Decoherence in composite quantum open systems: the effectiveness of chaotic degrees of freedom

FERNANDO C. LOMBARDO & PAULA I. VILLAR

INTERNATIONAL JOURNAL OF MODERN PHYSICS B

World Scientific Publishing Company

Lugar: Singapure; Año: 2006 vol. 20 p. 2951 - 2976

0217-9792

The effect induced by an environment on a composite quantum system is studied. The model considers the composite system as comprised by a subsystem A coupled to a subsystem B which is also coupled to an external environment. We studied all possible four combinations of subsystems A and B made up with a harmonic oscillator and an upside down oscillator. We analyzed the decoherence suffered by subsystem A due to an effective environment composed by subsystem B and the external reservoir. In all the cases we found that subsystem A decoheres even though it interacts with the environment only through its sole coupling to B. However, the effectiveness of the diffusion depends on the unstable nature of subsystem A and B. Therefore, the role of this degree of freedom in the effective environment is analyzed in detail.