title: Supernova Nucleosynthesis in the Early Universe

abstract:
  The first metal enrichment in the universe was made by supernova (SN)
explosions of population (Pop) III stars. The trace remains in abundance
patterns of extremely metal-poor (EMP) stars. We investigate the properties of
nucleosynthesis in Pop III SNe by means of comparing their yields with the
abundance patterns of the EMP stars. We focus on (1) jet-induced SNe with
various energy deposition rates [$\dot{E}_{\rm dep}=(0.3-1500)\times10^{51}{\rm
ergs s^{-1}}$], and (2) SNe of stars with various main-sequence masses ($M_{\rm
ms}=13-50M_\odot$) and explosion energies [$E=(1-40)\times10^{51}$ergs]. The
varieties of Pop III SNe can explain varieties of the EMP stars: (1) higher
[C/Fe] for lower [Fe/H] and (2) trends of abundance ratios [X/Fe] against
[Fe/H].


title: Evidence of Shock-Driven Turbulence in the Solar Chromosphere

abstract:
  We study the acoustic properties of the solar chromosphere in the
high-frequency regime using a time sequence of velocity measurements in the
chromospheric Ca II 854.2 nm line taken with the Interferometric Bidimensional
Spectrometer (IBIS). We concentrate on quiet-Sun behavior, apply Fourier
analysis, and characterize the observations in terms of the probability density
functions (PDFs) of velocity increments. We confirm the presence of significant
oscillatory fluctuation power above the cutoff frequency and find that it obeys
a power-law distribution with frequency up to our 25 mHz Nyquist limit. The
chromospheric PDFs are non-Gaussian and asymmetric and they differ among
network, fibril, and internetwork regions. This suggests that the chromospheric
high-frequency power is not simply the result of short-period waves propagating
upward from the photosphere but rather is the signature of turbulence generated
within the chromosphere from shock oscillations near the cutoff frequency. The
presence of this pervasive and broad spectrum of motions in the chromosphere is
likely to have implications for the excitation of coronal loop oscillations.


title: Nonlinear Digital Post-Processing to Mitigate Jitter in Sampling

abstract:
  This paper describes several new algorithms for estimating the parameters of
a periodic bandlimited signal from samples corrupted by jitter (timing noise)
and additive noise. Both classical (non-random) and Bayesian formulations are
considered: an Expectation-Maximization (EM) algorithm is developed to compute
the maximum likelihood (ML) estimator for the classical estimation framework,
and two Gibbs samplers are proposed to approximate the Bayes least squares
(BLS) estimate for parameters independently distributed according to a uniform
prior. Simulations are performed to demonstrate the significant performance
improvement achievable using these algorithms as compared to linear estimators.
The ML estimator is also compared to the Cramer-Rao lower bound to determine
the range of jitter for which the estimator is approximately efficient. These
simulations provide evidence that the nonlinear algorithms derived here can
tolerate 1.4-2 times more jitter than linear estimators, reducing on-chip ADC
power consumption by 50-75 percent.


title: Magnetic behaviour of PrPd2B2C

abstract:
  We have synthesized a new quaternary borocarbide PrPd$_{2}$B$_{2}$C and
measured its magnetization, electrical resistivity and specific heat. The
compound crystallizes in the LuNi$_{2}$B$_{2}$C-type tetragonal structure
(space group {\it I4/mmm}). Above 100 K the magnetic susceptibility follows
Curie-Weiss behavior with effective moment $\mu_{eff}$ = 3.60 $\mu_{B}$, which
is very close to the value expected for Pr$^{3+}$ ions. We do not find evidence
for magnetic or superconducting transition down to 0.5 K. Specific heat
exhibits a broad Schottky type anomaly with a peak at 24 K, very likely related
to crystal electric field (CEF) excitation. The magnetic properties suggest the
presence of a singlet CEF ground state leading to a Van-Vleck paramagnetic
ground state.


title: A geometric space without conjugate points

abstract:
  From a spray space $S$ on a manifold $M$ we construct a new geometric space
$P$ of larger dimension with the following properties:
  1. Geodesics in $P$ are in one-to-one correspondence with parallel Jacobi
fields of $M$.
  2. $P$ is complete if and only if $S$ is complete.
  3. If two geodesics in $P$ meet at one point, the geodesics coincide on their
common domain, and $P$ has no conjugate points.
  4. There exists a submersion $\pi\colon P \to M$ that maps geodesics in $P$
into geodesics on $M$.
  Space $P$ is constructed by first taking two complete lifts of spray $S$.
This will give a spray $S^{cc}$ on the second iterated tangent bundle $TTM$.
Then space $P$ is obtained by restricting tangent vectors of geodesics for
$S^{cc}$ onto a suitable $(2\dim M+2)$-dimensional submanifold of $TTTM$. Due
to the last restriction, space $P$ is not a spray space. However, the
construction shows that conjugate points can be removed if we add dimensions
and relax assumptions on the geometric structure.


title: Calibration of shielded microwave probes using bulk dielectrics

abstract:
  A stripline-type near-field microwave probe is microfabricated for microwave
impedance microscopy. Unlike the poorly shielded coplanar probe that senses the
sample tens of microns away, the stripline structure removes the stray fields
from the cantilever body and localizes the interaction only around the
focused-ion beam deposited Pt tip. The approaching curve of an oscillating tip
toward bulk dielectrics can be quantitatively simulated and fitted to the
finite-element analysis result. The peak signal of the approaching curve is a
measure of the sample dielectric constant and can be used to study unknown bulk
materials.


title:
Searching for modifications to the exponential radioactive decay law
  with the Cassini spacecraft

abstract:
  Data from the power output of the radioisotope thermoelectric generators
aboard the Cassini spacecraft are used to test the conjecture that small
deviations observed in terrestrial measurements of the exponential radioactive
decay law are correlated with the Earth-Sun distance. No significant deviations
from exponential decay are observed over a range of 0.7 - 1.6 A.U. A 90% Cl
upper limit of 0.84 x 10^-4 is set on a term in the decay rate of Pu-238
proportional to 1/R^2 and 0.99 x 10^-4 for a term proportional to 1/R.


title: The cosmic origin of carbon and manganese

abstract:
  [ABRIDGED] We have determined carbon abundances for 51 dwarf stars and
manganese abundances for 95 dwarf stars in two distinct and well defined
stellar populations - the Galactic thin and thick disks. As these two
populations have different chemical histories we have been able to, through a
differential abundance analysis using high-resolution spectra, constrain the
formation sites for carbon and manganese in the Galactic disk(s).
  The analysis of carbon is based on the forbidden [C I] line at 872.7 nm which
is an abundance indicator that is insensitive to errors in the stellar
atmosphere parameters. Combining these data with our previously published
oxygen abundances, based on the forbidden [O I] line at 630.0 nm, we can form
very robust [C/O] ratios that we then used to investigate the origin of carbon
and the chemical evolution of the Galactic thin and thick disks..... Our
interpretation of our abundance trends is that the sources that are responsible
for the carbon enrichment in the Galactic thin and thick disks have operated on
a time-scale very similar to those that are responsible for the Fe and Y
enrichment (i.e., SNIa and AGB stars, respectively).
  For manganese, when comparing our Mn abundances with O abundances for the
same stars we find that the abundance trends in the stars with kinematics
typical of the thick disk can be explained by metallicity dependent yields from
SN II. Furthermore, the [Mn/O] versus [O/H] trend in the halo is flat. We
conclude that the simplest interpretation of our data is that manganese most
likely is produced in SN II and that the Mn yields for such SNae must be
metallicity dependent.


title: When do two planted graphs have the same cotransversal matroid?

abstract:
  Cotransversal matroids are a family of matroids that arise from planted
graphs. We prove that two planted graphs give the same cotransversal matroid if
and only if they can be obtained from each other by a series of local moves.


title:
Small-x single-particle distributions in jets from the coherent
  branching formalism

abstract:
  We calculate single parton distributions inside quark and gluon jets within
the coherent branching formalism, which resums leading and next-to-leading
logarithmic contributions. This formalism is at the basis of the modified
leading logarithmic approximation (MLLA), and it conserves energy exactly. For
a wide preasymptotic range of the evolution variable Y=ln[E\theta/Q_0], we find
marked differences in the shape and norm of single parton distributions
calculated in the MLLA or in the coherent branching formalism, respectively.
For asymptotically large values Y>5-10, the difference in norm persists, while
differences in shape disappear. In this way, our numerical study delineates the
jet energy scale needed for a reliable application of both approaches. We also
study the dependence of the single parton distributions on the hadronization
scale Q_0 and on \Lambda_QCD, and we calculate within the coherent branching
formalism the identified quark and gluon distributions inside quark and gluon
jets.


title: The Unusual Object IC 2144/MWC 778

abstract:
  IC 2144 is a small reflection nebula located in the zone of avoidance near
the Galactic anticenter. It has been investigated here largely on the basis of
Keck/HIRES optical spectroscopy (R ~ 48,000) and a SpeX spectrogram in the
near-IR (R = 2000) obtained at the NASA IRTF. The only star in the nebula that
is obvious in the optical or near-IR is the peculiar emission-line object MWC
778 (V = 12.8), which resembles a T Tauri star in some respects. What appear to
be F- or G-type absorption features are detectable in its optical region under
the very complex emission line spectrum; their radial velocity agrees with the
CO velocity of the larger cloud in which IC 2144 is embedded. There are
significant differences between the spectrum of the brightest area of the
nebula and of MWC 778, the presumed illuminator, an issue discussed in some
detail. The distance of IC 2144 is inferred to be about 1.0 kpc by reference to
other star-forming regions in the vicinity. The extinction is large, as
demonstrated by [Fe II] emission line ratios in the near-IR and by the strength
of the diffuse interstellar band spectrum; a provisional value of A_V of 3.0
mag was assumed. The SED of MWC 778 rises steeply beyond about 1 $\mu$m, with a
slope characteristic of a Class I source. Integration of the flux distribution
leads to an IR luminosity of about 510 L_solar. If MWC 778 is indeed a F- or
G-type pre--main-sequence star several magnitudes above the ZAMS, a population
of faint emission Halpha stars would be expected in the vicinity. Such a
search, like other investigations that are recommended in this paper, has yet
to be carried out.


title:
Global Properties of Topological String Amplitudes and Orbifold
  Invariants

abstract:
  We derive topological string amplitudes on local Calabi-Yau manifolds in
terms of polynomials in finitely many generators of special functions. These
objects are defined globally in the moduli space and lead to a description of
mirror symmetry at any point in the moduli space. Holomorphic ambiguities of
the anomaly equations are fixed by global information obtained from boundary
conditions at few special divisors in the moduli space. As an illustration we
compute higher genus orbifold Gromov-Witten invariants for C^3/Z_3 and C^3/Z_4.


title: Long Term X-ray Monitoring Of The TeV Binary LS I +61 303 with RXTE

abstract:
  We report on the results of a long term X-ray monitoring campaign of the
galactic binary LS I +61 303 performed by the Rossi X-ray Timing Explorer. This
dataset consists of 1 ks pointings taken every other day between 2007 August 28
until 2008 February 2. The observations covered six full cycles of the 26.496
day binary period and constitute the largest continuous X-ray monitoring
dataset on LS I +61 303 to date with this sensitivity. There is no
statistically strong detection of modulation of flux or photon index with
orbital phase; however, we do find a strong correlation between flux and photon
index, with the spectrum becoming harder at higher fluxes. The dataset contains
three large flaring episodes, the largest of these reaching a flux level of 7.2
(+0.1,-0.2)*10^-11 erg cm^-2 s^-1 in the 3-10 keV band, which is a factor of
three times larger than flux levels typically seen in the system. Analysis of
these flares shows the X-ray emission from LS I +61 303 changing by up to a
factor of six over timescales of several hundred seconds as well as doubling
times as fast as 2 seconds. This is the fastest variability ever observed from
LS I +61 303 at this wavelength and places constraints on the size of the X-ray
emitting region.


title:
Front- vs. back-illuminated CCD cameras for photometric surveys: a noise
  budget analysis

abstract:
  Exoplanetary transit and stellar oscillation surveys require a very high
precision photometry. The instrumental noise has therefore to be minimized.
First, we perform a semi-analytical model of different noise sources. We show
that the noise due the CCD electrodes can be overcome using a Gaussian PSF
(Point Spread Function) of full width half maximum larger than 1.6 pixels. We
also find that for a PSF size of a few pixels, the photometric aperture has to
be at least 2.5 times larger than the PSF full width half maximum. Then, we
compare a front- with a back-illuminated CCD through a Monte-Carlo simulation.
Both cameras give the same results for a PSF full width half maximum larger
than 1.5 pixels. All these simulations are applied to the A STEP (Antarctica
Search for Transiting Extrasolar Planets) project. As a result, we choose a
front-illuminated camera for A STEP because of its better resolution and lower
price, and we will use a PSF larger than 1.6 pixels.


title: Calculation of supercritical Dirac resonances in heavy-ion collisions

abstract:
  This resonance is similar in character to other resonances in atomic physics.
It is parameterized by its energy and its lifetime. A numerical discretization
technique, the mapped Fourier grid method (MFG) is extended to the Dirac
equation and is used to solve for the resonance parameters of a quasimolecular
supercritical 1S$\sigma$ state which arises, e.g., in a uranium-uranium
collision. Direct methods using only the MFG method are shown to give
reasonable estimates for the resonance parameters. Analytic continuation
methods such as complex scaling (CS) of the coordinate or adding a complex
absorbing potential (CAP) are then applied. They allow for more accurate
determinations of the supercritical resonance parameters. The (extrapolated)
augmented analytic continuation methods are used to investigate the effects of
higher-order couplings, beyond the monopole approximation. For the nearly
charge symmetric system of U$^{92+}$-Cf$^{98+}$, it is shown that the S-D
quadrupole coupling is the next dominant interaction after the monopole
interaction. Collisions near the Coulomb barrier, in which supercritical
resonance states occur, are also calculated using the MFG. Results are
presented for the collision of U$^{92+}$-U$^{92+}$ for a zero-impact-parameter
Coulomb trajectory at a center-of-mass energy of 740MeV. The enhancement
effects to the positron spectrum due to nuclear sticking at closest approach is
examined. Results are given for sticking times of 2,5,10$\times10^{-21}$s.
Nuclear sticking is shown to offer the possibility of demonstrating
experimentally the existence of supercritical resonance states.


title: Holographic Multiverse

abstract:
  We explore the idea that the dynamics of the inflationary multiverse is
encoded in its future boundary, where it is described by a lower dimensional
theory which is conformally invariant in the UV. We propose that a measure for
the multiverse, which is needed in order to extract quantitative probabilistic
predictions, can be derived in terms of the boundary theory by imposing a UV
cutoff. In the inflationary bulk, this is closely related (though not
identical) to the so-called scale factor cutoff measure.


title: Borcherds-Kac-Moody Symmetry of N=4 Dyons

abstract:
  We consider compactifications of heterotic string theory to four dimensions
on CHL orbifolds of the type T^6 /Z_N with 16 supersymmetries. The exact
partition functions of the quarter-BPS dyons in these models are given in terms
of genus-two Siegel modular forms. Only the N=1,2,3 models satisfy a certain
finiteness condition, and in these cases one can identify a Borcherds-Kac-Moody
superalgebra underlying the symmetry structure of the dyon spectrum. We
identify the real roots, and find that the corresponding Cartan matrices
exhaust a known classification. We show that the Siegel modular form satisfies
the Weyl denominator identity of the algebra, which enables the determination
of all root multiplicities. Furthermore, the Weyl group determines the
structure of wall-crossings and the attractor flows of the theory. For N> 4, no
such interpretation appears to be possible.


title: High Redshift Galaxy Populations and their Descendants

abstract:
  We study model predictions for three high-redshift galaxy populations: Lyman
break galaxies at z~3 (LBGs), optically selected star-forming galaxies at z~2
(BXs), and distant red galaxies at z~2 (DRGs).Our galaxy formation model
simultaneously reproduces the abundances, redshift distributions and clustering
of all three observed populations. The star formation rates (SFRs) of model
LBGs and BXs are lower than those quoted for real samples, reflecting different
initial mass functions and scatter in model dust properties. About 85% of model
galaxies selected as DRGs are star-forming, with SFRs ranging up to 100
M_sun/yr. Model LBGs, BXs and DRGs together account for less than half of all
star formation over the range 1.5<z<3.2. Model BXs have metallicities which
agree roughly with observation, but model LBGs are only slightly more
metal-poor, in disagreement with recent observational results. Model galaxies
are predominantly disk-dominated. About 30% of model galaxies with
M>10^{11}M_sun are classified as LBGs or BXs at the relevant redshifts, while
65% are classified as DRGs. Almost all model LBGs and BXs are central galaxies,
but about a quarter of DRGs are satellites. Half of all LBG descendants at z=2
would be identified as BX's, but very few as DRGs. Clustering increases with
decreasing redshift for descendants of all three populations, becoming stronger
than that of L^* galaxies by z=0, when many have become satellite galaxies.
Their stellar mass growth is dominated by star formation until z~1 and
thereafter by mergers. Most LBGs and DRGs end up as red ellipticals, while BXs
have a more varied fate. 99% of local galaxies with M>10^{11.5}M_sun are
predicted to have at least one LBG/BX/DRG progenitor, and over 70% above
10^{11}M_sun. (abbreviated)


title:
The nature of dusty starburst galaxies in a rich cluster at z=0.4: the
  progenitors of lenticulars?

abstract:
  We present the results of a Spitzer Infrared Spectrograph (IRS) survey of
24um-selected luminous infrared galaxies (LIRGs, L_IR > 10^11 L_sun) in the
rich cluster Cl0024+16 at z=0.4. Optically, these LIRGs resemble unremarkable
spiral galaxies with e(a)/e(c) spectral classifications and [Oii]-derived star
formation rates (SFRs) of <2 M_sun/yr, generally indistinguishable from the
'quiescent' star forming population in the cluster. Our IRS spectra show that
the majority of the 24um-detected galaxies exhibit polycyclic aromatic
hydrocarbon (PAH) emission with implied SFRs ~30-60 M_sun/yr, with only one
(<10%) of the sample displaying unambiguous evidence of an active galactic
nucleus in the mid-infrared. This confirms the presence of a large population
of obscured starburst galaxies in distant clusters, which comprise the bulk of
the star formation occurring in these environments at z~0.5. We suggest that,
although several mechanisms could be at play, these dusty starbursts could be
the signature of an important evolutionary transition converting gas-rich
spiral galaxies in distant clusters into the passive, bulge-dominated
lenticular galaxies that become increasingly abundant in the cores of rich
clusters in the ~4Gyr to the present day.


title:
The propagation of uncertainties in stellar population synthesis
  modeling I: The relevance of uncertain aspects of stellar evolution and the
  IMF to the derived physical properties of galaxies

abstract:
  The stellar masses, mean ages, metallicities, and star formation histories of
galaxies are now commonly estimated via stellar population synthesis (SPS)
techniques. SPS relies on stellar evolution calculations from the main sequence
to stellar death, stellar spectral libraries, phenomenological dust models, and
stellar initial mass functions (IMFs). The present work is the first in a
series that explores the impact of uncertainties in key phases of stellar
evolution and the IMF on the derived physical properties of galaxies and the
expected luminosity evolution for a passively evolving set of stars. A
Monte-Carlo Markov-Chain approach is taken to fit near-UV through near-IR
photometry of a representative sample of low- and high-redshift galaxies with
this new SPS model. Significant results include the following: 1) including
uncertainties in stellar evolution, stellar masses at z~0 carry errors of ~0.3
dex at 95% CL with little dependence on luminosity or color, while at z~2, the
masses of bright red galaxies are uncertain at the ~0.6 dex level; 2) either
current stellar evolution models, current observational stellar libraries, or
both, do not adequately characterize the metallicity-dependence of the
thermally-pulsating asymptotic giant branch phase; 3) conservative estimates on
the uncertainty of the slope of the IMF in the solar neighborhood imply that
luminosity evolution per unit redshift is uncertain at the ~0.4 mag level in
the K-band, which is a substantial source of uncertainty for interpreting the
evolution of galaxy populations across time; 4) The more plausible assumption
of a distribution of stellar metallicities, rather than a fixed value as is
usually assumed, can have significant effects on the interpretation of colors
blueward of the V-band. (ABRIDGED)


title: Star Clusters Around Recoiled Black Holes in the Milky Way Halo

abstract:
  Gravitational wave emission by coalescing black holes (BHs) kicks the remnant
BH with a typical velocity of hundreds of km/s. This velocity is sufficiently
large to remove the remnant BH from a low-mass galaxy but is below the escape
velocity from the Milky Way (MW) galaxy. If central BHs were common in the
galactic building blocks that merged to make the MW, then numerous BHs that
were kicked out of low-mass galaxies should be freely floating in the MW halo
today. We use a large statistical sample of possible merger tree histories for
the MW to estimate the expected number of recoiled BH remnants present in the
MW halo today. We find that hundreds of BHs should remain bound to the MW halo
after leaving their parent low-mass galaxies. Each BH carries a compact cluster
of old stars that populated the core of its original host galaxy. Using the
time-dependent Fokker-Planck equation, we find that present-day clusters are ~<
1 pc in size, and their central bright regions should be unresolved in most
existing sky surveys. These compact systems are distinguishable from globular
clusters by their internal (Keplerian) velocity dispersion greater than one
hundred km/s and their high mass-to-light ratio owing to the central BH. An
observational discovery of this relic population of star clusters in the MW
halo, would constrain the formation history of the MW and the dynamics of BH
mergers in the early Universe. A similar population should exist around other
galaxies, and may potentially be detectable in M31 and M33.


title:
New Analysis of the Proper Motions of the Magellanic Clouds using
  HST/WFPC2

abstract:
  In HST Cycles 11 and 13 we obtained two epochs of ACS/HRC data for fields in
the Magellanic Clouds centered on background quasars. We used these data to
determine the proper motions of the LMC and SMC to better than 5% and 15%
respectively. The results had a number of unexpected implications for the Milky
Way-LMC-SMC system. The implied three-dimensional velocities were larger than
previously believed and close to the escape velocity in a standard 10^12 solar
mass Milky Way dark halo, implying that the Clouds may be on their first
passage. Also, the relative velocity between the LMC and SMC was larger than
expected, leaving open the possibility that the Clouds may not be bound to each
other. To further verify and refine our results we requested an additional
epoch of data in Cycle 16 which is being executed with WFPC2/PC due to the
failure of ACS. We present the results of an ongoing analysis of these WFPC2
data which indicate good consistency with the two-epoch results.


title: Holographic Description of AdS_2 Black Holes

abstract:
  We develop the holographic renormalization of AdS_2 gravity systematically.
We find that a bulk Maxwell term necessitates a boundary mass term for the
gauge field and verify that this unusual term is invariant under gauge
transformations that preserve the boundary conditions. We determine the
energy-momentum tensor and the central charge, recovering recent results by
Hartman and Strominger. We show that our expressions are consistent with
dimensional reduction of the AdS_3 energy-momentum tensor and the
Brown--Henneaux central charge. As an application of our results we interpret
the entropy of AdS_2 black holes as the ground state entropy of a dual CFT.


title:
The Binarity of the Magellanic Clouds and the Formation of the
  Magellanic Stream

abstract:
  The HST proper motion (PM) measurements of the Clouds have severe
implications for their interaction history with the Milky Way (MW) and with
each other. The Clouds are likely on their first passage about the MW and the
SMC's orbit about the LMC is better described as quasi-periodic rather than
circular. Binary L/SMC orbits that satisfy observational constraints on their
mutual interaction history (e.g. the formation of the Magellanic Bridge during
a collision between the Clouds ~300 Myr ago) can be located within 1 sigma of
the mean PMs. However, these binary orbits are not co-located with the
Magellanic Stream (MS) when projected on the plane of the sky and the
line-of-sight velocity gradient along the LMC's orbit is significantly steeper
than that along the MS. These combined results ultimately rule out a purely
tidal origin for the MS: tides are ineffective without multiple pericentric
passages and can neither decrease the velocity gradient nor explain the offset
stream in a polar orbit configuration. Alternatively, ram pressure stripping of
an extended gaseous disk may naturally explain the deviation. The offset also
suggests that observations of the little-explored region between RA 21h and 23h
are crucial for characterizing the full extent of the MS.


title: The Kerr/CFT Correspondence

abstract:
  Quantum gravity in the region very near the horizon of an extreme Kerr black
hole (whose angular momentum and mass are related by J=GM^2) is considered. It
is shown that consistent boundary conditions exist, for which the asymptotic
symmetry generators form one copy of the Virasoro algebra with central charge
c_L=12J / \hbar. This implies that the near-horizon quantum states can be
identified with those of (a chiral half of) a two-dimensional conformal field
theory (CFT). Moreover, in the extreme limit, the Frolov-Thorne vacuum state
reduces to a thermal density matrix with dimensionless temperature T_L=1/2\pi
and conjugate energy given by the zero mode generator, L_0, of the Virasoro
algebra. Assuming unitarity, the Cardy formula then gives a microscopic entropy
S_{micro}=2\pi J / \hbar for the CFT, which reproduces the macroscopic
Bekenstein-Hawking entropy S_{macro}=Area / 4\hbar G. The results apply to any
consistent unitary quantum theory of gravity with a Kerr solution. We
accordingly conjecture that extreme Kerr black holes are holographically dual
to a chiral two-dimensional conformal field theory with central charge c_L=12J
/ \hbar, and in particular that the near-extreme black hole GRS 1915+105 is
approximately dual to a CFT with c_L \sim 2 \times 10^{79}.


title: High Resolution K-band Spectroscopy of MWC 480 and V1331 Cyg

abstract:
  We present high resolution (R=25,000-35,000) K-band spectroscopy of two young
stars, MWC 480 and V1331 Cyg. Earlier spectrally dispersed (R=230)
interferometric observations of MWC 480 indicated the presence of an excess
continuum emission interior to the dust sublimation radius, with a spectral
shape that was interpreted as evidence for hot water emission from the inner
disk of MWC 480. Our spectrum of V1331 Cyg reveals strong emission from CO and
hot water vapor, likely arising in a circumstellar disk. In comparison, our
spectrum of MWC 480 appears mostly featureless. We discuss possible ways in
which strong water emission from MWC 480 might go undetected in our data. If
strong water emission is in fact absent from the inner disk, as our data
suggest, the continuum excess interior to the dust sublimation radius that is
detected in the interferometric data must have another origin. We discuss
possible physical origins for the continuum excess.


title: Kinematical Structure of the Magellanic System

abstract:
  We review our understanding of the kinematics of the LMC and the SMC, and
their orbit around the Milky Way. The line-of-sight velocity fields of both the
LMC and SMC have been mapped with high accuracy using thousands of discrete
traces, as well as HI gas. The LMC is a rotating disk for which the viewing
angles have been well-established using various methods. The disk is elliptical
in its disk plane. The disk thickness varies depending on the tracer
population, with V/sigma ranging from 2-10 from the oldest to the youngest
population. For the SMC, the old stellar population resides in a spheroidal
distribution with considerable line-of-sight depth and low V/sigma. Young stars
and HI gas reside in a more irregular rotating disk. Mass estimates based on
the kinematics indicate that each Cloud is embedded in a dark halo. Proper
motion measurements with HST show that both galaxies move significantly more
rapidly around the Milky Way than previously believed. This indicates that for
a canonical 10^12 solar mass Milky Way the Clouds are only passing by us for
the first time. Although a higher Milky Way mass yields a bound orbit, this
orbit is still very different from what has been previously assumed in models
of the Magellanic Stream. Hence, much of our understanding of the history of
the Magellanic System and the formation of the Magellanic Stream may need to be
revised. The accuracy of the proper motion data is insufficient to say whether
or not the LMC and SMC are bound to each other, but bound orbits do exist
within the proper motion error ellipse.


title:
A Comparative Study of Laplacians and
  Schroedinger-Lichnerowicz-Weitzenboeck Identities in Riemannian and
  Antisymplectic Geometry

abstract:
  We introduce an antisymplectic Dirac operator and antisymplectic gamma
matrices. We explore similarities between, on one hand, the
Schroedinger-Lichnerowicz formula for spinor bundles in Riemannian spin
geometry, which contains a zeroth-order term proportional to the Levi-Civita
scalar curvature, and, on the other hand, the nilpotent, Grassmann-odd,
second-order \Delta operator in antisymplectic geometry, which in general has a
zeroth-order term proportional to the odd scalar curvature of an arbitrary
antisymplectic and torsionfree connection that is compatible with the measure
density. Finally, we discuss the close relationship with the two-loop scalar
curvature term in the quantum Hamiltonian for a particle in a curved Riemannian
space.


title:
Calibrated griz magnitudes of Tycho stars: All-sky photometric
  calibration using bright stars

abstract:
  Photometric calibration to 5% accuracy is frequently needed at arbitrary
celestial locations; however, existing all-sky astronomical catalogs do not
reach this accuracy and time consuming photometric calibration procedures are
required. I fit the Hipparcos B_T and V_T magnitudes along with the 2MASS J, H,
and K magnitudes of Tycho-2 catalog-stars with stellar spectral templates. From
the best fit spectral template derived for each star, I calculate the synthetic
SDSS griz magnitudes and constructed an all-sky catalog of griz magnitudes for
bright stars (V<12). Testing this method on SDSS photometric telescope
observations, I find that the photometric accuracy for a single star is usually
about 0.12, 0.12, 0.10 and 0.08 mag (1 sigma), for the g, r, i, and z-bands,
respectively. However, by using ~10 such stars, the typical errors per
calibrated field (systematic + statistical) can be reduced to about 0.04, 0.03,
0.02, and 0.02,mag, in the g, r, i, and z-bands, respectively. Therefore, in
cases for which several calibration stars can be observed in the field of view
of an instrument, accurate photometric calibration is possible.


title: Self-Chaotization in Coupled Optical Waveguides

abstract:
  We consider theoretically two coupled optical waveguides with a varying
barrier height along the waveguides direction. The barrier could be constructed
by the elongated island with a reduced refractive index (which acts as a
potential barrier), such that in the middle region it splits a waveguide into
two weakly coupled parts. It is predicted by numerical simulations and
analytical consideration that the presence of some imperfection of the system
parameters can cause splitting of injected laser beam and one will observe two
intensity maximums at the output, while for small imperfections the input and
output beam intensity distributions will be the same. The switching between two
regimes could be achieved changing spectral width of the beam or refractive
index of the island. This nontrivial effect is explained by possibility of
transitions between the different eigenstates of the system in the region of
large potential barrier heights. The mentioned effect could be used for
all-optical readdressing and filtering purposes.


title: Conformal Nonlinear Fluid Dynamics from Gravity in Arbitrary Dimensions

abstract:
  We generalize recent work to construct a map from the conformal Navier Stokes
equations with holographically determined transport coefficients, in d
spacetime dimensions, to the set of asymptotically locally AdS_{d+1} long
wavelength solutions of Einstein's equations with a negative cosmological
constant, for all d>2. We find simple explicit expressions for the stress
tensor (slightly generalizing the recent result by Haack and Yarom
(arXiv:0806.4602)), the full dual bulk metric and an entropy current of this
strongly coupled conformal fluid, to second order in the derivative expansion,
for arbitrary d>2. We also rewrite the well known exact solutions for rotating
black holes in AdS_{d+1} space in a manifestly fluid dynamical form,
generalizing earlier work in d=4. To second order in the derivative expansion,
this metric agrees with our general construction of the metric dual to fluid
flows.


title: Phase Fluctuations in High Temperature Superconductors

abstract:
  Within the phase fluctuation picture for the pseudogap state of a
high-$T_{c}$ superconductor, we incorporate the phase fluctuations generated by
the classical XY model with the Bogoliubov-de Gennes formalism utilizing a
field-theoretical method. This picture delineates the inhomogeneous
characteristics of local order parameters observed in high-$T_{c}$
superconductors above $T_{c}$. We also compute the local density of states near
a non-magnetic impurity with a strong scattering potential. The resonance peak
smoothly evolves as temperature increases through $T_{c}$ without showing any
sudden broadening, which is consistent with recent experimental findings.


title:
Effect of Pt doping on the critical temperature and upper critical field
  in YNi2-xPtxB2C (x=0-0.2)

abstract:
  We investigate the evolution of superconducting properties by doping
non-magnetic impurity in single crystals of YNi2-xPtxB2C (x=0-0.2). With
increasing Pt doping the critical temperature (Tc) monotonically decreases from
15.85K and saturates to a value ~13K for x>0.14. However, unlike conventional
s-wave superconductors, the upper critical field (HC2) along both
crystallographic directions a and c decreases with increasing Pt doping.
Specific heat measurements show that the density of states (N(EF)) at the Fermi
level (EF) and the Debye temperatures (Theta_D) in this series remains constant
within the error bars of our measurement. We explain our results based on the
increase in intraband scattering in the multiband superconductor YNi2B2C.


title:
Heavy-traffic limits for waiting times in many-server queues with
  abandonment

abstract:
  We establish heavy-traffic stochastic-process limits for waiting times in
many-server queues with customer abandonment. If the system is asymptotically
critically loaded, as in the quality-and-efficiency-driven (QED) regime, then a
bounding argument shows that the abandonment does not affect waiting-time
processes. If instead the system is overloaded, as in the efficiency-driven
(ED) regime, following Mandelbaum et al. [Proceedings of the Thirty-Seventh
Annual Allerton Conference on Communication, Control and Computing (1999)
1095--1104], we treat customer abandonment by studying the limiting behavior of
the queueing models with arrivals turned off at some time $t$. Then, the
waiting time of an infinitely patient customer arriving at time $t$ is the
additional time it takes for the queue to empty. To prove stochastic-process
limits for virtual waiting times, we establish a two-parameter version of
Puhalskii's invariance principle for first passage times. That, in turn,
involves proving that two-parameter versions of the composition and inverse
mappings appropriately preserve convergence.


title: Entanglement properties of topological color codes

abstract:
  The entanglement properties of a class of topological stabilizer states, the
so called \emph{topological color codes} defined on a two-dimensional lattice
or \emph{2-colex}, are calculated. The topological entropy is used to measure
the entanglement of different bipartitions of the 2-colex. The dependency of
the ground state degeneracy on the genus of the surface shows that the color
code can support a topological order, and the contribution of the color in its
structure makes it interesting to compare with the Kitaev's toric code. While a
qubit is maximally entangled with rest of the system, two qubits are no longer
entangled showing that the color code is genuinely multipartite entangled. For
a convex region, it is found that entanglement entropy depends only on the
degrees of freedom living on the boundary of two subsystems. The boundary
scaling of entropy is supplemented with a topological subleading term which for
a color code defined on a compact surface is twice than the toric code. From
the entanglement entropy we construct a set of bipartitions in which the
diverging term arising from the boundary term is washed out, and the remaining
non-vanishing term will have a topological nature. Besides the color code on
the compact surface, we also analyze the entanglement properties of a version
of color code with border, i.e \emph{triangular color code}.


title:
Experimental demonstration of a hyper-entangled ten-qubit Schr\"odinger
  cat state

abstract:
  Coherent manipulation of an increasing number of qubits for the generation of
entangled states has been an important goal and benchmark in the emerging field
of quantum information science. The multiparticle entangled states serve as
physical resources for measurement-based quantum computing and high-precision
quantum metrology. However, their experimental preparation has proved extremely
challenging. To date, entangled states up to six, eight atoms, or six photonic
qubits have been demonstrated. Here, by exploiting both the photons'
polarization and momentum degrees of freedom, we report the creation of
hyper-entangled six-, eight-, and ten-qubit Schr\"odinger cat states. We
characterize the cat states by evaluating their fidelities and detecting the
presence of genuine multi-partite entanglement. Small modifications of the
experimental setup will allow the generation of various graph states up to ten
qubits. Our method provides a shortcut to expand the effective Hilbert space,
opening up interesting applications such as quantum-enhanced super-resolving
phase measurement, graph-state generation for anyonic simulation and
topological error correction, and novel tests of nonlocality with
hyper-entanglement.


title: Finite surgeries on three-tangle pretzel knots

abstract:
  We classify Dehn surgeries on (p,q,r) pretzel knots that result in a manifold
of finite fundamental group. The only hyperbolic pretzel knots that admit
non-trivial finite surgeries are (-2,3,7) and (-2,3,9). Agol and Lackenby's
6-theorem reduces the argument to knots with small indices p,q,r. We treat
these using the Culler-Shalen norm of the SL(2,C)-character variety. In
particular, we introduce new techniques for demonstrating that boundary slopes
are detected by the character variety.


title:
On the Detectability of the Hydrogen 3-cm Fine Structure Line from the
  EoR

abstract:
  A soft ultraviolet radiation field, 10.2 eV < E <13.6 eV, that permeates
neutral intergalactic gas during the Epoch of Reionization (EoR) excites the 2p
(directly) and 2s (indirectly) states of atomic hydrogen. Because the 2s state
is metastable, the lifetime of atoms in this level is relatively long, which
may cause the 2s state to be overpopulated relative to the 2p state. It has
recently been proposed that for this reason, neutral intergalactic atomic
hydrogen gas may be detected in absorption in its 3-cm fine-structure line
(2s_1/2 -> 2p_3/2) against the Cosmic Microwave Background out to very high
redshifts. In particular, the optical depth in the fine-structure line through
neutral intergalactic gas surrounding bright quasars during the EoR may reach
tau~1e-5. The resulting surface brightness temperature of tens of micro K (in
absorption) may be detectable with existing radio telescopes. Motivated by this
exciting proposal, we perform a detailed analysis of the transfer of Lyman
beta,gamma,delta,... radiation, and re-analyze the detectability of the
fine-structure line in neutral intergalactic gas surrounding high-redshift
quasars. We find that proper radiative transfer modeling causes the
fine-structure absorption signature to be reduced tremendously to tau< 1e-10.
We therefore conclude that neutral intergalactic gas during the EoR cannot
reveal its presence in the 3-cm fine-structure line to existing radio
telescopes.


title: Variational Formulation for Quaternionic Quantum Mechanics

abstract:
  A quaternionic version of Quantum Mechanics is constructed using the
Schwinger's formulation based on measurements and a Variational Principle.
Commutation relations and evolution equations are provided, and the results are
compared with other formulations.


title:
Nonthermal X-Rays from Supernova Remnant G330.2+1.0 and the
  Characteristics of its Central Compact Object

abstract:
  We present results from our X-ray data analysis of the SNR G330.2+1.0 and its
CCO, CXOU J160103.1--513353 (J1601). Using our XMM-Newton and Chandra
observations, we find that the X-ray spectrum of J1601 can be described by
neutron star atmosphere models (T ~ 2.5--3.7 MK). Assuming the distance of d ~
5 kpc for J1601 as estimated for SNR G330.2+1.0, a small emission region of R ~
1--2 km is implied. X-ray pulsations previously suggested by Chandra are not
confirmed by the XMM-Newton data, and are likely not real. However, our timing
analysis of the XMM-Newton data is limited by poor photon statistics, and thus
pulsations with a relatively low amplitude (i.e., an intrinsic pulsed-fraction
< 40%) cannot be ruled out. Our results indicate that J1601 is a CCO similar to
that in the Cassiopeia A SNR.X-ray emission from SNR G330.2+1.0 is dominated by
power law continuum (Gamma ~ 2.1--2.5) which primarily originates from thin
filaments along the boundary shell. This X-ray spectrum implies synchrotron
radiation from shock-accelerated electrons with an exponential roll-off
frequency ~ 2--3 x 10^17 Hz. For the measured widths of the X-ray filaments (D
~ 0.3 pc) and the estimated shock velocity (v_s ~ a few x 10^3 km s^-1), a
downstream magnetic field B ~ 10--50 $\mu$G is derived. The estimated maximum
electron energy E_max ~ 27--38 TeV suggests that G330.2+1.0 is a candidate TeV
gamma-ray source. We detect faint thermal X-ray emission in G330.2+1.0. We
estimate a low preshock density n_0 ~ 0.1 cm^-3, which suggests a dominant
contribution from an inverse Compton mechanism (than the proton-proton
collision) to the prospective gamma-ray emission. Follow-up deep radio, X-ray,
and gamma-ray observations will be essential to reveal the details of the shock
parameters and the nature of particle accelerations in this SNR.


title:
Measuring correlated electron dynamics with time-resolved photoemission
  spectroscopy

abstract:
  Time-resolved photoemission experiments can reveal fascinating quantum
dynamics of correlated electrons. However, the thermalization of the electronic
system is typically so fast that very short probe pulses are necessary to
resolve the time evolution of the quantum state, and this leads to poor energy
resolution due to the energy-time uncertainty relation. Although the
photoemission intensity can be calculated from the nonequilibrium electronic
Green functions, the converse procedure is therefore difficult. We analyze a
hypothetical time-resolved photoemission experiment on a correlated electronic
system, described by the Falicov-Kimball model in dynamical mean-field theory,
which relaxes between metallic and insulating phases. We find that the
real-time Green function which describes the transient behavior during the
buildup of the metallic state cannot be determined directly from the
photoemission signal. On the other hand, the characteristic
collapse-and-revival oscillations of an excited Mott insulator can be observed
as oscillating weight in the center of the Mott gap in the time-dependent
photoemission spectrum.


title:
Renormalization-Group Improved Prediction for Higgs Production at Hadron
  Colliders

abstract:
  We use renormalization-group methods in effective field theory to improve the
theoretical prediction for the cross section for Higgs-boson production at
hadron colliders. In addition to soft-gluon resummation at NNNLL, we also resum
enhanced contributions of the form (C_A\pi\alpha_s)^n, which arise in the
analytic continuation of the gluon form factor to time-like momentum transfer.
This resummation is achieved by evaluating the matching corrections arising at
the Higgs-boson mass scale at a time-like renormalization point \mu^2<0,
followed by renormalization-group evolution to \mu^2>0. We match our resummed
result to NNLO fixed-order perturbation theory and give numerical predictions
for the total production cross section as a function of the Higgs-boson mass.
Resummation effects are significant even at NNLO, where our improved
predictions for the cross sections at the Tevatron and the LHC exceed the
fixed-order predictions by about 13% and 8%, respectively, for m_H=120 GeV. We
also discuss the application of our technique to other time-like processes such
as Drell-Yan production, e^+ e^- --> hadrons, and hadronic decays of the Higgs
boson.


title:
Analytic solution for electrons and holes in graphene under
  electromagnetic radiation: gap appearance and non-linear current effects

abstract:
  We find the exact solution of graphene s carriers under electromagnetic
radiation. To obtain such solution, we combine Floquet theory with a trial
solution. Then the energy spectrum is obtained without using any approximation.
Using such results, we prove that the energy spectrum presents a gap opening
which depends on de radiation frequency and electric wave intensity, whereas
the current shows a strongly non-linear behaviour.


title:
Dynamical screening of the Coulomb interaction for two confined
  electrons in a magnetic field

abstract:
  We show that a difference in time scales of vertical and lateral dynamics
permits one to analyze the problem of interacting electrons confined in an
axially symmetric three-dimensional potential with a lateral oscillator
confinement by means of the effective two-dimensional Hamiltonian with a
screened Coulomb interaction. Using an adiabatic approximation based on
action-angle variables, we present solutions for the effective charge of the
Coulomb interaction (screening) for a vertical confinement potential simulated
by parabolic, square, and triangular wells. While for the parabolic potential
the solution for the effective charge is given in a closed anlytical form, for
the other cases similar solutions can be easily calculated numerically.


title: Magnetic topologies of the Herbig Ae/Be stars

abstract:
  Our recent discoveries of magnetic fields in a small number of Herbig Ae/Be
(HAeBe) stars, the evolutionary progenitors of main sequence A/B stars, raise
new questions about the origin of magnetic fields in the intermediate mass
stars. The favoured fossil field hypothesis suggests that a few percent of
magnetic pre-main sequence A/B stars should exhibit similar magnetic strengths
and topologies to the magnetic Ap/Bp stars. In this talk I will present the
methods that we have used to characterise the magnetic fields of the Herbig
Ae/Be stars, as well as our first conclusions on the origin of magnetism in
intermediate-mass stars.


title:
Manipulating the quantum information of the radial modes of trapped
  ions: Linear phononics, entanglement generation, quantum state transmission
  and non-locality tests

abstract:
  We present a detailed study on the possibility of manipulating quantum
information encoded in the "radial" modes of arrays of trapped ions (i.e., in
the ions' oscillations orthogonal to the trap's main axis). In such systems,
because of the tightness of transverse confinement, the radial modes pertaining
to different ions can be addressed individually. In the first part of the paper
we show that, if local control of the radial trapping frequencies is available,
any linear optical and squeezing operation on the locally defined modes - on
single as well as on many modes - can be reproduced by manipulating the
frequencies. Then, we proceed to describe schemes apt to generate unprecedented
degrees of bipartite and multipartite continuous variable entanglement under
realistic noisy working conditions, and even restricting only to a global
control of the trapping frequencies. Furthermore, we consider the transmission
of the quantum information encoded in the radial modes along the array of ions,
and show it to be possible to a remarkable degree of accuracy, for both
finite-dimensional and continuous variable quantum states. Finally, as an
application, we show that the states which can be generated in this setting
allow for the violation of multipartite non-locality tests, by feasible
displaced parity measurements. Such a demonstration would be a first test of
quantum non-locality for "massive" degrees of freedom (i.e., for degrees of
freedom describing the motion of massive particles).


title: Reorientation kinetics of superparamagnetic nanostructured rods

abstract:
  The attractive interactions between oppositely charged species (colloids,
macromolecules etc) dispersed in water are strong, and the direct mixing of
solutions containing such species generally yields to a precipitation, or to a
phase separation. We have recently developed means to control the
electrostatically-driven attractions between nanoparticles and polymers in
water, and at the same time to preserve the stability of the dispersions. We
give here an account of the formation of supracolloidal aggregates obtained by
co-assembly of 7 nm particles with copolymers. Nanostructured rods of length
comprised between 5 and 50 microns and diameter 500 nm were investigated. By
application of a magnetic field, the rods were found to reorient along with the
magnetic field lines. The kinetics of reorientation was investigated using step
changes of the magnetic field of amplitude 90 degrees. From the various results
obtained, among which an exponential decay of the tangent of the angle made
between the rod and the field, we concluded that the rods are
superparamagnetic.


title: The role of magnetic anisotropy in the Kondo effect

abstract:
  In the Kondo effect, a localized magnetic moment is screened by forming a
correlated electron system with the surrounding conduction electrons of a
non-magnetic host. Spin S=1/2 Kondo systems have been investigated extensively
in theory and experiments, but magnetic atoms often have a larger spin. Larger
spins are subject to the influence of magnetocrystalline anisotropy, which
describes the dependence of the magnetic moment's energy on the orientation of
the spin relative to its surrounding atomic environment. Here we demonstrate
the decisive role of magnetic anisotropy in the physics of Kondo screening. A
scanning tunnelling microscope is used to simultaneously determine the
magnitude of the spin, the magnetic anisotropy and the Kondo properties of
individual magnetic atoms on a surface. We find that a Kondo resonance emerges
for large-spin atoms only when the magnetic anisotropy creates degenerate
ground-state levels that are connected by the spin flip of a screening
electron. The magnetic anisotropy also determines how the Kondo resonance
evolves in a magnetic field: the resonance peak splits at rates that are
strongly direction dependent. These rates are well described by the energies of
the underlying unscreened spin states.


title:
Things decaying into top quarks, that are similar to top quarks, or that
  are produced with top quarks

abstract:
  Searches for new physics in the top-quark sector using data from
proton-antiproton collisions at the Fermilab Tevatron are discussed. The large
data sets collected by the D0 and CDF experiments allow for precision
measurements of the standard model (SM) top-quark production rates and top
quark properties so that deviations from the SM expectations can be interpreted
as signs of new physics. The presented analyses exploit the fact that the new
physics would reveal itself in final states that are similar or identical to
those of SM top-antitop production.


title: A multivariate phase distribution and its estimation

abstract:
  Circular variables such as phase or orientation have received considerable
attention throughout the scientific and engineering communities and have
recently been quite prominent in the field of neuroscience. While many analytic
techniques have used phase as an effective representation, there has been
little work on techniques that capture the joint statistics of multiple phase
variables. In this paper we introduce a distribution that captures empirically
observed pair-wise phase relationships. Importantly, we have developed a
computationally efficient and accurate technique for estimating the parameters
of this distribution from data. We show that the algorithm performs well in
high-dimensions (d=100), and in cases with limited data (as few as 100 samples
per dimension). We also demonstrate how this technique can be applied to
electrocorticography (ECoG) recordings to investigate the coupling of brain
areas during different behavioral states. This distribution and estimation
technique can be broadly applied to any setting that produces multiple circular
variables.

categories: q-bio.NC nlin.AO nlin.CD q-bio.QM stat.ME


title:
Planetary Lensing Signals of High-Magnification Events under Severe
  Finite-Source Effect

abstract:
  We investigate the effect of a finite source on the planetary-lensing signals
of high-magnification events. From this, we find that the dependency of the
finite-source effect on the caustic shape is weak and perturbations survive
even when the source is substantially bigger than the caustic. Specifically, we
find that perturbations with fractional magnification excess $\geq 5%$ survive
when the source star is roughly 4 times bigger than the caustic. We also find
characteristic features that commonly appear in the perturbation patterns of
planetary lens systems affected by severe finite-source effect and thus can be
used for the diagnosis of the existence of a companion. These features form in
and around a circle with its center located at the caustic center and a radius
corresponding to that of the source star. The light curve of an event where the
source crosses these features will exhibit a distinctive signal that is
characterized by short-duration perturbations of either positive or negative
excess and a flat residual region between these short-duration perturbations.


title: Hunting for Chameleons in ALP searches

abstract:
  We discuss some recent developments in chameleon models presented at the
Fourth Patras workshop on Axions, WIMPs and WISPs. In particular we discuss the
possibility of searching for chameleons in axion-like particle searches
performed in the laboratory. Such chameleons may couple to both photons and
matter with different coupling strengths. We discuss the exciting possibility
of searching for these dark energy candidates in quantum vacuum experiments -
in particular for the GammeV experiment at Fermilab.


title: Collapse times of dipolar Bose-Einstein condensates

abstract:
  We investigate the time taken for global collapse by a dipolar Bose-Einstein
condensate. Two semi-analytical approaches and exact numerical integration of
the mean-field dynamics are considered. The semi-analytical approaches are
based on a Gaussian ansatz and a Thomas-Fermi solution for the shape of the
condensate. The regimes of validity for these two approaches are determined,
and their predictions for the collapse time revealed and compared with
numerical simulations. The dipolar interactions introduce anisotropy into the
collapse dynamics and predominantly lead to collapse in the plane perpendicular
to the axis of polarization.


title: HAT-P-10b: A light and moderately hot Jupiter transiting a K dwarf

abstract:
  We report on the discovery of HAT-P-10b, the lowest mass (0.46 +/- 0.03 MJ)
transiting extrasolar planet (TEP) discovered to date by transit searches.
HAT-P-10b orbits the moderately bright V=11.89 K dwarf GSC 02340-01714, with a
period P = 3.7224690 +/- 0.0000067 d, transit epoch Tc = 2454729.90631 +/-
0.00030 (BJD) and duration 0.1100 +/- 0.0015 d. HAT-P-10b has a radius of 1.05
+(0.05)-(0.03) RJ yielding a mean density of 0.498+/-0.064 g cm^-3 . Comparing
these observations with recent theoretical models we find that HAT-P-10 is
consistent with a ~4.5 Gyr, coreless, pure hydrogen and helium gas giant
planet. With an equilibrium temperature of Teq = 1030 +(26)-(19)K, HAT-P-10b is
one of the coldest TEPs. Curiously, its Safronov number Theta = 0.047 +/- 0.003
falls close to the dividing line between the two suggested TEP populations.


title: State dependent computation using coupled recurrent networks

abstract:
  Although conditional branching between possible behavioural states is a
hallmark of intelligent behavior, very little is known about the neuronal
mechanisms that support this processing. In a step toward solving this problem
we demonstrate by theoretical analysis and simulation how networks of richly
inter-connected neurons, such as those observed in the superficial layers of
the neocortex, can embed reliable robust finite state machines. We show how a
multi-stable neuronal network containing a number of states can be created very
simply, by coupling two recurrent networks whose synaptic weights have been
configured for soft winner-take-all (sWTA) performance. These two sWTAs have
simple, homogenous locally recurrent connectivity except for a small fraction
of recurrent cross-connections between them, which are used to embed the
required states. This coupling between the maps allows the network to continue
to express the current state even after the input that elicted that state is
withdrawn. In addition, a small number of 'transition neurons' implement the
necessary input-driven transitions between the embedded states. We provide
simple rules to systematically design and construct neuronal state machines of
this kind. The significance of our finding is that it offers a method whereby
the cortex could construct networks supporting a broad range of sophisticated
processing by applying only small specializations to the same generic neuronal
circuit.


title: Testing composite hypotheses via convex duality

abstract:
  We study the problem of testing composite hypotheses versus composite
alternatives, using a convex duality approach. In contrast to classical results
obtained by Krafft and Witting (Z. Wahrsch. Verw. Gebiete 7 (1967) 289--302),
where sufficient optimality conditions are derived via Lagrange duality, we
obtain necessary and sufficient optimality conditions via Fenchel duality under
compactness assumptions. This approach also differs from the methodology
developed in Cvitani\'{c} and Karatzas (Bernoulli 7 (2001) 79--97).


title:
From isospin generators to BRST quantization of higher spin massless
  fields

abstract:
  Motivated by construction of isospin generators in particle physics (built
form the SU(2) algebra), we find an equivalence between the algebra of these
generators and those of the Virasoro algebra. The form of the starting
generators is fixed and in order to obtain a full equivalence we introduce a
new matrix product. The Cartan structure of the starting algebra is reproduced
for the Virasoro-like case and a natural BRST quantization as in String Field
Theory is ``induced'' in the Fock space of the creation/annihilation operators.
Following this procedure, we find a rather trivial Lie algebra form which we
obtain a gauge theory of an infinity on non-interacting massless particles of
arbitrary integer spin and symmetry. Among others we find the free Maxwell
field, the free (linearized) gravitational field and also the axion field with
their appropriate gauge transformations.


title:
The Formation & Evolution of Galaxies Making Up the CIRB : FIR/Submm
  Extragalactic Surveys From Dome C

abstract:
  The science case for FIR/Submm surveys of the extragalactic sky to be carried
from Dome C are reviewed. The main questions concerning the formation and
evolution of galaxies making up the CIRB are outlined and opportunities to
exploit Dome C unique observing conditions through single-dish observations are
discussed.


title: The 16OH/18OH and OD/OH isotope ratios in comet C/2002 T7 (LINEAR)

abstract:
  The 16OH/18OH and OD/OH isotope ratios are measured in the Oort-Cloud comet
C/2002 T7 (LINEAR) through ground-based observations of the OH ultraviolet
bands at 3063 A (0,0) and 3121 A (1,1) secured with the Very Large Telescope
(VLT) feeding the Ultraviolet-Visual Echelle Spectrograph (UVES). From the
16OH/18OH ratio, we find 16O/18O = 425 +/- 55, equal within the uncertainties
to the terrestrial value and to the ratio measured in other comets, although
marginally smaller. We also estimate OD/OH from which we derive D/H = 2.5 +/-
0.7 10-4 in water. This value is compatible with the water D/H ratios evaluated
in other comets and marginally higher than the terrestrial value.


title:
Surface response of spherical core-shell structured nanoparticle by
  optically induced elastic oscillations of soft shell against hard core

abstract:
  The optically induced oscillatory response of a spherical two-component,
shell-core structured, nanoparticle by nodeless elastic vibrations of soft
peripheral shell against hard and dynamically immobile inner core is
considered. The eigenfrequencies of the even-parity, spheroidal and odd-parity
torsional vibrational modes trapped in the finite-depth shell are obtained
which are of practical interest for modal specification of individual
resonances in spectra of resonant scattering of long wavelength electromagnetic
waves by ultrafine particles.


title: Formation of Jets and Equatorial Superrotation on Jupiter

abstract:
  The zonal flow in Jupiter's upper troposphere is organized into alternating
retrograde and prograde jets, with a prograde (superrotating) jet at the
equator. Existing models posit as the driver of the flow either differential
radiative heating of the atmosphere or intrinsic heat fluxes emanating from the
deep interior; however, they do not reproduce all large-scale features of
Jupiter's jets and thermal structure. Here it is shown that the difficulties in
accounting for Jupiter's jets and thermal structure resolve if the effects of
differential radiative heating and intrinsic heat fluxes are considered
together, and if upper-tropospheric dynamics are linked to a
magnetohydrodynamic (MHD) drag that acts deep in the atmosphere. Baroclinic
eddies generated by differential radiative heating can account for the
off-equatorial jets; meridionally propagating equatorial Rossby waves generated
by intrinsic convective heat fluxes can account for the equatorial
superrotation. The zonal flow extends deeply into the atmosphere, with its
speed changing with depth, up to depths at which the MHD drag acts. The theory
is supported by simulations with an energetically consistent general
circulation model of Jupiter's outer atmosphere. A simulation that incorporates
differential radiative heating and intrinsic heat fluxes reproduces Jupiter's
observed jets and thermal structure and makes testable predictions about as-yet
unobserved aspects thereof. A control simulation that incorporates only
differential radiative heating but not intrinsic heat fluxes produces
off-equatorial jets but no equatorial superrotation; another control simulation
that incorporates only intrinsic heat fluxes but not differential radiative
heating produces equatorial superrotation but no off-equatorial jets.


title: Exact vortex solutions in an extended Skyrme-Faddeev model

abstract:
  We construct exact vortex solutions in 3+1 dimensions to a theory which is an
extension, due to Gies, of the Skyrme-Faddeev model, and that is believed to
describe some aspects of the low energy limit of the pure SU(2) Yang-Mills
theory. Despite the efforts in the last decades those are the first exact
analytical solutions to be constructed for such type of theory. The exact
vortices appear in a very particular sector of the theory characterized by
special values of the coupling constants, and by a constraint that leads to an
infinite number of conserved charges. The theory is scale invariant in that
sector, and the solutions satisfy Bogomolny type equations. The energy of the
static vortex is proportional to its topological charge, and waves can travel
with the speed of light along them, adding to the energy a term proportional to
a U(1) Noether charge they create. We believe such vortices may play a role in
the strong coupling regime of the pure SU(2) Yang-Mills theory.


title:
Nonequilibrium Transport through Double Quantum Dots: Exact Results near
  Quantum Critical Point

abstract:
  We study a double quantum dot in the regime where each dot carries a
spin-1/2. This system is described by the 2-impurity Kondo model, having a
non-Fermi liquid fixed point for a critical value of the inter-impurity
coupling. The Hamiltonian describing the vicinity of the critical point,
including the relevant potential scattering perturbations, can be cast in
quadratic form. This allows us to predict a universal scaling function for the
finite temperature nonlinear conductance along the crossover from the critical
point to the surrounding stable fixed points.


title:
Predicting Ecosystem Response to Perturbation from Thermodynamic
  Criteria

abstract:
  The response of ecosystems to perturbations is considered from a
thermodynamic perspective by acknowledging that, as for all macroscopic systems
and processes, the dynamics and stability of ecosystems is subject to definite
thermodynamic law. For open ecosystems, exchanging energy, work, and mass with
the environment, the thermodynamic criteria come from non-equilibrium or
irreversible thermodynamics. For ecosystems during periods in which the
boundary conditions may be considered as being constant, it is shown that
criteria from irreversible thermodynamic theory are sufficient to permit a
quantitative prediction of ecosystem response to perturbation. This framework
is shown to provide a new perspective on the population dynamics of real
ecosystems. The formalism is applied to the problem of the population
oscillations of the southern pine beetle.


title:
Discovery of Molecular Shells Associated with Supernova Remnants. I.
  Kesteven 69

abstract:
  Supernova remnant (SNR) Kes 69 is morphologically characterized by brightened
radio, infrared, and X-ray emission on the southeastern rim, with the 1720 MHz
OH masers detected in the northeastern and southeastern regions at various
local standard rest (LSR) velocities. We have performed a millimeter
observation in CO and HCO+ lines toward \snr. From the northeastern compact
maser region, 12CO and 13CO emission's peaks around 65 km/s and 85 km/s, which
are consistent with the masers' LSR velocities, are detected. In the southeast,
a molecular (12CO) arc is revealed at 77--86 km/s, well coincident with the
partial SNR shell detected in the radio continuum and mid-infrared
observations. An 85 km/s HCO+ emission is found to arise from a radio peak on
the shell. Both the molecular arc and the HCO+ emission at ~85 km/s seem to be
consistent with the presence of extended OH masers along the southeastern
boundary of Kes 69. The morphology correspondence between the CO arc and other
band emission of the Kes 69 shell provides strong evidence for the association
between SNR Kes 69 and the ~85 km/s component of molecular gas. The
multiwavelength emissions along the southeastern shell can be accounted for by
the impact of the SNR shock on a dense, clumpy patch of molecular gas. This
pre-existing gas is likely to be a part of the cooled debris of the material
swept up by the progenitor's stellar wind. The association of SNR Kes 69 with
the molecular cloud at the systemic velocity of ~85 km/s enables us to place
the SNR at a kinematic distance of 5.2 kpc.


title:
Non-Abelian Josephson effect between two spinor Bose-Einstein
  condensates in double optical traps

abstract:
  We investigate the non-Abelian Josephson effect in spinor Bose-Einstein
condensates with double optical traps. We propose, for the first time, a real
physical system which contains non-Abelian Josephson effects. The collective
modes of this weak coupling system have very different density and spin
tunneling characters comparing to the Abelian case. We calculate the
frequencies of the pseudo Goldstone modes in different phases between two traps
respectively, which are a crucial feature of the non-Abelian Josephson effects.
We also give an experimental protocol to observe this novel effect in future
experiments.


title: New method for extracting neutron structure functions from nuclear data

abstract:
  We propose a new method for extracting neutron structure functions from
inclusive structure functions of nuclei. Unlike earlier approaches, the new
method is applicable to both spin-averaged and spin-dependent structure
functions. We test the reliability of the method on unpolarized F_2 and
polarized g_1 structure functions of the deuteron in both the nucleon resonance
and deep inelastic regions. The new method is able to reproduce known input
functions of almost arbitrary shape to very good accuracy with only several
iterations.


title: Deformation quantization modules II. Hochschild class

abstract:
  This paper is the continuation of arXiv:0802.1245. We construct the
Hochschild class for coherent modules over a deformation quantization algebroid
on a complex Poisson manifold. We also define the convolution of Hochschild
homologies, and prove that the Hochschild class of the convolution of two
coherent modules is the convolution of their Hochschild classes. We study with
some details the case of symplectic deformations.


title:
Ribosome collisions and Translation efficiency: Optimization by codon
  usage and mRNA destabilization

abstract:
  Individual mRNAs are translated by multiple ribosomes that initiate
translation with a few seconds interval. The ribosome speed is codon dependant,
and ribosome queuing has been suggested to explain specific data for
translation of some mRNAs in vivo. By modelling the stochastic translation
process as a traffic problem, we here analyze conditions and consequences of
collisions and queuing. The model allowed us to determine the on-rate (0.8 to
1.1 initiations per sec) and the time (1 sec) the preceding ribosome occludes
initiation for Escherichia coli lacZ mRNA in vivo. We find that ribosome
collisions and queues are inevitable consequences of a stochastic translation
mechanism that reduce the translation efficiency substantially on natural
mRNAs. The cells minimize collisions by having its mRNAs being unstable and by
a highly selected codon usage in the start of the mRNA. The cost of mRNA
breakdown is offset by the concomitant increase in translational efficiency.


title:
The theory of magnetic field induced domain-wall propagation in magnetic
  nanowires

abstract:
  A global picture of magnetic domain wall (DW) propagation in a nanowire
driven by a magnetic field is obtained: A static DW cannot exist in a
homogeneous magnetic nanowire when an external magnetic field is applied. Thus,
a DW must vary with time under a static magnetic field. A moving DW must
dissipate energy due to the Gilbert damping. As a result, the wire has to
release its Zeeman energy through the DW propagation along the field direction.
The DW propagation speed is proportional to the energy dissipation rate that is
determined by the DW structure. An oscillatory DW motion, either the precession
around the wire axis or the breath of DW width, should lead to the speed
oscillation.


title:
Short Distance Physics and Initial State Effects on the CMB Power
  Spectrum

abstract:
  We investigate a modification in the action of inflaton due to
noncommutativity leads to a nonstandard initial vacuum and oscillatory
corrections in the initial power spectrum. We show that the presence of these
oscillations causes a drop in the WMAP $\chi^{2}$ about $\Delta\chi^{2}\sim
8.5$. As a bonus, from the parameter estimation done in this work, we show that
the noncommutative parameters can be precisely bound to $10^{16}$ GeV or
$10^{4}$ GeV depending on the inflation scale.


title:
Extended Commissioning and Calibration of the Dual-Beam Imaging
  Polarimeter

abstract:
  In our previous paper (Masiero et al. 2007) we presented the design and
initial calibrations of the Dual-Beam Imaging Polarimeter (DBIP), a new optical
instrument for the University of Hawaii's 2.2 m telescope on the summit of
Mauna Kea, Hawaii. In this followup work we discuss our full-Stokes mode
commissioning including crosstalk determination and our typical observing
methodology.


title: Cosmic coincidence problem and variable constants of physics

abstract:
  The standard model of cosmology is investigated using time dependent
cosmological constant $\Lambda$ and Newton's gravitational constant $G$. The
total energy content is described by the modified Chaplygin gas equation of
state. It is found that the time dependent constants coupled with the modified
Chaplygin gas interpolate between the earlier matter to the later dark energy
dominated phase of the universe. We also achieve a convergence of parameter
$\omega\to-1$, with minute fluctuations, showing an evolving $\omega$. Thus our
model fairly alleviates the cosmic coincidence problem which demands
$\omega=-1$ at present time.


title: Hidden Thresholds: Reconstructing NP Masses

abstract:
  The Hidden Thresholds technique reconstructs New Physics (NP) masses from two
or more simultaneous NP decays at a hadron collider. We show how this works in
several MSSM examples: $\widetilde{\chi}_{i}^0 \widetilde{\chi}_{j}^0 \to e^+
e^- \mu^+ \mu^- \widetilde{\chi}_{1}^0 \widetilde{\chi}_{1}^0$ ($i,j=2,3,4$)
and ${\widetilde\chi_1}^\pm {\widetilde\chi_2}^0 \to {W^\pm}^*(\to \ell^\pm
\nu) {\widetilde\chi_1}^0 ~ {Z^0}^*(\to \ell^\pm \ell^\mp) {\widetilde\chi_1}^0
$.


title:
A Layered Lattice Coding Scheme for a Class of Three User Gaussian
  Interference Channels

abstract:
  The paper studies a class of three user Gaussian interference channels. A new
layered lattice coding scheme is introduced as a transmission strategy. The use
of lattice codes allows for an "alignment" of the interference observed at each
receiver. The layered lattice coding is shown to achieve more than one degree
of freedom for a class of interference channels and also achieves rates which
are better than the rates obtained using the Han-Kobayashi coding scheme.


title:
On the Effect of Quantum Interaction Distance on Quantum Addition
  Circuits

abstract:
  We investigate the theoretical limits of the effect of the quantum
interaction distance on the speed of exact quantum addition circuits. For this
study, we exploit graph embedding for quantum circuit analysis. We study a
logical mapping of qubits and gates of any $\Omega(\log n)$-depth quantum adder
circuit for two $n$-qubit registers onto a practical architecture, which limits
interaction distance to the nearest neighbors only and supports only one- and
two-qubit logical gates. Unfortunately, on the chosen $k$-dimensional practical
architecture, we prove that the depth lower bound of any exact quantum addition
circuits is no longer $\Omega(\log {n})$, but $\Omega(\sqrt[k]{n})$. This
result, the first application of graph embedding to quantum circuits and
devices, provides a new tool for compiler development, emphasizes the impact of
quantum computer architecture on performance, and acts as a cautionary note
when evaluating the time performance of quantum algorithms.


title: Topology of the octonionic flag manifold

abstract:
  The octonionic flag manifold $Fl(\mathbb{O})$ is the space of all pairs in
$\mathbb{O}P^2\times \mathbb{O}P^2$ (where $\mathbb{O}P^2$ denotes the
octonionic projective plane) which satisfy a certain "incidence" relation. It
comes equipped with the projections $\pi_1,\pi_2 : Fl(\mathbb{O})\to
\mathbb{O}P^2$, which are $\mathbb{O}P^1$ bundles, as well as with an action of
the group $Spin(8)$. The first two results of this paper give Borel type
descriptions of the usual, respectively $Spin(8)$-equivariant cohomology of
$Fl(\mathbb{O})$ in terms of $\pi_1$ and $\pi_2$ (actually the Euler classes of
the tangent spaces to the fibers of $\pi_1$, respectively $\pi_2$, which are
rank 8 vector bundles on $Fl(\mathbb{O})$). Then we obtain a
Goresky-Kottwitz-MacPherson type description of the ring
$H^*_{Spin(8)}(Fl(\mathbb{O}))$. Finally, we consider the $Spin(8)$-equivariant
$K$-theory ring of $Fl(\mathbb{O})$ and obtain a Goresky-Kottwitz-MacPherson
type description of this ring.


title:
Approximation of Sums of Experimental Radiative Strength Functions of
  Dipole Gamma-Transitions in the Region $E_\gamma \approx B_n$ for the Atomic
  Masses $40 \leq a \leq 200$

abstract:
  The sums k(E1)+k(M1) of radiative strength functions of dipole primary
gamma-transitions were approximated with high precision in the energy region of
$0.5 < E_1 < B_n-0.5$ MeV for nuclei: 40K, 60Co, 71,74Ge, 80Br, 114Cd, 118Sn,
124,125Te, 128I, 137,138,139Ba, 140La, 150Sm, 156,158Gd, 160Tb, 163,164,165Dy,
166Ho, 168Er, 170Tm, 174Yb, 176,177Lu, 181Hf, 182Ta, 183,184,185,187W,
188,190,191,193Os, 192Ir, 196Pt, 198Au, 200Hg by sum of two independent
functions. It has been shown that this parameter of gamma-decay are determined
by the structure of the decaying and excited levels, at least, up to the
neutron binding energy.


title: The Sizes and Luminosities of Massive Star Clusters

abstract:
  The masses of star clusters range over seven decades, from ten up to one
hundred million solar masses. Remarkably, clusters with masses in the range
10^4 to 10^6 solar mases show no systematic variation of radius with mass.
However, recent observations have shown that clusters with masses greater than
3x10^6 solar masses do show an increase in size with increasing mass. We point
out that clusters with m>10^6 solar masses were optically thick to far infrared
radiation when they formed, and explore the hypothesis that the size of
clusters with m> 3x10^6 solar masses is set by a balance between accretion
powered radiation pressure and gravity when the clusters formed, yielding a
mass-radius relation r~0.3(m/10^6M_\odot)^{3/5} pc. We show that the Jeans mass
in optically thick objects increases systematically with cluster mass. We
argue, by assuming that the break in the stellar initial mass function is set
by the Jeans mass, that optically thick clusters are born with top heavy
initial mass functions; it follows that they are over-luminous compared to
optically thin clusters when young, and have a higher mass to light ratio
Upsilon_V=m/L_V when older than ~1 Gyr. Old, optically thick clusters have
Upsilon_V~ mcl^{0.1-0.3}. It follows that L_V~\sigma^{\beta}, where \sigma is
the cluster velocity dispersion, and \beta~4. It appears that Upsilon_V is an
increasing function of cluster mass for compact clusters and ultra-compact
dwarf galaxies. We show that this is unlikely to be due to the presence of
non-baryonic dark matter, by comparing clusters to Milky Way satellite
galaxies, which are dark matter dominated. The satellite galaxies appear to
have a fixed mass inside a fiducial radius, M(r=r_0)=const.


title:
Conductance plateau transitions in quantum Hall wires with spatially
  correlated random magnetic fields

abstract:
  Quantum transport properties in quantum Hall wires in the presence of
spatially correlated disordered magnetic fields are investigated numerically.
It is found that the correlation drastically changes the transport properties
associated with the edge state, in contrast to the naive expectation that the
correlation simply reduces the effect of disorder. In the presence of
correlation, the separation between the successive conductance plateau
transitions becomes larger than the bulk Landau level separation determined by
the mean value of the disordered magnetic fields. The transition energies
coincide with the Landau levels in an effective magnetic field stronger than
the mean value of the disordered magnetic field. For a long wire, the strength
of this effective magnetic field is of the order of the maximum value of the
magnetic fields in the system. It is shown that the effective field is
determined by a part where the stronger magnetic field region connects both
edges of the wire.


title:
Non-Standard Analysis, Multiplication of Schwartz Distributions and
  Delta-Like Solution of Hopf's Equation

abstract:
  We construct an algebra of generalized functions
$^*\mathcal{E}(\mathbb{R}^d)$. We also construct an embedding of the space of
Schwartz distributions $\mathcal{D}^\prime(\mathbb{R}^d)$ into
$^*\mathcal{E}(\mathbb{R}^d)$ and thus present a solution of the problem of
multiplication of Schwartz distributions which improves J.F. Colombeau's
solution. As an application we prove the existence of a weak delta-like
solution in ${^*\mathcal{E}(\mathbb{R}^d)}$ of the Hopf equation. This solution
does not have a counterpart in the classical theory of partial differential
equations. Our result improves a similar result by M. Radyna obtained in the
framework of perturbation theory.


title:
Critical points between varieties generated by subspace lattices of
  vector spaces

abstract:
  We denote by Conc(A) the semilattice of compact congruences of an algebra A.
Given a variety V of algebras, we denote by Conc(V) the class of all
semilattices isomorphic to Conc(A) for some A in V. Given varieties V1 and V2
varieties of algebras, the critical point of V1 under V2, denote by crit(V1;V2)
is the smalest cardinality of a semilattice in Conc(V1) but not in Conc(V2).
Given a finitely generated variety V of modular lattices, we obtain an integer
l, depending of V, such that crit(V;Var(Sub F^n)) is at least aleph_2 for any n
> 1 and any field F. In a second part, we prove that crit(Var(Mn);Var(Sub
F^3))=aleph_2, for any finite field F and any integer n such that 1+card F< n.
Similarly crit(Var(Sub F^3);Var(Sub K^3))=aleph_2, for all finite fields F and
K such that card F>card K.


title: The Pythagorean Tree: A New Species

abstract:
  In 1967 the Dutch mathemetician F.J.M. Barning described an infinite, planar,
ternary tree*. Seven years later, A. Hall independently discovered the same
tree. Both used the method of uni-modular matrices to transform one triple to
another. A number of rediscoveries have occurred more recently. In this article
we announce the discovery of an entirely different ternary tree, and show how
it relates to the one found by Barning and Hall.


title:
On the Unicast Capacity of Stationary Multi-channel Multi-radio Wireless
  Networks: Separability and Multi-channel Routing

abstract:
  The first result is on the separability of the unicast capacity of stationary
multi-channel multi-radio wireless networks, i.e., whether the capacity of such
a network is equal to the sum of the capacities of the corresponding
single-channel single-radio wireless networks. For both the Arbitrary Network
model and the Random Network model, given a channel assignment, the
separability property does not always hold. However, if the number of radio
interfaces at each node is equal to the number of channels, the separability
property holds. The second result is on the impact of multi-channel routing
(i.e., routing a bit through multiple channels as opposed to through a single
channel) on the network capacity. For both network models, the network
capacities conditioned on a channel assignment under the two routing schemes
are not always equal, but if again the number of radio interfaces at each node
is equal to the number of channels, the two routing schemes yield equal network
capacities.


title: Algorithms for Game Metrics

abstract:
  Simulation and bisimulation metrics for stochastic systems provide a
quantitative generalization of the classical simulation and bisimulation
relations. These metrics capture the similarity of states with respect to
quantitative specifications written in the quantitative {\mu}-calculus and
related probabilistic logics. We first show that the metrics provide a bound
for the difference in long-run average and discounted average behavior across
states, indicating that the metrics can be used both in system verification,
and in performance evaluation. For turn-based games and MDPs, we provide a
polynomial-time algorithm for the computation of the one-step metric distance
between states. The algorithm is based on linear programming; it improves on
the previous known exponential-time algorithm based on a reduction to the
theory of reals. We then present PSPACE algorithms for both the decision
problem and the problem of approximating the metric distance between two
states, matching the best known algorithms for Markov chains. For the
bisimulation kernel of the metric our algorithm works in time O(n^4) for both
turn-based games and MDPs; improving the previously best known O(n^9\cdot
log(n)) time algorithm for MDPs. For a concurrent game G, we show that
computing the exact distance between states is at least as hard as computing
the value of concurrent reachability games and the square-root-sum problem in
computational geometry. We show that checking whether the metric distance is
bounded by a rational r, can be done via a reduction to the theory of real
closed fields, involving a formula with three quantifier alternations, yielding
O(|G|^O(|G|^5)) time complexity, improving the previously known reduction,
which yielded O(|G|^O(|G|^7)) time complexity. These algorithms can be iterated
to approximate the metrics using binary search.


title: Azimuthal Asymmetry of pions in pp and pA collisions

abstract:
  We investigate the azimuthal asymmetry v2 of produced pions in pp and pA
collisions at both RHIC and SPS energies. In our approach, based on the pQCD
parton model and the light-cone QCD-dipole formalism, the azimuthal asymmetry
results from a correlation between the color-dipole orientation and the impact
parameter of the collision. We introduce the color-dipole orientation within an
improved Born approximation and the saturation model which satisfies available
DIS data, showing that the azimuthal asymmetry of partons and pions is very
sensitive to the choice of the model, and that it is reduced in the saturation
model. We find that v2 of quarks and gluons in parton-nucleus collisions have
very different patterns. The azimuthal asymmetry of gluons in gluon-nucleus
collisions can be negative at small transverse momentum, changes the sign and
becomes positive at high transverse momentum. The azimuthal asymmetry of quarks
in quark-nucleus collisions is positive at all values of transverse momentum.
We find that the azimuthal anisotropy v2 of produced pions in both pp and pA
collisions is positive, albeit rather small.


title:
Coalgebraic Approach to the Loday Infinity Category, Stem Differential
  for $2n$-ary Graded and Homotopy Algebras

abstract:
  We define a graded twisted-coassociative coproduct on the tensor algebra $TW$
of any $\Z^n$-graded vector space $W$. If $W$ is the desuspension space $\da V$
of a graded vector space $V$, the coderivations (resp. quadratic ``degree 1''
codifferentials, arbitrary odd codifferentials) of this coalgebra are 1-to-1
with sequences $\zp_s$, $s\ge 1$, of $s$-linear maps on $V$ (resp.
$\Z^n$-graded Loday structures on $V$, sequences that we call Loday infinity
structures on $V$). We prove a minimal model theorem for Loday infinity
algebras, investigate Loday infinity morphisms, and observe that the
$\op{Lod}_{\infty}$ category contains the $\op{L}_{\infty}$ category as a
subcategory. Moreover, the graded Lie bracket of coderivations gives rise to a
graded Lie ``stem'' bracket on the cochain spaces of graded Loday, Loday
infinity, and $2n$-ary graded Loday algebras (the latter extend the
corresponding Lie algebras in the sense of Michor and Vinogradov). These
algebraic structures have square zero with respect to the stem bracket, so that
we obtain natural cohomological theories that have good properties with respect
to formal deformations. The stem bracket restricts to the graded
Nijenhuis-Richardson and--up to isomorphism--to the Grabowski-Marmo brackets
(the last bracket extends the Schouten-Nijenhuis bracket to the space of graded
antisymmetric first order polydifferential operators), and it encodes, beyond
the already mentioned cohomologies, those of graded Lie, graded Poisson, graded
Jacobi, Lie infinity, as well as that of $2n$-ary graded Lie algebras.


title: The AstraLux large M dwarf survey

abstract:
  AstraLux is the Lucky Imaging camera for the Calar Alto 2.2-m telescope and
the 3.5-m NTT at La Silla. It allows nearly diffraction limited imaging in the
SDSS i' and z' bands of objects as faint as i'=15.5mag with minimum technical
effort.
  One of the ongoing AstraLux observing programs is a binarity survey among
late-type stars with spectral types K7 to M8, covering more than 1000 targets
on the northern and southern hemisphere. The survey is designed to refine
binarity statistics and especially the dependency of binarity fraction on
spectral type. The choice of the SDSS i' and z' filters allows to obtain
spectral type and mass estimates for resolved binaries.
  With an observing efficiency of typically 6 targets per hour we expect to
complete the survey in mid-2009. Selected targets will be followed up
astrometrically and photometrically, contributing to the calibration of the
mass-luminosity relation at the red end of the main sequence and at visible
wavelengths.


title:
Short term aperiodic variability of X-ray binaries: its origin and
  implications

abstract:
  In this review I briefly describe the latest advances in studies of aperiodic
variability of accreting X-ray binaries and outline the model which currently
describe the majority of observational appearances of variability of accreting
sources in the best way. Then I concentrate on the case of luminous accreting
neutron star binaries (in the soft/high spectral state), where study of
variability of X-ray emission of sources allowed us to resolve long standing
problem of disentangling the contribution of accretion disk and
boundary/spreading layer components to the time average spectrum of sources.
The obtained knowledge of the shape of the spectrum of the boundary layer
allowed us to make estimates of the mass and radii of accreting neutron stars.


title: Stability of organic molecules against shocks in the young Solar nebula

abstract:
  One of the fundamental astrobiology questions is how life has formed in our
Solar System. In this context the formation and stability of abiotic organic
molecules such as CH4, formic acid and amino acids, is important for
understanding how organic material has formed and survived shocks and energetic
particle impact from winds in the early Solar System. Shock waves have been
suggested as a plausible scenario to create chondrules, small meteoritic
components that have been completely molten by energetic events such as shocks
and high velocity particle impacts. We study here the formation and destruction
of certain gas-phase molecules such as methane and water during such shock
events and compare the chemical timescales with the timescales for shocks
arising from gravitational instabilities in a protosolar nebula.


title:
From one solution of a 3-satisfiability formula to a solution cluster:
  Frozen variables and entropy

abstract:
  A solution to a 3-satisfiability (3-SAT) formula can be expanded into a
cluster, all other solutions of which are reachable from this one through a
sequence of single-spin flips. Some variables in the solution cluster are
frozen to the same spin values by one of two different mechanisms: frozen-core
formation and long-range frustrations. While frozen cores are identified by a
local whitening algorithm, long-range frustrations are very difficult to trace,
and they make an entropic belief-propagation (BP) algorithm fail to converge.
For BP to reach a fixed point the spin values of a tiny fraction of variables
(chosen according to the whitening algorithm) are externally fixed during the
iteration. From the calculated entropy values, we infer that, for a large
random 3-SAT formula with constraint density close to the satisfiability
threshold, the solutions obtained by the survey-propagation or the walksat
algorithm belong neither to the most dominating clusters of the formula nor to
the most abundant clusters. This work indicates that a single solution cluster
of a random 3-SAT formula may have further community structures.


title: Long-range self-avoiding walk converges to alpha-stable processes

abstract:
  We consider a long-range version of self-avoiding walk in dimension $d >
2(\alpha \wedge 2)$, where $d$ denotes dimension and $\alpha$ the power-law
decay exponent of the coupling function. Under appropriate scaling we prove
convergence to Brownian motion for $\alpha \ge 2$, and to $\alpha$-stable
L\'evy motion for $\alpha < 2$. This complements results by Slade (1988), who
proves convergence to Brownian motion for nearest-neighbor self-avoiding walk
in high dimension.


title:
Dynamics of impurity, local and non-local information for two non
  identical qubits

abstract:
  From the separability point of view the problem of two atoms interact with a
single cavity mode is investigated. The density matrix is calculated and used
to discuss the entanglement and to examine the dynamics of the local and
non-local information. Our examination concentrated on the variation in the
mean photon number and the ratio of the coupling parameters. Furthermore, we
have also assumed that the atomic system is initially in the ground states as
well as in the intermediate states. It has been shown that the local
information is transferred to non-local information when the impurity of one
qubit or both is maximum.


title:
An anisotropic, non-singular early universe model leading to a realistic
  cosmology

abstract:
  We present a novel cosmological model in which scalar field matter in a
biaxial Bianchi IX geometry leads to a non-singular `pancaking' solution: the
hypersurface volume goes to zero instantaneously at the `Big Bang', but all
physical quantities, such as curvature invariants and the matter energy density
remain finite, and continue smoothly through the Big Bang. We demonstrate that
there exist geodesics extending through the Big Bang, but that there are also
incomplete geodesics that spiral infinitely around a topologically closed
spatial dimension at the Big Bang, rendering it, at worst, a quasi-regular
singularity. The model is thus reminiscent of the Taub-NUT vacuum solution in
that it has biaxial Bianchi IX geometry and its evolution exhibits a
dimensionality reduction at a quasi-regular singularity; the two models are,
however, rather different, as we will show in a future work. Here we
concentrate on the cosmological implications of our model and show how the
scalar field drives both isotropisation and inflation, thus raising the
question of whether structure on the largest scales was laid down at a time
when the universe was still oblate (as also suggested by Pitrou et al and
Contaldi et al). We also discuss the stability of our model to small
perturbations around biaxiality and draw an analogy with cosmological
perturbations. We conclude by presenting a separate, bouncing solution, which
generalises the known bouncing solution in closed FRW universes.