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Main Authors: Hackl, Lucas, Bianchi, Eugenio
Format: Preprint
Published: 2020
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Online Access:https://arxiv.org/abs/2010.15518
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author Hackl, Lucas
Bianchi, Eugenio
author_facet Hackl, Lucas
Bianchi, Eugenio
contents We show that bosonic and fermionic Gaussian states (also known as "squeezed coherent states") can be uniquely characterized by their linear complex structure $J$ which is a linear map on the classical phase space. This extends conventional Gaussian methods based on covariance matrices and provides a unified framework to treat bosons and fermions simultaneously. Pure Gaussian states can be identified with the triple $(G,Ω,J)$ of compatible Kähler structures, consisting of a positive definite metric $G$, a symplectic form $Ω$ and a linear complex structure $J$ with $J^2=-1\!\!1$. Mixed Gaussian states can also be identified with such a triple, but with $J^2\neq -1\!\!1$. We apply these methods to show how computations involving Gaussian states can be reduced to algebraic operations of these objects, leading to many known and some unknown identities. We apply these methods to the study of (A) entanglement and complexity, (B) dynamics of stable systems, (C) dynamics of driven systems. From this, we compile a comprehensive list of mathematical structures and formulas to compare bosonic and fermionic Gaussian states side-by-side.
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id arxiv_https___arxiv_org_abs_2010_15518
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Bosonic and fermionic Gaussian states from Kähler structures
Hackl, Lucas
Bianchi, Eugenio
Quantum Physics
Statistical Mechanics
High Energy Physics - Theory
We show that bosonic and fermionic Gaussian states (also known as "squeezed coherent states") can be uniquely characterized by their linear complex structure $J$ which is a linear map on the classical phase space. This extends conventional Gaussian methods based on covariance matrices and provides a unified framework to treat bosons and fermions simultaneously. Pure Gaussian states can be identified with the triple $(G,Ω,J)$ of compatible Kähler structures, consisting of a positive definite metric $G$, a symplectic form $Ω$ and a linear complex structure $J$ with $J^2=-1\!\!1$. Mixed Gaussian states can also be identified with such a triple, but with $J^2\neq -1\!\!1$. We apply these methods to show how computations involving Gaussian states can be reduced to algebraic operations of these objects, leading to many known and some unknown identities. We apply these methods to the study of (A) entanglement and complexity, (B) dynamics of stable systems, (C) dynamics of driven systems. From this, we compile a comprehensive list of mathematical structures and formulas to compare bosonic and fermionic Gaussian states side-by-side.
title Bosonic and fermionic Gaussian states from Kähler structures
topic Quantum Physics
Statistical Mechanics
High Energy Physics - Theory
url https://arxiv.org/abs/2010.15518