Speaker
Description
The subsystem structure of quantum theory is relative to the choice of quantum reference frame (QRF). This raises a basic question for open quantum systems: is decoherence an intrinsic property of the system–environment interaction, or can part of it arise from the physical reference frame used to describe the system?
I will address this question through reduced quantum-reference-frame channels: completely positive trace-preserving maps obtained by performing a QRF transformation and then discarding inaccessible reference and environmental degrees of freedom. These channels capture the operational reduced description available to an observer after a change of frame, and allow one to characterize which features of an open-system dynamics are robust under changes of QRF.
I will apply the framework to pure dephasing dynamics, identifying a necessary and sufficient condition for its population structure to be preserved under changes of QRF. In particular, when the energy decomposition is preserved, coherences acquire an additional reference-dependent factor, leading to a split between environmental and reference-induced decoherence rates.
I will conclude with the operational interpretation of this split in Ramsey interferometry and with a gravity-motivated dephasing model, where degradation of a quantum phase reference can reproduce signatures usually associated with intrinsic decoherence.