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arXiv · 1812.07925

N-level ghost-spins and entanglement

Dileep P. Jatkar·Kedar S. Kolekar·K. Narayan
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Abstract

Ghost-spins, 2-level spin-like variables with indefinite norm have been studied in previous work. Here we explore various $N$-level generalizations of ghost-spins. First we discuss a flavoured generalization comprising $N$ copies of the ghost-spin system, as well as certain ghost-spin chains which in the continuum limit lead to 2-dim $bc$-ghost CFTs with $O(N)$ flavour symmetry. Then we explore a symplectic generalization that involves antisymmetric inner products, and finally a ghost-spin system exhibiting $N$ irreducible levels. We also study entanglement properties. In all these cases, we show the existence of positive norm "correlated ghost-spin" states in two copies of ghost-spin ensembles obtained by entangling identical ghost-spins from each copy: these exhibit positive entanglement entropy.

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Dileep P. Jatkar, Kedar S. Kolekar, K. Narayan. 2019-03-30. N-level ghost-spins and entanglement. https://doi.org/10.1103/physrevd.99.106003

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