Entanglement Phase Transitions in Measurement-Only Dynamics
Unitary circuits subject to repeated projective measurements can undergo an entanglement phase transition (EPT) as a function of the measurement rate. This transition is generally understood in terms of a competition between the scrambling effects of unitary dynamics and the disentangling effects of...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2021-02-01
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| Series: | Physical Review X |
| Online Access: | http://doi.org/10.1103/PhysRevX.11.011030 |
| _version_ | 1818421096536342528 |
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| author | Matteo Ippoliti Michael J. Gullans Sarang Gopalakrishnan David A. Huse Vedika Khemani |
| author_facet | Matteo Ippoliti Michael J. Gullans Sarang Gopalakrishnan David A. Huse Vedika Khemani |
| author_sort | Matteo Ippoliti |
| collection | DOAJ |
| description | Unitary circuits subject to repeated projective measurements can undergo an entanglement phase transition (EPT) as a function of the measurement rate. This transition is generally understood in terms of a competition between the scrambling effects of unitary dynamics and the disentangling effects of measurements. We find that, surprisingly, EPTs are possible even in the absence of scrambling unitary dynamics, where they are best understood as arising from measurements alone. This finding motivates us to introduce measurement-only models, in which the “scrambling” and “unscrambling” effects driving the EPT are fundamentally intertwined and cannot be attributed to physically distinct processes. These models represent a novel form of an EPT, conceptually distinct from that in hybrid unitary-projective circuits. We explore the entanglement phase diagrams, critical points, and quantum code properties of some of these measurement-only models. We find that the principle driving the EPTs in these models is frustration, or mutual incompatibility, of the measurements. Surprisingly, an entangling (volume-law) phase is the generic outcome when measuring sufficiently long but still local (≳3-body) operators. We identify a class of exceptions to this behavior (“bipartite ensembles”) which cannot sustain an entangling phase but display dual area-law phases, possibly with different kinds of quantum order, separated by self-dual critical points. Finally, we introduce a measure of information spreading in dynamics with measurements and use it to demonstrate the emergence of a statistical light cone, despite the nonlocality inherent to quantum measurements. |
| first_indexed | 2024-12-14T13:04:56Z |
| format | Article |
| id | doaj.art-a788681ae5d44405bb9def41fc8ab855 |
| institution | Directory Open Access Journal |
| issn | 2160-3308 |
| language | English |
| last_indexed | 2024-12-14T13:04:56Z |
| publishDate | 2021-02-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review X |
| spelling | doaj.art-a788681ae5d44405bb9def41fc8ab8552022-12-21T23:00:20ZengAmerican Physical SocietyPhysical Review X2160-33082021-02-0111101103010.1103/PhysRevX.11.011030Entanglement Phase Transitions in Measurement-Only DynamicsMatteo IppolitiMichael J. GullansSarang GopalakrishnanDavid A. HuseVedika KhemaniUnitary circuits subject to repeated projective measurements can undergo an entanglement phase transition (EPT) as a function of the measurement rate. This transition is generally understood in terms of a competition between the scrambling effects of unitary dynamics and the disentangling effects of measurements. We find that, surprisingly, EPTs are possible even in the absence of scrambling unitary dynamics, where they are best understood as arising from measurements alone. This finding motivates us to introduce measurement-only models, in which the “scrambling” and “unscrambling” effects driving the EPT are fundamentally intertwined and cannot be attributed to physically distinct processes. These models represent a novel form of an EPT, conceptually distinct from that in hybrid unitary-projective circuits. We explore the entanglement phase diagrams, critical points, and quantum code properties of some of these measurement-only models. We find that the principle driving the EPTs in these models is frustration, or mutual incompatibility, of the measurements. Surprisingly, an entangling (volume-law) phase is the generic outcome when measuring sufficiently long but still local (≳3-body) operators. We identify a class of exceptions to this behavior (“bipartite ensembles”) which cannot sustain an entangling phase but display dual area-law phases, possibly with different kinds of quantum order, separated by self-dual critical points. Finally, we introduce a measure of information spreading in dynamics with measurements and use it to demonstrate the emergence of a statistical light cone, despite the nonlocality inherent to quantum measurements.http://doi.org/10.1103/PhysRevX.11.011030 |
| spellingShingle | Matteo Ippoliti Michael J. Gullans Sarang Gopalakrishnan David A. Huse Vedika Khemani Entanglement Phase Transitions in Measurement-Only Dynamics Physical Review X |
| title | Entanglement Phase Transitions in Measurement-Only Dynamics |
| title_full | Entanglement Phase Transitions in Measurement-Only Dynamics |
| title_fullStr | Entanglement Phase Transitions in Measurement-Only Dynamics |
| title_full_unstemmed | Entanglement Phase Transitions in Measurement-Only Dynamics |
| title_short | Entanglement Phase Transitions in Measurement-Only Dynamics |
| title_sort | entanglement phase transitions in measurement only dynamics |
| url | http://doi.org/10.1103/PhysRevX.11.011030 |
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