Towards solid-state quantum computing

Guido Burkard

Department of Physics, University of Konstanz, D-78457 Konstanz, Germany

This talk will begin with a brief introduction into the field of quantum computing, its current state and perspectives. We then focus on solid-state and specifically semiconductor platforms for quantum information processing, where the spin of single or few electrons has been identified as a suitable carrier of quantum information [1]. The use of materials with dilute nuclear spin systems such as silicon and carbon has led to spin qubits with very long coherence times that are routinely in the micro- to millisecond range, in some cases even reaching many seconds. The suppression of magnetic noise from nuclear spins has uncovered the important role of charge fluctuations and the need to shield spin qubits against them. We will highlight recent advances towards spin-based quantum computing including electric spin control and the coupling of individual spins to the quantized field of a superconducting coplanar waveguide resonator.  The development of such “super-semi” hybrid quantum systems comprising superconducting microwave resonators with embedded semiconductor systems opens new opportunities for the coupling of spin qubits over long distances and the exploration of spin-cavity quantum electrodynamics [2].


Exchange of quantum information between two spin qubits in semiconductor devices via a superconducting resonator in a solid-state hybrid quantum system (schematic).

References

[1] D. D. Awschalom et al., Quantum Spintronics: Engineering and Manipulating Atom-Like Spins in Semiconductors (review article), Science 339, 1174 (2013).

[2] G. Burkard, M. J. Gullans, X. Mi, and J. R. Petta, Superconductor-semiconductor hybrid cavity quantum electrodynamics (review article), submitted [arXiv:1905.01155].