TY - JOUR
T1 - Entanglement Phase Transitions in Measurement-Only Dynamics
AU - Ippoliti, Matteo
AU - Gullans, Michael J.
AU - Gopalakrishnan, Sarang
AU - Huse, David A.
AU - Khemani, Vedika
N1 - Funding Information:
We thank Roderich Moessner, Jed Pixley, Romain Vasseur, Dominic Williamson, Justin Wilson, and Aidan Zabalo for insightful discussions and collaborations on related topics. M. I. and D. A. H. were supported with funding from the Defense Advanced Research Projects Agency (DARPA) via the DRINQS program. The views, opinions and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government. M. I. was also funded in part by the Gordon and Betty Moore Foundation's EPiQS Initiative through Grants No. GBMF4302 and No. GBMF8686. S. G. acknowledges support from NSF DMR-1653271. V. K. acknowledges support from the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Early Career Award No. DE-SC0021111. D. A. H. was also supported in part by a Simons Fellowship.
Funding Information:
We thank Roderich Moessner, Jed Pixley, Romain Vasseur, Dominic Williamson, Justin Wilson, and Aidan Zabalo for insightful discussions and collaborations on related topics. M. I. and D. A. H. were supported with funding from the Defense Advanced Research Projects Agency (DARPA) via the DRINQS program. The views, opinions and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government. M. I. was also funded in part by the Gordon and Betty Moore Foundation’s EPiQS Initiative through Grants No. GBMF4302 and No. GBMF8686. S. G. acknowledges support from NSF DMR-1653271. V. K. acknowledges support from the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Early Career Award No. DE-SC0021111. D. A. H. was also supported in part by a Simons Fellowship.
Publisher Copyright:
© 2021 authors. Published by the American Physical Society.
PY - 2021/2/15
Y1 - 2021/2/15
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85100884489&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85100884489&partnerID=8YFLogxK
U2 - 10.1103/PhysRevX.11.011030
DO - 10.1103/PhysRevX.11.011030
M3 - Article
AN - SCOPUS:85100884489
SN - 2160-3308
VL - 11
JO - Physical Review X
JF - Physical Review X
IS - 1
M1 - 011030
ER -