A research team led by Professor Jaedong Lee from the Department of Chemical Physics at DGIST (President Kunwoo Lee) has unveiled a groundbreaking quantum state and an innovative mechanism for manipulating quantum information through exciton and Floquet states.
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Collaborating with Professor Noejung Park from UNIST’s Department of Physics (President Chongrae Park), the team has, for the first time, demonstrated the formation and synthesis process of exciton and Floquet states, which result from light-matter interactions in two-dimensional semiconductors.
This research captures quantum information in real-time as it develops through entanglement, providing significant insights into the exciton formation process in these materials and advancing quantum information technology.
Unlike conventional three-dimensional solids, where quantum coherence is difficult to maintain due to thermal effects, two-dimensional semiconductors have energy levels for excitons and conduction bands that remain distinct due to weaker screening effects. This characteristic allows coherence to be preserved for longer periods, making two-dimensional semiconductors promising candidates for quantum information devices. However, the coherence and decoherence mechanisms of electrons during exciton formation have not been well understood until now.
Using theoretical calculations with time-resolved angular-resolved photoelectron spectroscopy on two-dimensional semiconductor materials, Professor Lee’s team confirmed that exciton formation occurs alongside the creation of a Floquet state, resulting in a combined new quantum state. They also identified the mechanism for quantum entanglement within this state and proposed a real-time method for extracting, unfolding, and controlling quantum information.
We have discovered a new quantum state, known as the exciton-Floquet synthesis state, and proposed a novel mechanism for quantum entanglement and quantum information extraction. This is anticipated to drive forward quantum information technology research in two-dimensional semiconductors. This research sets a new paradigm for quantum information technology, including quantum computers, marking an important milestone for its realization.
Jaedong Lee, Professor, Department of Chemical Physics, Daegu Gyeongbuk Institute of Science and Technology
Journal Reference:
Park, H. et. al. (2024) Novel Quantum States of Exciton–Floquet Composites: Electron–Hole Entanglement and Information. Nano Letters. doi.org/10.1021/acs.nanolett.4c03100