Characterizing entanglement robustness of an N-qubit W superposition state against particle loss from quantum Fisher information

Abstract

We investigate the entanglement robustness of an N-qubit W superposition state against particle loss with quantum Fisher information. In the noninteracting environment, the quantum Fisher information of reduced W superposition state is found same as it from W superposition state when the number of qubits is larger than 5, which shows very strong entanglement robustness compared to Twin-Fock state and Greenberger–Horne–Zeilinger state. Meanwhile, the re-particle-loss effect is also studied and it presents a rapid decay of quantum Fisher information with the increase of the number of losing qubits, indicating the weak entanglement robustness. In the Ising-type interacting environment, the results show that reduced W superposition state performs better than it in noninteracting environment. With the increasing qubits (N>5) the reduced W superposition state behaves much more robust than original W state. To simulate a real noisy environment, the effects of different decoherence channels are also considered.

Keywords

• Entanglement robustness
• Quantum fisher information
• W superposition state
• Particle loss
• GHZ state