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arXiv · 1510.03644

Exact finite reduced density matrix and von Neumann entropy for the Calogero model

Omar Osenda·Federico M. Pont·Anna Okopińska·Pablo Serra
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Abstract

The information content of continuous quantum variables systems is usually studied using a number of well known approximation methods. The approximations are made to obtain the spectrum, eigenfunctions or the reduced density matrices that are essential to calculate the entropy-like quantities that quantify the information. Even in the sparse cases where the spectrum and eigenfunctions are exactly known the entanglement spectrum, {\em i.e.} the spectrum of the reduced density matrices that characterize the problem, must be obtained in an approximate fashion. In this work, we obtain analytically a finite representation of the reduced density matrices of the fundamental state of the N-particle Calogero model for a discrete set of values of the interaction parameter. As a consequence, the exact entanglement spectrum and von Neumann entropy is worked out.

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Omar Osenda, Federico M. Pont, Anna Okopińska, Pablo Serra. 2015-10-13. Exact finite reduced density matrix and von Neumann entropy for the Calogero model. https://arxiv.org/abs/1510.03644

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