A Korean research team has become the first in the world to identify the mechanism behind "ultrafast electronic decoherence," a phenomenon that has been a major obstacle to realizing quantum technologies. The finding is expected to provide a critical clue to bridging the gap between theoretical models that assume a "perfectly isolated" quantum system and real-world conditions.
A research team led by Professor Lee Jae-dong of the Department of Physics and Chemistry at DGIST (Daegu Gyeongbuk Institute of Science and Technology) announced on the 25th that it has identified the microscopic mechanism by which quantum order is lost and collapses in an "open quantum environment" that exists in nature.
"High-order harmonics" generated when intense light is directed at solid materials are used for analyzing material properties, producing ultrafast pulses and generating high-energy light, making them highly valuable for both academic and industrial applications.
However, during this process, a phenomenon called "ultrafast electronic decoherence" occurs, in which the intrinsic quantum state becomes disrupted within an extremely brief span of one to two femtoseconds (one quadrillionth of a second). The fundamental cause of this phenomenon had remained unsolved.
Professor Lee's team cracked the puzzle by developing and applying a new "Lindblad master equation" computational method that overcomes the limitations of conventional quantum master equations. This enabled researchers to simultaneously and precisely account for not only electron-to-electron interactions but also interactions between electrons and their surrounding environment.
The team analyzed "superradiance" and "broadband emission" phenomena that appear during the generation of high-order harmonics in solids. They discovered that interference occurs between the two phenomena, with each canceling the other's effects.
