Coupling spin ensembles via superconducting flux qubits

Abstract

We study a hybrid quantum system consisting of spin ensembles and superconducting flux qubits, where each spin ensemble is realized using the nitrogen-vacancy centers in a diamond crystal and the nearest-neighbor spin ensembles are effectively coupled via a flux qubit.We show that the coupling strengths between flux qubits and spin ensembles can reach the strong and even ultrastrong coupling regimes by either engineering the hybrid structure in advance or tuning the excitation frequencies of spin ensembles via external magnetic fields. When extending the hybrid structure to an array with equal coupling strengths, we find that in the strong-coupling regime, the hybrid array is reduced to a tight-binding model of a one-dimensional bosonic lattice. In the ultrastrong-coupling regime, it exhibits quasiparticle excitations separated from the ground state by an energy gap. Moreover, these quasiparticle excitations and the ground state are stable under a certain condition that is tunable via the external magnetic field. This may provide an experimentally accessible method to probe the instability of the system.

8 pages,3 figures

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Cited by in corpus (15)

• Quantum technologies with hybrid systems
• Implementation of the Dicke lattice model in hybrid quantum system arrays
• Nonperturbative Leakage Elimination Operators and Control of a Three-Level System
• Strong tunable spin-spin interaction in a weakly coupled nitrogen vacancy spin-cavity electromechanical system
• Charge Qubit-Atom Hybrid
• Quantum phase transition in a multi-connected superconducting Jaynes-Cummings lattice
• Strong single-photon optomechanical coupling in a hybrid quantum system
• Amplification of the coupling strength in a hybrid quantum system
• Quantum phase transition in a multiconnected Jaynes-Cummings lattice
• Hybrid quantum computing with ancillas
• Experimental Simulation of Hybrid Quantum Systems and Entanglement on a Quantum Computer
• Optimal Spin Squeezed Steady State induced by the dynamics of non-hermtian hamiltonians
• Mott insulator-superfluid phase transition in a detuned multi-connected Jaynes-Cummings lattice
• Transferring multiqubit entanglement onto memory qubits in a decoherence-free subspace
• Minimal ancilla mediated quantum computation