Groundbreaking Quantum Theory Explores Light-Influenced Matter, Propels Optical Tech Innovation

A pictorial representation depicts the process of time-resolved spectroscopy for the light-influenced phase of molecules, a concept emerging from a new quantum theory. The emission signal captured in the detector follows laser pulses exciting the molecules, allowing multi-dimensional real-time imaging of exciton dynamics. Credit: Dr. Zhedong Zhang/City University of Hong Kong

Scientists at the City University of Hong Kong have developed an innovative quantum theory that deepens our understanding of matter’s ‘light-induced phase’. This breakthrough could transform quantum photonics and control, even at room temperature. The theory significantly improves our comprehension of the excited state dynamics and optical attributes of molecules, contributing to the advancement of light-harvesting technologies and setting the stage for developments in optical communications, biological imaging, and quantum metrology.

Under the leadership of a physicist from City University of Hong Kong (CityU), a team has devised a pioneering quantum theory that decodes the “light-induced phase” of matter, unveiling its unique features. This theoretical development has the potential to reshape the landscape of quantum photonics and quantum control at room temperature, paving the way for future light-based applications such as optical communications, quantum computing, and light-harvesting technologies.

In addition to the commonly known phases of matter – solid, liquid, and gas – scientists have discovered exotic phases, where atoms assume different spatial arrangements, resulting in varied properties. Among these newly identified phases, the light-induced ones have attracted significant scientific attention over the past decade, being viewed as a promising foundation for innovative photovoltaic panels, chemical platforms, and quantum technology.

Dr. Zhang Zhedong (2nd from right) and his research group at City University of Hong Kong. Credit: Dr. Zhang Zhedong / City University of Hong Kong

Dr. Zhang Zhedong, Assistant Professor of Physics at CityU, who guided the study, elaborated, “The ultrafast processes of photoactive molecules, such as electron transfer and energy redistribution – typically measured at the femtosecond scale (10-15s) – are fundamentally important for light-harvesting devices, energy conversion, and quantum computing. Despite their importance, current research on these processes is still obscure. Existing theories on light-induced phases are hindered by time and energy scales and fail to explain the transient properties and ultrafast processes of molecules when short laser pulses are applied. This creates a fundamental challenge in exploring light-induced phases of matter.”

To overcome these issues, Dr. Zhang and his colleagues have created an innovative quantum theory for the optical signals of light-induced molecular phases – a world-first achievement. This groundbreaking theory, derived from mathematical analysis and numerical simulations, explains the excited state dynamics and optical attributes of molecules in real-time, bypassing the limitations posed by existing theories and methods.

The theory incorporates advanced quantum electrodynamics into ultrafast spectroscopy, utilizing modern algebra to illustrate the nonlinear dynamics of molecules. This lays the groundwork for the creation of cutting-edge applications for lasers and material characterization, offering new principles for optical detection and quantum metrology.

Dr. Zhang highlights, “What sets our new theory apart is the wave-like behavior exhibited by a group of molecules moving cooperatively. Such a phenomenon, unattainable in conventional studies, can persist at room temperature, unlike the previous limitation to extremely low, cryogenic temperatures. This suggests that precise control and sensing of particle motion might be possible at room temperature, opening up exciting new research directions like collective-driven chemistry that could radically change photochemistry studies.”

This innovative quantum theory aids in designing the next generation of light-harvesting and emitting devices, laser operation, and detection. The coherence arising from the light-induced cooperative action of molecules may lead

Frequently Asked Questions (FAQs) about Quantum Theory

More about Quantum Theory

• Physical Review Letters
• Quantum Physics Basics
• City University of Hong Kong
• Light-Induced Phases of Matter
• Quantum Photonics