# Vacuum Entanglement Harvesting from the Electromagnetic Field with Hydrogen-like Atoms

### Tuesday, 10 May. 2016, 15:00 - 16:30

**Presenter:** Alejandro Pozas-Kerstjens

**Host:** Zizhu WANG

**Where:** IQOQI Seminar Room, 2nd Floor, Boltzmanngasse 3, 1090 Vienna

It is known (since 1985) that the vacuum state of a scalar quantum field contains both classical and quantum correlations, even between spacelike-separated regions. It was later discussed that it is possible to harvest entanglement from the field via locally coupling detectors. This phenomenon has become known as “vacuum entanglement harvesting”.

In entanglement harvesting, the field-detectors interaction has been earlier modelled via the Unruh-DeWitt Hamiltonian. However, past studies relied on the analysis of simplified scalar fields, which, among other things, fails to capture the features of entanglement harvesting when exchange of angular momentum between detectors and fields is allowed. The proper study of electromagnetic entanglement harvesting requires careful consideration of the shape of the atomic orbitals and the exact

gauge-invariant coupling with the field.

In this talk, we will first review some basic interesting features of entanglement harvesting in the usual scalar field-Unruh-DeWitt setup, and after that we will analyze the harvesting of entanglement from an electromagnetic field beyond the Unruh-DeWitt approximation, considering a realistic interaction through which two fully-featured Hydrogen-like atoms interact with the vacuum state of the (vector) electromagnetic field. Since we carefully considered the angular momentum dynamics in the atom-field interactions we can now discuss, among other features, subtleties that appear due to changes in the relative orientation between the two atoms.