Stochastic processes in classical and quantum systems

Sergio A Albeverio, Giulio Casati, D. Merlini

Qi Yu, Daoyi Dong, Ian R. Petersen +1 more

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.

C. V. Heer

Diego Campos, Narasimha Reddy Gosala, Arundhati Dasgupta

We suggest that quantum algorithms can be used to model classical stochastic simulations as the measurement process is inherently random. To illustrate, we solve the classical Lorenz system with stochastic behavior using a Python random number generator. We compare the classical stochasticity of the Lorenz system with the measured output of the system obtained using quantum algorithms.

Qi Yu, Daoyi Dong, Ian R. Petersen +2 more

We present filtering equations for a class of hybrid quantum-classical systems where a quantum optical cavity system is continuously disturbed by a classical linear stochastic process. Another quantum cavity system is employed to describe the classical stochastic process as an analog. The initial hybrid quantum-classical system consisting of both a classical signal and a quantum cavity system is then modeled by a combined quantum system with two quantum cavity systems. The stochastic master equations, or filtering equations, are then derived using quantum filtering theory. A quantum extended Kalman filter method is adopted as a convenient solution to this filtering problem. The effectiveness of both methods is illustrated by numerical examples.

Sergio A Albeverio, Ph. Combe, M. Sirugue-Collin