Semiclassical Methods

The phenomenon of Euclidean resonance (a strong enhancement of quantum tunneling through a nonstationary potential barrier) is applied to disintegration of atoms and molecules through tunnel barriers formed by applied constant and time-dependent electric fields. There are two different channels for such disintegration, electronic and ionic. The electronic mechanism is associated with the ionization of a molecule into an electron and a positive ion. The required frequencies are in a wide range between 100 MHZ and infrared. This mechanism may constitute a method of selective destruction of chemical bonds. The ionic mechanism consists of dissociation of a molecule into two ions. Since an ion is more massive than an electron, the necessary frequency is about 1 MHZ. This provides a theoretical possibility of a different method of isotope separation by radio frequency waves. The small sub-barrier tunneling probability of nuclear processes can be dramatically enhanced by collision with incident charged particles. Semiclassical methods of theory of complex trajectories have been applied to nuclear tunneling, and conditions for the effect have been obtained. The enhancement of α particle decay by incident proton with energy of about 0.25 MeV has been demonstrated. The general features of this process are common for other sub-barrier nuclear processes and can be applied to nuclear fission.

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Semiclassical Methods in Molecular Scattering and Spectroscopy

10.1007/978-94-009-8996-2 ◽

1980 ◽

Cited By ~ 12

Keyword(s):

Molecular Scattering ◽

Semiclassical Methods

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SEMICLASSICAL METHODS IN 2D QFT: SPECTRA AND FINITE-SIZE EFFECTS

Modern Physics Letters A ◽

10.1142/s0217732306021621 ◽

2006 ◽

Vol 21 (28) ◽

pp. 2099-2115 ◽

Cited By ~ 1

Author(s):

VALENTINA RIVA

Keyword(s):

Size Effects ◽

Finite Size ◽

Large Mass ◽

Field Theories ◽

Quantum Field Theories ◽

Quantum Field ◽

Finite Size Effects ◽

Small Coupling ◽

Semiclassical Methods ◽

Semiclassical Expansion

We review some recent results obtained in the analysis of two-dimensional quantum field theories by means of semiclassical techniques, which generalize methods introduced during the '70s by Dashen, Hasllacher and Neveu and by Goldstone and Jackiw. The approach is best suited to deal with quantum field theories characterized by a nonlinear interaction potential with different degenerate minima, that generates kink excitations of large mass in the small coupling regime. Under these circumstances, although the results obtained are based on a small coupling assumption, they are nevertheless nonperturbative, since the kink backgrounds around which the semiclassical expansion is performed are nonperturbative too. We will discuss the efficacy of the semiclassical method as a tool to control analytically spectrum and finite-size effects in these theories.

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