Probing scrambling and operator size distributions using random mixed states and local measurements

Fuente: arXiv
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Hauptverfasser: Blocher, Philip Daniel, Chinni, Karthik, Omanakuttan, Sivaprasad, Poggi, Pablo M.
Format: Preprint
Veröffentlicht: 2023
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author Blocher, Philip Daniel
Chinni, Karthik
Omanakuttan, Sivaprasad
Poggi, Pablo M.
author_facet Blocher, Philip Daniel
Chinni, Karthik
Omanakuttan, Sivaprasad
Poggi, Pablo M.
contents The dynamical spreading of quantum information through a many-body system, typically called scrambling, is a complex process that has proven to be essential to describe many properties of out-of-equilibrium quantum systems. Scrambling can, in principle, be fully characterized via the use of out-of-time-ordered correlation functions, which are notoriously hard to access experimentally. In this work, we put forward an alternative toolbox of measurement protocols to experimentally probe scrambling by accessing properties of the operator size probability distribution, which tracks the size of the support of observables in a many-body system over time. Our measurement protocols require the preparation of separable mixed states together with local operations and measurements, and combine the tools of randomized operations, a modern development of near-term quantum algorithms, with the use of mixed states, a standard tool in NMR experiments. We demonstrate how to efficiently probe the probability-generating function of the operator distribution and discuss the challenges associated with obtaining the moments of the operator distribution. We further show that manipulating the initial state of the protocol allows us to directly obtain the individual elements of the distribution for small system sizes.
format Preprint
id arxiv_https___arxiv_org_abs_2305_16992
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Probing scrambling and operator size distributions using random mixed states and local measurements
Blocher, Philip Daniel
Chinni, Karthik
Omanakuttan, Sivaprasad
Poggi, Pablo M.
Quantum Physics
The dynamical spreading of quantum information through a many-body system, typically called scrambling, is a complex process that has proven to be essential to describe many properties of out-of-equilibrium quantum systems. Scrambling can, in principle, be fully characterized via the use of out-of-time-ordered correlation functions, which are notoriously hard to access experimentally. In this work, we put forward an alternative toolbox of measurement protocols to experimentally probe scrambling by accessing properties of the operator size probability distribution, which tracks the size of the support of observables in a many-body system over time. Our measurement protocols require the preparation of separable mixed states together with local operations and measurements, and combine the tools of randomized operations, a modern development of near-term quantum algorithms, with the use of mixed states, a standard tool in NMR experiments. We demonstrate how to efficiently probe the probability-generating function of the operator distribution and discuss the challenges associated with obtaining the moments of the operator distribution. We further show that manipulating the initial state of the protocol allows us to directly obtain the individual elements of the distribution for small system sizes.
title Probing scrambling and operator size distributions using random mixed states and local measurements
topic Quantum Physics
url https://arxiv.org/abs/2305.16992