Quantum walking in curved spacetime: discrete metric

A discrete-time quantum walk (QW) is essentially a unitary operator driving the evolution of a single particle on the lattice. Some QWs have familiar physics PDEs as their continuum limit. Some slight generalization of them (allowing for prior encoding and larger neighbourhoods) even have the curved...

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Main Authors: Pablo Arrighi, Giuseppe Di Molfetta, Stefano Facchini
Format: Article
Language:English
Published: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften 2018-08-01
Series:Quantum
Online Access:https://quantum-journal.org/papers/q-2018-08-22-84/pdf/
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author Pablo Arrighi
Giuseppe Di Molfetta
Stefano Facchini
author_facet Pablo Arrighi
Giuseppe Di Molfetta
Stefano Facchini
author_sort Pablo Arrighi
collection DOAJ
description A discrete-time quantum walk (QW) is essentially a unitary operator driving the evolution of a single particle on the lattice. Some QWs have familiar physics PDEs as their continuum limit. Some slight generalization of them (allowing for prior encoding and larger neighbourhoods) even have the curved spacetime Dirac equation, as their continuum limit. In the $(1+1)-$dimensional massless case, this equation decouples as scalar transport equations with tunable speeds. We characterise and construct all those QWs that lead to scalar transport with tunable speeds. The local coin operator dictates that speed; we provide concrete techniques to tune the speed of propagation, by making use only of a finite number of coin operators-differently from previous models, in which the speed of propagation depends upon a continuous parameter of the quantum coin. The interest of such a discretization is twofold : to allow for easier experimental implementations on the one hand, and to evaluate ways of quantizing the metric field, on the other.
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spelling doaj.art-d9be55cea92648179c7332bcdb287c372022-12-21T18:41:25ZengVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenQuantum2521-327X2018-08-0128410.22331/q-2018-08-22-8410.22331/q-2018-08-22-84Quantum walking in curved spacetime: discrete metricPablo ArrighiGiuseppe Di MolfettaStefano FacchiniA discrete-time quantum walk (QW) is essentially a unitary operator driving the evolution of a single particle on the lattice. Some QWs have familiar physics PDEs as their continuum limit. Some slight generalization of them (allowing for prior encoding and larger neighbourhoods) even have the curved spacetime Dirac equation, as their continuum limit. In the $(1+1)-$dimensional massless case, this equation decouples as scalar transport equations with tunable speeds. We characterise and construct all those QWs that lead to scalar transport with tunable speeds. The local coin operator dictates that speed; we provide concrete techniques to tune the speed of propagation, by making use only of a finite number of coin operators-differently from previous models, in which the speed of propagation depends upon a continuous parameter of the quantum coin. The interest of such a discretization is twofold : to allow for easier experimental implementations on the one hand, and to evaluate ways of quantizing the metric field, on the other.https://quantum-journal.org/papers/q-2018-08-22-84/pdf/
spellingShingle Pablo Arrighi
Giuseppe Di Molfetta
Stefano Facchini
Quantum walking in curved spacetime: discrete metric
Quantum
title Quantum walking in curved spacetime: discrete metric
title_full Quantum walking in curved spacetime: discrete metric
title_fullStr Quantum walking in curved spacetime: discrete metric
title_full_unstemmed Quantum walking in curved spacetime: discrete metric
title_short Quantum walking in curved spacetime: discrete metric
title_sort quantum walking in curved spacetime discrete metric
url https://quantum-journal.org/papers/q-2018-08-22-84/pdf/
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AT stefanofacchini quantumwalkingincurvedspacetimediscretemetric