Light-matter interaction reveals new paradigm of quantum information technology

A research team led by Professor Jaedong Lee from the Department of Chemical Âé¶¹ÒùÔºics of DGIST has introduced a novel quantum state and a pioneering mechanism for extracting and controlling quantum information using exciton and Floquet states.
Collaborating with Professor Noejung Park from UNIST's Department of Âé¶¹ÒùÔºics, the team has, for the first time, demonstrated the formation and synthesis process of exciton and Floquet states, which arise from light-matter interactions in two-dimensional semiconductors.
The study, in Nano Letters in October, captures quantum information in real-time as it unfolds through entanglement, offering valuable insights into the exciton formation process in these materials, thereby advancing quantum information technology.
Unlike traditional three-dimensional solids, where quantum coherence is challenging to maintain owing to thermal influences, two-dimensional semiconductors feature energy levels for excitons and conduction bands that remain distinct owing to weaker screening effects, thus preserving coherence over extended periods.
This distinction makes two-dimensional semiconductors promising for developing quantum information devices. Yet, until now, the coherence and decoherence mechanisms of electrons during exciton formation have been poorly understood.
Through theoretical calculations using time-resolved angular-resolved photoelectron spectroscopy on two-dimensional semiconductor materials, Professor Lee's team confirmed that exciton formation coincides with the creation of a Floquet state, producing a combined new quantum state.
Additionally, they identified the mechanism by which quantum entanglement occurs within this state and proposed a real-time method to extract, unfold, and control quantum information.
Professor Jaedong Lee, of DGIST's Department of Chemical Âé¶¹ÒùÔºics, said, "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."
UNIST's Professor Noejung Park added, "This research sets a new paradigm for quantum information technology, including quantum computers, marking an important milestone for its realization."
More information: Hyosub Park et al, Novel Quantum States of Exciton–Floquet Composites: Electron–Hole Entanglement and Information, Nano Letters (2024).
Journal information: Nano Letters
Provided by DGIST (Daegu Gyeongbuk Institute of Science and Technology)