6,578 research outputs found
Thermalization of acoustic excitations in a strongly interacting one-dimensional quantum liquid
We study inelastic decay of bosonic excitations in a Luttinger liquid. In a
model with linear excitation spectrum the decay rate diverges. We show that
this difficulty is resolved when the interaction between constituent particles
is strong, and the excitation spectrum is nonlinear. Although at low energies
the nonlinearity is weak, it regularizes the divergence in the decay rate. We
develop a theoretical description of the approach of the system to thermal
equilibrium. The typical relaxation rate scales as the fifth power of
temperature
Scattering of hole excitations in a one-dimensional spinless quantum liquid
Luttinger liquid theory accounts for the low energy boson excitations of
one-dimensional quantum liquids, but disregards the high energy excitations.
The most important high energy excitations are holes which have infinite
lifetime at zero temperature. At finite temperatures they can be scattered by
thermally excited bosons. We describe the interaction of the hole with the
bosons by treating it as a mobile impurity in a Luttinger liquid. This approach
enables us to evaluate the scattering probability at arbitrary interaction
strength. In general, the result is expressed in terms of the hole spectrum,
its dependence on the density and momentum of the fluid, and the parameters of
the Luttinger liquid Hamiltonian. In the special case of Galilean invariant
systems the scattering probability is expressed in terms of only the hole
spectrum and its dependence on the fluid density. We apply our results to the
problem of equilibration of one-dimensional quantum liquids
Some Properties of the Calogero-Sutherland Model with Reflections
We prove that the Calogero-Sutherland Model with reflections (the BC_N model)
possesses a property of duality relating the eigenfunctions of two Hamiltonians
with different coupling constants. We obtain a generating function for their
polynomial eigenfunctions, the generalized Jacobi polynomials. The symmetry of
the wave-functions for certain particular cases (associated to the root systems
of the classical Lie groups B_N, C_N and D_N) is also discussed.Comment: 16 pages, harvmac.te
Long Range Interaction Models and Yangian Symmetry
The generalized Sutherland-Romer models and Yan models with internal spin
degrees are formulated in terms of the Polychronakos' approach and RTT relation
associated to the Yang-Baxter equation in consistent way. The Yangian symmetry
is shown to generate both models. We finally introduce the reflection algebra
K(u) to the long range models.Comment: 13 pages, preprint of Nankai Institute of Mathematics ( Theoretical
Physics Division ), published in Physical Review E of 1995. For hard copy,
write to Prof. Mo-lin GE directly. Do not send emails to this accoun
Fermi Surface Reconstruction in CeRhCoIn
The evolution of the Fermi surface of CeRhCoIn was studied as
a function of Co concentration via measurements of the de Haas-van Alphen
effect. By measuring the angular dependence of quantum oscillation frequencies,
we identify a Fermi surface sheet with -electron character which undergoes
an abrupt change in topology as is varied. Surprisingly, this
reconstruction does not occur at the quantum critical concentration ,
where antiferromagnetism is suppressed to T=0. Instead we establish that this
sudden change occurs well below , at the concentration x ~ 0.4 where long
range magnetic order alters its character and superconductivity appears. Across
all concentrations, the cyclotron effective mass of this sheet does not
diverge, suggesting that critical behavior is not exhibited equally on all
parts of the Fermi surface.Comment: 4 pages, 4 figure
Taxonomy of particles in Ising spin chains
The statistical mechanics of particles with shapes on a one-dimensional
lattice is investigated in the context of the Ising chain with uniform
nearest-neighbor coupling, quadratic single-site potential, and magnetic field,
which supports four distinct ground states:
, ,
, . The complete
spectrum is generated from each ground state by particles from a different set
of six or seven species. Particles and elements of pseudo-vacuum are
characterized by motifs (patterns of several consecutive site variables).
Particles are floating objects that can be placed into open slots on the
lattice. Open slots are recognized as permissible links between motifs. The
energy of a particle varies between species but is independent of where it is
placed. Placement of one particle changes the open-slot configuration for
particles of all species. This statistical interaction is encoded in a
generalized Pauli principle, from which the multiplicity of states for a given
particle combination is determined and used for the exact statistical
mechanical analysis. Particles from all species belong to one of four
categories: compacts, hosts, tags, or hybrids. Compacts and hosts find open
slots in segments of pseudo-vacuum. Tags find open slots inside hosts. Hybrids
are tags with hosting capability. In the taxonomy of particles proposed here,
`species' is indicative of structure and `category' indicative of function. The
hosting function splits the Pauli principle into exclusion and accommodation
parts. Near phase boundaries, the state of the Ising chain at low temperature
is akin to that of miscible or immiscible liquids with particles from one
species acting as surfactant molecules.Comment: 12 pages, 6 tables, 6 figure
Discovery of Extreme Examples of Superclustering in Aquarius
We report the discovery of two highly extended filaments and one extremely
high density knot within the region of Aquarius. The supercluster candidates
were chosen via percolation analysis of the Abell and ACO catalogs and include
only the richest clusters (R >= 1). The region examined is a 10x45 degree strip
and is now 87% complete in cluster redshift measurements to mag_10 = 18.3. In
all, we report 737 galaxy redshifts in 46 cluster fields. One of the
superclusters, dubbed Aquarius, is comprised of 14 Abell/ACO clusters and
extends 110h^-1Mpc in length only 7 degrees off the line-of-sight. On the
near-end of the Aquarius filament, another supercluster, dubbed Aquarius-Cetus,
extends for 75h^-1Mpc perpendicular to the line-of-sight. After fitting
ellipsoids to both Aquarius and Aquarius-Cetus, we find axis ratios (long-to-
midlength axis) of 4.3 for Aquarius and 3.0 for Aquarius-Cetus. We fit
ellipsoids to all N>=5 clumps of clusters in the Abell/ACO measured-z cluster
sample. The frequency of filaments with axis ratios >=3.0 (~20%) is nearly
identical with that found among `superclusters' in Monte Carlo simulations of
random and random- clumped clusters, however, so the rich Abell/ACO clusters
have no particular tendency toward filamentation. The Aquarius filament also
contains a `knot' of 6 clusters at Z ~0.11, with five of the clusters near
enough togeteher to represent an apparent overdensity of 150. There are
three other R >= 1 cluster density enhancements similar to this knot at lower
redshifts: Corona Borealis, the Shapely Concentration, and another grouping of
seven clusters in Microscopium. All four of these dense superclusters appear
near the point of breaking away from the Hubble Flow, and some may now be in
collapse, but there is little evidence of any being virialized.Comment: 45 pages (+ e-tables), 7 figures, AASTeX Accepted for Publication in
Ap
Coherently Controlled Nanoscale Molecular Deposition
Quantum interference effects are shown to provide a means of controlling and
enhancing the focusing a collimated neutral molecular beam onto a surface. The
nature of the aperiodic pattern formed can be altered by varying laser field
characteristics and the system geometry.Comment: 13 pages (inculding 4 figures), LaTeX (Phys. Rev. Lett., 2000, in
Press
Exact Solution of Heisenberg-liquid models with long-range coupling
We present the exact solution of two Heisenberg-liquid models of particles
with arbitrary spin interacting via a hyperbolic long-range potential. In
one model the spin-spin coupling has the simple antiferromagnetic Heisenberg
exchange form, while for the other model the interaction is of the
ferromagnetic Babujian-Takhatajan type. It is found that the Bethe ansatz
equations of these models have a similar structure to that of the
Babujian-Takhatajan spin chain. We also conjecture the integrability of a third
new spin-lattice model with long-range interaction.Comment: 7pages Revte
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