Momentum as a bridge between the quantum and classical worlds: the role of relaxation time in the pulsed tunneling effect

This paper develops the concept of momentum as a universal bridge between the quantum and classical descriptions of physical processes. The governing parameter of the transition between regimes is the ratio of the pulse rise time τr to the characteristic relaxation time of the system τrel dimensionless parameter α = τr/τrel. At α = 1 a non-adiabatic (quantum-coherent) regime is realized; at α ? 1 the regime is adiabatic (classical). On the basis of the developed concept of the Pulsed Tunneling Effect (PTE) and the photon–phonon–photon conversion mechanism in functional ceramics, it is shown how broadband solar radiation is transformed into coherent pulses with a prescribed rise time. The mechanisms of thermal stabilization in greenhouse systems are examined and the results of composite-film tests are presented. The PTE concept is compared with Keldysh theory and is discussed in the context of current research in non-adiabatic photochemistry and femtosecond spectroscopy.