Tomography of entangling two-qubit logic operations in exchange-coupled donor electron spin qubits

Understand

Scalable quantum processors require high-fidelity universal quantum logic operations in a manufacturable physical platform.

• Donors in silicon provide atomic size, excellent quantum coherence and compatibility with standard semiconductor processing, but no entanglement between donor-bound electron spins has been demonstrated to date.
• Here we present the experimental demonstration and tomography of universal 1- and 2-qubit gates in a system of two weakly exchange-coupled electrons, bound to single phosphorus donors introduced in silicon by ion implantation.
• We surprisingly observe that the exchange interaction has no effect on the qubit coherence.