Entanglement Phase Transitions in Measurement-Only Dynamics

By Matteo Ippoliti, Michael J. Gullans, S. Gopalakrishnan, D. Huse, V. Khemani. Physical Review X, 2020

254 citations recorded by the source corpus.

Unitary circuits subject to repeated projective measurements can undergo an entanglement transition 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, entanglement transitions are possible even in the absence of scrambling unitary dynamics. We illustrate this phenomenon in models where the unitary dynamics is non-scrambling, as well as models where the dynamics is entirely due to local few-site measurements. This opens the door to a vast landscape of measurement-only models, in which the ``scrambling'' and ``un-scrambling'' effects that drive the entanglement transition are not separable into distinct physical processes. We show numerical results on the entanglement phase diagrams, critical points, locality, and quantum code properties of some of these measurement-only models. We find that an entangling (volume-law) phase is the default outcome, while disentangling (area-law) phases are possible in the presence of special restrictions on the size or commutativity of the measurements. We propose `frustration' of the measurement ensemble as the principle driving the entanglement transition in this class of dynamics.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/40bc39e1a4677da82df1a33067532cb9563da434

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Artificial Intelligence

1. A. Nahum
2. Matthew Fisher
3. B. Skinner
4. V. Khemani
5. J. Ruhman
6. Yaodong Li
7. S. Vijay
8. Sthitadhi Roy

In Atomic and Molecular Physics, and Optics

1. Matthew Fisher
2. A. Nahum
3. Yaodong Li
4. V. Khemani
5. B. Skinner
6. J. Ruhman
7. S. Vijay
8. Sthitadhi Roy

Citations in the corpus

• Entanglement Phase Transition Induced by the Non-Hermitian Skin Effect (2022, background): “It should also be noted that a couple of recent works on random nonunitary quantum dynamics have reported a similar subextensive growth of the steady-state entanglement entropy with the parameter-dependent effective central charge [20, 22, 67].”
• Measurement and Entanglement Phase Transitions in All-To-All Quantum Circuits, on Quantum Trees, and in Landau-Ginsburg Theory (2020, background): “An alternative profitable direction is to study circuits made from Clifford unitaries [7, 12, 15, 17, 22, 36–40].”
• Random Quantum Circuits (2022, background): “Monitored pure-states in measurement-only dynamics can also display phase transitions between volume and area law-scaling of the entanglement entropy (78).”
• Statistical mechanics of quantum error correcting codes (2020, background): “(7)), but remains unchanged otherwise [23, 40].”