Robust quantum parameter estimation: Coherent magnetometry with feedback

Robust quantum parameter estimation: Coherent magnetometry with feedback

We describe the formalism for optimally estimating and controlling both the state of a spin ensemble and a scalar magnetic field with information obtained from a continuous quantum limited measurement of the spin precession due to the field. The full quantum parameter estimation model is reduced to a simplified equivalent representation to which classical estimation and control theory is applie...

Robust H∞ coherent-classical estimation of linear quantum systems

Abstract— We study robust H∞ coherent-classical estimation for a class of physically realizable linear quantum systems with parameter uncertainties. Such a robust coherent-classical estimator, with or without coherent feedback, can yield better disturbance-to-error performance than the corresponding robust purely-classical estimator for an uncertain plant. Moreover, coherent feedback allows for...

Robust Parameter Design With Feedback Control

Robust parameter design (or, briefly, parameter design) has been widely used as a cost effective tool to reduce process variability by appropriate selection of control factors to make the process insensitive to noise. However, when there are strong noise factors in the process, use of parameter design alone may not be effective and an on-line control strategy can be used to compensate for the e...

Robust Parameter Estimation in ComputerVisionCharles

Amplified Quantum Dynamics and Enhanced Parameter Sensitivity via Coherent Feedback in Collective Atomic Spin Systems

We consider the effective dynamics obtained by double-passing a fardetuned laser probe through a large atomic spin system. The net result of the atomfield interaction is a type of coherent positive feedback that amplifies the values of selected spin observables. An effective equation of motion for the atomic system is presented, and an approximate 2-parameter model of the dynamics is developed ...