Spin squeezing and pairwise entanglement for symmetric multiqubit states
- Department of Physics and Australian Centre of Excellence for Quantum Computer Technology, Macquarie University, Sydney, New South Wales 2109, (Australia)
We show that spin squeezing implies pairwise entanglement for arbitrary symmetric multiqubit states. If the squeezing parameter is less than or equal to 1, we demonstrate a quantitative relation between the squeezing parameter and the concurrence for the even and odd states. We prove that the even states generated from the initial state with all qubits being spin down, via the one-axis twisting Hamiltonian, are spin squeezed if and only if they are pairwise entangled. For the states generated via the one-axis twisting Hamiltonian with an external transverse field for any number of qubits greater than 1 or via the two-axis countertwisting Hamiltonian for any even number of qubits, the numerical results suggest that such states are spin squeezed if and only if they are pairwise entangled.
- OSTI ID:
- 20639856
- Journal Information:
- Physical Review. A, Vol. 68, Issue 1; Other Information: DOI: 10.1103/PhysRevA.68.012101; (c) 2003 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
Similar Records
Multiqubit maximally entangled states in the NMR model
Fungible dynamics: There are only two types of entangling multiple-qubit interactions