On the Response of Linear Quantum Systems to Single Photon Input Fields

Guofeng Zhang (The Australian National University)

SYSTEMS AND CONTROL SERIES

DATE: 2011-07-08
TIME: 11:00:00 - 12:00:00
LOCATION: RSISE Seminar Room, ground floor, building 115, cnr. North and Daley Roads, ANU
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ABSTRACT:
Gaussian distributions play a fundamental role in classical (non-quantum) linear systems theory, and the fact that Gaussian distributions are preserved through the dynamics of linear systems underlies many well-known and fundamental results including LQG control and Kalman filtering. In linear quantum optics, coherent states and squeezed states are examples of quantum Gaussian states. These states are also preserved by the linear quantum dynamics, and there are many parallels with classical Gaussian states and linear systems. However, quantum states have unique features not shared by classical distributions, and it is the exploitation of such features that hold promise for new quantum technologies. In this paper we present several results that illustrate the potential for linear systems methods for processing highly non-classical quantum states. Specifically, in this paper we characterize the class of states (which we call pulsed-Gaussian states) that result when multichannel photons are input to a quantum linear system. We show that this class of quantum states is preserved by quantum linear systems. Multichannel pulsed-Gaussian states are defined via the action of certain creation and annihilation operators on Gaussian states. The Gaussian part of this specification is needed to allow for quantum linear systems with active elements, such as degenerate parametric amplifiers.
BIO:
Guofeng Zhang received a B.Sc degree and M.Sc. degree from Northeastern University, Shenyang, China, in 1998 and 2000 respectively. He received a Ph.D. degree in applied mathematics from the University of Alberta, Edmonton, Canada, in 2005. During 2005-2006, he was a Postdoctoral Fellow in the department of Electrical and Computer Engineering at the University of Windsor, Windsor, Canada. He joined the School of Electronic Engineering of the University of Electronic Science and Technology of China, Chengdu, Sichuan, China, in 2007. He is currently a Research Fellow in the School of Engineering of the Australian National University. His research interests include quantum control, sampled-data control and nonlinear dynamics.

MEDIA:
GZ_photon.pdf