Europhys. Lett.
Volume 71, Number 3, August 2005
Page(s) 387 - 393
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 14 July 2005
Europhys. Lett., 71 (3), pp. 387-393 (2005)
DOI: 10.1209/epl/i2005-10104-5

Proposal for measuring the entanglement of nearby spins by multiphoton interference

M. N. Leuenberger1, M. E. Flatté1 and D. D. Awschalom2

1  Department of Physics and Astronomy, University of Iowa, IATL - Iowa City IA 52242, USA
2  Department of Physics, University of California - Santa Barbara CA 93106-9530, USA

received 3 January 2005; accepted in final form 8 June 2005
published online 14 July 2005

We propose a method to measure the entanglement of nearby spins by means of multiphoton correlation interference patterns generated by the scattering of two perpendicular pulsed laser beams with opposite circular polarization. As this method is based on optical read-out only, it provides the possibility to monitor with minimal intrusion the evolution and the decoherence of many-spin entanglement. This method is capable of retrieving all the amplitudes of a general many-spin state of arbitrary dimension. Explicit calculations are presented for a quantum dot spin system.

42.25.Hz - Interference.
42.50.-p - Quantum optics.
03.65.Ud - Entanglement and quantum nonlocality (e.g. EPR paradox, Bell's inequalities, GHZ states, etc.).

© EDP Sciences 2005