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[en] Laser induced multiphoton processes are reviewed. The effects of strong fields on atoms are discussed. The perturbation treatment is presented and also its generalization to treat intermediate resonances. The influence of atomic coherence is discussed heuristically and the relation between quantal and classical descriptions of the field is elucidated by reference to the dressed atom description. Atomic ionization experiments are reviewed and the present understanding of multiphoton dissociation of molecules is explained. Finally some prospects for the future are discussed. (author)
Source
Jun 1978; 45 p; ISBN 951-45-1419-X; 
[en] This paper summarizes the basic parameters characterizing a laser cooling configuration. It is stressed that the cooling of a trapped particle introduces additional frequency parameters, the trap frequencies, as compared with the free particles case. These can be used to classify the trapped situation in various limiting cases. The main theoretical results obtained in these limiting cases are outlined. (orig.)
Journal
Physica Scripta. T; ISSN 0281-1847; ; v. 22 p. 69-72
; v. 22 p. 69-72
[en] In this paper I consider the general mathematical problem of the polar decomposition of an operator in a linear space. Extending the space makes it possible to define a unitary operator related to the original nonhermitean one. By Stone's theorem this guarantees the existence of a phase operator in the extended space. The connection with supersymmetry is pointed out. Applying the general results to harmonic oscillator creation and annihilation operators we regain a phase description originally introduced by Newton. Projecting the phase operator from the extended space to the original one, we find a phase representation for the Boson operators. Introducing the conjugate rotation operator, one can describe the oscillator dynamics in the phase representation. The connection with the Barnett-Pegg phase operator is pointed out. (orig.)
Journal
[en] It is being argued that even in non-relativistic quantum mechanics the coordinate and momentum variables cannot be interpreted directly as observables. Only by defining these by suitable test bodies can we obtain verifiable predictions. When these arguments are implemented on a Wigner distribution it is shown that positive phase space probabilities always ensue, and hence this function can be used as a quantum mechanical phase space function. (author)
Journal
European Journal of Physics; ISSN 0143-0807; ; v. 1(4); p. 244-248
; v. 1(4); p. 244-248
[en] The laser is an essential feature of modern life, from telecommunications to medicine. Its history has been told many times, but Beam focuses on the three intense years from the birth of the idea of the laser to its first demonstration in 1960. Jeff Hecht, a science journalist who has written about lasers and optical physics for the past 30 years, describes the emergence of the concept of a source of coherent optical light. But who really invented the laser? Hecht portrays the varied characters involved at several competing laboratories, examining the dramatic claims and bizarre twists along the road to success. The book's chapters are divided between the different labs, meaning some duplication of material as the different players are affected by the same events. (U.K.)
Journal
Physics World; ISSN 0953-8585; ; v. 19(3); p. vp
; v. 19(3); p. vp
[en] We write the density matrix of a two-level atom interacting with a single-mode radiation field in terms of the average photon number and the degree of off-diagonality. The latter represents quantum correlations, which are transformed to a phase variable analogous to the phase of the classical field. Using a consistent expansion in the inverse powers of the square root of the average photon number we obtain the ordinary classical limit. The surprising feature which emerges is that the zero point energy contributes to the classical field parameter as efficiently as the photon occupation number; this result agrees with one derived differently by Bialynicki-Birula and Bialynicka-Birula
Journal
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