4,794 research outputs found

### High density limit of the two-dimensional electron liquid with Rashba spin-orbit coupling

We discuss by analytic means the theory of the high-density limit of the
unpolarized two-dimensional electron liquid in the presence of Rashba or
Dresselhaus spin-orbit coupling. A generalization of the ring-diagram expansion
is performed. We find that in this regime the spin-orbit coupling leads to
small changes of the exchange and correlation energy contributions, while
modifying also, via repopulation of the momentum states, the noninteracting
energy. As a result, the leading corrections to the chirality and total energy
of the system stem from the Hartree-Fock contributions. The final results are
found to be vanishing to lowest order in the spin-orbit coupling, in agreement
with a general property valid to every order in the electron-electron
interaction. We also show that recent quantum Monte Carlo data in the presence
of Rashba spin-orbit coupling are well understood by neglecting corrections to
the exchange-correlation energy, even at low density values.Comment: 11 pages, 5 figure

### Exchange energy and generalized polarization in the presence of spin-orbit coupling in two dimensions

We discuss a general form of the exchange energy for a homogeneous system of
interacting electrons in two spatial dimensions which is particularly suited in
the presence of a generic spin-orbit interaction. The theory is best formulated
in terms of a generalized fractional electronic polarization. Remarkably we
find that a net generalized polarization does not necessarily translate into an
increase in the magnitude of the exchange energy, a fact that in turn favors
unpolarized states. Our results account qualitatively for the findings of
recent experimental investigations

### Correlation energy in a spin polarized two dimensional electron liquid in the high density limit

We have obtained an analytic expression for the ring diagrams contribution to
the correlation energy of a two dimensional electron liquid as a function of
the uniform fractional spin polarization. Our results can be used to improve on
the interpolation formulas which represent the basic ingredient for the
constructions of modern spin-density functionals in two dimensions.Comment: 3 pages, 1 figur

### Two exact properties of the perturbative expansion for the two-dimensional electron liquid with Rashba or Dresselhaus spin-orbit coupling

We have identified two useful exact properties of the perturbative expansion
for the case of a two-dimensional electron liquid with Rashba or Dresselhaus
spin-orbit interaction and in the absence of magnetic field. The results allow
us to draw interesting conclusions regarding the dependence of the exchange and
correlation energy and of the quasiparticle properties on the strength of the
spin-orbit coupling which are valid to all orders in the electron-electron
interaction.Comment: 6 pages, 1 figur

### Fluctuation Relation beyond Linear Response Theory

The Fluctuation Relation (FR) is an asymptotic result on the distribution of
certain observables averaged over time intervals T as T goes to infinity and it
is a generalization of the fluctuation--dissipation theorem to far from
equilibrium systems in a steady state which reduces to the usual Green-Kubo
(GK) relation in the limit of small external non conservative forces. FR is a
theorem for smooth uniformly hyperbolic systems, and it is assumed to be true
in all dissipative ``chaotic enough'' systems in a steady state. In this paper
we develop a theory of finite time corrections to FR, needed to compare the
asymptotic prediction of FR with numerical observations, which necessarily
involve fluctuations of observables averaged over finite time intervals T. We
perform a numerical test of FR in two cases in which non Gaussian fluctuations
are observable while GK does not apply and we get a non trivial verification of
FR that is independent of and different from linear response theory. Our
results are compatible with the theory of finite time corrections to FR, while
FR would be observably violated, well within the precision of our experiments,
if such corrections were neglected.Comment: Version accepted for publication on the Journal of Statistical
Physics; minor changes; two references adde

### On the RKKY range function of a one dimensional non interacting electron gas

We show that the pitfalls encountered in earlier calculations of the RKKY
range function for a non interacting one dimensional electron gas at zero
temperature can be unraveled and successfully dealt with through a proper
handling of the impurity potential.Comment: to appear in Phys. Re

### Fluctuations relation and external thermostats: an application to granular materials

In this note we discuss a paradigmatic example of interacting particles
subject to non conservative external forces and to the action of thermostats
consisting of external (finite) reservoirs of particles. We then consider a
model of granular materials of interest for experimental tests that had
recently attracted lot of attentions. This model can be reduced to the
previously discussed example under a number of assumptions, in particular that
inelasticity due to internal collisions can be neglected for the purpose of
measuring the large deviation functional for entropy production rate. We show
that if the restitution coefficient in the granular material model is close to
one, then the required assuptions are verified on a specific time scale and we
predict a fluctuation relation for the entropy production rate measured on the
same time scale.Comment: 7 pages; updated to take into account comments received on the first
version; to appear on J.Stat.Mech.(2006

### Density-wave phases of dipolar fermions in a bilayer

We investigate the phase diagram of dipolar fermions with aligned dipole
moments in a two-dimensional (2D) bilayer. Using a version of the
Singwi-Tosi-Land-Sjolander scheme recently adapted to dipolar fermions in a
single layer [M. M. Parish and F. M. Marchetti, Phys. Rev. Lett. 108, 145304
(2012)], we determine the density-wave instabilities of the bilayer system
within linear response theory. We find that the bilayer geometry can stabilize
the collapse of the 2D dipolar Fermi gas with intralayer attraction to form a
new density wave phase that has an orientation perpendicular to the density
wave expected for strong intralayer repulsion. We thus obtain a quantum phase
transition between stripe phases that is driven by the interplay between strong
correlations and the architecture of the low dimensional system.Comment: 5 pages, 3 figure

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