Single photons emitted by trapped ions: From fundamental physics to applications in quantum computing

by Prof. Gabriel Araneda (University of Oxford)

Wednesday 13 May 2020, 13:00 → 15:00 Europe/Stockholm

Fysikum equipment

https://stockholmuniversity.zoom.us/j/65444576560

Atomic ions confined in Paul traps present features that allow the study of quantum emitters with a unique degree of control. These features include the possibility of working with a well-defined and conserved number of atomic emitters, each of them with sub-wavelength localization, and with high degree of control of their internal and external quantum states, including the on-demand creation of entanglement.

In the first part of this talk I will present some experiments performed in the University of Innsbruck where we used Barium ions and the collection of single photons via high numerical aperture lenses to study some properties of the emission by entangled atoms [1] and some fundamental issues related with spin-orbit coupling of light in the spontaneous decay process [2].

In the second part, I will present our new setup in the University of Oxford, where single photons emitted by single ions located some meters apart are used to generate high-fidelity remote entanglement [3]. This new setup consists of two separated identical segmented ion traps, where we trap and control both Strontium and Calcium ions. The collection of photons used to entangle ions in different traps is done with high numerical aperture lenses. This system would allow us to demonstrate some important features of a elementary quantum network.

[1] “Interference of single photons emitted by entangled atoms in free space”, G. Araneda, D.B. Higginbottom, L. Slodicka, Y. Colombe and R. Blatt, Physical Review Letters 120, 193603 (2018)
[2] “Wavelength-scale errors in optical localization due to spin-orbit coupling of light”, G. Araneda, S. Walser, Y. Colombe, D. B. Higginbottom, J. Volz, R. Blatt and A. Rauschenbeutel, Nature Physics 15, 17 (2019)
[3] “High-rate, high-fidelity entanglement of qubits across an elementary quantum network” L. J. Stephenson, D. P. Nadlinger, B. C. Nichol, S. An, P. Drmota, T. G. Ballance, K. Thirumalai, J. F. Goodwin, D. M. Lucas, C. J. Ballance Physical Review Letters 124, 110501 (2020)