(Poster) Time-reversal mirror for quantum systems

HERNAN L. CALVO; HORACIO M. PASTAWSKI

Trieste

Otro; Summer School on Novel Quantum Phases and Non-equilibrium Phenomena in Cold Atomic Gases; 2007

The Abdus Salam International Centre for Theoretical Physics

Refocusing of ultrasonic waves in heterogeneous media is made possible by the time-reversal mirror procedure developed experimentally by M. Fink: the propagation of a wave excitation generated by a local source is detected and recorded by a set of transducers that surrounds the control region (a closed cavity). Once the whole excitation escapes, all the registries are played back in the inverted time sequence and the wave propagates backwards until a form of the Loschmidt echo that appears at the source. The robustness of this technique against inhomogeneities allows many applications in medical physics, oceanography and telecommunications. In order to apply these concepts in a quantum system, we introduce a formal prescription to obtain perfect focusing called the perfect inverse filter. This last corrects the signals to be played-back by accounting for the correlations imposed by the system and could be used also in chains of classical coupled oscillators. We discuss the basics of these novel concepts and its implementation for a "quantum bazooka".