Probing measurement-induced effects in quantum walks via recurrence

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21340%2F18%3A00323064" target="_blank" >RIV/68407700:21340/18:00323064 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1126/sciadv.aar6444" target="_blank" >http://dx.doi.org/10.1126/sciadv.aar6444</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1126/sciadv.aar6444" target="_blank" >10.1126/sciadv.aar6444</a>

Result language

angličtina

Original language name

Probing measurement-induced effects in quantum walks via recurrence

Original language description

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.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10306 - Optics (including laser optics and quantum optics)

Project

<a href="/en/project/GA17-00844S" target="_blank" >GA17-00844S: Photonic Quantum Networks</a><br>

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Science Advances

ISSN

2375-2548

e-ISSN

2375-2548

Volume of the periodical

4

Issue of the periodical within the volume

6

Country of publishing house

US - UNITED STATES

Number of pages

8

Pages from-to

1-8

UT code for WoS article

000443175500035

EID of the result in the Scopus database

2-s2.0-85049747957