Quantum coherent interface of an electron and a nuclear ensemble

Coherent excitation of an ensemble of quantum objects offers the opportunity to realise robust entanglement generation and information storage in a quantum memory. In quantum dots, a single electron spin qubit is a coherent interface to an isolated nuclear spin ensemble. Recently, we have developed an all-optical electron spin resonance technique that, together with our ability to optically cool the nuclear ensemble [1], has allowed us to perform complex qubit manipulations on the electron spin, such as to run a spin-locking sequence [2], to coherently excite spin-wave modes in the nuclear spin ensemble [3], and to sense the effective magnetic field from a single nuclear-spin excitation [4]. Combined, these results open a promising avenue for quantum state engineering of a mesoscopic ensemble, and we have recently proposed a realistic path to a nuclear quantum memory based on electron-activated spin waves in GaAs quantum dots [5]. In my talk, I will briefly summarise these recent experimental results and proposals for the future.

[1] Ethier-Majcher, Gangloff et al., (2017), Phys. Rev. Lett. 119, 130503
[2] Bodey et al. (2019) npj Quantum Information 5 (95)
[3] Gangloff, Ethier-Majcher, et al. (2019) Science 364 (6435)
[4] Jackson, Gangloff, et al. (2020) manuscript in preparation
[5] Denning, Gangloff, Atature, Mork, Le Gall (2019) Phys. Rev. Lett. 123, 140502