Perspective: Quantum or classical coherence?

Area of Science:

• Chemical dynamics
• Molecular dynamics
• Quantum mechanics

Background:

• Coherence effects in chemical dynamics can be explained by classical or quantum mechanics.
• Distinguishing between classical and quantum origins of observed coherence effects can be challenging.

Purpose of the Study:

• To explore the utility of semiclassical theory in differentiating classical and quantum coherence in chemical dynamics.
• To analyze specific examples illustrating both classical and quantum coherence phenomena.

Main Methods:

• Application of semiclassical theory to classical molecular dynamics.
• Analysis of coherence effects in various chemical processes.

Main Results:

• Demonstration that semiclassical theory systematically incorporates quantum coherence into classical dynamics.
• Identification of cases where coherence effects are purely classical or require quantum treatment.
• Observation that the classical or quantum nature of coherence can depend on the observed aspect of non-adiabatic processes.

Conclusions:

• Semiclassical theory offers a valuable framework for understanding and distinguishing coherence in chemical dynamics.
• The interpretation of coherence effects, particularly in non-adiabatic processes, requires careful consideration of the observed phenomena.