Testing Bell's inequality and measuring the entanglement using superconducting nanocircuits

Abstract

An experimental scheme is proposed to test Bell's inequality by using superconducting nanocircuits. In this scheme, quantum entanglement of a pair of charge qubits separated in a sufficient long distance may be created by cavity quantum electrodynamic techniques; the population of qubits is experimentally measurable by dc currents through the probe junctions, and one measured outcome may be recorded for every experiment. Therefore, both locality and detection efficiency loopholes should be closed in the same experiment. We also propose a useful method to measure the amount of entanglement based on the concurrence between Josephson qubits. The measurable variables for Bell's inequality as well as the entanglement are expressed in terms of a useful phase-space Q function.

6 pages; Typos in Eqs. (8) and (9) in the published version were corrected

References in corpus (6)

• Quantum state engineering with Josephson-junction devices
• Quantum oscillations in two coupled charge qubits
• Long distance quantum teleportation of qubits from photons at 1300 nm to photons at 1550 nm wavelength
• Implementation of universal quantum gates based on nonadiabatic geometric phases
• Universal quantum gates based on a pair of orthogonal cyclic states: Application to NMR systems
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Cited by in corpus (8)

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• Scheme for direct measurement of a general two-qubit Hamiltonian
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• Spin in Compton scattering with pronounced polarization dynamics
• Entanglement of topological phase factors
• An interdisciplinary approach to certain fundamental issues in the fields of physics and biology: towards a Unified Theory