pinecone/core-2020-05-10-deduplication huggingface dataset:
Critical level statistics of a quantum Hall system with Dirichlet
  boundary conditions

We investigate numerically the influence of Dirichlet boundary conditions on
the nearest neighbor level spacing distribution $P(s)$ of a two-dimensional
disordered tight-binding model in the presence of a strong perpendicular
magnetic field. From the calculation of the second moment of $P(s)$ it is shown
that for Dirichlet boundary conditions, due to the presence of edge states, the
position of the critical energy shifts with increasing system size to the
location of the critical energy for periodic boundary conditions. An
extrapolation to infinite system size results in different critical (scale
independent) $P(s)$ distributions for periodic and Dirichlet boundary
conditions.Comment: 5 pages LaTeX, 2 ps-figures included. Proceedings of PILS'98, Berlin,
  Germany 1998; to appear in Annalen der Physi
Low-temperature dephasing in disordered conductors: experimental aspects

What is the lowest temperature to which one can trace the growth of the
dephasing time in low-dimensional conductors? I consider the fundamental
limitation, the crossover from weak to strong localization, as well as several
experimental reasons for frequently observed saturation of the dephasing time
(hot-electron effects, dephasing by external noise). Recent progress in our
understanding of the electron-phonon interaction in disordered conductors is
also briefly discussed.Comment: 10 pages, 5 figures, uses annalen.cls, presented at Localization-99,
  to be published in Annalen der Physi
Overlap Fermions on a $20^4$ Lattice

We report results on hadron masses, fitting of the quenched chiral log, and
quark masses from Neuberger's overlap fermion on a quenched $20^4$ lattice with
lattice spacing $a = 0.15$ fm. We used the improved gauge action which is shown
to lower the density of small eigenvalues for $H^2$ as compared to the Wilson
gauge action. This makes the calculation feasible on 64 nodes of CRAY-T3E. Also
presented is the pion mass on a small volume ($6^3 \times 12$ with a Wilson
gauge action at $\beta = 5.7$). We find that for configurations that the
topological charge $Q \ne 0$, the pion mass tends to a constant and for
configurations with trivial topology, it approaches zero possibly linearly with
the quark mass.Comment: Lattice 2000 (Chiral Fermion), 4 pages, 4 figure
Single-spin Azimuthal Asymmetries in the ``Reduced Twist-3
  Approximation''

We consider the single-spin azimuthal asymmetries recently measured at the
HERMES experiment for charged pions produced in semi-inclusive deep inelastic
scattering of leptons off longitudinally polarized protons. Guided by the
experimental results and assuming a vanishing twist-2 transverse quark spin
distribution in the longitudinally polarized nucleon, denoted as ``reduced
twist-3 approximation'', a self-consistent description of the observed
single-spin asymmetries is obtained. In addition, predictions are given for the
z dependence of the single target-spin asymmetry.Comment: 8 pages, 2 figures, typos corrected, very small changes to text,
  reference adde
Supersymmetric Black Holes in AdS4 from Very Special Geometry

Supersymmetric black holes in AdS spacetime are inherently interesting for
the AdS/CFT correspondence. Within a four dimensional gauged supergravity
theory coupled to vector multiplets, the only analytic solutions for regular,
supersymmetric, static black holes in AdS4 are those in the STU-model due to
Cacciatori and Klemm. We study a class of U(1)-gauged supergravity theories
coupled to vector multiplets which have a cubic prepotential, the scalar
manifold is then a very special Kahler manifold. When the resulting very
special Kahler manifold is a homogeneous space, we find analytic solutions for
static, supersymmetric AdS4 black holes with vanishing axions. The horizon
geometries of our solutions are constant curvature Riemann surfaces of
arbitrary genus.Comment: 22 page
A Sub-Earth-Mass Moon Orbiting a Gas Giant Primary or a High Velocity
  Planetary System in the Galactic Bulge

We present the first microlensing candidate for a free-floating
exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of M_host
~ 4 Jupiter masses hosting a sub-Earth mass moon. The data are well fit by this
exomoon model, but an alternate star+planet model fits the data almost as well.
Nevertheless, these results indicate the potential of microlensing to detect
exomoons, albeit ones that are different from the giant planet moons in our
solar system. The argument for an exomoon hinges on the system being relatively
close to the Sun. The data constrain the product M pi_rel, where M is the lens
system mass and pi_rel is the lens-source relative parallax. If the lens system
is nearby (large pi_rel), then M is small (a few Jupiter masses) and the
companion is a sub-Earth-mass exomoon. The best-fit solution has a large
lens-source relative proper motion, mu_rel = 19.6 +- 1.6 mas/yr, which would
rule out a distant lens system unless the source star has an unusually high
proper motion. However, data from the OGLE collaboration nearly rule out a high
source proper motion, so the exoplanet+exomoon model is the favored
interpretation for the best fit model. However, the alternate solution has a
lower proper motion, which is compatible with a distant (so stellar) host. A
Bayesian analysis does not favor the exoplanet+exomoon interpretation, so
Occam's razor favors a lens system in the bulge with host and companion masses
of M_host = 0.12 (+0.19 -0.06) M_solar and m_comp = 18 (+28 -100 M_earth, at a
projected separation of a_perp ~ 0.84 AU. The existence of this degeneracy is
an unlucky accident, so current microlensing experiments are in principle
sensitive to exomoons. In some circumstances, it will be possible to
definitively establish the low mass of such lens systems through the
microlensing parallax effect. Future experiments will be sensitive to less
extreme exomoons.Comment: 32 pages with 9 included figure
Non-circular features in Saturn's D ring: D68

D68 is a narrow ringlet located only 67,627 km (1.12 planetary radii) from
Saturn's spin axis. Images of this ringlet obtained by the Cassini spacecraft
reveal that this ringlet exhibits persistent longitudinal brightness variations
and a substantial eccentricity (ae=25+/-1 km). By comparing observations made
at different times, we confirm that the brightness variations revolve around
the planet at approximately the local orbital rate (1751.6 degrees/day), and
that the ringlet's pericenter precesses at 38.243+/-0.008 degrees/day,
consistent with the expected apsidal precession rate at this location due to
Saturn's higher-order gravitational harmonics. Surprisingly, we also find that
the ringlet's semi-major axis appears to be decreasing with time at a rate of
2.4+/-0.4 km/year between 2005 and 2013. A closer look at these measurements,
along with a consideration of earlier Voyager observations of this same
ringlet, suggests that the mean radius of D68 moves back and forth, perhaps
with a period of around 15 Earth years or about half a Saturn year. These
observations could place important constraints on both the ringlet's local
dynamical environment and the planet's gravitational field.Comment: 39 Pages, 11 Figures accepted for publication in Icarus Text slightly
  modified to match corrections to proof
A method of `speed coefficients' for biochemical model reduction applied
  to the NF-kappaB system

The relationship between components of biochemical network and the resulting
dynamics of the overall system is a key focus of computational biology.
However, as these networks and resulting mathematical models are inherently
complex and non-linear, the understanding of this relationship becomes
challenging. Among many approaches, model reduction methods provide an avenue
to extract components responsible for the key dynamical features of the system.
Unfortunately, these approaches often require intuition to apply. In this
manuscript we propose a practical algorithm for the reduction of biochemical
reaction systems using fast-slow asymptotics. This method allows the ranking of
system variables according to how quickly they approach their momentary steady
state, thus selecting the fastest for a steady state approximation. We applied
this method to derive models of the Nuclear Factor kappa B network, a key
regulator of the immune response that exhibits oscillatory dynamics. Analyses
with respect to two specific solutions, which corresponded to different
experimental conditions identified different components of the system that were
responsible for the respective dynamics. This is an important demonstration of
how reduction methods that provide approximations around a specific steady
state, could be utilised in order to gain a better understanding of network
topology in a broader context.Comment: 29 pages, 13 figures, as accepted to J Math Biol 2014/03/0
Higgs vacuum stability from the dark matter portal

We consider classically scale-invariant extensions of the Standard Model (CSI
ESM) which stabilise the Higgs potential and have good dark matter candidates.
In this framework all mass scales, including electroweak and dark matter
masses, are generated dynamically and have a common origin. We consider Abelian
and non-Abelian hidden sectors portally coupled to the SM with and without a
real singlet scalar. We perform a careful analysis of RG running to determine
regions in the parameter space where the SM Higgs vacuum is stabilised. After
combining this with the LHC Higgs constraints, in models without a singlet,
none of the regained parameter space in Abelian ESMs, and only a small section
in the non-Abelian ESM survives. However, in all singlet-extended models we
find that the Higgs vacuum can be stabilised in all of the parameter space
consistent with the LHC constraints. These models naturally contain two dark
matter candidates: the real singlet and the dark gauge boson in non-Abelian
models. We determine the viable range of parameters in the CSI ESM framework by
computing the relic abundance, imposing direct detection constraints and
combining with the LHC Higgs constraints. In addition to being instrumental in
Higgs stabilisation, we find that the singlet component is required to explain
the observed dark matter density.Comment: 33 pages, 11 figures v2: typos correcte
Dynamics of monopole walls

The moduli space of centred Bogomolny-Prasad-Sommmerfield 2-monopole fields
is a 4-dimensional manifold M with a natural metric, and the geodesics on M
correspond to slow-motion monopole dynamics. The best-known case is that of
monopoles on R^3, where M is the Atiyah-Hitchin space. More recently, the case
of monopoles periodic in one direction (monopole chains) was studied a few
years ago. Our aim in this note is to investigate M for doubly-periodic fields,
which may be visualized as monopole walls. We identify some of the geodesics on
M as fixed-point sets of discrete symmetries, and interpret these in terms of
monopole scattering and bound orbits, concentrating on novel features that
arise as a consequence of the periodicity.Comment: 12 pages, 3 figure
Associated ZH production at hadron colliders: the fully differential
  NNLO QCD calculation

We consider Standard Model Higgs boson production in association with a Z
boson in hadron collisions. We present a fully exclusive computation of QCD
radiative corrections up to next-to-next-to-leading order (NNLO). Our
calculation includes the Higgs boson decay to bottom quarks (b) in
next-to-leading order QCD and the leptonic decay of the Z boson with
finite-width effects and spin correlations. The computation is implemented in a
parton level Monte Carlo program that makes possible to consider arbitrary
kinematical cuts on the final-state leptons, the b jets and the associated QCD
radiation, and to compute the corresponding distributions in the form of bin
histograms. We assess the impact of QCD radiative effects in the boosted
kinematics at the LHC and show that the inclusion of the NNLO corrections is
crucial to control the pT spectrum of the Higgs boson candidate.Comment: 10 pages, 2 figure
The ALHAMBRA survey: Accurate merger fractions by PDF analysis of
  photometric close pairs

Our goal is to develop and test a novel methodology to compute accurate close
pair fractions with photometric redshifts. We improve the current methodologies
to estimate the merger fraction f_m from photometric redshifts by (i) using the
full probability distribution functions (PDFs) of the sources in redshift
space, (ii) including the variation in the luminosity of the sources with z in
both the selection of the samples and in the luminosity ratio constrain, and
(iii) splitting individual PDFs into red and blue spectral templates to deal
robustly with colour selections. We test the performance of our new methodology
with the PDFs provided by the ALHAMBRA photometric survey. The merger fractions
and rates from the ALHAMBRA survey are in excellent agreement with those from
spectroscopic work, both for the general population and for red and blue
galaxies. With the merger rate of bright (M_B <= -20 - 1.1z) galaxies evolving
as (1+z)^n, the power-law index n is larger for blue galaxies (n = 2.7 +- 0.5)
than for red galaxies (n = 1.3 +- 0.4), confirming previous results.
Integrating the merger rate over cosmic time, we find that the average number
of mergers per galaxy since z = 1 is N_m = 0.57 +- 0.05 for red galaxies and
N_m = 0.26 +- 0.02 for blue galaxies. Our new methodology exploits
statistically all the available information provided by photometric redshift
codes and provides accurate measurements of the merger fraction by close pairs
only using photometric redshifts. Current and future photometric surveys will
benefit of this new methodology.Comment: Submitted to A&A, 15 pages, 15 figures, 6 tables. Comments are
  welcome. Close pair systems available at
  https://cloud.iaa.csic.es/alhambra/catalogues/ClosePairs
VLT/X-shooter spectroscopy of the afterglow of the Swift GRB 130606A:
  Chemical abundances and reionisation at $z\sim6$

The reionisation of the Universe is thought to have ended around z~6, as
inferred from spectroscopy of distant bright background sources, such as
quasars (QSO) and gamma-ray burst (GRB) afterglows. Furthermore, spectroscopy
of a GRB afterglow provides insight in its host galaxy, which is often too dim
and distant to study otherwise. We present the high S/N VLT/X-shooter spectrum
of GRB130606A at z=5.913. We aim to measure the degree of ionisation of the IGM
between 5.02<z<5.84 and to study the chemical abundance pattern and dust
content of its host galaxy. We measured the flux decrement due to absorption at
Ly$\alpha$, $\beta$ and $\gamma$ wavelength regions. The hydrogen and metal
absorption lines formed in the host galaxy were fitted with Voigt profiles to
obtain column densities. Our measurements of the Ly$\alpha$-forest optical
depth are consistent with previous measurements of QSOs, but have a much
smaller uncertainty. The analysis of the red damping wing yields a neutral
fraction $x_{HI}<0.05$ (3$\sigma$). We obtain column density measurements of
several elements. The ionisation corrections due to the GRB is estimated to be
negligible (<0.03 dex), but larger corrections may apply due to the
pre-existing radiation field (up to 0.4 dex based on sub-DLA studies). Our
measurements confirm that the Universe is already predominantly ionised over
the redshift range probed in this work, but was slightly more neutral at z>5.6.
GRBs are useful probes of the ionisation state of the IGM in the early
Universe, but because of internal scatter we need a larger statistical sample
to draw robust conclusions. The high [Si/Fe] in the host can be due to dust
depletion, alpha-element enhancement, or a combination of both. The very high
value of [Al/Fe]=2.40+/-0.78 might connected to the stellar population history.
We estimate the host metallicity to be -1.7<[M/H]<-0.9 (2%-13% of solar).
(trunc.)Comment: 15 pages, 12 figure
Noncommutative Multi-Instantons on R^{2n} x S^2

Generalizing self-duality on R^2 x S^2 to higher dimensions, we consider the
Donaldson-Uhlenbeck-Yau equations on R^{2n} x S^2 and their noncommutative
deformation for the gauge group U(2). Imposing SO(3) invariance (up to gauge
transformations) reduces these equations to vortex-type equations for an
abelian gauge field and a complex scalar on R^{2n}_\theta. For a special
S^2-radius R depending on the noncommutativity \theta we find explicit
solutions in terms of shift operators. These vortex-like configurations on
R^{2n}_\theta determine SO(3)-invariant multi-instantons on R^{2n}_\theta x
S^2_R for R=R(\theta). The latter may be interpreted as sub-branes of
codimension 2n inside a coincident pair of noncommutative Dp-branes with an S^2
factor of suitable size.Comment: 1+8 pages, v2: reference added, version published in PL
Estimation of hydrodynamical model parameters from the invariant spectrum and the Bose-Einstein correlations of $\pi$-mesons produced in ($\pi^{+}/K^{+})p$ interactions at 250 GeV/c

The invariant spectra of pi- mesons produced in (pi+/K+)p interactions at 250 GeV/c are analysed in the framework of the hydrodynamical model of three-dimensionally expanding cylindrically symmetric finite systems. A satisfactory description of experimental data is achieved. The data favour the pattern according to which the hadron matter undergoes predominantly longitudinal expansion and non-relativistic transverse expansion with mean transverse velocity <u_t> = 0.20(7), and is characterized by a large temperature inhomogeneity in the transverse direction: the extracted freeze-out temperature at the center of the tube and at the transverse rms radius are 140(3) MeV and 82(7) MeV, respectively. The width of the (longitudinal) space-time rapidity distribution of the pion source is found to be Delta eta = 1.36(2). Combining this estimate with results of the Bose-Einstein correlation analysis in the same experiment, one extracts a mean freeze-out time of the source of <tau_f> = 1.4(1) fm/c and its transverse geometrical rms radius, R_G (rms)=1.2(2) fm
Quantum dynamics of massive particles in a non-commutative two-sheeted
  space-time

We study a formal extension of the Dirac equation in the framework of a
non-commutative two-sheeted space-time. It is shown that this approach
naturally extends the classical Dirac theory by doubling the number of
fermionic states, which can then be identified as matter and hidden-matter
states. Our model exhibit several interesting features that could have
observational consequences. Among them, we predict a small electromagnetic
coupling between matter and hidden matter universes which should lead to
matter/hidden matter oscillations in presence of intense electromagnetic vector
potentials.Comment: 10 pages, no figures. Slightly improved version. Accepted for
  publication in Physics Letters
(BPS) Fayet-Iliopoulos Terms in 5D Orbifold SUGRA

We discuss Fayet-Iliopoulos terms in the context of five-dimensional
supergravity compactified on an orbifold. For this purpose we use our
superfield formulation of the off-shell 5D SUGRA. In the case of tuned FI
terms, contrary to other claims, we find BPS solutions which ensure that N=1
supersymmetry is unbroken also in warped geometries. As in the rigid case, the
FI terms induce odd masses for charged hypermultiplets, leading to the
(de)localisation of the KK wave-functions near the fix-point branes. In the
case of ungauged U(1)_R symmetry, we present also supersymmetric warped
solutions in the presence of non-trivial profiles of charged hyperscalars.Comment: LaTeX, 11 pages, 2 figures, extended discussion after (25) and (49),
  version published in PL
Fourth Order Gradient Symplectic Integrator Methods for Solving the Time-Dependent Schrödinger Equation

We show that the method of splitting the operator ${\rm e}^{\epsilon(T+V)}$ to fourth order with purely positive coefficients produces excellent algorithms for solving the time-dependent Schr\"odinger equation. These algorithms require knowing the potential and the gradient of the potential. One 4th order algorithm only requires four Fast Fourier Transformations per iteration. In a one dimensional scattering problem, the 4th order error coefficients of these new algorithms are roughly 500 times smaller than fourth order algorithms with negative coefficient, such as those based on the traditional Ruth-Forest symplectic integrator. These algorithms can produce converged results of conventional second or fourth order algorithms using time steps 5 to 10 times as large. Iterating these positive coefficient algorithms to 6th order also produced better converged algorithms than iterating the Ruth-Forest algorithm to 6th order or using Yoshida's 6th order algorithm A directly
Near-threshold measurement of the 4He(g,n) reaction

A near-threshold 4He(g,n) cross-section measurement has been performed at
MAX-lab. Tagged photons from 23 < Eg < 42 MeV were directed toward a liquid 4He
target, and neutrons were detected by time-of-flight in two liquid-scintillator
arrays. Seven-point angular distributions were measured for eight photon
energies. The results are compared to experimental data measured at comparable
energies and Recoil-Corrected Continuum Shell Model, Resonating Group Method,
and recent Hyperspherical-Harmonic Expansion calculations. The angle-integrated
cross-section data is peaked at a photon energy of about 28 MeV, in
disagreement with the value recommended by Calarco, Berman, and Donnelly in
1983.Comment: 10 pages, 3 figures, some revisions, submitted to Physics Letters
Structures and Stabilities of Doubly-charged (MgO)nMg2+ (n=1-29) Cluster
  Ions

Ab initio perturbed ion plus polarization calculations are reported for
doubly-charged nonstoichiometric (MgO)nMg2+ (n=1-29) cluster ions. We consider
a large number of isomers with full relaxations of the geometries, and add the
correlation correction to the Hartree-Fock energies for all cluster sizes. The
polarization contribution is included at a semiempirical level also for all
cluster sizes. Comparison is made with theoretical results for neutral (MgO)n
clusters and singly-charged alkali-halide cluster ions. Our method is also
compared to phenomenological pair potential models in order to asses their
reliability for calculations on small ionic systems. The large
coordination-dependent polarizabilities of oxide anions favor the formation of
surface sites, and thus bulklike structures begin to dominate only after n=24.
The relative stabilities of the cluster ions against evaporation of a MgO
molecule show variations that are in excellent agreement with the experimental
abundance spectra.Comment: Final version accepted in Journal of Chemical Physics; 8 pages plus 8
  figures (6 GIFs and 2 PSs). The main difference with respect to the original
  submission is the inclusion of coordination-dependent polarizabilities for
  oxide anions. That results in substantial changes in the result
Flavor violating $Z'$ from $SO(10)$ SUSY GUT in High-Scale SUSY

We propose an $SO(10)$ supersymmetric grand unified theory (SUSY GUT), where
the $SO(10)$ gauge symmetry breaks down to $SU(3)_c \times SU(2)_L \times
U(1)_Y\times U(1)_{X}$ at the GUT scale and $U(1)_X$ is radiatively broken at
the SUSY-braking scale. In order to achieve the observed Higgs mass around
$126$ GeV and also to satisfy constraints on flavor- and/or CP-violating
processes, we assume that the SUSY-breaking scale is $O(100)$ TeV, so that the
$U(1)_X$ breaking scale is also $O(100)$ TeV. One big issue in the SO(10) GUTs
is how to realize realistic Yukawa couplings. In our model, not only ${\bf
16}$-dimensional but also ${\bf 10}$-dimensional matter fields are introduced
to predict the observed fermion masses and mixings. The Standard-Model quarks
and leptons are linear combinations of the ${\bf 16}$- and ${\bf
10}$-dimensional fields so that the $U(1)_{X}$ gauge interaction may be
flavor-violating. We investigate the current constraints on the
flavor-violating $Z'$ interaction from the flavor physics and discuss prospects
for future experiments.Comment: 13 pages, IPMU-15-003