Related papers: Trace decreasing quantum dynamical maps: Divisibility and entanglement dynamics

Trace decreasing quantum dynamical maps: Divisibility and entanglement dynamics

URL: http://arxiv.org/abs/2108.13372v1
Date: Mon, 30 Aug 2021 16:45:23 GMT
Title: Trace decreasing quantum dynamical maps: Divisibility and entanglement dynamics
Authors: Sergey N. Filippov
Abstract summary: Trace decreasing quantum operations naturally emerge in experiments involving postselection. Here we show that this approach leads to incorrect conclusions about the dynamics divisibility. We propose solutions to that problem and introduce proper indicators of the information backflow and the indivisibility.
Score: 0.0
License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Abstract: Trace decreasing quantum operations naturally emerge in experiments involving postselection. However, the experiments usually focus on dynamics of the conditional output states as if the dynamics were trace preserving. Here we show that this approach leads to incorrect conclusions about the dynamics divisibility, namely, one can observe an increase in the trace distance or the system-ancilla entanglement although the trace decreasing dynamics is completely positive divisible. We propose solutions to that problem and introduce proper indicators of the information backflow and the indivisibility. We also review a recently introduced concept of the generalized erasure dynamics that includes more experimental data in the dynamics description. The ideas are illustrated by explicit physical examples of polarization dependent losses.

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