8,265 research outputs found
Brownian scattering of a spinon in a Luttinger liquid
We consider strongly interacting one-dimensional electron liquids where
elementary excitations carry either spin or charge. At small temperatures a
spinon created at the bottom of its band scatters off low-energy spin- and
charge-excitations and follows the diffusive motion of a Brownian particle in
momentum space. We calculate the mobility characterizing these processes, and
show that the resulting diffusion coefficient of the spinon is parametrically
enhanced at low temperatures compared to that of a mobile impurity in a
spinless Luttinger liquid. We briefly discuss that this hints at the relevance
of spin in the process of equilibration of strongly interacting one-dimensional
electrons, and comment on implications for transport in clean single channel
quantum wires
Incoherent pair tunneling in the pseudogap phase of cuprates
Motivated by a recent experiment by Bergeal et al., we reconsider incoherent
pair tunneling in a cuprate junction formed from an optimally doped
superconducting lead and an underdoped normal metallic lead. We study the
impact of the pseudogap on the pair tunneling by describing fermions in the
underdoped lead with a model self-energy that has been developed to reproduce
photoemission data. We find that the pseudogap causes an additional temperature
dependent suppression of the pair contribution to the tunneling current. We
discuss consistency with available experimental data and propose future
experimental directions.Comment: 5 pages, 3 figure
Magnetic penetration depth in disordered iron-based superconductors
We study the effect of disorder on the London penetration depth in iron-based
superconductors. The theory is based on a two-band model with
quasi-two-dimensional Fermi surfaces, which allows for the coexistence region
in the phase diagram between magnetic and superconducting states in the
presence of intraband and interband scattering. Within the quasiclassical
approximation we derive and solve Eilenberger's equations, which include a weak
external magnetic field, and provide analytical expressions for the penetration
depth in the various limiting cases. A complete numerical analysis of the
doping and temperature dependence of the London penetration depth reveals the
crucial effect of disorder scattering, which is especially pronounced in the
coexistence phase. The experimental implications of our results are discussed.Comment: 10 pages, 6 figure
Interaction-induced backscattering in short quantum wires
We study interaction-induced backscattering in clean quantum wires with
adiabatic contacts exposed to a voltage bias. Particle backscattering relaxes
such systems to a fully equilibrated steady state only on length scales
exponentially large in the ratio of bandwidth of excitations and temperature.
Here we focus on shorter wires in which full equilibration is not accomplished.
Signatures of relaxation then are due to backscattering of hole excitations
close to the band bottom which perform a diffusive motion in momentum space
while scattering from excitations at the Fermi level. This is reminiscent to
the first passage problem of a Brownian particle and, regardless of the
interaction strength, can be described by an inhomogeneous Fokker-Planck
equation. From general solutions of the latter we calculate the hole
backscattering rate for different wire lengths and discuss the resulting length
dependence of interaction-induced correction to the conductance of a clean
single channel quantum wire.Comment: 10 pages, 4 figure
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