Herman-Kluk propagator is free from zero-point energy leakage

TL;DR

This paper demonstrates that the Herman-Kluk semiclassical propagator can accurately simulate quantum dynamics without suffering from zero-point energy leakage, enabling more efficient simulations of complex systems.

Contribution

It shows that the Herman-Kluk propagator avoids ZPE leakage, a common problem in semiclassical methods, despite using classical trajectories.

Findings

Herman-Kluk propagator is free from ZPE leakage.

Enables accurate semiclassical simulations of large systems.

Facilitates quantum dynamics studies with reduced computational cost.

Abstract

Semiclassical techniques constitute a promising route to approximate quantum dynamics based on classical trajectories starting from a quantum-mechanically correct distribution. One of their main drawbacks is the so-called zero-point energy (ZPE) leakage, that is artificial redistribution of energy from the modes with high frequency and thus high ZPE to that with low frequency and ZPE due to classical equipartition. Here, we show that an elaborate semiclassical formalism based on the Herman-Kluk propagator is free from the ZPE leakage despite utilizing purely classical propagation. This finding opens the road to correct dynamical simulations of systems with a multitude of degrees of freedom that cannot be treated fully quantum-mechanically due to the exponential increase of the numerical effort.