Hybrid Filtering for a Class of Quantum Systems with Classical Disturbances
This work provides a method for estimating classical disturbances in quantum systems, which is relevant for quantum control applications, but the approach is incremental as it combines existing techniques.
The paper addresses filtering for quantum systems with classical disturbances by modeling the disturbance as a quantum cavity and using quantum filtering and extended Kalman filter methods to estimate the combined quantum-classical system, with numerical results demonstrating effectiveness.
A filtering problem for a class of quantum systems disturbed by a classical stochastic process is investigated in this paper. The classical disturbance process, which is assumed to be described by a linear stochastic differential equation, is modeled by a quantum cavity model. Then the hybrid quantum-classical system is described by a combined quantum system consisting of two quantum cavity subsystems. Quantum filtering theory and a quantum extended Kalman filter method are employed to estimate the states of the combined quantum system. An estimate of the classical stochastic process is derived from the estimate of the combined quantum system. The effectiveness and performance of the proposed methods are illustrated by numerical results.