Quantum versus classical domains for teleportation with continuous variables
Abstract
By considering the utilization of a classical channel without quantum entanglement, fidelity Fclassical=12 has been established as setting the boundary between classical and quantum domains in the teleportation of coherent states of the electromagnetic field [S. L. Braunstein, C. A. Fuchs, and H. J. Kimble, J. Mod. Opt. 47, 267 (2000)]. We further examine the quantum-classical boundary by investigating questions of entanglement and Bell-inequality violations for the Einstein-Podolsky-Rosen states relevant to continuous variable teleportation. The threshold fidelity for employing entanglement as a quantum resource in teleportation of coherent states is again found to be Fclassical=12. Likewise, violations of local realism onset at this same threshold, with the added requirement of overall efficiency η>23 in the unconditional case. By contrast, recently proposed criteria adapted from the literature on quantum-nondemolition detection are shown to be largely unrelated to the questions of entanglement and Bell-inequality violations.
- Publication:
-
Physical Review A
- Pub Date:
- August 2001
- DOI:
- 10.1103/PhysRevA.64.022321
- arXiv:
- arXiv:quant-ph/0012001
- Bibcode:
- 2001PhRvA..64b2321B
- Keywords:
-
- 03.67.-a;
- 42.50.Dv;
- 03.65.Ta;
- Quantum information;
- Nonclassical states of the electromagnetic field including entangled photon states;
- quantum state engineering and measurements;
- Foundations of quantum mechanics;
- measurement theory;
- Quantum Physics
- E-Print:
- 15 pages with 4 figures, submitted to Phys. Rev. A. Minor corrections made, conclusions unchanged