INVESTIGADORES
PASTAWSKI Horacio Miguel
artículos
Título:
Loschmidt echo as a robust decoherence quantifier for many-body systems
Autor/es:
PABLO ZANGARA; AXEL D. DENTE; P. R. LEVSTEIN; HORACIO M. PASTAWSKI
Revista:
PHYSICAL REVIEW A - ATOMIC, MOLECULAR AND OPTICAL PHYSICS
Editorial:
AMER PHYSICAL SOC
Referencias:
Lugar: New York; Año: 2012 vol. 86 p. 12322 - 12322
ISSN:
1050-2947
Resumen:
PHYSICAL
REVIEW A 86, 012322 (2012)
Loschmidt
echo as a robust decoherence quantifier for many-body systems
Pablo R. Zangara, Axel D. Dente, Patricia R. Levstein, and
Horacio M. Pastawski*
We employ
the Loschmidt echo, i.e., the signal recovered after the reversal of an
evolution, to identify and quantify the processes contributing to decoherence. This
procedure, which has been extensively used in single-particle physics, is employed
here in a spin ladder. The isolated chains have 1/2 spins with XY interaction and
their excitations would sustain a one-body-like propagation. One of them
constitutes the controlled system S whose reversible dynamics is degraded by
the weak coupling with the uncontrolled second chain, i.e., the environment E.
The perturbative SE coupling is swept through arbitrary combinations of XY and
Ising-like interactions, that contain the standard Heisenberg and dipolar ones.
Different time regimes are identified for the
Loschmidt echo dynamics in this perturbative configuration. In particular, the
exponential decay scales as a Fermi golden rule, where the contributions of the
different SE terms are individually evaluated and analyzed. Comparisons with
previous analytical and numerical evaluations of decoherence based on the
attenuation of specific interferences show that the Loschmidt echo is an
advantageous decoherence quantifier at any time, regardless of the S internal
dynamics.
DOI: 10.1103/PhysRevA.86.012322