124 research outputs found
Universal theory of nonlinear Luttinger liquids
One-dimensional quantum fluids are conventionally described by using an
effective hydrodynamic approach known as Luttinger liquid theory. As the
principal simplification, a generic spectrum of the constituent particles is
replaced by a linear one, which leads to a linear hydrodynamic theory. We show
that to describe the measurable dynamic response functions one needs to take
into account the nonlinearity of the generic spectrum and thus of the resulting
quantum hydrodynamic theory. This nonlinearity leads, for example, to a
qualitative change in the behavior of the spectral function. The universal
theory developed in this article is applicable to a wide class of
one-dimensional fermionic, bosonic, and spin systems.Comment: final published version with supporting online materia
Pairing of 1D Bose-Fermi mixtures with unequal masses
We have considered one-dimensional Bose-Fermi mixture with equal densities
and unequal masses using numerical density matrix renormalization group (DMRG).
For the mass ratio of K-Rb mixture and attraction between bosons and fermions,
we determined the phase diagram. For weak boson-boson interactions, there is a
direct transition between two-component Luttinger liquid and collapsed phases
as the boson-fermion attraction is increased. For strong enough boson-boson
interactions, we find an intermediate "paired" phase, which is a
single-component Luttinger liquid of composite particles. We investigated
correlation functions of such a "paired" phase, studied the stability of
"paired" phase to density imbalance, and discussed various experimental
techniques which can be used to detect it.Comment: 7 pages, 5 figure
Mapping of Coulomb gases and sine-Gordon models to statistics of random surfaces
We introduce a new class of sine-Gordon models, for which interaction term is
present in a region different from the domain over which quadratic part is
defined. We develop a novel non-perturbative approach for calculating partition
functions of such models, which relies on mapping them to statistical
properties of random surfaces. As a specific application of our method, we
consider the problem of calculating the amplitude of interference fringes in
experiments with two independent low dimensional Bose gases. We calculate full
distribution functions of interference amplitude for 1D and 2D gases with
nonzero temperatures.Comment: final published versio
The fate of 1D spin-charge separation away from Fermi points
We consider the dynamic response functions of interacting one dimensional
spin-1/2 fermions at arbitrary momenta. We build a non-perturbative
zero-temperature theory of the threshold singularities using mobile impurity
Hamiltonians. The interaction induced low-energy spin-charge separation and
power-law threshold singularities survive away from Fermi points. We express
the threshold exponents in terms of the spinon spectrum.Comment: 5 pages, 1 figur
A Possibility to Observe Short-Range NN Properties in the Deuteron Breakup
Quasi-binary reaction of the deuteron breakup with the final
proton-proton pair in the
state is analyzed at initial energies GeV in the kinematics
of backward elastic pd-scattering . On the basis of the main
mechanisms of the process, including initial and final state
interaction, we show that unpolarized cross section and spin observables of
this reaction exhibit important properties of the half-off-shell
-scattering amplitude, which are relevant to the nucleon-nucleon
interaction at short distances.Comment: 9 pages, Latex, 3 Postscript figure
On contribution of three-body forces to interaction at intermediate energies
Available data on large-angle nucleon-deuteron elastic scattering
below the pion threshold give a signal for three-body forces. There is a
problem of separation of possible subtle aspects of these forces from off-shell
effects in two-nucleon potentials.
By considering the main mechanisms of the process, we show qualitatively that
in the quasi-binary reaction with the final spin singlet
NN-pair in the S-state the relative contribution of the 3N forces differs
substantially from the elastic channel.
It gives a new testing ground for the problem in question.Comment: 9 pages, Latex, 3 Postscript figure
Phenomenology of One-Dimensional Quantum Liquids Beyond the Low-Energy Limit
We consider zero temperature behavior of dynamic response functions of 1D
systems near edges of support in momentum-energy plane The
description of the singularities of dynamic response functions near an edge
is given by the effective Hamiltonian of a mobile impurity moving
in a Luttinger liquid. For Galilean-invariant systems, we relate the parameters
of such an effective Hamiltonian to the properties of the function This allows us to express the exponents which characterize singular
response functions of spinless bosonic or fermionic liquids in terms of
and Luttinger liquid parameters for any For an
antiferromagnetic Heisenberg spin-1/2 chain in a zero magnetic field, SU(2)
invariance fixes the exponents from purely phenomenological considerations.Comment: final published versio
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