April 26, 2022
RIKEN
Keio University
Japan Science and Technology Agency (JST)
A joint research team, comprising Tomohiro Kuwahara, a researcher at the Mathematical Science Team, RIKEN Center for Advanced Intelligence Project (AIP) at the time of the research (currently a RIKEN Hakubi Team Leader at the Kuwahara Quantum Complexity RIKEN Hakubi Research Team, RIKEN Cluster for Pioneering Research (CPR), and the Quantum Complexity RIKEN Hakubi Research Team, RIKEN Center for Quantum Computing (RQC)), and Professor Keiji Saito of the Faculty of Science and Technology at Keio University, has shown that in thermal equilibrium states of many-particle systems governed by quantum mechanics (quantum many-body systems), long-range "quantum entanglement" generally does not exist.
These research findings are expected to provide significant insights into quantum computation, including quantum machine learning, and contribute to the classification of quantum entanglement involved in various quantum physical phenomena observed at finite temperatures.
Since quantum entanglement plays an essential role in quantum computation using quantum computers, elucidating its effects at finite temperatures has been a major unsolved problem.
In this study, the joint research team analytically evaluated the amount of standard bipartite quantum entanglement between two regions and found that the entanglement between two sufficiently separated regions becomes dramatically smaller at finite temperatures. This result indicates that while bipartite quantum entanglement can exist in general quantum many-body systems at absolute zero (approximately -273°C), only special tripartite quantum entanglement can survive at finite temperatures.
This research will be published in the online scientific journal "Physical Review X" on April 27.
For the full press release, please see below.