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Volumn 47, Issue 1, 1993, Pages 449-455

How to reset an atom after a photon detection: Applications to photon-counting processes

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EID: 0000326019     PISSN: 10502947     EISSN: None     Source Type: Journal    
DOI: 10.1103/PhysRevA.47.449     Document Type: Article
Times cited : (160)

References (58)
  • 20
    • 84926887574 scopus 로고    scopus 로고
    • T. Wilser, doctoral dissertation, Göttingen, 1991.
  • 22
    • 0001183096 scopus 로고
    • generalizes von Neumann's prescription for observables with nondegenerate eigenvalues to the degenerate case, but differs from von Neumann's proposal for the latter [cf. J. von Neumann, Mathematical Foundations of Quantum Mechanics (Princeton University Press, Princeton, 1955) Chap. V.1].
    • (1951) Ann. Phys. (Leipzig) , vol.8 , pp. 323
    • Lüders, G.1
  • 28
  • 31
    • 84926924971 scopus 로고    scopus 로고
    • R. Reibold, Physica (to be published); J. Phys. A (to be published).
  • 47
    • 84926924970 scopus 로고    scopus 로고
    • This argument neglects a part of the radiation field in the vicinity of the atom.
  • 48
    • 84926932886 scopus 로고
    • uses a similar point of view to determine the reset matrix for a nuclear cascade involving two γ's.
    • (1964) Ann. Phys. (Leipzig) , vol.14 , pp. 166
    • Paul, H.1
  • 49
    • 84926905955 scopus 로고    scopus 로고
    • Photon frequencies are not observed, and therefore this detection does not imply restrictions on Δ t. If frequencies were observed also, the time frequency uncertainty relation would apply.
  • 52
    • 84926905954 scopus 로고    scopus 로고
    • For the determination of the reset matrix it has been essential that the radiation field is known to have been in the vacuum state a time Δ t before the photon detection. This is due to the gedanken measurements. Without this knowledge it would be much more complicated to determine the state of an atom after the detection because then U(t,0) would enter for larger times. Moreover, since the photon detection times are random a single gedanken measurement before a photon detection would not do.
  • 54
    • 84926905952 scopus 로고    scopus 로고
    • Equation ( ref13) should be compared with the expression P0U(t, t0) mid 0ph > mid ψA (t0) > which was calculated in Ref. citePP and whose norm squared gives the probability for a single measurement to find no photon at t, with no measurements, and no knowledge thereof, in between. In principle both expressions are different, e.g., the former decays exponentially while the latter can do this only approximately in some finite interval, not truly asymptotically. This is due to positivity of the energy and ensuing analyticity. As regards the calculation of P0(t), for the external fields considered in Ref. citePP, both results are compatible within the approximations employed. The underlying reason for this agreement has been investigated and clarified in a very general context by means of the projector formalism in Ref. citeRb. However, to find a reset matrix within the approach of Ref. citePP and without gedanken measurements would involve the difficulties mentioned in Ref. citeRem.
  • 55
    • 84926944125 scopus 로고    scopus 로고
    • Cf., e.g., D.R. Cox, Renewal Theory (Methuen, London, 1962).
  • 56
    • 84926924968 scopus 로고    scopus 로고
    • One can also show direct ly from Eq. ( ref7) that tr hatJ ρA = tr (Hred ρA - ρA Hsup *red).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.