A new theorem from researchers at the RIKEN Center for Advanced Intelligence Project, Tokyo, and Keio University, Yokohama, provides an understanding of what types of long-range quantum entanglement survive at non-zero temperatures, revealing a fundamental aspect of macroscopic quantum phenomena and guiding the way towards further understanding of quantum systems and designing new room-temperature stable quantum devices.
Long-range entanglement is central to quantum information theory, and its further understanding could lead to a breakthrough in quantum computing technologies. However, long-range quantum entanglement is stable at specific conditions, such as between three or more parties and at temperatures close to absolute zero (-273°C). What happens to two-party entangled systems at non-zero temperatures?
The researchers’ findings are consistent with previous observations that long-range entanglement survives at a non-zero temperature only when more than three subsystems are involved. The results suggest this is a fundamental aspect of macroscopic quantum phenomena at room temperatures, and that quantum devices need to be engineered to have multipartite entangled states.
The team provides simple no-go theorems that show what kinds of long-range entanglement can survive at non-zero temperatures. At temperatures above absolute zero, particles in a material vibrate and move around due to thermal energy, which acts against quantum entanglement. At arbitrary non-zero temperatures, no long-range entanglement can persist between only two subsystems.
The study has been published in Physical Review X.
