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arXiv · 0903.0021

Master Equation and Control of an Open Quantum System with Leakage

Lian-Ao Wu·Gershon Kurizki·Paul Brumer
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Abstract

Given a multilevel system coupled to a bath, we use a Feshbach P,Q partitioning technique to derive an exact trace-nonpreserving master equation for a subspace $\mathcal{S}_{i}$ of the system. The resultant equation properly treats the leakage effect from $\mathcal{S}_{i}$ into the remainder of the system space. Focusing on a second-order approximation, we show that a one-dimensional master equation is sufficient to study problems of quantum state storage and is a good approximation, or exact, for several analytical models. It allows a natural definition of a leakage function and its control, and provides a general approach to study and control decoherence and leakage. Numerical calculations on an harmonic oscillator coupled to a room temperature harmonic bath show that the leakage can be suppressed by the pulse control technique without requiring ideal pulses.

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Lian-Ao Wu, Gershon Kurizki, Paul Brumer. 2009-02-27. Master Equation and Control of an Open Quantum System with Leakage. https://doi.org/10.1103/physrevlett.102.080405

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