2003/07/09 by J. L. van Velsen, M. Kindermann, C. W. J. Beenakker
Physics and Astronomy · #cond-mat #quant-ph
published as Turk. J. Phys. 27, 323 (2003) · 7 pages with 3 figures, special style file included; To appear in a special issue on "Quantum Computation at the Atomic Scale" in Turkish Journal of Physics
arxiv created 2003/07/09 · arxiv updated 2009/12/01
A tunnel barrier in a degenerate electron gas was recently discovered as a source of entangled electron-hole pairs. Here, we investigate the loss of entanglement by dephasing. We calculate both the maximal violation Emax of the Bell inequality and the degree of entanglement (concurrence) C. If the initially maximally entangled electron-hole pair is in a Bell state, then the Bell inequality is violated for arbitrary strong dephasing. The same relation Emax=2√1+C2 then holds as in the absence of dephasing. More generally, for a maximally entangled superposition of Bell states, the Bell inequality is satisfied for a finite dephasing strength and the entanglement vanishes for somewhat stronger (but still finite) dephasing strength. There is then no one-to-one relation between Emax and C.