5,997 research outputs found
Guaranteed Non-quadratic Performance for Quantum Systems with Nonlinear Uncertainties
This paper presents a robust performance analysis result for a class of
uncertain quantum systems containing sector bounded nonlinearities arising from
perturbations to the system Hamiltonian. An LMI condition is given for
calculating a guaranteed upper bound on a non-quadratic cost function. This
result is illustrated with an example involving a Josephson junction in an
electromagnetic cavity.Comment: A version of this paper is to appear in the Proceedings of the 2014
American Control Conferenc
Coherent-Classical Estimation for Quantum Linear Systems
This paper introduces a problem of coherent-classical estimation for a class
of linear quantum systems. In this problem, the estimator is a mixed
quantum-classical system which produces a classical estimate of a system
variable. The coherent-classical estimator may also involve coherent feedback.
An example involving optical squeezers is given to illustrate the efficacy of
this idea.Comment: A version of this paper will appear in the Proceedings of the 2013
Australian Control Conferenc
A Robust Continuous Time Fixed Lag Smoother for Nonlinear Uncertain Systems
This paper presents a robust fixed lag smoother for a class of nonlinear
uncertain systems. A unified scheme, which combines a nonlinear robust
estimator with a stable fixed lag smoother, is presented to improve the error
covariance of the estimation. The robust fixed lag smoother is based on the use
of Integral Quadratic Constraints and minimax LQG control. The state estimator
uses a copy of the system nonlinearity in the estimator and combines an
approximate model of the delayed states to produce a smoothed signal. In order
to see the effectiveness of the method, it is applied to a quantum optical
phase estimation problem. Results show significant improvement in the error
covariance of the estimator using fixed lag smoother in the presence of
nonlinear uncertainty.Comment: 8 pages, will be presented in 52nd Conference on Decision and Contro
Quantum control theory and applications: A survey
This paper presents a survey on quantum control theory and applications from
a control systems perspective. Some of the basic concepts and main developments
(including open-loop control and closed-loop control) in quantum control theory
are reviewed. In the area of open-loop quantum control, the paper surveys the
notion of controllability for quantum systems and presents several control
design strategies including optimal control, Lyapunov-based methodologies,
variable structure control and quantum incoherent control. In the area of
closed-loop quantum control, the paper reviews closed-loop learning control and
several important issues related to quantum feedback control including quantum
filtering, feedback stabilization, LQG control and robust quantum control.Comment: 38 pages, invited survey paper from a control systems perspective,
some references are added, published versio
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