Spin entanglement, decoherence and Bohm's EPR paradox

被引：32

作者：

Cavalcanti, E. G. ^{[1
]}

Drummond, P. D. ^{[2
]}

Bachor, H. A. ^{[3
]}

Reid, M. D. ^{[2
]}

机构：

[1] Griffith Univ, Ctr Quantum Dynam, Brisbane, Qld 4111, Australia

[2] Swinburne Univ Technol, ARC Ctr Excellence Quantum Atom Opt, Melbourne, Vic 3122, Australia

[3] Australian Natl Univ, ARC Ctr Excellence Quantum Atom Opt, Canberra, ACT 0200, Australia

来源：

OPTICS EXPRESS | 2009年 / 17卷 / 21期

基金：

澳大利亚研究理事会;

关键词：

BELL INEQUALITY; SUDDEN-DEATH; QUANTUM; STATE; SUPERPOSITIONS;

D O I：

10.1364/OE.17.018693

中图分类号：

O43 [光学];

学科分类号：

070207 ; 0803 ;

摘要：

We obtain criteria for entanglement and the EPR paradox for spin-entangled particles and analyse the effects of decoherence caused by absorption and state purity errors. For a two qubit photonic state, entanglement can occur for all transmission efficiencies. In this case, the state preparation purity must be above a threshold value. However, Bohm's spin EPR paradox can be achieved only above a critical level of loss. We calculate a required efficiency of 58%, which appears achievable with current quantum optical technologies. For a macroscopic number of particles prepared in a correlated state, spin entanglement and the EPR paradox can be demonstrated using our criteria for efficiencies eta > 1/3 and eta > 2/3 respectively. This indicates a surprising insensitivity to loss decoherence, in a macroscopic system of ultra-cold atoms or photons. (C) 2009 Optical Society of America

引用

页码：18693 / 18702

页数：10

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