Experimental Snapshot Verification of non-Markovianity with Unknown System-Probe Coupling

Abstract

We apply the recently proposed quantum probing protocols with an unknown system-probe coupling to probe the convex coefficients in mixtures of commuting states. By using two reference states instead of one as originally suggested, we are able to probe both lower and upper bounds for the convex coefficient. We perform extensive analysis for the roles of the parameters characterizing the double peaked Gaussian frequency spectrum in the Markovian-to-non-Markovian transition of the polarization dynamics of a single photon. We apply the probing of the convex coefficient to the transition-inducing frequency parameter and show that the non-Markovianity of the polarization dynamics can be confirmed with a single snapshot measurement of the polarization qubit performed at unknown time and even with unknown coupling. We also show how the protocol can identify Markovian and non-Markovian time intervals in the dynamics. The results are validated with single photon experiments.

Correlations, information backflow, and objectivity in a class of pure dephasing models

“…These correlations are the basis for notions of classical objectivity [3][4][5][6][7] and are also known to play a key role in the characterisation of the dynamics, in particular, if the system undergoes a Markovian (memoryless) or non-Markovian evolution [8,9]. Both notions of classical objectivity and non-Markovian evolution have been the object of experimental investigations, see for example [10][11][12][13] and [14][15][16][17][18][19][20] respectively.…”