Room 117

Non-Markovianity Hierarchy of Gaussian Processes and Quantum Amplification

Prathik Cherian J.

IMSc

We investigate the dynamics of Gaussian states of continuous variable systems under Gaussianity-preserving channels. We introduce a hierarchy of such evolutions encompassing Markovian and weakly and strongly non-Markovian processes and provide simple criteria to distinguish between the classes, based on the degree of positivity of intermediate Gaussian maps. We present an intuitive classification of all one-mode Gaussian channels according to their non-Markovianity degree and show that weak non-Markovianity has an operational significance, as it leads to a temporary phase-insensitive amplification of Gaussian inputs beyond the fundamental quantum limit. Explicit examples and applications are discussed.

Paper link: journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.050401

Link to a related (but previous) work: journals.aps.org/prl/abstract/10.1103/PhysRevLett.115.070401