Eternal non-Markovianity: from random unitary to Markov chain realisations



: Nina Megier, Dariusz Chruściński, Jyrki Piilo, Walter T. Strunz

Publisher: NATURE PUBLISHING GROUP

: 2017

: Scientific Reports

: SCIENTIFIC REPORTS

: SCI REP-UK

: 6379

: 7

: 11

: 2045-2322

DOI: https://doi.org/10.1038/s41598-017-06059-5

: https://research.utu.fi/converis/portal/detail/Publication/27562715


The theoretical description of quantum dynamics in an intriguing way does not necessarily imply the underlying dynamics is indeed intriguing. Here we show how a known very interesting master equation with an always negative decay rate [eternal non-Markovianity (ENM)] arises from simple stochastic Schrodinger dynamics (random unitary dynamics). Equivalently, it may be seen as arising from a mixture of Markov (semi-group) open system dynamics. Both these approaches lead to a more general family of CPT maps, characterized by a point within a parameter triangle. Our results show how ENM quantum dynamics can be realised easily in the laboratory. Moreover, we find a quantum time-continuously measured (quantum trajectory) realisation of the dynamics of the ENM master equation based on unitary transformations and projective measurements in an extended Hilbert space, guided by a classical Markov process. Furthermore, a Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) representation of the dynamics in an extended Hilbert space can be found, with a remarkable property: there is no dynamics in the ancilla state. Finally, analogous constructions for two qubits extend these results from non-CP-divisible to non-P-divisible dynamics.

Last updated on 2024-26-11 at 15:32