Quantum open systems

Esteban A. Calzetta, B. L. Hu

Ming Zhang, Wei Kang Zhu, Dewen Hu

This paper demonstrates that the decoherence-free subsystem of open quantum dynamical system is open-loop controllable if the suitable coherent controls are permitted. This result is in marked contrast to the fact that open quantum dynamical systems are not open-loop controllable. In other words, combining the decoherence-free subsystem condition with coherent control on the open quantum dynamical systems will enhance the ability to suppress the decoherence and to manipulate open quantum dynamical systems.

H. J. Carmichael

Shan Ma, Chuan‐Cun Shu, Chengdi Xiang

Linear passive open quantum systems are a simple yet interesting class of open quantum systems. In this paper, we first define the class of linear passive open quantum systems. Then some properties of these systems developed in recent years are reviewed.

I. Rotter

Information on quantum systems can be obtained only when they are open (or opened) in relation to a certain environment. As a matter of fact, realistic open quantum systems appear in very different shape. We sketch the theoretical description of open quantum systems by means of a projection operator formalism elaborated many years ago, and applied by now to the description of different open quantum systems. The Hamiltonian describing the open quantum system is non-Hermitian. Most studied are the eigenvalues of the non-Hermitian Hamiltonian of many-particle systems embedded in one environment. We point to the unsolved problems of this method when applied to the description of realistic many-body systems. We then underline the role played by the eigenfunctions of the non-Hermitian Hamiltonian. Very interesting results originate from the fluctuations of the eigenfunctions in systems with gain and loss of excitons. They occur with an efficiency of nearly 100\%. An example is the photosynthesis.

Daniel F. Walls, Gerard J Milburn