discuss a few new characteristic features of the loop-induced MSSM
Higgs-sector CP violation at the LHC based on two scenarios: (i) CPX and (ii)
Trimixing.


title:
Towards the Distribution of the Size of a Largest Planar Matching and
  Largest Planar Subgraph in Random Bipartite Graphs

abstract:
  We address the following question: When a randomly chosen regular bipartite
multi--graph is drawn in the plane in the ``standard way'', what is the
distribution of its maximum size planar matching (set of non--crossing disjoint
edges) and maximum size planar subgraph (set of non--crossing edges which may
share endpoints)? The problem is a generalization of the Longest Increasing
Sequence (LIS) problem (also called Ulam's problem). We present combinatorial
identities which relate the number of r-regular bipartite multi--graphs with
maximum planar matching (maximum planar subgraph) of at most d edges to a
signed sum of restricted lattice walks in Z^d, and to the number of pairs of
standard Young tableaux of the same shape and with a ``descend--type''
property. Our results are obtained via generalizations of two combinatorial
proofs through which Gessel's identity can be obtained (an identity that is
crucial in the derivation of a bivariate generating function associated to the
distribution of LISs, and key to the analytic attack on Ulam's problem).
  We also initiate the study of pattern avoidance in bipartite multigraphs and
derive a generalized Gessel identity for the number of bipartite 2-regular
multigraphs avoiding a specific (monotone) pattern.


title: Existence of Kirillov-Reshetikhin crystals for nonexceptional types

abstract:
  Using the methods of Kang et al. and recent results on the characters of
Kirillov-Reshetikhin modules by Nakajima and Hernandez, the existence of
Kirillov-Reshetikhin crystals B^{r,s} is established for all nonexceptional
affine types. We also prove that the crystals B^{r,s} of type B_n^{(1)},
D_n^{(1)}, and A_{2n-1}^{(2)} are isomorphic to recently constructed
combinatorial crystals for r not a spin node.


title: Significance Tests for Periodogram Peaks

abstract:
  We discuss methods currently in use for determining the significance of peaks
in the periodograms of time series. We discuss some general methods for
constructing significance tests, false alarm probability functions, and the
role played in these by independent random variables and by empirical and
theoretical cumulative distribution functions. We also discuss the concept of
"independent frequencies" in periodogram analysis. We propose a practical
method for estimating the significance of periodogram peaks, applicable to all
time series irrespective of the spacing of the data. This method, based on
Monte Carlo simulations, produces significance tests that are tailor-made for
any given astronomical time series.


title: The Photonic Module: an on-demand resource for photonic entanglement

abstract:
  Photonic entanglement has a wide range of applications in quantum computation
and communication. Here we introduce a new device: the "photonic module", which
allows for the rapid, deterministic preparation of a large class of entangled
photon states. The module is an application independent, "plug and play"
device, with sufficient flexibility to prepare entanglement for all major
quantum computation and communication applications in a completely
deterministic fashion without number-discriminated photon detection. We present
two alternative constructions for the module, one using free-space components
and one in a photonic bandgap structures. The natural operation of the module
is to generate states within the stabilizer formalism and we present an
analysis on the cavity-QED requirements to experimentally realize this device.


title:
The Norma Cluster (ACO 3627): I. A Dynamical Analysis of the Most
  Massive Cluster in the Great Attractor

abstract:
  A detailed dynamical analysis of the nearby rich Norma cluster (ACO 3627) is
presented. From radial velocities of 296 cluster members, we find a mean
velocity of 4871 +/- 54 km/s and a velocity dispersion of 925 km/s. The mean
velocity of the E/S0 population (4979 +/- 85 km/s) is offset with respect to
that of the S/Irr population (4812 +/- 70 km/s) by `Delta' v = 164 km/s in the
cluster rest frame. This offset increases towards the core of the cluster. The
E/S0 population is free of any detectable substructure and appears relaxed. Its
shape is clearly elongated with a position angle that is aligned along the
dominant large-scale structures in this region, the so-called Norma wall. The
central cD galaxy has a very large peculiar velocity of 561 km/s which is most
probably related to an ongoing merger at the core of the cluster. The
spiral/irregular galaxies reveal a large amount of substructure; two
dynamically distinct subgroups within the overall spiral-population have been
identified, located along the Norma wall elongation. The dynamical mass of the
Norma cluster within its Abell radius is 1 - 1.1 x 10^15 h^-1_73 M_Sun. One of
the cluster members, the spiral galaxy WKK 6176 which recently was observed to
have a 70 kpc X-ray tail, reveals numerous striking low-brightness filaments
pointing away from the cluster centre suggesting strong interaction with the
intracluster medium.


title:
Periodic harmonic functions on lattices and points count in positive
  characteristic

abstract:
  This survey addresses pluri-periodic harmonic functions on lattices with
values in a positive characteristic field. We mention, as a motivation, the
game "Lights Out" following the work of Sutner, Goldwasser-Klostermeyer-Ware,
Barua-Ramakrishnan-Sarkar, Hunzikel-Machiavello-Park e.a.; see also 2 previous
author's preprints for a more detailed account. Our approach explores harmonic
analysis and algebraic geometry over a positive characteristic field. The
Fourier transform allows us to interpret pluri-periods of harmonic functions on
lattices as torsion multi-orders of points on the corresponding affine
algebraic variety.


title:
AF-embedding of the crossed products of AH-algebras by finitely
  generated abelian groups

abstract:
  Let $X$ be a compact metric space and let $\Lambda$ be a $\Z^k$ ($k\ge 1$)
action on $X.$ We give a solution to a version of Voiculescu's problem of
AF-embedding: The crossed product $C(X)\rtimes_{\Lambda}\Z^k$ can be embedded
into a unital simple AF-algebra if and only if $X$ admits a strictly positive
$\Lambda$-invariant Borel probability measure.
  Let $C$ be a unital AH-algebra, let $G$ be a finitely generated abelian group
and let $\Lambda: G\to Aut(C)$ be a monomorphism. We show that
$C\rtimes_{\Lambda} G$ can be embedded into a unital simple AF-algebra if and
only if $C$ admits a faithful $\Lambda$-invariant tracial state.


title:
Limited resolution and multiresolution methods in complex network
  community detection

abstract:
  Detecting community structure in real-world networks is a challenging
problem. Recently, it has been shown that the resolution of methods based on
optimizing a modularity measure or a corresponding energy is limited;
communities with sizes below some threshold remain unresolved. One possibility
to go around this problem is to vary the threshold by using a tuning parameter,
and investigate the community structure at variable resolutions. Here, we
analyze the resolution limit and multiresolution behavior for two different
methods: a q-state Potts method proposed by Reichard and Bornholdt, and a
recent multiresolution method by Arenas, Fernandez, and Gomez. These methods
are studied analytically, and applied to three test networks using simulated
annealing.


title: Study of tau- -> K_S pi- nu_tau decay at Belle

abstract:
  We present a study of the decay tau- -> K_S pi- nu_tau using a 351 fb^-1 data
sample collected with the Belle detector. The analysis is based on 53110
lepton-tagged signal events. The measured branching fraction B(tau- -> K_S pi-
nu_tau)=(0.404 +- 0.002(stat.) +- 0.013(syst.))% is consistent with the world
average value and has better accuracy. An analysis of the K_S pi- invariant
mass spectrum reveals contributions from the K*(892)- as well as other states.
For the first time the K*(892)- mass and width have been measured in tau decay:
M(K*(892)-)=(895.47 +- 0.20(stat.) +- 0.44(syst.) +- 0.59(mod.)) MeV/c2,
Gamma(K*(892)-)=(46.2 +- 0.6(stat.) +- 1.0(syst.) +- 0.7(mod.)) MeV. The
K*(892)- mass is significantly different from the current world average value.


title: Characterization of intrinsically harmonic forms

abstract:
  Let $M$ be a closed oriented manifold of dimension $n$ and $\omega$ a closed
1-form on it. We discuss the question whether there exists a Riemannian metric
for which $\omega$ is co-closed. For closed 1-forms with nondegenerate zeros
the question was answered completely by Calabi in 1969. The goal of this paper
is to give an answer in the general case, i.e. not making any assumptions on
the zero set of $\omega$.


title: Two-dimensional defect modes in optically induced photonic lattices

abstract:
  In this article, localized linear defect modes due to bandgap guidance in
two-dimensional photonic lattices with localized or non-localized defects are
investigated theoretically. First, when the defect is localized and weak,
eigenvalues of defect modes bifurcated from edges of Bloch bands are derived
analytically. It is shown that in an attractive (repulsive) defect, defect
modes bifurcate out from Bloch-band edges with normal (anomalous) diffraction
coefficients. Furthermore, distances between defect-mode eigenvalues and
Bloch-band edges are exponentially small functions of the defect strength,
which is very different from the one-dimensional case where such distances are
quadratically small with the defect strength. It is also found that some
defect-mode branches bifurcate not from Bloch-band edges, but from quasi-edge
points within Bloch bands, which is very unusual. Second, when the defect is
localized but strong, defect modes are determined numerically. It is shown that
both the repulsive and attractive defects can support various types of defect
modes such as fundamental, dipole, quadrupole, and vortex modes. These modes
reside in various bandgaps of the photonic lattice. As the defect strength
increases, defect modes move from lower bandgaps to higher ones when the defect
is repulsive, but remain within each bandgap when the defect is attractive,
similar to the one-dimensional case. The same phenomena are observed when the
defect is held fixed while the applied dc field (which controls the lattice
potential) increases. Lastly, if the defect is non-localized (i.e. it persists
at large distances in the lattice), it is shown that defect modes can be
embedded inside the continuous spectrum, and they can bifurcate out from edges
of the continuous spectrum algebraically rather than exponentially.


title:
A wide deep infrared look at the Pleiades with UKIDSS: new constraints
  on the substellar binary fraction and the low mass IMF

abstract:
  We present the results of a deep wide-field near-infrared survey of 12 square
degrees of the Pleiades conducted as part of the UKIDSS Deep Infrared Sky
Survey (UKIDSS) Galactic Cluster Survey (GCS). We have extracted over 340 high
probability proper motion members down to 0.03 solar masses using a combination
of UKIDSS photometry and proper motion measurements obtained by
cross-correlating the GCS with data from the Two Micron All Sky Survey (2MASS),
the Isaac Newton (INT) and the Canada-France-Hawai'i (CFHT) telescopes.
Additionally, we have unearthed 73 new candidate brown dwarf members on the
basis of five band UKIDSS photometry alone. We have identified 23 substellar
multiple system candidates out of 63 candidate brown dwarfs from the (Y-K,Y)
and (J-K,J) colour-magnitude diagrams, yielding a binary frequency of 28-44% in
the 0.075-0.030 Msun mass range. Our estimate is three times larger than the
binary fractions reported from high-resolution imaging surveys of field
ultracool dwarfs and Pleiades brown dwarfs. However, it is marginally
consistent with our earlier ``peculiar'' photometric binary fraction of
50+/-10% presented in Pinfield et al. (2003), in good agreement with the 32-45%
binary fraction derived from the recent Monte-Carlo simulations of Maxted &
Jeffries (2005) and compatible with the 26+/-10% frequency recently estimated
by Basri & Reiners (2006). A tentative estimate of the mass ratios from
photometry alone seems to support the hypothesis that binary brown dwarfs tend
to reside in near equal-mass ratio systems. (abridged)


title: Sn1987a Revisited after 20 Years: May the Supernova Bang More Than Once?

abstract:
  The observations of supernova 1987A in underground detectors are revisited.
It is shown that, while the LSD detector in the Mont Blanc Laboratory observed
only one burst at 2h 52min 36.8sec U.T., the Kamiokande data show a possible
second burst, in addition to the well known one at 7h 35min 33.7sec U.T. This
second burst consists of a cluster of seven pulses, well above the energy
threshold of the detector, observed during 6.2 seconds starting at 7h 54min
22.2sec U.T. Do these observations imply a long duration of the collapse?


title: Solution of the Dirac Equation using the Lanczos Algorithm

abstract:
  Covergent eigensolutions of the Dirac Equation for a relativistic electron in
an external Coulomb potential are obtained using the Lanczos Algorithm. A
tri-diagonal matrix representation of the Dirac Hamiltonian operator is
constructed iteratively and diagonalized after each iteration step to form a
sequence of convergent eigenvalue solutions. Any spurious solutions which arise
from the presence of continuum states can easily be identified.


title: A brief note on how to unify dark matter, dark energy, and inflation

abstract:
  A scenario in which inflation, dark energy and dark matter can be unified
into a single scalar field, the inflaton field $\phi$, is studied. The inflaton
is identified with the sneutrino, the scalar partner of the heavy neutrino. We
determine the conditions needed for avoiding the gravitino problem and not
having negligible plasma effects and we obtain the allowed range for the
sneutrino coupling.


title: Renormalization Reductions for Systems with Delay

abstract:
  The renormalization method which is a type of perturbation method is extended
to a tool to study weakly nonlinear time-delay systems. For systems with
order-one delay, we show that the renormalization method leads to reduced
systems without delay. For systems with order-one and large-delay, we propose
an extended renormalization method which leads to reduced systems with delay.
In some examples, the validities of our perturbative results are confirmed
analytically and numerically. We also compare our reduced equations with
reduced ones obtained by another perturbation method.


title: Infinitesimal Castelnuovo Theory in Abelian Varieties

abstract:
  The purpose of this article is to show that the Castelnuovo theory for
abelian varieties, developed by G. Pareschi and M. Popa, can be
infinitesimalized. More precisely, we prove that an irreducible principally
polarized abelian variety has a finite scheme in extremal position, in the
sense of Castelnuovo theory for abelian varieties, if, and only if, it is a
Jacobian and the scheme is contained in a unique Abel-Jacobi curve.


title:
Vibration-mediated resonant tunneling and shot noise through a molecular
  quantum dot

abstract:
  Motivated by a recent experiment on nonlinear tunneling in a suspended Carbon
nanotube connected to two normal electrodes [S. Sapmaz, {\it et al}., Phys.
Rev. Lett. {\bf 96}, 26801 (2006)], we investigate nonequilibrium
vibration-mediated sequential tunneling through a molecular quantum dot with
two electronic orbitals asymmetrically coupled to two electrodes and strongly
interacting with an internal vibrational mode, which is itself weakly coupled
to a dissipative phonon bath. For this purpose, we establish rate equations
using a generic quantum Langevin equation approach. Based on these equations,
we study in detail the current-voltage characteristics and zero-frequency shot
noise, paying special attention to the advanced or postponed of the appearance
of negative differential conductance and super-Poissonian current noise
resulting from electron-phonon-coupling induced {\em selective unidirectional
cascades of single-electron transitions}.


title:
Dynamics-Controlled Truncation Scheme for Nonlinear Dynamics in
  Semiconductor Microcavities

abstract:
  We present a systematic theory of Coulomb-induced correlation effects in the
nonlinear optical processes within the strong-coupling regime. In this paper we
shall set a dynamics controlled truncation scheme \cite{Axt Stahl} microscopic
treatment of nonlinear parametric processes in SMCs including the
electromagnetic field quantization. It represents the starting point for the
microscopic approach to quantum optics experiments in the strong coupling
regime without any assumption on the quantum statistics of electronic
excitations (excitons) involved. We exploit a previous technique, used in the
semiclassical context, which, once applied to four-wave mixing in quantum
wells, allowed to understand a wide range of observed phenomena \cite{Sham
PRL95}. We end up with dynamical equations for exciton and photon operators
which extend the usual semiclassical description of Coulomb interaction
effects, in terms of a mean-field term plus a genuine non-instantaneous
four-particle correlation, to quantum optical effects.


title:
HERMES measurements of Collins and Sivers asymmetries from a
  transversely polarised hydrogen target

abstract:
  Azimuthal single-spin asymmetries (SSA) in semi-inclusive electroproduction
of pi-mesons and charged K-mesons in deep-inelastic scattering of positrons and
electrons on a transversely polarised hydrogen target were observed.
Significant SSA amplitudes for both the Collins and the Sivers mechanism are
presented for the full data set recorded with transverse target polarisation at
the HERMES experiment.


title: GAVO Tools for the Analysis of Stars and Nebulae

abstract:
  Within the framework of the German Astrophysical Virtual Observatory (GAVO),
we provide synthetic spectra, simulation software for the calculation of NLTE
model atmospheres, as well as necessary atomic data. This will enable a VO user
to directly compare observation and model-atmosphere spectra on three levels:
The easiest and fastest way is the use of our pre-calculated flux-table grid in
which one may inter- and extrapolate. For a more precise analysis of an
abservation, the VO user may improve the fit to the observation by the
calculation of individual model atmospheres with fine-tuned photospheric
parameters via the WWW interface TMAW. The more experienced VO user may create
own atomic-data files for a more detailed analysis and calculate model
atmosphere and flux tables with these.


title:
The Yule distribution and frailty--a note on spurious preferential
  attachment

abstract:
  Preferential attachment is a popular generative mechanism to explain the
widespread observation of power law distributed networks. We introduce an
alternative explanation for the phenomenon by allowing the link growth rates to
vary across the nodes according to a randomized Poisson process. The
distribution of rates, which reproduces the degree distribution of a
preferential attachment process (Yule process) is derived analytically. We
demonstrate with use of simulations that the degree distribution and growth
rates in single time intervals are similar for the random process and the
preferential attachment process. Structural differences are analyzed by
examining the joint degree distribution and network coreness.


title: HST Spectroscopy of the Hottest White Dwarfs

abstract:
  Spectral analysis needs the observation of lines of successive ionization
stages in order to evaluate the ionization equilibrium (of a particular
species) which is a sensitive indicator for the effective temperature. Since
stars with effective temperatures as high as 100000 K have their flux maximum
in the extreme ultraviolet (EUV) wavelength range and due to the high degree of
ionization, most of the metal lines are found in the ultraviolet (UV) range.
Thus, high-S/N and high-resolution UV spectra are a pre-requisite for a precise
analysis. Consequently, we employed the Faint Object Spectrograph (FOS), the
Goddard High Resolution Spectrograph (GHRS), and the Space Telescope Imaging
Spectrograph (STIS) aboard the Hubble Space Telescope (HST) in order to obtain
suitable data. We present state-of-the-art analyses of the hottest (pre-) white
dwarfs by means of NLTE model atmospheres which include the metal-line
blanketing of all elements from hydrogen to nickel.


title:
Effect of Zn substitution on the suppression of Tc of
  Y1-xCaxBa2(Cu1-yZny)3O7-delta superconductors: pseudogap and the systematic
  shift of the optimum hole content

abstract:
  The effect of Zn substitution on the superconducting transition temperature,
Tc, was investigated for the sintered Y1-xCaxBa2(Cu1-yZny)3O7-delta compounds
over a wide range of hole concentration per CuO2 plane, p. Ca substitution
enabled us to study the deeply overdoped region. p was changed by changing the
oxygen deficiency (delta). A strongly p-dependent rate of suppression of Tc
with Zn (dTc/dy) was found. From the analysis of the dTc(p)/dy and Tc(p,y)
data, we found that the optimum hole content, popt, shifts to higher values
with increasing Zn and superconductivity is at its strongest when p = 0.185 +/-
0.005. Various complementary experiments have identified this as the hole
content where the pseudogap vanishes quite abruptly. We have discussed the
possible relevance to these ideas with our findings.


title: A refinement of Khovanov-Rozansky link homology

abstract:
  This paper has been withdrawn by the author due to an error in the proof of
Theorem 1.


title:
Anticorrelation between temperature and fluctuations in moderately
  damped Josephson junctions

abstract:
  We study the influence of dissipation on the switching current statistics of
moderately damped Josephson junctions. Different types of both low- and high-
$T_c$ junctions with controlled damping are studied. The damping parameter of
the junctions is tuned in a wide range by changing temperature, magnetic field,
gate voltage, introducing a ferromagnetic layer or in-situ capacitive shunting.
A paradoxical collapse of switching current fluctuations occurs with increasing
$T$ in all studied junctions. The phenomenon critically depends on dissipation
in the junction and is explained by interplay of two counteracting consequences
of thermal fluctuations, which on the one hand assist in premature switching
into the resistive state and on the other hand help in retrapping back to the
superconducting state. This is one of the rare examples of anticorrelation
between temperature and fluctuation amplitude of a physically measurable
quantity.


title: Distributed implementation of standard oracle operators

abstract:
  The standard oracle operator corresponding to a function f is a unitary
operator that computes this function coherently, i.e. it maintains
superpositions. This operator acts on a bipartite system, where the subsystems
are the input and output registers. In distributed quantum computation, these
subsystems may be spatially separated, in which case we will be interested in
its classical and entangling capacities. For an arbitrary function f, we show
that the unidirectional classical and entangling capacities of this operator
are log_{2}(n_{f}) bits/ebits, where n_{f} is the number of different values
this function can take. An optimal procedure for bidirectional classical
communication with a standard oracle operator corresponding to a permutation on
Z_{M} is given. The bidirectional classical capacity of such an operator is
found to be 2log_{2}(M) bits. The proofs of these capacities are facilitated by
an optimal distributed protocol for the implementation of an arbitrary standard
oracle operator.


title: Sign lemma for dimension shifting

abstract:
  There is a surprising occurrence of some minus signs in the isomorphisms
produced in the well-known technique of dimension shifting in calculating
derived functors in homological algebra. We explicitly determine these signs.
Getting these signs right is important in order to avoid basic contradictions.
We illustrate the lemma by some de Rham cohomology and Chern class
considerations for compact Riemann surfaces.


title: A polaritonic two-component Bose-Hubbard model

abstract:
  We show that polaritons in an array of interacting micro-cavities with strong
atom-photon coupling can form a two-component Bose-Hubbard model. Both
polariton species are thereby protected against spontaneous emission as their
atomic part is stored in two ground states of the atoms. The parameters of the
effective model can be tuned via the driving strength of external lasers. We
also describe a method to measure the number statistics in one cavity for each
polariton species independently.


title: Time and M-theory

abstract:
  We review our recent proposal for a background independent formulation of a
holographic theory of quantum gravity. The present review incorporates the
necessary background material on geometry of canonical quantum theory,
holography and spacetime thermodynamics, Matrix theory, as well as our specific
proposal for a dynamical theory of geometric quantum mechanics, as applied to
Matrix theory. At the heart of this review is a new analysis of the conceptual
problem of time and the closely related and phenomenologically relevant problem
of vacuum energy in quantum gravity. We also present a discussion of some
observational implications of this new viewpoint on the problem of vacuum
energy.


title: A note on fermions in holographic QCD

abstract:
  We study the fermionic sector of a probe D8-brane in the supergravity
background made of D4-branes compactified on a circle with supersymmetry broken
explicitly by the boundary conditions. At low energies the dual field theory is
effectively four-dimensional and has proved surprisingly successful in
recovering qualitative and quantitative properties of QCD. We investigate
fluctuations of the fermionic fields on the probe D8-brane and interpret these
as mesinos (fermionic superpartners of mesons). We demonstrate that the masses
of these modes are comparable to meson masses and show that their interactions
with ordinary mesons are not suppressed.


title: Dynamics of cluster deposition on Ar surface

abstract:
  Using a combined quantum mechanical/classical method, we study the dynamics
of deposition of small Na clusters on Ar(001) surface. We work out basic
mechanisms by systematic variation of substrate activity, impact energy,
cluster orientations, cluster sizes, and charges. The soft Ar material is found
to serve as an extremely efficient shock absorber which provides cluster
capture in a broad range of impact energies. Reflection is only observed in
combination with destruction of the substrate. The kinetic energy of the
impinging cluster is rapidly transfered at first impact. The distribution of
the collision energy over the substrate proceeds very fast with velocity of
sound. The full thermalization of ionic and atomic energies goes at a much
slower pace with times of several ps. Charged clusters are found to have a much
stronger interface interaction and thus get in significantly closer contact
with the surface.


title: The magnetic field topology in the reconnecting pulsar magnetosphere

abstract:
  We show that toroidal magnetic field annihilation in the equatorial current
sheet of the pulsar magnetosphere is related to how fast poloidal magnetic
field lines close as we move away from the light cylinder. This determines the
reconnection radial electric field which directly accelerates particles in the
neutral layer inside the equatorial current sheet. The efficiency of poloidal
magnetic field closure near the light cylinder may be measurable through the
pulsar braking index. We argue that, the lower the efficiency of pair
formation, the higher the braking index. We also argue that synchrotron
radiation reaction in the neutral layer does not inhibit the accelerated
particles from reaching the maximum energy of about 10^16 eV available in the
open pulsar magnetosphere.


title:
High-resolution FUSE and HST ultraviolet spectroscopy of the white dwarf
  central star of Sh 2-216

abstract:
  LS V +4621 is the DAO-type central star of the planetary nebula Sh 2-216. We
perform a comprehensive spectral analysis of high-resolution, high-S/N
ultraviolet observations obtained with FUSE and STIS aboard the HST as well as
the optical spectrum of LS V +4621 by means of state-of-the-art NLTE
model-atmosphere techniques in order to compare its photospheric properties to
theoretical predictions from stellar evolution theory as well as from diffusion
calculations.
  From the N IV - NV, O IV - O VI, Si IV - Si V, and Fe V - Fe VII ionization
equilibria, we determined an effective temperature of 95 +/- 2 kK with high
precision. The surface gravity is log g = 6.9 +/- 0.2. An unexplained
discrepancy appears between the spectroscopic distance d = 224 +46/-58 pc and
the parallax distance d = 129 +6/-5 pc of LS V +4621. For the first time, we
have identified Mg IV and Ar VI absorption lines in the spectrum of a
hydrogen-rich central star and determined the Mg and Ar abundances as well as
the individual abundances of iron-group elements (Cr, Mn, Fe, Co, and Ni). With
the realistic treatment of metal opacities up to the iron group in the
model-atmosphere calculations, the so-called Balmer-line problem (found in
models that neglect metal-line blanketing) vanishes.
  Spectral analysis by means of NLTE model atmospheres has presently arrived at
a high level of sophistication, which is now hampered largely by the lack of
reliable atomic data and accurate line-broadening tables. Strong efforts should
be made to improve upon this situation.


title: Algebraic K-theory and cubical descent

abstract:
  In this note we apply Guillen-Navarro descent theorem, \cite{GN02}, to define
a descent variant of the algebraic $K$-theory of varieties over a field of
characteristic zero, $\mathcal{KD}(X)$, which coincides with $\mathcal{K}(X)$
for smooth varieties. After a result of Haesemeyer, this new theory is
equivalent to the homotopy algebraic $K$-theory introduced by Weibel. We also
prove that there is a natural weight filtration on the groups $KH_\ast(X)$.


title:
Growth mechanisms and structure of fullerene-like carbon-based thin
  films: superelastic materials for tribological applications

abstract:
  In this chapter we review our findings on the bonding structure and growth
mechanisms of carbon-based thin solid films with fullerene-like (FL)
microstructure. The so-called FL arrangements arise from the curvature and
cross-linking of basal planes in graphitic-like structures, partially
resembling that of molecular fullerenes. This three-dimensional superstructure
takes advantage of the strength of planar pi bonds in sp2 hybrids and confers
the material interesting mechanical properties, such as high hardness, high
elastic recovery, low-friction and wear-resistance. These properties can be
tailored by controlling the curvature, size and connectivity of the FL
arrangements, making these materials promising coatings for tribological
applications. We have focused our interest mostly on carbon nitride (CNx) since
nitrogen promotes the formation of FL arrangements at low substrate
temperatures and they are emerging over pure carbon coatings in tribological
applications such as protective overcoats in magnetic hard disks. We address
structural issues such as origin of plane curvature, nature of the
cross-linking sites and sp2 clustering, together with growth mechanisms based
on the role of film-forming precursors, chemical re-sputtering or concurrent
ion assistance during growth.


title: Non-equilibrium coherence dynamics in one-dimensional Bose gases

abstract:
  Low-dimensional systems are beautiful examples of many-body quantum physics.
For one-dimensional systems the Luttinger liquid approach provides insight into
universal properties. Much is known of the equilibrium state, both in the
weakly and strongly interacting regime. However, it remains a challenge to
probe the dynamics by which this equilibrium state is reached. Here we present
a direct experimental study of the coherence dynamics in both isolated and
coupled degenerate 1d Bose gases. Dynamic splitting is used to create two 1d
systems in a phase coherent state. The time evolution of the coherence is
revealed in local phase shifts of the subsequently observed interference
patterns. Completely isolated 1d Bose gases are observed to exhibit a universal
sub-exponential coherence decay in excellent agreement with recent predictions
by Burkov et al. [Phys. Rev. Lett. 98, 200404 (2007)]. For two coupled 1d Bose
gases the coherence factor is observed to approach a non-zero equilibrium value
as predicted by a Bogoliubov approach. This coupled-system decay to finite
coherence is the matter wave equivalent of phase locking two lasers by
injection. The non-equilibrium dynamics of superfluids plays an important role
in a wide range of physical systems, such as superconductors, quantum-Hall
systems, superfluid Helium, and spin systems. Our experiments studying
coherence dynamics show that 1d Bose gases are ideally suited for investigating
this class of phenomena.