Quantum State Smoothing for Linear Gaussian Systems

Fuente: arXiv
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Autori principali: Laverick, Kiarn T., Chantasri, Areeya, Wiseman, Howard M.
Natura: Preprint
Pubblicazione: 2019
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author Laverick, Kiarn T.
Chantasri, Areeya
Wiseman, Howard M.
author_facet Laverick, Kiarn T.
Chantasri, Areeya
Wiseman, Howard M.
contents Quantum state smoothing is a technique for assigning a valid quantum state to a partially observed dynamical system, using measurement records both prior and posterior to an estimation time. We show that the technique is greatly simplified for Linear Gaussian quantum systems, which have wide physical applicability. We derive a closed-form solution for the quantum smoothed state, which is more pure than the standard filtered state, whilst still being described by a physical quantum state, unlike other proposed quantum smoothing techniques. We apply the theory to an on-threshold optical parametric oscillator, exploring optimal conditions for purity recovery by smoothing. The role of quantum efficiency is elucidated, in both low and high efficiency limits.
format Preprint
id arxiv_https___arxiv_org_abs_1901_00225
institution arXiv
publishDate 2019
record_format arxiv
spellingShingle Quantum State Smoothing for Linear Gaussian Systems
Laverick, Kiarn T.
Chantasri, Areeya
Wiseman, Howard M.
Quantum Physics
Quantum state smoothing is a technique for assigning a valid quantum state to a partially observed dynamical system, using measurement records both prior and posterior to an estimation time. We show that the technique is greatly simplified for Linear Gaussian quantum systems, which have wide physical applicability. We derive a closed-form solution for the quantum smoothed state, which is more pure than the standard filtered state, whilst still being described by a physical quantum state, unlike other proposed quantum smoothing techniques. We apply the theory to an on-threshold optical parametric oscillator, exploring optimal conditions for purity recovery by smoothing. The role of quantum efficiency is elucidated, in both low and high efficiency limits.
title Quantum State Smoothing for Linear Gaussian Systems
topic Quantum Physics
url https://arxiv.org/abs/1901.00225