Controllable Coupling in Phase-Coupled Flux Qubits

Abstract

We propose a scheme for tunable coupling of phase-coupled flux qubits. The phase-coupling scheme can provide a strong coupling strength of the order of Josephson coupling energy of Josephson junctions in the connecting loop, while the previously studied inductive coupling scheme cannot provide due to small mutual inductance and induced currents. We show that, in order to control the coupling, we need {\it two} dc-SQUID's in the connecting loop and the control fluxes threading the dc-SQUID's must be in {\it opposite} directions. The coupling strength is analytically calculated as a function of the control flux at the co-resonance point.

version to appear in Phys. Rev. B

References in corpus (21)

• Quantum state engineering with Josephson-junction devices
• Coherent control of macroscopic quantum states in a single-Cooper-pair box
• Coherent Quantum Dynamics of a Superconducting Flux Qubit
• A Superconducting Persistent Current Qubit
• Quantum oscillations in two coupled charge qubits
• Demonstration of conditional gate operation using superconducting charge qubits
• Information and Computation: Classical and Quantum Aspects
• Dephasing of a superconducting qubit induced by photon noise
• Spectroscopy on two coupled flux qubits
• Tunable coupling of superconducting qubits
• Variable electrostatic transformer: controllable coupling of two charge qubits
• Evidence for entangled states of two coupled flux qubits
• Controllable coupling between flux qubits
• Parametric coupling for superconducting qubits
• Controllable manipulation and entanglement of macroscopic quantum states in coupled charge qubits
• Tunable coupling scheme for flux qubits at the optimal point
• Entangling flux qubits with a bipolar dynamic inductance
• Four-qubit device with mixed couplings
• Direct Josephson coupling between superconducting flux qubits
• Coupling of Josephson current qubits using a connecting loop
• Double-Well Potentials in Current Qubits

Cited by in corpus (8)

• Interqubit coupling mediated by a high-excitation-energy quantum object
• Superconducting qubits can be coupled and addressed as trapped ions
• Macroscopic Greenberger-Horne-Zeilinger and W States in Flux Qubits
• Entanglement and Bell States in Superconducting Flux Qubits
• Tunable coupling between a superconducting resonator and an artificial atom
• Hubbard bands, Mott transition and deconfinement in strongly correlated systems
• Macroscopic Many-Qubit Interactions in Superconducting Flux Qubits
• Superconductor-ferromagnet junction phase qubit