- Conference date: 20–23 September 2010
- Location: Umhlanga, South Africa
Decoherence indicates the process that a quantum system undergoes through the interaction with its external environment. A two-level system (qubit) interacting with Lorentzian type continuous distributions of field modes, according to the Jaynes-Cummings model, provides exponential like relaxations of the reduced density matrix. In this scenario, a special class of reservoirs is designed in order to control or delay the destructive effect of the environment on qubit coherence. In this way, decoherence processes slower than the usual exponential ones are obtained: over estimated long time scales, inverse power law relaxations reveal with powers decreasing continuously to unity according to the choice of the particular reservoir. The designed reservoirs exhibit a photonic band gap coinciding with the qubit transition frequency and are piecewise similar to those usually adopted in Quantum Optics, i.e., sub-ohmic at low frequencies and inverse power laws at high frequencies. Initially, the reservoir is assumed to be in the vacuum state and is unentangled from the qubit versing in a generic state. The exact dynamics results to be described by series of Fox H-functions. The simple form of the designed reservoir can be accessible experimentally.
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