A measure of qubit environment entanglement for pure dephasing evolutions

Seminaria robocze kwantowej informacji i komputerów kwantowych

Katarzyna

Roszak

PWr

November 26, 2020 3:15 PM

We propose a qubit-environment entanglement measure which is tailored for evolutions that lead to pure dephasing of the qubit, such as are abundant in solid state scenarios. The measure can be calculated directly from the density matrix without minimization of any kind. In fact it does not require the knowledge of the full density matrix, and it is enough to know the initial qubit state and the states of the environment conditional on qubit pointer states. This yields a computational advantage over standard entanglement measures, which becomes large when there are no correlations between environmental components in the conditional environmental states. In contrast to all other measures of mixed state entanglement, the measure has a straightforward physical interpretation directly linking the amount of information about the qubit state which is contained in the environment to the amount of qubit-environmnent entanglement. This allows for a direct extension of the pure state interpretation of entanglement generated during pure dephasing to mixed states, even though pure-state conclusions about qubit decoherence are not transferable.


__________________________________________________________________
Zoom meeting details (NEW HOUR!)

Topic: Quantum Information and Quantum Computing Working Group
Time: November 26, 2020, 3:15 PM Warsaw

Join Zoom Meeting link:
https://tinyurl.com/quantum-ctp

Meeting ID: 94552545103
Passcode: 323395

If you encounter any problems with connecting to the Zoom meeting, please email maciejewski@cft.edu.pl directly.