51,523 research outputs found
Event-by-event simulation of the Hanbury Brown-Twiss experiment with coherent light
We present a computer simulation model for the Hanbury Brown-Twiss experiment
that is entirely particle-based and reproduces the results of wave theory. The
model is solely based on experimental facts, satisfies Einstein's criterion of
local causality and does not require knowledge of the solution of a wave
equation. The simulation model is fully consistent with earlier work and
provides another demonstration that it is possible to give a particle-only
description of wave phenomena, rendering the concept of wave-particle duality
superfluous.Comment: Submitted to Commmun. Comput. Phy
Finite-temperature charge transport in the one-dimensional Hubbard model
We study the charge conductivity of the one-dimensional repulsive Hubbard
model at finite temperature using the method of dynamical quantum typicality,
focusing at half filling. This numerical approach allows us to obtain current
autocorrelation functions from systems with as many as 18 sites, way beyond the
range of standard exact diagonalization. Our data clearly suggest that the
charge Drude weight vanishes with a power law as a function of system size. The
low-frequency dependence of the conductivity is consistent with a finite dc
value and thus with diffusion, despite large finite-size effects. Furthermore,
we consider the mass-imbalanced Hubbard model for which the charge Drude weight
decays exponentially with system size, as expected for a non-integrable model.
We analyze the conductivity and diffusion constant as a function of the mass
imbalance and we observe that the conductivity of the lighter component
decreases exponentially fast with the mass-imbalance ratio. While in the
extreme limit of immobile heavy particles, the Falicov-Kimball model, there is
an effective Anderson-localization mechanism leading to a vanishing
conductivity of the lighter species, we resolve finite conductivities for an
inverse mass ratio of .Comment: 13 pages, 11 figure
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