pinecone/core-2020-05-10-deduplication huggingface dataset:
Well-posedness of the Einstein-Euler system in asymptotically flat spacetimes: The constraint equations

This paper deals with the construction of initial data for the coupled Einstein-Euler system. We consider the condition where the energy density might vanish or tend to zero at infinity, and where the pressure is a fractional power of the energy density. In order to achieve our goals we use a type of weighted Sobolev space of fractional order. \ud
The common Lichnerowicz-York scaling method (Choquet-Bruhat and York, 1980 [9]; Cantor, 1979 [7]) for solving the constraint equations cannot be applied here directly. The basic problem is that the matter sources are scaled conformally and the fluid variables have to be recovered from the conformally transformed matter sources. This problem has been addressed, although in a different context, by Dain and Nagy (2002) [11]. We show that if the matter variables are restricted to a certain region, then the Einstein constraint equations have a unique solution in the weighted Sobolev spaces of fractional order. The regularity depends upon the fractional power of the equation of state. \u
The Swift Burst Analyser I: BAT and XRT spectral and flux evolution of
  Gamma Ray Bursts

Context: Gamma Ray Burst models predict the broadband spectral evolution and
the temporal evolution of the energy flux. In contrast, standard data analysis
tools and data repositories provide count-rate data, or use single flux
conversion factors for all of the data, neglecting spectral evolution. Aims: To
produce Swift BAT and XRT light curves in flux units, where the spectral
evolution is accounted for. Methods: We have developed software to use the
hardness ratio information to track spectral evolution of GRBs, and thus to
convert the count-rate light curves from the BAT and XRT instruments on Swift
into accurate, evolution-aware flux light curves. Results: The Swift Burst
Analyser website (http://www.swift.ac.uk/burst_analyser) contains BAT, XRT and
combined BAT-XRT flux light curves in three energy regimes for all GRBs
observed by the Swift satellite. These light curves are automatically built and
updated when data become available, are presented in graphical and plain-text
format, and are available for download and use in research.Comment: 7 pages, 5 figures, with related website
  http://www.swift.ac.uk//burst_analyser
Tevatron Higgs Mass Bounds: Projecting U(1)' Models to LHC Domain

We study Higgs boson masses in supersymmetric models with an extra U(1)
symmetry to be called U(1)$^{\prime}$. Such extra gauge symmetries are urged by
the $\mu$ problem of the MSSM, and they also arise frequently in low-energy
supersymmetric models stemming from GUTs and strings. We analyze mass of the
lightest Higgs boson and various other particle masses and couplings by taking
into account the LEP bounds as well as the recent bounds from Tevatron
experiments. We find that the $\mu$-problem motivated generic low-energy
U(1)$^{\prime}$ model yields Higgs masses as large as $\sim 200\ {\rm GeV}$ and
violate the Tevatron bounds for certain ranges of parameters. We analyze
correlations among various model parameters, and determine excluded regions by
both scanning the parameter space and by examining certain likely parameter
values. We also make educated projections for LHC measurements in light of the
Tevatron restrictions on the parameter space. We further analyze certain
benchmark models stemming from E(6) breaking, and find that they elevate Higgs
boson mass into Tevatron's forbidden band when U(1)$^{\prime}$ gauge coupling
takes larger values than the one corresponding to one-step GUT breaking.Comment: 11 pages, 3 figure
The Gapeev-Kuhn stochastic game driven by a spectrally positive Levy process

In Gapeev and Kuhn (2005) [8], the Dynkin game corresponding to perpetual convertible bonds was considered, when driven by a Brownian motion and a compound Poisson process with exponential jumps. We consider the same stochastic game but driven by a spectrally positive Levy process. We establish a complete solution to the game indicating four principle parameter regimes as well as characterizing the occurrence of continuous and smooth fit. In Gapeev and Kuhn (2005) [8], the method of proof was mainly based on solving a free boundary value problem. In this paper, we instead use fluctuation theory and an auxiliary optimal stopping problem to find a solution to the game
Nonadiabatiic superconductivity in MgB2 and cuprates

The Fermi energy, Ef of newly discovered high-Tc superconductor MgB2 and
cuprates is estimated from the measured London penetration depth using a
parameter-free expression. Ef of MgB2 and more than 30 lanthanum, yttrium and
mercury-based cuprates appears to be about or below 100 meV, depending on
doping. There is every evidence that the remarkable low value of Ef and the
strong coupling of carriers with high-frequency phonons is the cause of high Tc
in all newly discovered superconductors. Taking into account that the carriers
mainly reside on oxygen in cuprates, on boron in magnesium diborade, and on
carbon in doped fullerenes, these superconductors form what is essentially
$nonadiabatic$ 'metallic' oxygen, boron and carbon, respectively. The boron
isotope effect on the carrier mass in magnesium-diboride similar to the oxygen
isotope effect on the supercarrier mass observed by Guo-meng Zhao et al. in
cuprates is predicted.Comment: 4 pages, 1 table, submitted to Physical Revie
Topological Description of (Spin) Hall Conductances on Brillouin Zone
  Lattices : Quantum Phase Transitions and Topological Changes

It is widely accepted that topological quantities are useful to describe
quantum liquids in low dimensions. The (spin) Hall conductances are typical
examples. They are expressed by the Chern numbers, which are topological
invariants given by the Berry connections of the ground states. We present a
topological description for the (spin) Hall conductances on a discretized
Brillouin Zone. At the same time, it is quite efficient in practical numerical
calculations for concrete models. We demonstrate its validity in a model with
quantum phase transitions. Topological changes supplemented with the transition
is also described in the present lattice formulation.Comment: proceeding of EP2DS-1
Obtaining a class of Type O pure radiation metrics with a cosmological
  constant, using invariant operators

Using the generalised invariant formalism we derive a class of conformally
flat spacetimes whose Ricci tensor has a pure radiation and a Ricci scalar
component. The method used is a development of the methods used earlier for
pure radiation spacetimes of Petrov types O and N respectively. In this paper
we demonstrate how to handle, in the generalised invariant formalism,
spacetimes with isotropy freedom and rich Killing vector structure. Once the
spacetimes have been constructed, it is straightforward to deduce their
Karlhede classification: the Karlhede algorithm terminates at the fourth
derivative order, and the spacetimes all have one degree of null isotropy and
three, four or five Killing vectors.Comment: 29 page
Semi-Simple Unification on T^6/Z_12 Orientifold in the Type IIB
  Supergravity

The semi-simple unification model based on SU(5)_GUT \times U(3)_H gauge
group is an interesting extension of the minimal SU(5)_GUT grand unification
theory (GUT), since it solves the two serious problems in the standard GUT: the
triplet-doublet splitting problem and the presence of dangerous dimension five
operators for proton decay. Here, the extra U(3)_H gauge interaction plays a
crucial role on the GUT breaking. In this paper, we show that the full
multiplet structure of the U(3)_H sector required for the desired GUT breaking
is reproduced naturally on T^6/Z_12 orientifold in the type IIB supergravity
with a D3-D7 system. The SU(5)_GUT vector multiplet lives on D7-branes and the
U(3)_H sector resides on D3-branes. We also show that various interesting
features in the original SU(5)_GUT \times U(3)_H model are explained in the
present brane-world scenario. A possible extension to the type IIB string
theory is also discussed.Comment: 13 pages, including 1 table and 1 figure, UT-95
Ultra high energy cosmic rays: clustering, GUT scale and neutrino masses

The clustering of ultra high energy (above 5\cdot 10^{19} eV) cosmic rays
(UHECR) suggests that they might be emitted by compact sources. We present a
statistical analysis on the source density based on the multiplicities. The
propagation of UHECR protons is studied in detail. The UHECR spectrum is
consistent with the decay of GUT scale particles and/or with the Z-burst. The
predicted GUT mass is m_X=10^b GeV, where b=14.6_{-1.7}^{+1.6}. Our neutrino
mass prediction depends on the origin of the power part of the spectrum:
m_\nu=2.75^{+1.28}_{-0.97} eV for halo and 0.26^{+0.20}_{-0.14} eV for
extragalactic (EG) origin.Comment: 4 pages, 5 figures. Talk given at TAUP 2001, September 8-12, 2001 in
  Gran Sass
Mass assembly in quiescent and star-forming galaxies since z=4 from
  UltraVISTA

We estimate the galaxy stellar mass function and stellar mass density for
star-forming and quiescent galaxies with 0.2<z<4. We construct a deep K<24
sample of 220000 galaxies selected using the UltraVISTA DR1 data release. Our
analysis is based on precise 30-band photometric redshifts. By comparing these
photometric redshifts with 10800 spectroscopic redshifts from the zCOSMOS
bright and faint surveys, we find a precision of sigma(dz/(1+z))=0.008 at
i<22.5 and sigma(dz/(1+zs))=0.03 at 1.5<z<4. We derive the stellar mass
function and correct for the Eddington bias. We find a mass-dependent evolution
of the global and star-forming populations. This mass-dependent evolution is a
direct consequence of the star formation being quenched in galaxies more
massive than M>10^10.7Msun. For the mass function of the quiescent galaxies, we
do not find any significant evolution of the high-mass end at z<1; however we
observe a clear flattening of the faint-end slope. From z~3 to z~1, the density
of quiescent galaxies increases over the entire mass range. Their comoving
stellar mass density increases by 1.6 dex between z~3 and z~1 and by less than
0.2dex at z<1. We infer the star formation history from the mass density
evolution and we find an excellent agreement with instantaneous star formation
rate measurements at z<1.5, while we find differences of 0.2dex at z>1.5
consistent with the expected uncertainties. We also develop a new method to
infer the specific star formation rate from the mass function of star-forming
galaxies. We find that the specific star formation rate of 10^10Msun galaxies
increases continuously in the redshift range 1<z<4. Finally, we compare our
results with a semi-analytical model and find that these models overestimate
the density of low mass quiescent galaxies by an order of magnitude, while the
density of low-mass star-forming galaxies is successfully reproduced.Comment: 20 pages, 17 figures, Accepted for publication in A&
Baryon Antibaryon Nonets

The baryon-antibaryon SU(3) nonets are proposed as a scheme to classify the
increased number of experimentally observed enhancements near the baryon
antibaryon mass threshold. The scheme is similar to the Fermi-Yang-Sakata
model, which was put forth about fifty years ago in explaining the mesons
observed at that time. According to the present scheme, many new
baryon-antibaryon bound states are predicted, and their possible productions in
quarkonium decays and B decays are suggested for experimental search.Comment: 5 pages, 1 figur
A custodial symmetry for Zbb

We show that a subgroup of the custodial symmetry O(3) that protects delta
rho from radiative corrections can also protect the Zbb coupling. This allows
one to build models of electroweak symmetry breaking, such as Higgsless, Little
Higgs or 5D composite Higgs models, that are safe from corrections to Z-> bb.
We show that when this symmetry protects Zbb it cannot simultaneously protect
Ztt and Wtb. Therefore one can expect to measure sizable deviations from the SM
predictions of these couplings at future collider experiments. We also show
under what circumstances Zb_R b_R can receive corrections in the right
direction to explain the anomaly in the LEP/SLD forward-backward asymmetry
A^b_{FB}.Comment: 11 pages. v2: minor correction
MT2-reconstructed invisible momenta as spin analizers, and an
  application to top polarization

Full event reconstruction is known to be challenging in cases with more than
one undetected final-state particle, such as pair production of two states each
decaying semi-invisibly. On the other hand, full event reconstruction would
allow to access angular distributions sensitive to the spin fractions of the
decaying particles, thereby dissecting their production mechanism. We explore
this possibility in the case of Standard-Model t-tbar production followed by a
leptonic decay of both W bosons, implying two undetected final-state neutrinos.
We estimate the t and tbar momentum vectors event by event using information
extracted from the kinematic variable MT2. The faithfulness of the estimated
momenta to the true momenta is then tested in observables sensitive to top
polarization and t-tbar spin correlations. Our method thereby provides a novel
approach towards the evaluation of these observables, and towards testing
t-tbar production beyond the level of the total cross section. While our
discussion is confined to t-tbar production as a benchmark, the method is
applicable to any process whose decay topology allows to construct MT2.Comment: 28 pages, 14 figures, 3 tables. Changes in v2: new paragraph on ISR
  (end of sec. 2.2); new sec. 3.3 on the method's comparison with existing
  ones; typos fixed; reference added. Matches journal version (JHEP
Quiescent thermal emission from neutron stars in LMXBs

We monitored the quiescent thermal emission from neutron stars in low-mass
X-ray binaries after active periods of intense activity in x-rays (outbursts).
The theoretical modeling of the thermal relaxation of the neutron star crust
may be used to establish constraints on the crust composition and transport
properties, depending on the astrophysical scenarios assumed. We numerically
simulated the thermal evolution of the neutron star crust and compared them
with inferred surface temperatures for five sources: MXB 1659-29, KS 1731-260,
EXO 0748-676, XTE J1701-462 and IGR J17480-2446. We find that the evolution of
MXB 1659-29, KS 1731-260 and EXO 0748-676 can be well described within a deep
crustal cooling scenario. Conversely, we find that the other two sources can
only be explained with models beyond crustal cooling. For the peculiar emission
of XTE J1701-462 we propose alternative scenarios such as residual accretion
during quiescence, additional heat sources in the outer crust, and/or thermal
isolation of the inner crust due to a buried magnetic field. We also explain
the very recent reported temperature of IGR J17480-2446 with an additional heat
deposition in the outer crust from shallow sources.Comment: 19 pages, 32 figures, 2 Append., revised version accepted for
  publication in Astronomy & Astrophysic
Probing electron acceleration and X-ray emission in laser-plasma
  accelerator

While laser-plasma accelerators have demonstrated a strong potential in the
acceleration of electrons up to giga-electronvolt energies, few experimental
tools for studying the acceleration physics have been developed. In this paper,
we demonstrate a method for probing the acceleration process. A second laser
beam, propagating perpendicular to the main beam is focused in the gas jet few
nanosecond before the main beam creates the accelerating plasma wave. This
second beam is intense enough to ionize the gas and form a density depletion
which will locally inhibit the acceleration. The position of the density
depletion is scanned along the interaction length to probe the electron
injection and acceleration, and the betatron X-ray emission. To illustrate the
potential of the method, the variation of the injection position with the
plasma density is studied
Metal-Poor Stars Observed with the Magellan Telescope II. Discovery of
  Four Stars with [Fe/H] < -3.5

We report on the discovery of seven low-metallicity stars selected from the
Hamburg/ESO Survey, six of which are extremely metal-poor ([Fe/H]<-3.0), with
four having [Fe/H]<-3.5. Chemical abundances or upper limits are derived for
these stars based on high-resolution (R~35,000) Magellan/MIKE spectroscopy, and
are in general agreement with those of other very and extremely metal-poor
stars reported in the literature. Accurate metallicities and abundance patterns
for stars in this metallicity range are of particular importance for studies of
the shape of the metallicity distribution function of the Milky Way's halo
system, in particular for probing the nature of its low-metallicity tail. In
addition, taking into account suggested evolutionary mixing effects, we find
that six of the program stars (with [Fe/H]<-3.35) possess atmospheres that were
likely originally enriched in carbon, relative to iron, during their
main-sequence phases. These stars do not exhibit over-abundances of their
s-process elements, and hence may be additional examples of the so-called
CEMP-no class of objects.Comment: 21 pages, 10 figures; accepted for publication in Ap
Hypergravity in AdS_3

Thirty years ago Aragone and Deser showed that in three dimensions there
exists a consistent model describing interaction for massless spin-2 and
spin-5/2 fields. It was crucial that these fields lived in a flat Minkowski
space and as a result it was not possible to deform such model into anti-de
Sitter space. In this short note we show that such deformation becomes possible
provided one compliment to the model with massless spin-4 field. Resulting
theory can be considered as a Chern-Simons one with a well-known supergroup
OSp(1,4). Moreover there exists straightforward generalization to the OSp(1,2n)
case containing a number of bosonic fields with even spins 2,4,...,2n and one
fermionic field with spin n+1/2.Comment: 8 pages, no figures. One reference and some comments added. Version
  to appear in Phys. Lett.
Photon-pair generation in photonic crystal fibrebre with a 1.5GHz
  modelocked VECSEL

Four-wave mixing (FWM) in optical fibre is a leading technique for generating
high-quality photon pairs. We report the generation of photon pairs by
spontaneous FWM in photonic crystal fibre pumped by a 1.5 GHz repetition-rate
vertical-external-cavity surface-emitting laser (VECSEL). The photon pairs
exhibit high count rates and a coincidence-to-accidental ratio of over 80. The
VECSEL's high repetition-rate, high average power, tunability, and small
footprint make this an attractive source for quantum key distribution and
photonic quantum-state engineering.Comment: 17 Pages, 5 Figure
The thermoelectric properties of inhomogeneous holographic lattices

We consider inhomogeneous, periodic, holographic lattices of D=4
Einstein-Maxwell theory. We show that the DC thermoelectric conductivity matrix
can be expressed analytically in terms of the horizon data of the corresponding
black hole solution. We numerically construct such black hole solutions for
lattices consisting of one, two and ten wave-numbers. We numerically determine
the AC electric conductivity which reveals Drude physics as well as resonances
associated with sound modes. No evidence for an intermediate frequency scaling
regime is found. All of the monochromatic lattice black holes that we have
constructed exhibit scaling behaviour at low temperatures which is consistent
with the appearance of $AdS_2\times\mathbb{R}^2$ in the far IR at T=0.Comment: 52 pages, 29 figures, very minor changes, version published in JHE
Reaction dynamics in Pb + Pb at the CERN/SPS: from partonic degrees of freedom to freeze-out

We analyze the reaction dynamics of central Pb+Pb collisions at 160 GeV/nucleon. First we estimate the energy density pile-up at mid-rapidity and calculate its excitation function: The energy density is decomposed into hadronic and partonic contributions. A detailed analysis of the collision dynamics in the framework of a microscopic transport model shows the importance of partonic degrees of freedom and rescattering of leading (di)quarks in the early phase of the reaction for E > 30 GeV/nucleon. The energy density reaches up to 4 GeV/fm^3, 95% of which are contained in partonic degrees of freedom. It is shown that cells of hadronic matter, after the early reaction phase, can be viewed as nearly chemically equilibrated. This matter never exceeds energy densities of 0.4 GeV/fm^3, i.e. a density above which the notion of separated hadrons loses its meaning. The final reaction stage is analyzed in terms of hadron ratios, freeze-out distributions and a source analysis for final state pions
Remarks on the Calculations of Charged Open String Amplitudes: the 1-loop Tadpole

In string theory, there are various physical situations where the world-sheet fields have a shifted moding. For instance, this is the case for the twisted closed string in Z_N orbifold or for the charged open string in a constant electro-magnetic field. Because of this feature, it is quite challenging to give explicit formulae describing the string interaction, even for the bosonic case. In this note, we focus on the case of the charged open bosonic string and construct the 1-loop tadpole which is an object generating all 1-point functions from the annulus in the presence of an external field. In the operator formalism, this represents one of the basic building blocks for the construction of a general loop amplitude
Field Effects in the Thermal Bath of Chiral Fermions

The dispersion relations for leptons in the symmetric phase of the electroweak model in the presence of a constant hypermagnetic field are investigated. The one-loop fermion self-energies are calculated in the lower Landau level approximation and used to show that the hypermagnetic field forbids the generation of the ''effective mass'' found as a pole of the fermions' propagators at high temperature and zero fields. In the considered approximation leptons behave as massles particles propagating only along the direction of the external field. The reported results can be of interest for the cosmological implications of primordial hypermagnetic fields
The conformal Killing equation on forms -- prolongations and
  applications

We construct a conformally invariant vector bundle connection such that its
equation of parallel transport is a first order system that gives a
prolongation of the conformal Killing equation on differential forms. Parallel
sections of this connection are related bijectively to solutions of the
conformal Killing equation. We construct other conformally invariant
connections, also giving prolongations of the conformal Killing equation, that
bijectively relate solutions of the conformal Killing equation on $k$-forms to
a twisting of the conformal Killing equation on (k - l)-forms for various
integers l. These tools are used to develop a helicity raising and lowering
construction in the general setting and on conformally Einstein manifolds.Comment: 37 page
Low noise temperature control : application to an active cavity
  radiometer

We have designed low noise temperature sensing and control units with the
objective of using them for the fabrication of far infrared active cavity
radiometers. The sensing unit, first characterized at 300K using industrial
platinium resistance thermometers, has a noise level of
  25E-6 to 30E-6 Keff for a 3 hours measuring time and in a 1Hz bandwidth.
Using YBCO superconducting thermometers, the noise level goes down to 2.5E-6
Keff, which is strongly limited by excess 1/f noise in the YBCO film at the
superconducting transition. The sample holder used in the 90K experiments is
built with an auxiliary heating resistor, which enables an easy and accurate
identification of the electrothermal model, even in the closed loop operation.
Based on a design previously published by NIST, we estimate from these
experimental results that the overall noise limitations of radiometers could be
lowered by one order of magnitude.Comment: 19 pages, 12 figures, Accepted to Rev. Sci. Instru