IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Time reversal focusing as a novel Loschmidt echo procedure in wave dynamics
Autor/es:
HERNAN L. CALVO; RODOLFO A. JALABERT; HORACIO M. PASTAWSKI
Lugar:
Trieste, Italia
Reunión:
Workshop; Workshop on Pseudochaos and Stable-Chaos in Statistical Mechanics and Quantum Physics; 2009
Institución organizadora:
Abdus Salam International Centre for Theoretical Physics
Resumen:
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The
focalization of acoustic waves through the time reversal mirror technique in
a non-homogeneous medium was an experimental deed showing that an initially
localized pulse can be accurately reconstructed by an array of receiver-emitter
transducers that re-inject the recorded signal. These experiments provoked a
natural surprise while yielding reconstructions, that albeit not perfect, were
highly faithful. In this time-reversal focusing (TRF)
procedure the play back signal builds up in the region of the original
excitation, in the form of a reversed wave amplitude and can be viewed as the
wave version of the Loschmidt echo. A salient feature of the TRF
experiments is that the refocusing improves when the wave-propagation occurs in
a disordered medium or in a chaotic cavity, as compared with the homogeneous or
integrable case. In this work we develop a semiclassical theory of the TRF
in order to explain this robustness and the role played by chaos. Considering
the ergodic properties in the cavities, we propose different models for the
perturbation and analyze those regimes where the focusing takes place. Finally,
we compare the obtained analytical results with numerical simulations.