Study of a quantum CNOT logic gate with electron spins of diamond impurities

• A quantum CNOT logic gate based on spin impurities of diamond is proposed.
• The usual hyperfine interaction is not considered.
• It uses the electron spins carried by the NV color center and a nitrogen impurity (P1 center).
• The gate time is equal to 96 ns while the decoherence time is about 350μs.
• It has a fidelity close to the maximal value (equal to 1).

Quantum computing requires a set of universal quantum gates. The standard set includes single quantum bit (qubit) gates and the controlled-NOT (CNOT) which is the analog of the classical XOR gate. It flips the state of the target qubit conditioned on the state of the control qubit. We investigated the possibility of implementing a CNOT logic gate using magnetically coupled impurity spins of diamond, namely the electron spin-1 carried by the nitrogen-vacancy color center and the electron spin-12 carried by a nearby nitrogen atom in substitutional position (P1 center). It is shown that a 96 ns gate time with a high-fidelity can be realized by means of pulsed electron spin resonance spectroscopy.