Coherence-assisted entanglement activation during open evolution

Masaya Takahashi^1,2*, Jarosław K. Korbicz¹

¹Center for Theoretical Physics, Warsaw, Poland
²Department of Physics, National Taiwan Normal University, Taipei, Taiwan

* Presenter:Masaya Takahashi, email:masayatakahashi@ntnu.edu.tw

In the course of open evolution, the creation of system-environment entanglement out of the initial coherence occurs in the vast majority of cases. However, how much entanglement can be created under general assumptions has not been analyzed yet. In this work, we investigated system-environment entanglement generation under a broad and important class of interactions known as pure-dephasing interactions for arbitrary initial conditions. Our main results are the following bounds on the relative entropy of entanglement E_r(σ_SE) after evolution: C_r(ρ_S)−H(I|M)≤E_r(σ_SE)≤C_r(ρ_S)−C_r⁡(σ_Sr(ρ_S) and information extractable from the environment H(I|M) and on the other side to the decoherence strength, C_r⁡(ρ_Sr(σ_S), making the statement that larger entanglement leads to more decoherence quantitatively precise. We also present an example applying our result to the spin-Boson model, where a qubit interacts with a bosonic bath, showing the time evolution of the entanglement and the crossover between Markovian and non-Markovian dynamics.

Keywords: Entanglement generation, Open quantum system, Quantum resource theory