0000000000133064
AUTHOR
Victor Fleurov
Location- and observation time-dependent quantum-tunneling
We investigate quantum tunneling in a translation invariant chain of particles. The particles interact harmonically with their nearest neighbors, except for one bond, which is anharmonic. It is described by a symmetric double well potential. In the first step, we show how the anharmonic coordinate can be separated from the normal modes. This yields a Lagrangian which has been used to study quantum dissipation. Elimination of the normal modes leads to a nonlocal action of Caldeira-Leggett type. If the anharmonic bond defect is in the bulk, one arrives at Ohmic damping, i.e. there is a transition of a delocalized bond state to a localized one if the elastic constant exceeds a critical value $…
Nonlocality and fluctuations near the optical analog of a sonic horizon
We consider the behavior of fluctuations near the sonic horizon and the role of the nonlocality of interaction (nonlinearity) on their regularization. The nonlocality dominates if its characteristic length scale is larger than the regularization length. The influence of nonlocality may be important in the current experiments on the transonic flow in Kerr nonlinear media. Experimental conditions, under which the observation of straddled fluctuations can be observed, are discussed.
Tunneling in a ?breathing? double well: Adiabatic and antiadiabatic limits and tunneling suppression
Tunneling in a piecewise harmonic potential coupled to a harmonic oscillator is considered by means of the path integral technique. The reduced propagator for the tunneling particle is calculated explicitly and the tunneling splitting is found in semiclassical approximation. The result holds for arbitrary values of the parameters of the system. From this the adiabatic and antiadiabatic approximations are obtained as particular cases and compared with the results obtained differently. The limit of a strong interaction is also considered. It is found that for strong interaction or equivalently for the harmonic frequency tending to zero the preexponential factor in the tunneling splitting tend…
Diffusion of single particles in cellular media
Diffusion of single particles in cellular media Victor Pereyra, "Andrey Milchev, and Victor Fleurov Institut fur Physik, Universitst Mainz, D 55-099 Mainz, Republic Federal of Germany Institute of Physical Chemistry, Bulgarian Academy of Sciences, 10)0 Sofia, Bulgaria Beverly and Raymond Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel (Received 3 November 1993)