Some implications of the quantum nature of laser fields for quantum computations

Physical Review A - Atomic, Molecular, and Optical Physics

Volumn 65, Issue 2, 2002, Pages 6-

  Gea Banacloche, Julio ^a  

^a UNIVERSITY OF ARKANSAS   (United States)

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EID: 85035263035     PISSN: 10502947     EISSN: 10941622     Source Type: Journal    
DOI: 10.1103/PhysRevA.65.022308     Document Type: Article

References (21)

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6. See the paper by C. Caves, Phys. Rev. D 26, 1817 (1982) for the whole story.
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9. Regarding the use of error-correcting codes, it must be noted that Barnes and Warren 1 have argued that the quantum nature of the control fields may result in uncorrectable (to lowest order) two-qubit errors in the operation of CNOT gates. As presented there, this conclusion applies to a specific scheme in which a coupling between the qubits similar to that found in some nuclear magnetic resonance systems was assumed, and frequency-selective pulses were used. It is certainly an interesting question to try to determine just how generally this result may hold but, for simplicity, this particular complication will be ignored in this paper; it will be assumed, in what follows, that at optical frequencies the qubits are spatially resolved and each is addressed by a separate laser pulse.
10. A. L. Schwalow and C. H. Townes, Phys. Rev. 112, 1940 (1958).For a derivation in the context of the quantum theory of the laser, see M. Sargent III, M. O. Scully, and W. E. Lamb, Jr., Laser Physics (Addison-Wesley, Reading, MA, 1974), Chap. 17.
11. This is an example of a “decoherence-free subspace” under collective decoherence conditions. See J. Kempe, D. Bacon, D. A. Lidar, and K. B. Whaley, Phys. Rev. A 63, 042307 (2001) for a recent, very comprehensive review.
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14. Phys. Rev. Asee also D. Beckman, A. N. Chari, S. Devabhaktuni, and J. Preskill, 54, 1034 (1996).
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16. See, e.g., D. Kielpinski, e-print quant-ph/0102086.
17. D. Gottesman, J. Mod. Opt. 47, 333 (2000).
18. I have not been able to find a reliable estimate for r in the literature, but comments in 14 suggest that r should be at least several times greater than (Formula presented)
19. A. M. Steane, Nature (London) 399, 124 (1999).
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