455 research outputs found
A Composite Fermion Approach to the Ultracold Dilute Fermi Gas
It is argued that the recently observed Fermi liquids in strongly interacting
ultracold Fermi gases are adiabatically connected to a projected Fermi gas.
This conclusion is reached by constructing a set of Jastrow wavefunctions,
following Tan's observations on the structure of the physical Hilbert space
[Annals of Physics 323, 2952 (2008)]. The Jastrow projection merely implements
the Bethe-Peierls condition on the BCS and Fermi gas wavefunctions. This
procedure provides a simple picture of the emergence of Fermi polarons as
composite fermions in the normal state of the highly polarized gas. It is also
shown that the projected BCS wavefunction can be written as a condensate of
pairs of composite fermions (or Fermi polarons). A Hamiltonian for the
composite fermions is derived. Within a mean-field theory, it is shown that the
ground state and excitations of this Hamiltonian are those of a non-interacting
Fermi gas although they are described by Jastrow-Slater wavefunctions.Comment: 9 pages, no figure
Low-Energy Properties of a One-dimensional System of Interacting bosons with Boundaries
The ground state properties and low-lying excitations of a (quasi)
one-dimensional system of longitudinally confined interacting bosons are
studied. This is achieved by extending Haldane's harmonic-fluid description to
open boundary conditions. The boson density, one-particle density matrix, and
momentum distribution are obtained accounting for finite-size and boundary
effects. Friedel oscillations are found in the density. Finite-size scaling of
the momentum distribution at zero momentum is proposed as a method to obtain
from the experiment the exponent that governs phase correlations. The strong
correlations between bosons induced by reduced dimensionality and interactions
are displayed by a Bijl-Jastrow wave function for the ground state, which is
also derived.Comment: Final published version. Minor changes with respect to the previous
versio
Quantum quench dynamics of the Luttinger model
The dynamics of the Luttinger model after a quantum quench is studied. We
compute in detail one and two-point correlation functions for two types of
quenches: from a non-interacting to an interacting Luttinger model and
vice-versa. In the former case, the non-interacting Fermi gas features in the
momentum distribution and other correlation functions are destroyed as time
evolves. In the infinite-time limit, equal-time correlations are power-laws but
the critical exponents are found to differ from their equilibrium values. In
all cases, we find that these correlations are well described by a generalized
Gibbs ensemble [M. Rigol et al., Phys. Rev. Lett. 98, 050405 (2007)], which
assigns a momentum dependent temperature to each eigenmode.Comment: 16 pages, 3 figure
Spin-charge conversion in disordered two-dimensional electron gases lacking inversion symmetry
We study the spin-charge conversion mechanisms in a two-dimensional gas of
electrons moving in a smooth disorder potential by accounting for both
Rashba-type and Mott's skew scattering contributions. We find that quantum
interference effects between spin-flip and skew scattering give rise to
anisotropic spin precession scattering (ASP), a direct spin-charge conversion
mechanism that was discovered in an earlier study of graphene decorated with
adatoms [C. Huang \emph{et al.} Phys.~Rev.~B \textbf{94} 085414.~(2016)]. Our
findings suggest that, together with other spin-charge conversion mechanisms
such as the inverse galvanic effect, ASP is a fairly universal phenomenon that
should be present in disordered two-dimensional systems lacking inversion
symmetry.Comment: 9 pages, 2 figure
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