Aspelmeyer Group
Universität Wien   Quantum Optics, Quantum Nanophysics and Quantum Information / Faculty of Physics
Quantum Foundations and Quantum Information on the Nano- and Microscale - Aspelmeyer Group
Quantum Foundations and Quantum Information on the Nano- and Microscale – Aspelmeyer Group

Time-Continuous Bell Measurements

Author(s): S. Hofer, D. Vasilyev, M. Aspelmeyer, K. Hammerer

Journal: Physical Review Letters

Volume: 111

Page(s): 170404

Year: 2013

DOI Number: 10.1103/PhysRevLett.111.170404

Link: Link to publication


We combine the concept of Bell measurements, in which two systems are projected into a maximally entangled state, with the concept of continuous measurements, which concerns the evolution of a continuously monitored quantum system. For such time-continuous Bell measurements we derive the corresponding stochastic Schrödinger equations, as well as the unconditional feedback master equations. Our results apply to a wide range of physical systems, and are easily adapted to describe an arbitrary number of systems and measurements. Time-continuous Bell measurements therefore provide a versatile tool for the control of complex quantum systems and networks. As examples we show that (i) two two-level systems can be deterministically entangled via homodyne detection, tolerating photon loss up to 50%, and (ii) a quantum state of light can be continuously teleported to a mechanical oscillator, which works under the same conditions as are required for optomechanical ground-state cooling.


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