Probing measurement-induced effects in quantum walks via recurrence

Thomas Nitsche, Sonja Barkhofen, Regina Kruse, Linda Sansoni, Martin Stefaňák, A. Gábris, Václav Potoček, Tamás Kiss, Igor Jex, Christine Silberhorn

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Measurements on a quantum particle unavoidably affect its state, since the otherwise unitary evolution of the system is interrupted by a nonunitary projection operation. To probe measurement-induced effects in the state dynamics using a quantum simulator, the challenge is to implement controlled measurements on a small subspace of the system and continue the evolution from the complementary subspace. A powerful platform for versatile quantum evolution is represented by photonic quantum walks because of their high control over all relevant parameters. However, measurement-induced dynamics in such a platform have not yet been realized. We implement controlled measurements in a discrete-time quantum walk based on time-multiplexing. This is achieved by adding a deterministic outcoupling of the optical signal to include measurements constrained to specific positions resulting in the projection of the walker’s state on the remaining ones. With this platform and coherent input light, we experimentally simulate measurement-induced single-particle quantum dynamics. We demonstrate the difference between dynamics with only a single measurement at the final step and those including measurements during the evolution. To this aim, we study recurrence as a figure of merit, that is, the return probability to the walker’s starting position, which is measured in the two cases. We track the development of the return probability over 36 time steps and observe the onset of both recurrent and transient evolution as an effect of the different measurement schemes, a signature which only emerges for quantum systems. Our simulation of the observed one-particle conditional quantum dynamics does not require a genuine quantum particle but is demonstrated with coherent light.

Original languageEnglish
Article numbereaar6444
JournalScience advances
Volume4
Issue number6
DOIs
Publication statusPublished - Jun 29 2018

Fingerprint

platforms
projection
coherent light
multiplexing
figure of merit
simulators
optical communication
signatures
photonics
probes
simulation

ASJC Scopus subject areas

  • General

Cite this

Nitsche, T., Barkhofen, S., Kruse, R., Sansoni, L., Stefaňák, M., Gábris, A., ... Silberhorn, C. (2018). Probing measurement-induced effects in quantum walks via recurrence. Science advances, 4(6), [eaar6444]. https://doi.org/10.1126/sciadv.aar6444

Probing measurement-induced effects in quantum walks via recurrence. / Nitsche, Thomas; Barkhofen, Sonja; Kruse, Regina; Sansoni, Linda; Stefaňák, Martin; Gábris, A.; Potoček, Václav; Kiss, Tamás; Jex, Igor; Silberhorn, Christine.

In: Science advances, Vol. 4, No. 6, eaar6444, 29.06.2018.

Research output: Contribution to journalArticle

Nitsche, T, Barkhofen, S, Kruse, R, Sansoni, L, Stefaňák, M, Gábris, A, Potoček, V, Kiss, T, Jex, I & Silberhorn, C 2018, 'Probing measurement-induced effects in quantum walks via recurrence', Science advances, vol. 4, no. 6, eaar6444. https://doi.org/10.1126/sciadv.aar6444
Nitsche T, Barkhofen S, Kruse R, Sansoni L, Stefaňák M, Gábris A et al. Probing measurement-induced effects in quantum walks via recurrence. Science advances. 2018 Jun 29;4(6). eaar6444. https://doi.org/10.1126/sciadv.aar6444
Nitsche, Thomas ; Barkhofen, Sonja ; Kruse, Regina ; Sansoni, Linda ; Stefaňák, Martin ; Gábris, A. ; Potoček, Václav ; Kiss, Tamás ; Jex, Igor ; Silberhorn, Christine. / Probing measurement-induced effects in quantum walks via recurrence. In: Science advances. 2018 ; Vol. 4, No. 6.
@article{afef0114a04548229745d41e8daff9dd,
title = "Probing measurement-induced effects in quantum walks via recurrence",
abstract = "Measurements on a quantum particle unavoidably affect its state, since the otherwise unitary evolution of the system is interrupted by a nonunitary projection operation. To probe measurement-induced effects in the state dynamics using a quantum simulator, the challenge is to implement controlled measurements on a small subspace of the system and continue the evolution from the complementary subspace. A powerful platform for versatile quantum evolution is represented by photonic quantum walks because of their high control over all relevant parameters. However, measurement-induced dynamics in such a platform have not yet been realized. We implement controlled measurements in a discrete-time quantum walk based on time-multiplexing. This is achieved by adding a deterministic outcoupling of the optical signal to include measurements constrained to specific positions resulting in the projection of the walker’s state on the remaining ones. With this platform and coherent input light, we experimentally simulate measurement-induced single-particle quantum dynamics. We demonstrate the difference between dynamics with only a single measurement at the final step and those including measurements during the evolution. To this aim, we study recurrence as a figure of merit, that is, the return probability to the walker’s starting position, which is measured in the two cases. We track the development of the return probability over 36 time steps and observe the onset of both recurrent and transient evolution as an effect of the different measurement schemes, a signature which only emerges for quantum systems. Our simulation of the observed one-particle conditional quantum dynamics does not require a genuine quantum particle but is demonstrated with coherent light.",
author = "Thomas Nitsche and Sonja Barkhofen and Regina Kruse and Linda Sansoni and Martin Stefaň{\'a}k and A. G{\'a}bris and V{\'a}clav Potoček and Tam{\'a}s Kiss and Igor Jex and Christine Silberhorn",
year = "2018",
month = "6",
day = "29",
doi = "10.1126/sciadv.aar6444",
language = "English",
volume = "4",
journal = "Science advances",
issn = "2375-2548",
publisher = "American Association for the Advancement of Science",
number = "6",

}

TY - JOUR

T1 - Probing measurement-induced effects in quantum walks via recurrence

AU - Nitsche, Thomas

AU - Barkhofen, Sonja

AU - Kruse, Regina

AU - Sansoni, Linda

AU - Stefaňák, Martin

AU - Gábris, A.

AU - Potoček, Václav

AU - Kiss, Tamás

AU - Jex, Igor

AU - Silberhorn, Christine

PY - 2018/6/29

Y1 - 2018/6/29

N2 - Measurements on a quantum particle unavoidably affect its state, since the otherwise unitary evolution of the system is interrupted by a nonunitary projection operation. To probe measurement-induced effects in the state dynamics using a quantum simulator, the challenge is to implement controlled measurements on a small subspace of the system and continue the evolution from the complementary subspace. A powerful platform for versatile quantum evolution is represented by photonic quantum walks because of their high control over all relevant parameters. However, measurement-induced dynamics in such a platform have not yet been realized. We implement controlled measurements in a discrete-time quantum walk based on time-multiplexing. This is achieved by adding a deterministic outcoupling of the optical signal to include measurements constrained to specific positions resulting in the projection of the walker’s state on the remaining ones. With this platform and coherent input light, we experimentally simulate measurement-induced single-particle quantum dynamics. We demonstrate the difference between dynamics with only a single measurement at the final step and those including measurements during the evolution. To this aim, we study recurrence as a figure of merit, that is, the return probability to the walker’s starting position, which is measured in the two cases. We track the development of the return probability over 36 time steps and observe the onset of both recurrent and transient evolution as an effect of the different measurement schemes, a signature which only emerges for quantum systems. Our simulation of the observed one-particle conditional quantum dynamics does not require a genuine quantum particle but is demonstrated with coherent light.

AB - Measurements on a quantum particle unavoidably affect its state, since the otherwise unitary evolution of the system is interrupted by a nonunitary projection operation. To probe measurement-induced effects in the state dynamics using a quantum simulator, the challenge is to implement controlled measurements on a small subspace of the system and continue the evolution from the complementary subspace. A powerful platform for versatile quantum evolution is represented by photonic quantum walks because of their high control over all relevant parameters. However, measurement-induced dynamics in such a platform have not yet been realized. We implement controlled measurements in a discrete-time quantum walk based on time-multiplexing. This is achieved by adding a deterministic outcoupling of the optical signal to include measurements constrained to specific positions resulting in the projection of the walker’s state on the remaining ones. With this platform and coherent input light, we experimentally simulate measurement-induced single-particle quantum dynamics. We demonstrate the difference between dynamics with only a single measurement at the final step and those including measurements during the evolution. To this aim, we study recurrence as a figure of merit, that is, the return probability to the walker’s starting position, which is measured in the two cases. We track the development of the return probability over 36 time steps and observe the onset of both recurrent and transient evolution as an effect of the different measurement schemes, a signature which only emerges for quantum systems. Our simulation of the observed one-particle conditional quantum dynamics does not require a genuine quantum particle but is demonstrated with coherent light.

UR - http://www.scopus.com/inward/record.url?scp=85049747957&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85049747957&partnerID=8YFLogxK

U2 - 10.1126/sciadv.aar6444

DO - 10.1126/sciadv.aar6444

M3 - Article

VL - 4

JO - Science advances

JF - Science advances

SN - 2375-2548

IS - 6

M1 - eaar6444

ER -