Two-colorable graph states with maximal Schmidt measure

Abstract

The Schmidt measure was introduced by Eisert and Briegel for quantifying the degree of entanglement of multipartite quantum systems [Phys. Rev. A 64, 022306 (2001)]. Although generally intractable, it turns out that there is a bound on the Schmidt measure for two-colorable graph states [Phys. Rev. A 69, 062311 (2004)]. For these states, the Schmidt measure is in fact directly related to the number of nonzero eigenvalues of the adjacency matrix of the associated graph. We remark that almost all two-colorable graph states have maximal Schmidt measure and we construct specific examples. These involve perfect trees, line graphs of trees, cographs, graphs from anti-Hadamard matrices, and unyciclic graphs. We consider some graph transformations, with the idea of transforming a two-colorable graph state with maximal Schmidt measure into another one with the same property. In particular, we consider a transformation introduced by Francois Jaeger, line graphs, and switching. By making appeal to a result of Ehrenfeucht et al. [Discrete Math. 278 (2004)], we point out that local complementation and switching form a transitive group acting on the set of all graph states of a given dimension.

6 pages, 1 figure

References in corpus (9)

• Measurement-based quantum computation with cluster states
• Multi-party entanglement in graph states
• Graphical description of the action of local Clifford transformations on graph states
• Multiparticle entanglement purification for two-colorable graph states
• Graphs, Quadratic Forms, and Quantum Codes
• On the Classification of All Self-Dual Additive Codes over GF(4) of Length up to 12
• Entanglement in the stabilizer formalism
• On Self-Dual Quantum Codes, Graphs, and Boolean Functions
• Multi-partite quantum cryptographic protocols with noisy GHZ states

Cited by in corpus (7)

• Entanglement in eight-qubit graph states
• Efficient Entanglement Measure for Graph States
• On the Minimum Degree up to Local Complementation: Bounds and Complexity
• Entanglement of multi-qubit states representing directed networks and its detection with quantum computing
• Tensor Rank and Other Multipartite Entanglement Measures of Graph States
• Seidel Minor, Permutation Graphs and Combinatorial Properties
• $\chi$-Colorable Graph States: Closed-Form Expressions and Quantum Orthogonal Arrays