Dymanics of Generalized Coherent States

We show that generalized coherent states follow Schr\"{o}dinger dynamics in time-dependent potentials. The normalized wave-packets follow a classical evolution without spreading; in turn, the Schr\"{o}dinger potential depends on the state through the classical trajectory. This feedback mechanism with continuous dynamical re-adjustement allows the packets to remain coherent indefinetely.Comment: 8 pages, plain latex, no figure

Non-Newtonian Gravity, Fluctuative Hypothesis and the Sizes of Astrophysical Structures

We show that the characteristic sizes of astrophysical and cosmological structures, where gravity is the only overall relevant interaction assembling the system, have a phenomenological relation to the microscopic scales whose order of magnitude is essentially ruled by the Compton wavelength of the proton. This result agrees with the absence of screening mechanisms for the gravitational interaction and could be connected to the presence of Yukawa correcting terms in the Newtonian potential which introduce typical interaction lengths. Furthermore, we are able to justify, in a straightforward way, the Sanders--postulated mass of a vector boson considered in order to obtain the characteristic sizes of galaxies.Comment: 11 pages. to appear in Mod. Phys. Lett.

Diffusion Processes and Coherent States

It is shown that stochastic processes of diffusion type possess, in all generality, a structure of uncertainty relations and of coherent and squeezed states. This fact is used to obtain, via Nelson stochastic formulation of quantum mechanics, the harmonic-oscillator coherent and squeezed states. The method allows to derive new minimum uncertainty states in time-dependent oscillator potentials and for the Caldirola-Kanai model of quantum damped oscillator.Comment: 11 pages, plain LaTe