Macroscopic Greenberger-Horne-Zeilinger and W states in flux qubits
نویسندگان
چکیده
We investigate two types of genuine three-qubit entanglement, known as the Greenberger-Horne-Zeilinger GHZ and W states, in a macroscopic quantum system. Superconducting flux qubits are theoretically considered in order to generate such states. A phase coupling is proposed to offer enough strength of interactions between qubits. While an excited state can be the W state, the GHZ state is formed at the ground state of the three flux qubits. The GHZ and W states are shown to be robust against external flux fluctuations for feasible experimental realizations.
منابع مشابه
Macroscopic entangled states in superconducting flux qubits
We theoretically study the macroscopic quantum entanglement in superconducting flux qubits. A phase-coupling scheme is proposed to offer enough strength of interactions between qubits. It is shown that due to the two-qubit tunneling processes both the ground state and excited states of coupled two flux qubits can be Bell type states, maximally entangled, in experimentally accessible regimes. Th...
متن کاملGeneration and control of Greenberger-Horne-Zeilinger entanglement in superconducting circuits.
Going beyond the entanglement of microscopic objects (such as photons, spins, and ions), here we propose an efficient approach to produce and control the quantum entanglement of three macroscopic coupled superconducting qubits. By conditionally rotating, one by one, selected Josephson-charge qubits, we show that their Greenberger-Horne-Zeilinger (GHZ) entangled states can be deterministically g...
متن کاملGreenberger-Horne-Zeilinger nonlocality in phase space
We show that the continuous-variable analogues to the multipartite entangled Greenberger-Horne-Zeilinger states of qubits violate Bell-type inequalities imposed by local realistic theories. Our results suggest that the degree of nonlocality of these nonmaximally entangled continuous-variable states, represented by the maximum violation, grows with increasing number of parties. This growth does ...
متن کاملEntanglement classification of relaxed Greenberger-Horne-Zeilinger symmetric states
In this paper we analyze entanglement classification of relaxed Greenberger-HorneZeilinger-symmetric states ρES , which is parametrized by four real parameters x, y1, y2 and y3. The condition for separable states of ρES is analytically derived. The higher classes such as bi-separable, W, and Greenberger-Horne-Zeilinger classes are roughly classified by making use of the class-specific optimal w...
متن کاملN-tangle of the Superposition of Greenberger-Horne- Zeilinger States
In the paper, use the n-tangle, as a measure of entanglement to investigate the superposition of Greenberger-Horne-Zeilinger states for even n qubits. The paper show that orthogonal basis with the GHZ state can be divided into two group via SLOCC –invariant. In the same group, an expression for any two superposed state is provided, when the superposition coefficient is real, the n-tangle of sup...
متن کامل