High-temperature limit penalising high-frequency quantum fluctuations

Within the semiclassical limit, Markovian quantum Brownian motion is adequately described by the Caldeira-Leggett master equation, which is famously known to be in non-GKSL form.

In this talk, I will discuss a new approach to quantum Brownian motion in which an additional contribution to the decoherence kernel is derived in a new high temperature limit. This contribution is shown to reveal a novel mechanism for the classicalisation of high-frequency quantum fluctuations. I will also demonstrate that it leads to a Markovian master equation in guaranteed GKSL form, and argue that this master equation describes the correct Markovian limit of quantum Brownian motion.