January 6, 2022
Keio University
RIKEN
A research team, including Takahiro Minato, a second-year master's student at the Graduate School of Science and Technology at Keio University; Assistant Professor Takahiro Sugimoto and Professor Keiji Saito of the Department of Physics, Faculty of Science and Technology at the same university; and Tomotaka Kuwahara, a researcher at the Mathematical Science Team, RIKEN Center for Advanced Intelligence Project, has discovered new conditions for the emergence of a measurement-induced phase transition caused by the competition between the strength of quantum entanglement and quantum measurement. In a many-particle system exhibiting quantum mechanical time evolution, quantum entanglement generally increases over time. On the other hand, the effects of quantum measurement and quantum dissipation reduce quantum entanglement. As a result, as the frequency of quantum measurements increases, a phase transition (measurement-induced phase transition) occurs in the growth rate of quantum entanglement. The research team derived a general condition for the occurrence of a measurement-induced phase transition when many particles exert forces on each other over long distances. This discovery is expected to provide not only new insights into measurement-induced phase transitions but also useful knowledge regarding the robustness of quantum entanglement generation in noisy quantum computers. The results of this research were published online in the American Physical Society journal "Physical Review Letters" on January 5, 2022 (local time). It was also selected as an Editors’ Suggestion in the same journal.
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