Publications - Detailseite

Long-range photon-mediated gate scheme between nuclear spin qubits in diamond

Defect centers in diamond are exceptional solid-state quantum systems that can have exceedingly long electron and nuclear spin coherence times. So far, single-qubit gates for the nitrogen nuclear spin, a two-qubit gate with a nitrogen-vacancy (NV) center electron spin, and entanglement between nearby nitrogen nuclear spins have been demonstrated.
Here, we develop a scheme to implement a universal two-qubit gate between two distant nitrogen nuclear spins. Virtual excitation of an NV center that is embedded in an optical cavity can scatter a laser photon into the cavity mode; we show that this process depends on the nuclear spin state of the nitrogen atom. If two NV centers are simultaneously coupled to a common cavity mode and individually excited, virtual cavity photon exchange can mediate an effective interaction between the nuclear spin qubits, conditioned on the spin state of both nuclei, which implements a universal controlled-Ζ gate. We predict operation times below 10 μs, which is four orders of magnitude faster than the decoherence time of nuclear spin qubits in diamond.

Adrian Auer and Guido Burkard
Phys. Rev. B 93, 035402 – Published 04 January 2016
DOI: 10.1103/PhysRevB.93.035402