Method and system for operating a quantum network node

Abstract

Method for operating a quantum network node comprising an electron spin host providing an electron spin for a communication qubit and a nuclear spin host providing a nuclear spin for a data qubit. The method comprises: data qubit state preparation; entanglement, comprising subjecting the electron spin to a protocol comprising multiple repetitions of a primitive for entangling with another quantum system; and data qubit state use, comprising performing operations on and/or readout of the data qubit state or causing entanglement between the data qubit state and a further quantum system. When the wanted (unwanted) state of the electron spin host is a wanted (an unwanted) charge state, the protocol comprises charge state resetting. The method may also or alternatively comprise determining an average unwanted state electron spin value when the electron spin host is in the unwanted state, and further steps in the entanglement protocol.