QLunch: Entanglement Extraction, Energy and Einstein Equation – University of Copenhagen

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QLunch: Entanglement Extraction, Energy and Einstein Equation

Speaker: Robert Jonsson from QMATH

Title: Entanglement Extraction, Energy and Einstein Equation

Entanglement is a resource required by a variety of quantum information processing tasks. Hence providing future quantum technology with entanglement extracted from natural sources would be a valuable ability.

Candidate sources of entanglement could be large, spatially extended quantum systems such as quantum many body systems or, potentially, the ubiquitous fundamental quantum fields of nature.

A central question in this context is how much "bang for the buck" a given source can offer: The amount of energy required to extract entanglement from a particular system is obviously relevant, e.g., to the design of entanglement reservoirs. Moreover, in the context of quantum fields on curved spacetime, the question may link to novel insights into the interplay of quantum theory and gravity.

In this talk, I introduce the general framework of entanglement extraction, in particular, reviewing results on so called 'entanglement harvesting' from relativistic quantum fields.  I put this into context with the energy cost of entanglement extraction, whose study was recently initiated by Beny et al. [1]. To conclude, I will discuss the connection of this problem to recent work by Jacobson [2] which showed how Einsteins equations follow from a maximal vacuum entanglement hypothesis for quantum fields.

[1] Beny, Cedric, Christopher T. Chubb, Terry Farrelly, and Tobias J.
Osborne. “Energy Cost of Entanglement Extraction in Complex Quantum Systems.” ArXiv:1711.06658 [Quant-Ph], November 17, 2017.

[2] Jacobson, Ted. “Entanglement Equilibrium and the Einstein Equation.”
Physical Review Letters 116, no. 20 (May 20, 2016).https://doi.org/10.1103/PhysRevLett.116.201101.