Relatore
Prof.
Dariusz Chru ́sci ́nski
(Nicolaus Copernicus University Torun)
Descrizione
We analyze the relation between CP-divisibility and the lack of information back flow
for an arbitrary not necessarily invertible dynamical map [1,2,3]. It is well known that
CP-divisibility always implies lack of information back flow. Moreover, these two notions
are equivalent for invertible maps. We show that for a map which is not invertible the
lack of information back flow always implies the existence of completely positive (CP)
propagator which, however, needs not be trace-preserving. Interestingly, for a class of
image non-increasing dynamical maps [majority of examples studied in the literature do
belong to this class] this propagator becomes trace-preserving as well and hence the lack
of information back flow implies CP-divisibility. This result sheds new light into the
structure of the time-local generators giving rise to CP-divisible evolutions. It is shown
that if the map is not invertible then positivity of dissipation/decoherence rates is no
longer necessary for CP-divisibility.
[1] D. Chru ́sci ́nski, A. Kossakowski, and A. Rivas, Phys. Rev. A 83, 052128 (2011).
[2] B. Bylicka, M. Johansson, and A. Ac ́ın, Phys. Rev. Lett. 118 , 120501 (2017).
[3] D. Chru ́sci ́nski, A. Rivas, and E. Størmer, arXiv:1710.06771
Autore principale
Prof.
Dariusz Chru ́sci ́nski
(Nicolaus Copernicus University Torun)
