Preparing Dicke states in a spin ensemble using phase estimation

We present a Dicke state preparation scheme which uses global control of N spin qubits: our scheme is based on the standard phase estimation algorithm, which estimates the eigenvalue of a unitary operator. The scheme prepares a Dicke state nondeterministically by collectively coupling the spins to an ancilla qubit via a ZZ interaction, using inverted right perpendicularlog(2) Ninverted left perpendicular + 1 ancilla qubit measurements. The preparation of such Dicke states can be useful if the spins in the ensemble are used for magnetic sensing: we discuss a possible realization using an ensemble of electronic spins located at diamond nitrogen-vacancy centers coupled to a single superconducting flux qubit. We also analyze the effect of noise and limitations in our scheme.

Automated summary

We propose a scheme for preparing Dicke states using global control of N spin qubits, based on the standard phase estimation algorithm. The scheme involves collectively coupling the spins to an ancilla qubit via ZZ interaction for non-deterministic state preparation. Potential applications include magnetic sensing using electronic spins coupled to a superconducting flux qubit, with analysis of noise and limitations in the scheme.