Nonexponential decay in the quantum dynamics of nanosystems
Abstract
The quantum dynamical problem is solved for a system coupled to an equidistantspectrum bath with the energy difference Ω between the neighboring levels n and n + 1 and the coupling matrix elements C {_{/n } ^{2}} = C ^{2}(1 + Δ^{2} n ^{2})^{1} constraining the energy interval comprising the bath states interacting with the system. The evolution in the strongcoupling limit is determined by two parameters, Γ = π C ^{2}/Ω ≫ 1 and α = Γ/Δ. If α ≠ 0, then the decrease in the population in the initial cycle with a period of 2π/Ω is not exponential and the effective rate constant increases with time. The results qualitatively explain the appearance of nonexponential relaxation regimes for a densespectrum nanosystem and predict the possibility of the multiple recovery of the initialstate population.
 Publication:

Soviet Journal of Experimental and Theoretical Physics Letters
 Pub Date:
 November 2008
 DOI:
 10.1134/S0021364008170116
 Bibcode:
 2008JETPL..88..338B
 Keywords:

 03.65.w;
 82.20.w