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arXiv · 1303.4976

Time-Continuous Bell Measurements

Sebastian G. Hofer·Denis V. Vasilyev·Markus Aspelmeyer·Klemens Hammerer
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Abstract

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 Schr\"odinger 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 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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Sebastian G. Hofer, Denis V. Vasilyev, Markus Aspelmeyer, Klemens Hammerer. 2013-03-20. Time-Continuous Bell Measurements. https://doi.org/10.1103/physrevlett.111.170404

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