10,600 research outputs found
Multipartite entangled coherent states
We propose a scheme for generating multipartite entangled coherent states via
entanglement swapping, with an example of a physical realization in ion traps.
Bipartite entanglement of these multipartite states is quantified by the
concurrence. We also use the --tangle to compute multipartite entanglement
for certain systems. Finally we establish that these results for entanglement
can be applied to more general multipartite entangled nonorthogonal states.Comment: 7 pages, two figures. We added more detail discussions on the
generation of multipartite entangled coherent states and multipartite
entangelemen
Multipartite entanglement detection for hypergraph states
We study the entanglement properties of quantum hypergraph states of
qubits, focusing on multipartite entanglement. We compute multipartite
entanglement for hypergraph states with a single hyperedge of maximum
cardinality, for hypergraph states endowed with all possible hyperedges of
cardinality equal to and for those hypergraph states with all possible
hyperedges of cardinality greater than or equal to . We then find a lower
bound to the multipartite entanglement of a generic quantum hypergraph state.
We finally apply the multipartite entanglement results to the construction of
entanglement witness operators, able to detect genuine multipartite
entanglement in the neighbourhood of a given hypergraph state. We first build
entanglement witnesses of the projective type, then propose a class of
witnesses based on the stabilizer formalism, hence called stabilizer witnesses,
able to reduce the experimental effort from an exponential to a linear growth
in the number of local measurement settings with the number of qubits
Bounds for multipartite concurrence
We study the entanglement of a multipartite quantum state. An inequality
between the bipartite concurrence and the multipartite concurrence is obtained.
More effective lower and upper bounds of the multipartite concurrence are
obtained. By using the lower bound, the entanglement of more multipartite
states are detected.Comment: 8 page
Multipartite entanglement in spin chains
We investigate the presence of multipartite entanglement in macroscopic spin
chains. We discuss the Heisenberg and the XY model and derive bounds on the
internal energy for systems without multipartite entanglement. Based on this we
show that in thermal equilibrium the above mentioned spin systems contain
genuine multipartite entanglement, even at finite modest temperatures.Comment: 5 pages, 1 figure, to appear in New J. Phy
Multipartite entanglement, quantum-error-correcting codes, and entangling power of quantum evolutions
We investigate the average bipartite entanglement, over all possible
divisions of a multipartite system, as a useful measure of multipartite
entanglement. We expose a connection between such measures and
quantum-error-correcting codes by deriving a formula relating the weight
distribution of the code to the average entanglement of encoded states.
Multipartite entangling power of quantum evolutions is also investigated.Comment: 13 pages, 1 figur
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