1,784 research outputs found
Irreversibility in quantum maps with decoherence
The Bolztmann echo (BE) is a measure of irreversibility and sensitivity to
perturbations for non-isolated systems. Recently, different regimes of this
quantity were described for chaotic systems. There is a perturbative regime
where the BE decays with a rate given by the sum of a term depending on the
accuracy with which the system is time-reversed and a term depending on the
coupling between the system and the environment. In addition, a parameter
independent regime, characterised by the classical Lyapunov exponent, is
expected. In this paper we study the behaviour of the BE in hyperbolic maps
that are in contact with different environments. We analyse the emergence of
the different regimes and show that the behaviour of the decay rate of the BE
is strongly dependent on the type of environment.Comment: 13 pages, 3 figures
Multifractality of quantum wave packets
We study a version of the mathematical Ruijsenaars-Schneider model, and
reinterpret it physically in order to describe the spreading with time of
quantum wave packets in a system where multifractality can be tuned by varying
a parameter. We compare different methods to measure the multifractality of
wave packets, and identify the best one. We find the multifractality to
decrease with time until it reaches an asymptotic limit, different from the
mulifractality of eigenvectors, but related to it, as is the rate of the
decrease. Our results could guide the study of experimental situations where
multifractality is present in quantum systems.Comment: 6 pages, 4 figures, final version including a new figure (figure 1
Semiclassical approach to the work distribution
Work in closed quantum systems is usually defined by a two-point measurement. This definition of work is compatible with quantum fluctuation theorems but it fundamentally differs from its classical counterpart. In this paper, we study the correspondence principle in quantum chaotic systems. We derive a semiclassical expression of the work distribution for chaotic systems undergoing a general, finite time, process. This semiclassical distribution converges to the classical distribution in the usual classical limit. We show numerically that, for a particle inside a chaotic cavity, the semiclassical distribution provides a good approximation to quantum distribution.Fil: Garcia-Mata, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Físicas de Mar del Plata. Universidad Nacional de Mar del Plata. Facultad de Cs.exactas y Naturales. Instituto de Investigaciones Físicas de Mar del Plata; ArgentinaFil: Roncaglia, Augusto Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Wisniacki, Diego Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentin
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