The search for novel entangled phases of matter has lead to the recent discovery of a new class of “entanglement transitions,” exemplified by random tensor networks and monitored quantum circuits. Most known examples can be understood as some classical ordering transitions in an underlying statistical mechanics model, where entanglement maps onto the free-energy cost of inserting a domain wall. In this paper we study the possibility of entanglement transitions driven by physics beyond such statistical mechanics mappings. Motivated by recent applications of neural-network-inspired variational Ansätze, we investigate under what conditions on the variational parameters these Ansätze can capture an entanglement transition. We study the entanglement scaling of short-range restricted Boltzmann machine (RBM) quantum states with random phases. For uncorrelated random phases, we analytically demonstrate the absence of an entanglement transition and reveal subtle finite-size effects in finite-size numerical simulations. Introducing phases with correlations decaying as 1/r^α in real space, we observe three regions with a different scaling of entanglement entropy depending on the exponent α. We study the nature of the transition between these regions, finding numerical evidence for critical behavior. Our work establishes the presence of long-range correlated phases in RBM-based wave functions as a required ingredient for entanglement transitions.
Physical Review B
We would like to thank S. De Nicola, P. Brighi, and V. Karle for fruitful discussions and valuable feedback on the manuscript. R.M. and M.S. acknowledge support by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (Grant Agreement No. 850899). R.V. acknowledges support from the US Department of Energy, Office of Science, Basic Energy Sciences, under Early Career Award No. DE-SC0019168, and the Alfred P. Sloan Foundation through a Sloan Research Fellowship.
Medina Ramos RA, Vasseur R, Serbyn M. Entanglement transitions from restricted Boltzmann machines. Physical Review B. 2021;104(10). doi:10.1103/physrevb.104.104205
Medina Ramos, R. A., Vasseur, R., & Serbyn, M. (2021). Entanglement transitions from restricted Boltzmann machines. Physical Review B. American Physical Society. https://doi.org/10.1103/physrevb.104.104205
Medina Ramos, Raimel A, Romain Vasseur, and Maksym Serbyn. “Entanglement Transitions from Restricted Boltzmann Machines.” Physical Review B. American Physical Society, 2021. https://doi.org/10.1103/physrevb.104.104205.
R. A. Medina Ramos, R. Vasseur, and M. Serbyn, “Entanglement transitions from restricted Boltzmann machines,” Physical Review B, vol. 104, no. 10. American Physical Society, 2021.
Medina Ramos RA, Vasseur R, Serbyn M. 2021. Entanglement transitions from restricted Boltzmann machines. Physical Review B. 104(10), 104205.
Medina Ramos, Raimel A., et al. “Entanglement Transitions from Restricted Boltzmann Machines.” Physical Review B, vol. 104, no. 10, 104205, American Physical Society, 2021, doi:10.1103/physrevb.104.104205.