pinecone/core-2020-05-10-deduplication huggingface dataset:
Electron-positron pair oscillation in spatially inhomogeneous electric
  fields and radiation

It is known that strong electric fields produce electron and positron pairs
from the vacuum, and due to the back-reaction these pairs oscillate back and
forth coherently with the alternating electric fields in time. We study this
phenomenon in spatially inhomogeneous and bound electric fields by integrating
the equations of energymomentum and particle-number conservations and Maxwell
equations. The space and time evolutions of the pair-induced electric field,
electric charge- and currentdensities are calculated. The results show that
non-vanishing electric charge-density and the propagation of pair-induced
electric fields, differently from the case of homogeneous and unbound electric
fields. The space and time variations of pair-induced electric charges and
currents emit an electromagnetic radiation. We obtain the narrow spectrum and
intensity of this radiation, whose peak {\omega}peak locates in the region
around 4 KeV for electric field strength \sim Ec. We discuss their relevances
to both the laboratory experiments for electron and positron pair-productions
and the astrophysical observations of compact stars with an electromagnetic
structure.Comment: 15 pages, 8 figures. Accepted by Phys. Lett.
Herschel ATLAS: The cosmic star formation history of quasar host
  galaxies

We present a derivation of the star formation rate per comoving volume of
quasar host galaxies, derived from stacking analyses of far-infrared to mm-wave
photometry of quasars with redshifts 0<z<6 and absolute I-band magnitudes
-22>I_AB>-32. We use the science demonstration observations of the first ~16
deg^2 from the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) in
which there are 240 quasars from the Sloan Digital Sky Survey (SDSS) and a
further 171 from the 2dF-SDSS LRG and QSO (2SLAQ) survey. We supplement this
data with a compilation of data from IRAS, ISO, Spitzer, SCUBA and MAMBO.
H-ATLAS alone statistically detects the quasars in its survey area at >5sigma
at 250, 350 and 500um. From the compilation as a whole we find striking
evidence of downsizing in quasar host galaxy formation: low-luminosity quasars
with absolute magnitudes in the range -22>I_AB>-24 have a comoving star
formation rate (derived from 100um rest-frame luminosities) peaking between
redshifts of 1 and 2, while high-luminosity quasars with I_AB<-26 have a
maximum contribution to the star formation density at z~3. The volume-averaged
star formation rate of -22>I_AB>-24 quasars evolves as (1+z)^{2.3 +/- 0.7} at
z<2, but the evolution at higher luminosities is much faster reaching (1+z)^{10
+/- 1} at -26>I_AB>-28. We tentatively interpret this as a combination of a
declining major merger rate with time and gas consumption reducing fuel for
both black hole accretion and star formation.Comment: Accepted by Astronomy and Astrophysics, Herschel special issu
Expansions of one density via polynomials orthogonal with respect to the
  other

We expand the Chebyshev polynomials and some of its linear combination in
linear combinations of the q-Hermite, the Rogers (q-utraspherical) and the
Al-Salam--Chihara polynomials and vice versa. We use these expansions to obtain
expansions of some densities, including q-Normal and some related to it, in
infinite series constructed of the products of the other density times
polynomials orthogonal to it, allowing deeper analysis and discovering new
properties. On the way we find an easy proof of expansion of the
Poisson--Mehler kernel as well as its reciprocal. We also formulate simple rule
relating one set of orthogonal polynomials to the other given the properties of
the ratio of the respective densities of measures orthogonalizing these
polynomials sets
B physics constraints on a flavor symmetric scalar model to account for
  the ttbar asymmetry and Wjj excess at CDF

Recently Nelson et al. proposed an interesting flavor symmetric model to
account for the top quark forward-backward asymmetry and the dijet anomaly at
CDF simultaneously with just three parameters: a coupling constant of order
one, and two scalar masses of 160 GeV and 220 GeV. However these fiducial
values of the parameters lead to the branching ratio of a almost pure penguin B
-> pi K decay about one hundred times larger than the experimental results.
Consider also the precision electroweak constraints, the scalar masses should
be at least around 500 GeV. Actually with the coupling constant larger than
one, it is impossible to explain either of the two CDF measurements
consistently in this model. But one may raise the charged scalar mass to, for
example, 250 GeV and reduce the coupling strength to 0.6 to meet the B physics
constraints. With this parameter set, the Wjj cross section is found to be in
the right range. But due to the scalar mass splitting, its correction to
T-parameter is about 3 sigma away from the precision electroweak constraints.
In addition, the top quark forward-backward asymmetry should be well below 0.1
with this small coupling constant.Comment: 9 pages, 2 figures, accepted for publication in Phys. Lett.
Lithium-Beryllium-Boron : Origin and Evolution

The origin and evolution of Lithium-Beryllium-Boron is a crossing point
between different astrophysical fields : optical and gamma spectroscopy, non
thermal nucleosynthesis, Big Bang and stellar nucleosynthesis and finally
galactic evolution. We describe the production and the evolution of
Lithium-Beryllium-Boron from Big Bang up to now through the interaction of the
Standard Galactic Cosmic Rays with the interstellar medium, supernova neutrino
spallation and a low energy component related to supernova explosions in
galactic superbubbles.Comment: 28 pages, 7 figures, to be published in a special memorial volume of
  Physics Reports in honor of David Schram
Electronic states in topologically disordered systems

Networks generated from Voronoi tessellations of space are prototypes for
topologically disordered systems. In order to assess the effects of random
coordination on the statistical properties of energy spectra, we analyze
tight-binding models for planar topologically disordered systems. To this end,
the networks are generated by a simple topological model covering a wide range
of naturally observed random structures. We find that the energy-level-spacing
distributions exhibit level repulsion, similar to the spacings in the
energetically disordered Anderson model of localization in the metallic regime.Comment: 5 pages, 6 figures, to appear in the proceedings of PILS'98, Annalen
  der Physik (Leipzig
Resonant Raman scattering in NaV2O5 as a probe of its electronic
  structure

In order to investigate the origin of the phase transition observed in
NaV$_2$O$_5$, as well as its electronic structure, we have measured Raman
intensities as a function of the laser wavelength above and below the phase
transition temperature. In the polarized Raman spectra at room temperature we
observe resonant enhancement of the 969 $cm^{-1}$ phonon mode when the laser
energy approaches 2.7 eV, presumably related to the (p-d) electron hopping
band, $O_3$($p_y$)-V($d_{xy}$), at 3.2 eV. The 969 $cm^{-1}$ mode originates
from the stretching vibrations along the c-axis involving the V-$O_1$ bonds.
Since an ellipsometric determination of the dielectric function $\epsilon_{cc}$
yields no structure in the 1.7 to 5.5 eV photon energy range, we conclude that
plane bonds couple strongly with the apical oxygens leading to a large Raman
efficiency. In the low-temperature Raman spectra, almost all modes that become
active below the phase transition temperature T$_c$=34 K show resonant
behavior. The most interesting ones, those at 66 and 106 $cm^{-1}$, possibly of
magnetic origin, exhibit a resonant intensity enhancement, approximately by an
order of magnitude, for laser photon energies around 1.85 eV with respect to
2.43 eV. This resonance effect may be associated with a weak absorption band
around 2 eV. Finally, a destructive interference between the resonant and the
nonresonant contribution to the Raman scattering amplitude (i.e. an
antiresonance) is found in the spectra for most of the (bb) low-temperature
modes.Comment: to be publish in physica status solidi (proceedings issue of ICSSS
The binary black-hole dynamics at the third post-Newtonian order in the
  orbital motion

The orbital dynamics of the binary point-mass systems is ambiguous at the
third post-Newtonian order of approximation. The static ambiguity is known to
be related to the difference between the Brill-Lindquist solution and the
Misner-Lindquist solution of the time-symmetric conformally flat initial value
problem for binary black holes. The kinetic ambiguity is noticed to violate in
general the standard relation between the center-of-mass velocity and the total
linear momentum as demanded by global Lorentz invariance.Comment: Will appear in: Proceedings of the International European Conference
  on Gravitation "Journ\'ees Relativistes 99", September 12-17, 1999,
  Weimar/Germany Annalen der Physik (Leipzig), Vol.
Bottomonium and Drell-Yan production in p-A collisions at 450 GeV

The NA50 Collaboration has measured heavy-quarkonium production in p-A
collisions at 450 GeV incident energy (sqrt(s) = 29.1 GeV). We report here
results on the production of the Upsilon states and of high-mass Drell-Yan muon
pairs (m > 6 GeV). The cross-section at midrapidity and the A-dependence of the
measured yields are determined and compared with the results of other
fixed-target experiments and with the available theoretical estimates. Finally,
we also address some issues concerning the transverse momentum distributions of
the measured dimuons.Comment: 18 pages, 9 figures, to be published in Phys. Lett.
The need for an early anti-neutrino run of NOvA

The moderately large value of $\ty$, measured recently by reactor
experiments, is very welcome news for the future neutrino experiments. In
particular, the \nova experiment, with 3 years each of $\nu$ and $\anu$ runs,
will be able to determine the mass hierarchy if one of the following two
favourable combinations is true: normal hierarchy with $-180^\circ \leq \dcp
\leq 0$ or inverted hierarchy with $0\leq \dcp \leq 180^\circ$. In this report,
we study the hierarchy reach of the first 3 years of \nova data. Since $\sin^2
2 \tz$ is measured to be non-maximal, $\tz$ can be either in the lower or
higher octant. Pure $\nu$ data is affected by $\ty$-hierarchy and
octant-hierarchy degeneracies, which limit the hierarchy sensitivity of such
data. A combination of $\nu$ and $\anu$ data is not subject to these
degeneracies and hence has much better hierarchy discrimination capability. We
find that, with a 3 year $\nu$ run, hierarchy determination is possible for
only two of the four octant-hierarchy combinations. Equal 1.5 year runs in
$\nu$ and $\anu$ modes give good hierarchy sensitivity for all the four
combinations
Ionization in atmospheres of Brown Dwarfs and extrasolar planets IV. The
  Effect of Cosmic Rays

Cosmic rays provide an important source for free electrons in the Earth's
atmosphere and also in dense interstellar regions where they produce a
prevailing background ionization. We utilize a Monte Carlo cosmic ray transport
model for particle energies of 1 MeV < E < 1 GeV, and an analytic cosmic ray
transport model for particle energies of 1 GeV < E < 1 TeV in order to
investigate the cosmic ray enhancement of free electrons in substellar
atmospheres of free-floating objects. The cosmic ray calculations are applied
to Drift-Phoenix model atmospheres of an example brown dwarf with effective
temperature Teff = 1500 K, and two example giant gas planets (Teff = 1000 K,
1500 K). For the model brown dwarf atmosphere, the electron fraction is
enhanced significantly by cosmic rays when the pressure pgas < 10^-2 bar. Our
example giant gas planet atmosphere suggests that the cosmic ray enhancement
extends to 10^-4 - 10^-2 bar, depending on the effective temperature. For the
model atmosphere of the example giant gas planet considered here (Teff = 1000
K), cosmic rays bring the degree of ionization to fe ~ 10^-8 when pgas < 10^-8
bar, suggesting that this part of the atmosphere may behave as a weakly ionized
plasma. Although cosmic rays enhance the degree of ionization by over three
orders of magnitude in the upper atmosphere, the effect is not likely to be
significant enough for sustained coupling of the magnetic field to the gas.Comment: 16 pages, 9 figures, accepted to Ap
A Grassmann Path From AdS_3 to Flat Space

We show that interpreting the inverse AdS_3 radius 1/l as a Grassmann
variable results in a formal map from gravity in AdS_3 to gravity in flat
space. The underlying reason for this is the fact that ISO(2,1) is the
Inonu-Wigner contraction of SO(2,2). We show how this works for the
Chern-Simons actions, demonstrate how the general (Banados) solution in AdS_3
maps to the general flat space solution, and how the Killing vectors, charges
and the Virasoro algebra in the Brown-Henneaux case map to the corresponding
quantities in the BMS_3 case. Our results straightforwardly generalize to the
higher spin case: the recently constructed flat space higher spin theories
emerge automatically in this approach from their AdS counterparts. We conclude
with a discussion of singularity resolution in the BMS gauge as an application.Comment: 20 pages, 1 figure; v2: many refs added, minor changes, v3: typos
  fixed, one more ref added, JHEP versio
The bottomonium spectrum at finite temperature from $N_f=2+1$ lattice
  QCD

We present results on the bottomonium spectrum at temperatures above and
below the deconfinement crossover temperature, $T_c$, from dynamical lattice
QCD simulations. The heavy quark is treated with a non-relativistic effective
field theory on the lattice and serves as a probe of the hot medium. Ensembles
with a finer spatial lattice spacing and a greater range of temperatures below
$T_c$ than those previously employed by this collaboration are used. In
addition, there are $N_f=2+1$ flavours of Wilson clover quark in the sea with
$M_\pi\approx400$ MeV and we perform a more careful tuning of the bottom quark
mass in this work. We calculate the spectral functions of S and P wave
bottomonium states using the maximum entropy method and confirm earlier
findings on the survival of the ground state S wave states up to at least
$2T_c$ and the immediate dissociation of the P wave states above $T_c$.Comment: 17 pages, 11 figure
Massive Jackiw-Rebbi Model

In this paper we analyze a generalized Jackiw-Rebbi (J-R) model in which a
massive fermion is coupled to the kink of the $\lambda\phi^4$ model as a
prescribed background field. We solve this massive J-R model exactly and
analytically and obtain the whole spectrum of the fermion, including the bound
and continuum states. The mass term of the fermion makes the potential of the
decoupled second order Schrodinger-like equations asymmetric in a way that
their asymptotic values at two spatial infinities are different. Therefore, we
encounter the unusual problem in which two kinds of continuum states are
possible for the fermion: reflecting and scattering states. We then show the
energies of all the states as a function of the parameters of the kink, i.e.
its value at spatial infinity ($\theta_0$) and its slope at $x=0$ ($\mu$). The
graph of the energies as a function of $\theta_0$, where the bound state
energies and the two kinds of continuum states are depicted, shows peculiar
features including an energy gap in the form of a triangle where no bound
states exist. That is the zero mode exists only for $\theta_0$ larger than a
critical value $(\theta_0^{\textrm{c}})$. This is in sharp contrast to the
usual (massless) J-R model where the zero mode and hence the fermion number
$\pm1/2$ for the ground state is ever present. This also makes the origin of
the zero mode very clear: It is formed from the union of the two threshold
bound states at $\theta_0^{\textrm{c}}$, which is zero in the massless J-R
model.Comment: 10 pages, 3 figure
Single Interval R\'enyi Entropy At Low Temperature

In this paper, we calculate the R\'enyi entropy of one single interval on a
circle at finite temperature in 2D CFT. In the low temperature limit, we expand
the thermal density matrix level by level in the vacuum Verma module, and
calculate the first few leading terms in $e^{-\pi/TL}$ explicitly. On the other
hand, we compute the same R\'enyi entropy holographically. After considering
the dependence of the R\'enyi entropy on the temperature, we manage to fix the
interval-independent constant terms in the classical part of holographic
R\'enyi entropy. We furthermore extend the analysis in Xi Dong's paper to
higher orders and find exact agreement between the results from field theory
and bulk computations in the large central charge limit. Our work provides
another piece of evidence to support holographic computation of R\'enyi entropy
in AdS$_3$/CFT$_2$ correspondence, even with thermal effect.Comment: 22 pages, 0 figure
Particle energisation in a collapsing magnetic trap model: the
  relativistic regime

In solar flares, a large number of charged particles is accelerated to high
energies. By which physical processes this is achieved is one of the main open
problems in solar physics. It has been suggested that during a flare, regions
of the rapidly relaxing magnetic field can form a collapsing magnetic trap
(CMT) and that this trap may contribute to particle energisation.} In this
Research Note we focus on a particular analytical CMT model based on kinematic
magnetohydrodynamics. Previous investigations of particle acceleration for this
CMT model focused on the non-relativistic energy regime. It is the specific aim
of this Research Note to extend the previous work to relativistic particle
energies. Particle orbits were calculated numerically using the relativistic
guiding centre equations. We also calculated particle orbits using the
non-relativistic guiding centre equations for comparison. For mildly
relativistic energies the relativistic and non-relativistic particle orbits
mainly agree well, but clear deviations are seen for higher energies. In
particular, the final particle energies obtained from the relativistic
calculations are systematically lower than the energies reached from the
corresponding non-relativistic calculations, and the mirror points of the
relativistic orbits are systematically higher than for the corresponding
non-relativistic orbits. While the overall behaviour of particle orbits in CMTs
does not differ qualitatively when using the relativistic guiding centre
equations, there are a few systematic quantitative differences between
relativistic and non-relativistic particle dynamics.Comment: 4 pages, 2 figures, accepted by Astronomy and Astrophysic
New Einstein-Hilbert Type Action for Unity of Nature

The fundamental action of superon-graviton model(SGM) for space-time and
matter is written down explicitly in terms of the fields of the graviton and
superons by using the affine and the spin connection formalisms, alternatively.
Some characteristic structures including some hidden symmetries of the
gravitational coupling of superons are manifested (in two dimensional
space-time) with some details of the calculations. SGM cosmology is discussed
briefly.Comment: 10 pages, Latex, Invited talk given at 100 Years Werner Heisenberg
  -Works and Impact- Sep.26-30,2001, Bamberg, German
Duality transformations in supersymmetric Yang-Mills theories coupled to supergravity

We consider duality transformations in N=2, d=4 Yang-Mills theory coupled to N=2 supergravity. A symplectic and coordinate covariant framework is established, which allows one to discuss stringy `classical and quantum duality symmetries' (monodromies), incorporating T and S dualities. In particular, we shall be able to study theories (like N=2 heterotic strings) which are formulated in symplectic basis where a `holomorphic prepotential' F does not exist, and yet give general expressions for all relevant physical quantities. Duality transformations and symmetries for the N=1 matter coupled Yang--Mills supergravity system are also exhibited. The implications of duality symmetry on all N>2 extended supergravities are briefly mentioned. We finally give the general form of the central charge and the N=2 semiclassical spectrum of the dyonic BPS saturated states (as it comes by truncation of the N=4 spectrum)
Dimensions of fractals related to languages defined by tagged string s in complete genomes

A representation of frequency of strings of length K in complete genomes of many organisms in a square has led to seemingly self-similar patterns when K increases. These patterns are caused by under-represented strings with a certain "tag"-string and they define some fractals when K tends to infinite. The Box and Hausdorff dimensions of the limit set are discussed. Although the method proposed by Mauldin and Williams to calculate Box and Hausdorff dimension=0Dis valid in our case, a different and sampler method is proposed in this paper
Two-Loop Quark Self-Energy in a New Formalism; 2, Renormalization of the Quark Propagator in the Light-Cone Gauge

The complete two-loop correction to the quark propagator, consisting of the spider, rainbow, gluon bubble and quark bubble diagrams, is evaluated in the noncovariant light-cone gauge (lcg). (The overlapping self-energy diagram had already been computed.) The chief technical tools include the powerful matrix integration technique, the n^*-prescription for the spurious poles of 1/qn, and the detailed analysis of the boundary singularities in five- and six-dimensional parameter space. It is shown that the total divergent contribution to the two-loop correction Sigma_2 contains both covariant and noncovariant components, and is a local function of the external momentum p, even off the mass-shell, as all nonlocal divergent terms cancel exactly. Consequently, both the quark mass and field renormalizations are local. The structure of Sigma_2 implies a quark mass counterterm of the form $\delta m (lcg) = m\tilde\alpha_s C_F(3+\tilde\alpha_sW) + {\rm O} (\tilde\alpha_s^3)$, the dimensional regulator epsilon, and on the numbers of colors and flavors. It turns out that \delta m(lcg) is identical to the mass counterterm in the general linear covariant gauge. Our results are in agreement with the Bassetto-Dalbosco-Soldati renormalization scheme
A Universal Lagrangian for Massive Yang-Mills Theories without Higgs
  Bosons

A universal Lagrangian that defines various four-dimensional massive
Yang-Mills theories without Higgs bosons is presented. Each of the theories is
characterized by a constant k contained in the Lagrangian. For k=0, the
Lagrangian reduces to one defining the topologically massive Yang-Mills theory,
and for k=1, the Lagrangian reduces to one defining the Freedman-Townsend
model. New massive Yang-Mills theories are obtained by choosing k to be real
numbers other than 0 and 1.Comment: 9 pages, latex, no figure