8,807 research outputs found
Spectral edge mode in interacting one-dimensional systems
A continuum of excitations in interacting one-dimensional systems is bounded
from below by a spectral edge that marks the lowest possible excitation energy
for a given momentum. We analyse short-range interactions between Fermi
particles and between Bose particles (with and without spin) using Bethe-Ansatz
techniques and find that the dispersions of the corresponding spectral edge
modes are close to a parabola in all cases. Based on this emergent phenomenon
we propose an empirical model of a free, non-relativistic particle with an
effective mass identified at low energies as the bare electron mass
renormalised by the dimensionless Luttinger parameter (or for
particles with spin).
The relevance of the Luttinger parameters beyond the low energy limit
provides a more robust method for extracting them experimentally using a much
wide range of data from the bottom of the one-dimensional band to the Fermi
energy. The empirical model of the spectral edge mode complements the mobile
impurity model to give a description of the excitations in proximity of the
edge at arbitrary momenta in terms of only the low energy parameters and the
bare electron mass. Within such a framework, for example, exponents of the
spectral function are expressed explicitly in terms of only a few Luttinger
parameters.Comment: 11 pages, 7 figure
Luttinger parameters of interacting fermions in 1D at high energies
Interactions between electrons in one-dimension are fully described at low
energies by only a few parameters of the Tomonaga-Luttinger model which is
based on linearisation of the spectrum. We consider a model of spinless
fermions with a short range interaction via the Bethe-Ansatz technique and show
that a Luttinger parameter emerges in an observable beyond the low energy
limit. A distinct feature of the spectral function, the edge that marks the
lowest possible excitation energy for a given momentum, is parabolic for
arbitrary momenta and the prefactor is a function of the Luttinger parameter,
K.Comment: 7 pages, 4 figure
Small-angle scattering in a marginal Fermi-liquid
We study the magnetotransport properties of a model of small-angle scattering
in a marginal Fermi liquid. Such a model has been proposed by Varma and
Abrahams [Phys. Rev. Lett. 86, 4652 (2001)] to account for the anomalous
temperature dependence of in-plane magnetotransport properties of the high-Tc
cuprates. We study the resistivity, Hall angle and magnetoresistance using both
analytical and numerical techniques. We find that small-angle scattering only
generates a new temperature dependence for the Hall angle near particle-hole
symmetric Fermi surfaces where the conventional Hall term vanishes. The
magnetoresistance always shows Kohler's rule behavior.Comment: 4 pages, 3 figures, Revtex
Phase diagram and quasiparticle properties of the Hubbard model within cluster two-site DMFT
We present a cluster dynamical mean-field treatment of the Hubbard model on a
square lattice to study the evolution of magnetism and quasiparticle properties
as the electron filling and interaction strength are varied. Our approach for
solving the dynamical mean-field equations is an extension of Potthoff's
"two-site" method [Phys. Rev. B. 64, 165114 (2001)] where the self-consistent
bath is represented by a highly restricted set of states. As well as the
expected antiferromagnetism close to half filling, we observe distortions of
the Fermi surface. The proximity of a van Hove point and the incipient
antiferromagnetism lead to the evolution from an electron-like Fermi surface
away from the Mott transition, to a hole-like one near half-filling. Our
results also show a gap opening anisotropically around the Fermi surface close
to the Mott transition (reminiscent of the pseudogap phenomenon seen in the
cuprate high-Tc superconductors). This leaves Fermi arcs which are closed into
pockets by lines with very small quasiparticle residue.Comment: 10 pages, 8 figures, latex (revtex4
Phenomenological Transport Equation for the Cuprate Metals
We observe that the appearance of two transport relaxation times in the
various transport coefficients of cuprate metals may be understood in terms of
scattering processes that discriminate between currents that are even, or odd
under the charge conjugation operator. We develop a transport equation that
illustrates these ideas and discuss its experimental and theoretical
consequences.Comment: Replaced with journal ref. Latex+ p
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