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arXiv · 2302.05572

Werner states from diagrams

David W. Lyons·Cristina Mullican·Adam Rilatt·Jack D. Putnam
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Abstract

We present two results on multiqubit Werner states, defined to be those states that are invariant under the collective action of any given single-qubit unitary that acts simultaneously on all the qubits. Motivated by the desire to characterize entanglement properties of Werner states, we construct a basis for the real linear vector space of Werner invariant Hermitian operators on the Hilbert space of pure states; it follows that any mixed Werner state can be written as a mixture of these basis operators with unique coefficients. Continuing a study of "polygon diagram" Werner states constructed in earlier work, with a goal to connect diagrams to entanglement properties, we consider a family of multiqubit states that generalize the singlet, and show that their 2-qubit reduced density matrices are separable.

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David W. Lyons, Cristina Mullican, Adam Rilatt, Jack D. Putnam. 2023-02-11. Werner states from diagrams. https://doi.org/10.1088/1751-8121%2Facd039

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