Decoherence effects in reactive scattering

Abstract

Decoherence effects on quantum and classical dynamics in reactive scattering are examined using a Caldeira-Leggett type model. Through a study of dynamics of the collinear H + H 2 reaction and the transmission over simple one-dimensional barrier potentials, we show that decoherence leads to improved agreement between quantum and classical reaction and transmission probabilities, primarily by increasing the energy dispersion in a well defined way. Increased potential nonlinearity is seen to require larger decoherence in order to attain comparable quantum-classical agreement.

Quantum-Classical Correspondence in Response Theory

“…Many theoretical and experimental works have demonstrated that decoherence plays an essential role in quantum-classical correspondence and that in the presence of decoherence the quantum dynamics behaves more classically than in the absence of decoherence [83,84,85,86]. This suggests that the agreement between the quantum and the classical response functions will agree better if coupling to bath is introduced.…”

Effects of initial coherence on distinguishability of pure/mixed states and chiral stability in an open chiral system

“…To invoke a two-level approximation, we assume that for an isolated system the potential barrier is very high or equivalently the energy of the system is sufficiently low that the higher energy levels are not involved in the dynamics. In addition, since this is an open system, we should point out that the position measurement of the system is known to cause its energy and its energy width to increase over time [11,17]. The system energy and energy width will eventually become greater than the potential barrier, leading to the breakdown in the validity of the two-level approximation.…”

“…As easily can be seen from Eqs. (11) and (14), the difference between the time-evolution of Z of the initially pure state and that of the corresponding mixed state, ∆Z(≡ Z P − Z M ) is given by:…”

“…However, for the long time region the effects of X 0 and Y 0 on the purity decay are different due to different time-evolutions of X and Y (see Eqs. (9)- (11) and Eqs. (12)- (14)).…”

“…In this Letter, we study the role of initial coherences, in an open chiral system, on the distinguishability of initially pure versus initially mixed states as measured by population difference between the chiral states, and the vulnerability to decoherence as measured by the purity decay. The influence of an environment on the system is modeled by continuous position measurements, an approach often used in the studies of the quantum Zeno effect [10] and in the studies of decoherence effects in chemical reactions [11]. In particular, Milburn and his coworkers [12,13] studied a model of continuous position measurements on a quantum system in a double-well potential, and within a two-level approximation their resultant master equation is identical to ours.…”