Entanglement Transitions in Unitary Circuit Games

Repeated projective measurements in unitary circuits can lead to an entanglement phase transition as the measurement rate is tuned. In this work, we consider a different setting in which the projective measurements are replaced by dynamically chosen unitary gates that minimize the entanglement. This...

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Main Authors: Raúl Morral-Yepes, Adam Smith, S.L. Sondhi, Frank Pollmann
Format: Article
Language:English
Published: American Physical Society 2024-01-01
Series:PRX Quantum
Online Access:http://doi.org/10.1103/PRXQuantum.5.010309
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author Raúl Morral-Yepes
Adam Smith
S.L. Sondhi
Frank Pollmann
author_facet Raúl Morral-Yepes
Adam Smith
S.L. Sondhi
Frank Pollmann
author_sort Raúl Morral-Yepes
collection DOAJ
description Repeated projective measurements in unitary circuits can lead to an entanglement phase transition as the measurement rate is tuned. In this work, we consider a different setting in which the projective measurements are replaced by dynamically chosen unitary gates that minimize the entanglement. This can be seen as a one-dimensional unitary circuit game in which two players get to place unitary gates on randomly assigned bonds at different rates: the “entangler” applies a random local unitary gate with the aim of generating extensive (volume-law) entanglement. The “disentangler,” based on limited knowledge about the state, chooses a unitary gate to reduce the entanglement entropy on the assigned bond with the goal of limiting to only finite (area-law) entanglement. In order to elucidate the resulting entanglement dynamics, we consider three different scenarios: (i) a classical discrete height model, (ii) a Clifford circuit, and (iii) a general U(4) unitary circuit. We find that both the classical and Clifford circuit models exhibit phase transitions as a function of the rate that the disentangler places a gate, which have similar properties that can be understood through a connection to the stochastic Fredkin chain. In contrast, the entangler always wins when using Haar random unitary gates and we observe extensive, volume-law entanglement for all nonzero rates of entangling.
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spelling doaj.art-eabd4dc059914325937c2e5fe665e4372024-01-24T15:06:13ZengAmerican Physical SocietyPRX Quantum2691-33992024-01-015101030910.1103/PRXQuantum.5.010309Entanglement Transitions in Unitary Circuit GamesRaúl Morral-YepesAdam SmithS.L. SondhiFrank PollmannRepeated projective measurements in unitary circuits can lead to an entanglement phase transition as the measurement rate is tuned. In this work, we consider a different setting in which the projective measurements are replaced by dynamically chosen unitary gates that minimize the entanglement. This can be seen as a one-dimensional unitary circuit game in which two players get to place unitary gates on randomly assigned bonds at different rates: the “entangler” applies a random local unitary gate with the aim of generating extensive (volume-law) entanglement. The “disentangler,” based on limited knowledge about the state, chooses a unitary gate to reduce the entanglement entropy on the assigned bond with the goal of limiting to only finite (area-law) entanglement. In order to elucidate the resulting entanglement dynamics, we consider three different scenarios: (i) a classical discrete height model, (ii) a Clifford circuit, and (iii) a general U(4) unitary circuit. We find that both the classical and Clifford circuit models exhibit phase transitions as a function of the rate that the disentangler places a gate, which have similar properties that can be understood through a connection to the stochastic Fredkin chain. In contrast, the entangler always wins when using Haar random unitary gates and we observe extensive, volume-law entanglement for all nonzero rates of entangling.http://doi.org/10.1103/PRXQuantum.5.010309
spellingShingle Raúl Morral-Yepes
Adam Smith
S.L. Sondhi
Frank Pollmann
Entanglement Transitions in Unitary Circuit Games
PRX Quantum
title Entanglement Transitions in Unitary Circuit Games
title_full Entanglement Transitions in Unitary Circuit Games
title_fullStr Entanglement Transitions in Unitary Circuit Games
title_full_unstemmed Entanglement Transitions in Unitary Circuit Games
title_short Entanglement Transitions in Unitary Circuit Games
title_sort entanglement transitions in unitary circuit games
url http://doi.org/10.1103/PRXQuantum.5.010309
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AT adamsmith entanglementtransitionsinunitarycircuitgames
AT slsondhi entanglementtransitionsinunitarycircuitgames
AT frankpollmann entanglementtransitionsinunitarycircuitgames