564 research outputs found
Most unwanted pests in the United States - have you seen these insects?
This publication illustrates some of the most unwanted pests in the U.S. including beetles and weevils, scales, mealybugs, and bugs, moths and their caterpillars, and thrips. It includes their description, distribution and host plants, as well as information for reporting of pests
Mutual influence of structural distortion and superconductivity in systems with degenerate bands
The interplay between the band Jahn-Teller distortion and the
superconductivity is studied for the system whose Fermi level lies in two-fold
degenerate band. Assuming that the lattice distortion is coupled to the orbital
electron density and the superconductivity arises due to BCS pairing mechanism
between the electrons, the phase diagram is obtained for different doping with
respect to half-filled band situation. The coexistence phase of
superconductivity and distortion occurs within limited range of doping and the
distortion lowers the superconducting transition temperature . In presence
of strong electron-lattice interaction the lattice strain is found to be
maximum at half-filling and superconductivity does not appear for low doping.
The maximum value of obtainable for an optimum doping is limited by the
structural transition temperature . The growth of distortion is arrested
with the onset of superconductivity and the distortion is found to disappear at
lower temperature for some hole density. Such arresting of the growth of
distortion at produces discontinuous jump in thermal expansion
coefficient. The variation of strain with temperature as well as with doping,
thermal expansion coefficient, the vs behaviour are in
qualitative agreement with recent experimental observations on interplay of
distortion and superconductivity in cuprates.Comment: 15 pages Revtex style, 9 figures available on request to first Autho
Spectral networks
We introduce new geometric objects called spectral networks. Spectral
networks are networks of trajectories on Riemann surfaces obeying certain local
rules. Spectral networks arise naturally in four-dimensional N=2 theories
coupled to surface defects, particularly the theories of class S. In these
theories spectral networks provide a useful tool for the computation of BPS
degeneracies: the network directly determines the degeneracies of solitons
living on the surface defect, which in turn determine the degeneracies for
particles living in the 4d bulk. Spectral networks also lead to a new map
between flat GL(K,C) connections on a two-dimensional surface C and flat
abelian connections on an appropriate branched cover Sigma of C. This
construction produces natural coordinate systems on moduli spaces of flat
GL(K,C) connections on C, which we conjecture are cluster coordinate systems.Comment: 87 pages, 48 figures; v2: typos, correction to general rule for signs
of BPS count
Hybrid stars with the color dielectric and the MIT bag models
We study the hadron-quark phase transition in the interior of neutron stars
(NS). For the hadronic sector, we use a microscopic equation of state (EOS)
involving nucleons and hyperons derived within the Brueckner-Bethe-Goldstone
many-body theory, with realistic two-body and three-body forces. For the
description of quark matter, we employ both the MIT bag model with a density
dependent bag constant, and the color dielectric model. We calculate the
structure of NS interiors with the EOS comprising both phases, and we find that
the NS maximum masses are never larger than 1.7 solar masses, no matter the
model chosen for describing the pure quark phase.Comment: 11 pages, 5 figures, submitted to Phys. Rev.
Recent developments in unconventional superconductivity theory
The review of recent developments in the unconventional superconductivity
theory is given. In the fist part I consider the physical origin of the Kerr
rotation polarization of light reflected from the surface of superconducting
. Then the comparison of magneto-optical responses in
superconductors with orbital and spin spontaneous magnetization is presented.
The latter result is applied to the estimation of the magneto-optical
properties of neutral superfluids with spontaneous magnetization. The second
part is devoted to the natural optical activity or gyrotropy properties of
noncentrosymmetric metals in their normal and superconducting states. The
temperature behavior of the gyrotropy coefficient is compared with the
temperature behavior of paramagnetic susceptibility determining the noticeable
increase of the paramagnetic limiting field in noncentrosymmetric
superconductors. In the last chapter I describe the order parameter and the
symmetry of superconducting state in the itinerant ferromagnet with
orthorhombic symmetry. Finally the Josephson coupling between two adjacent
ferromagnet superconducting domains is discussed.Comment: 15 page
Selberg Supertrace Formula for Super Riemann Surfaces III: Bordered Super Riemann Surfaces
This paper is the third in a sequel to develop a super-analogue of the
classical Selberg trace formula, the Selberg supertrace formula. It deals with
bordered super Riemann surfaces. The theory of bordered super Riemann surfaces
is outlined, and the corresponding Selberg supertrace formula is developed. The
analytic properties of the Selberg super zeta-functions on bordered super
Riemann surfaces are discussed, and super-determinants of Dirac-Laplace
operators on bordered super Riemann surfaces are calculated in terms of Selberg
super zeta-functions.Comment: 43 pages, amste
An estimate of the flavour singlet contributions to the hyperfine splitting in charmonium
We explore the splitting between flavour singlet and non-singlet mesons in
charmonium. This has implications for the hyperfine splitting in charmonium
The anomalous Higgs-top couplings in the MSSM
The anomalous couplings of the top quark and the Higgs boson has been studied
in an effective theory resulting in the framework of the minimal supersymmetric
extension of the standard model (MSSM) when the heavy fields are integrated
out. Constraints on the parameters of the model from the experimental data on
the ratio are derived.Comment: Latex, 26 pages + 13 ps figures, final version in PR
Anomalous Heat Conduction and Anomalous Diffusion in Low Dimensional Nanoscale Systems
Thermal transport is an important energy transfer process in nature. Phonon
is the major energy carrier for heat in semiconductor and dielectric materials.
In analogy to Ohm's law for electrical conductivity, Fourier's law is a
fundamental rule of heat transfer in solids. It states that the thermal
conductivity is independent of sample scale and geometry. Although Fourier's
law has received great success in describing macroscopic thermal transport in
the past two hundreds years, its validity in low dimensional systems is still
an open question. Here we give a brief review of the recent developments in
experimental, theoretical and numerical studies of heat transport in low
dimensional systems, include lattice models, nanowires, nanotubes and
graphenes. We will demonstrate that the phonon transports in low dimensional
systems super-diffusively, which leads to a size dependent thermal
conductivity. In other words, Fourier's law is breakdown in low dimensional
structures
Top Squarks and Bottom Squarks in the MSSM with Complex Parameters
We present a phenomenological study of top squarks (~t_1,2) and bottom
squarks (~b_1,2) in the Minimal Supersymmetric Standard Model (MSSM) with
complex parameters A_t, A_b, \mu and M_1. In particular we focus on the CP
phase dependence of the branching ratios of (~t_1,2) and (~b_1,2) decays. We
give the formulae of the two-body decay widths and present numerical results.
We find that the effect of the phases on the (~t_1,2) and (~b_1,2) decays can
be quite significant in a large region of the MSSM parameter space. This could
have important implications for (~t_1,2) and (~b_1,2) searches and the MSSM
parameter determination in future collider experiments. We have also estimated
the accuracy expected in the determination of the parameters of ~t_i and ~b_i
by a global fit of the measured masses, decay branching ratios and production
cross sections at e^+ e^- linear colliders with polarized beams. Analysing two
scenarios, we find that the fundamental parameters apart from A_t and A_b can
be determined with errors of 1% to 2%, assuming an integrated luminosity of 1
ab^-1 and a sufficiently large c.m.s. energy to produce also the heavier ~t_2
and ~b_2 states. The parameter A_t can be determined with an error of 2 - 3%,
whereas the error on A_b is likely to be of the order of 50%.Comment: 31 pages, 8 figures, comments and references added, conclusions
unchanged; version to appear in Phys. Rev.
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