Quaderni di Dipartimento

• 257/P - 01/11/1996
  Colli P. ; Gilardi G. ; Grasselli M.
  Asymptotic analysis of a phase-field model with memory for vanishing time relaxation
• 258/P - 01/11/1996
  Frontini M. ; Gotusso L.
  Some results about boundary conditions for a discrete model in elasticity
• 247/P - 01/10/1996
  Barchielli A.
  On the quantum theory of direct detection

  Abstract

  Abstract

  By using the theory of measurements continuous in time in quantum mechanics [1] – [8] , a photon detection theory has been formulated [9]–[12] ; see Refs. [10]–[12] and [8] for detailed references. A quantum source as an atom, an ion or a more complicated system, eventually placed inside an optical cavity, is stimulated by lasers or by a thermal bath. The emitted light is detected by photon counters (direct detection) , possibly after interference with a reference laser beam (heterodyne and homodyne detection) . Just to illustrate detection theory, in this paper I shall present only counting processes [1] , [3] – [12] (direct detection) . Moreover, I shall consider only a concrete example: I shall take as a source a three–level atom in the so called Λ configuration; although simple, such a system shows, when suitably stimulated by lasers, an interesting behaviour: the so called electron–shelving effect (or quantum jumps) [13, 9]

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• 248/P - 01/10/1996
  Pagani C.D. ; Pierotti D.
  Exact solution of the wave resistance problem for a submerged cylinder. I. linearized theory
• 249/P - 01/10/1996
  Terracini S.
  Non degeneracy and chaotic motions for a class of almost-periodi Lagrangean Systems
• 244/P - 01/09/1996
  Frontini M. ; Tagliani A.
  Entropy convergence, instability in Stieltjes anf Hamburger moment problems
• 245/P - 01/09/1996
  Colli P. ; Grasselli M. ; Sprekels J.
  Automatic control via thermostats of a hyperbolic Stefan problem with memory
• 246/P - 01/09/1996
  Frontini M. ; Tagliani A.
  Trasfomata inversa di Laplace per funzioni positive e problema dei momenti

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