2,276 research outputs found
The long delayed solution of the Bukhvostov Lipatov model
In this paper I complete the solution of the Bukhvostov Lipatov model by
computing the physical excitations and their factorized S matrix. I also
explain the paradoxes which led in recent years to the suspicion that the model
may not be integrable.Comment: 9 page
Boundary interactions changing operators and dynamical correlations in quantum impurity problems
Recent developments have made possible the computation of equilibrium
dynamical correlators in quantum impurity problems. In many situations however,
one is rather interested in correlators subject to a non equilibrium initial
preparation; this is the case for instance for the occupation probability
in the double well problem of dissipative quantum mechanics (DQM). We
show in this paper how to handle this situation in the framework of integrable
quantum field theories by introducing ``boundary interactions changing
operators''. We determine the properties of these operators by using an
axiomatic approach similar in spirit to what is done for form-factors. This
allows us to obtain new exact results for ; for instance, we find that
that at large times (or small ), the leading behaviour for g < 1/2} is
, with the universal ratio.
.Comment: 4 pages, revte
Exact Friedel oscillations in the g=1/2 Luttinger liquid
A single impurity in the 1D Luttinger model creates a local modification of
the charge density analogous to the Friedel oscillations. In this paper, we
present an exact solution of the case (the equivalent of the
Toulouse point) at any temperature and impurity coupling, expressing the
charge density in terms of a hypergeometric function. We find in particular
that at , the oscillatory part of the density goes as at small
distance and at large distance.Comment: 1 reference added. 13 pages, harvma
Green Function of the Sutherland Model with SU(2) internal symmetry
We obtain the hole propagator of the Sutherland model with SU(2) internal
symmetry for coupling parameter , which is the simplest nontrivial
case. One created hole with spin down breaks into two quasiholes with spin down
and one quasihole with spin up. While these elementary excitations are
energetically free, the form factor reflects their anyonic character. The
expression for arbitrary integer is conjectured.Comment: 13pages, Revtex, one ps figur
Single-particle Green's functions of the Calogero-Sutherland model at couplings \lambda = 1/2, 1, and 2
At coupling strengths lambda = 1/2, 1, or 2, the Calogero-Sutherland model
(CSM) is related to Brownian motion in a Wigner-Dyson random matrix ensemble
with orthogonal, unitary, or symplectic symmetry. Using this relation in
conjunction with superanalytic techniques developed in mesoscopic conductor
physics, we derive an exact integral representation for the CSM two-particle
Green's function in the thermodynamic limit. Simple closed expressions for the
single-particle Green's functions are extracted by separation of points. For
the advanced part, where a particle is added to the ground state and later
removed, a sum of two contributions is found: the expected one with just one
particle excitation present, plus an extra term arising from fractionalization
of the single particle into a number of elementary particle and hole
excitations.Comment: 19 REVTeX page
MASCARA-2 b: A hot Jupiter transiting the A-star HD185603
In this paper we present MASCARA-2 b, a hot Jupiter transiting the
A2 star HD 185603. Since early 2015, MASCARA has taken more than 1.6 million
flux measurements of the star, corresponding to a total of almost 3000 hours of
observations, revealing a periodic dimming in the flux with a depth of .
Photometric follow-up observations were performed with the NITES and IAC80
telescopes and spectroscopic measurements were obtained with the Hertzsprung
SONG telescope. We find MASCARA-2 b orbits HD 185603 with a period of
at a distance of , has a radius of and place a
upper limit on the mass of . HD 185603 is a
rapidly rotating early-type star with an effective temperature of
and a mass and radius of
, , respectively. Contrary
to most other hot Jupiters transiting early-type stars, the projected planet
orbital axis and stellar spin axis are found to be aligned with . The brightness of the host star and the high equilibrium
temperature, , of MASCARA-2 b make it a suitable target for
atmospheric studies from the ground and space. Of particular interest is the
detection of TiO, which has recently been detected in the similarly hot planets
WASP-33 b and WASP-19 b.Comment: 8 pages, 4 figures, Accepted for publication in A&
Scaling and universality in the anisotropic Kondo model and the dissipative two-state system
Scaling and universality in the Ohmic two-state system is investigated by
exploiting the equivalence of this model to the anisotropic Kondo model. For
the Ohmic two-state system, we find universal scaling functions for the
specific heat, , static susceptibility, , and
spin relaxation function depending on the reduced
temperature (frequency ), with
the renormalized tunneling frequency, and uniquely specified by the dissipation
strength (). The scaling functions can be used to extract
and in experimental realizations.Comment: 5 pages (LaTeX), 4 EPS figures. Minor changes, typos corrected,
journal reference adde
An exactly solvable three-particle problem with three-body interaction
The energy spectrum of the three-particle Hamiltonian obtained by replacing
the two-body trigonometric potential of the Sutherland problem by a three-body
one of a similar form is derived. When expressed in appropriate variables, the
corresponding wave functions are shown to be expressible in terms of Jack
polynomials. The exact solvability of the problem with three-body interaction
is explained by a hidden sl(3,\R) symmetry.Comment: LaTeX, 15 pages, no figures, slightly shortened version to appear in
Phys. Rev. A, one error correcte
Haldane Gapped Spin Chains: Exact Low Temperature Expansions of Correlation Functions
We study both the static and dynamic properties of gapped, one-dimensional,
Heisenberg, anti-ferromagnetic, spin chains at finite temperature through an
analysis of the O(3) non-linear sigma model. Exploiting the integrability of
this theory, we are able to compute an exact low temperature expansion of the
finite temperature correlators. We do so using a truncated `form-factor'
expansion and so provide evidence that this technique can be successfully
extended to finite temperature. As a direct test, we compute the static
zero-field susceptibility and obtain an exact match to the susceptibility
derived from the low temperature expansion of the exact free energy. We also
study transport properties, computing both the spin conductance and the
NMR-relaxation rate, 1/T_1. We find these quantities to show ballistic
behaviour. In particular, the computed spin conductance exhibits a non-zero
Drude weight at finite temperature and zero applied field. The physics thus
described differs from the spin diffusion reported by Takigawa et al. from
experiments on the Haldane gap material, AgVP_2S_6.Comment: 51 pages, 5 figure
- …