Quantum codes and macroscopic superpositions

Physical Review A - Atomic, Molecular, and Optical Physics

Volumn 61, Issue 2, 2000, Pages 223021-223025

  Gea Banacloche, Julio ^a  

^a UNIVERSITY OF ARKANSAS   (United States)

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EID: 0347108623     PISSN: 10502947     EISSN: None     Source Type: Journal    
DOI: None     Document Type: Article

References (12)

1. As in e.g., S. Haroche and J.-M. Raimond, Phys. Today 49 (8), 51 (1996). "Manipulating such a quantum monster would be a feat almost as difficult as keeping Schrödinger's famous cat in a superposition of its alive and dead states."
2. See, e.g., W.H. Zurek, Phys. Today 44 (10), 36 (1991), and references therein.
3. See, e.g., E. Knill, R. Laflamme, and W.H. Zurek, Science 279, 342 (1998), and references therein.
4. A.M. Steane, Phys. Rev. Lett. 77, 793 (1996). See also A.R. Calderbank and P.W. Shor, Phys. Rev. A 54, 1098 (1996).
5. A.M. Steane, Phys. Rev. Lett. 77, 793 (1996). See also A.R. Calderbank and P.W. Shor, Phys. Rev. A 54, 1098 (1996).
6. For a recent proposal to quantify the extent to which a state would show "quantum uncertainty on the macroscopic level" and associated estimations of its fragility, see D. Janzing and Th. Beth, LANL e-print quant-ph/9907042.
7. E. Knill and R. Laflamme, Phys. Rev. A 55, 900 (1997).
8. α. For instance, for a concatenated code three levels deep that means all moments up to the fourteenth order.
9. α. For instance, for a concatenated code three levels deep that means all moments up to the fourteenth order.
10. iα}, one must conclude that such a code does not yield a decoherence- free subspace for the particular kind of perturbation considered here.
11. iα}, one must conclude that such a code does not yield a decoherence-free subspace for the particular kind of perturbation considered here.
12. L〉 would be macroscopically indistinguishable up to the 200th order moment, their superposition would certainly not be called a "Schrödinger cat" from the conventional point of view which I have adopted here.