Shared randomness allows violation of macroscopic realism using a single measurement

Macro-realistic description of systems is based majorly on two basic intuitions about the classical world, namely, macrorealism per se, that is, the system is always in a distinct state, and non-invasive measurements, that is, measurements do not disturb the system. Given the assumption of no-signal...

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Main Author: Shubhayan Sarkar
Format: Article
Language:English
Published: AIP Publishing LLC 2025-06-01
Series:APL Quantum
Online Access:http://dx.doi.org/10.1063/5.0252123
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author Shubhayan Sarkar
author_facet Shubhayan Sarkar
author_sort Shubhayan Sarkar
collection DOAJ
description Macro-realistic description of systems is based majorly on two basic intuitions about the classical world, namely, macrorealism per se, that is, the system is always in a distinct state, and non-invasive measurements, that is, measurements do not disturb the system. Given the assumption of no-signaling in time, one utilizes Leggett–Garg inequalities to observe a violation of macroscopic realism, which requires at least three measurements. In this work, we show that if one has access to shared randomness, then one can observe a violation of macroscopic realism using a single measurement even if no signaling in time is satisfied. Interestingly, using the proposed scheme one can also rule out a larger class of models, which we term macroscopic no-signaling theories that cannot violate the no-signaling in time conditions. We further construct a witness to observe the violation of macroscopic no-signaling.
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spelling doaj-art-cb112f5910f847aa9d23aa7acd4c8c2b2025-08-20T03:28:47ZengAIP Publishing LLCAPL Quantum2835-01032025-06-0122026128026128-510.1063/5.0252123Shared randomness allows violation of macroscopic realism using a single measurementShubhayan Sarkar0Laboratoire d’Information Quantique, Université libre de Bruxelles (ULB), Av. F. D. Roosevelt 50, 1050 Bruxelles, BelgiumMacro-realistic description of systems is based majorly on two basic intuitions about the classical world, namely, macrorealism per se, that is, the system is always in a distinct state, and non-invasive measurements, that is, measurements do not disturb the system. Given the assumption of no-signaling in time, one utilizes Leggett–Garg inequalities to observe a violation of macroscopic realism, which requires at least three measurements. In this work, we show that if one has access to shared randomness, then one can observe a violation of macroscopic realism using a single measurement even if no signaling in time is satisfied. Interestingly, using the proposed scheme one can also rule out a larger class of models, which we term macroscopic no-signaling theories that cannot violate the no-signaling in time conditions. We further construct a witness to observe the violation of macroscopic no-signaling.http://dx.doi.org/10.1063/5.0252123
spellingShingle Shubhayan Sarkar
Shared randomness allows violation of macroscopic realism using a single measurement
APL Quantum
title Shared randomness allows violation of macroscopic realism using a single measurement
title_full Shared randomness allows violation of macroscopic realism using a single measurement
title_fullStr Shared randomness allows violation of macroscopic realism using a single measurement
title_full_unstemmed Shared randomness allows violation of macroscopic realism using a single measurement
title_short Shared randomness allows violation of macroscopic realism using a single measurement
title_sort shared randomness allows violation of macroscopic realism using a single measurement
url http://dx.doi.org/10.1063/5.0252123
work_keys_str_mv AT shubhayansarkar sharedrandomnessallowsviolationofmacroscopicrealismusingasinglemeasurement