A new quantum theory led by a physicist from the City University of Hong Kong (CityU) recently predicted the novel functionalities of the “light-induced phase” of matter and provided an explanation for them. At room temperature, the new theory has the potential to transform quantum photonics and quantum control. Additionally, it opens the door to a wide range of light-based applications of the next generation, including technologies for light harvesting, quantum computing, and optical communications.
In addition to the standard phases of matter—solid, liquid, and gas—scientists have also discovered exotic phases. Additionally, the matter may have distinct properties in various phases characterized by specific spatial arrangements of the atoms. Light-induced phases, one of the newly discovered phases, have received a lot of attention from scientists over the past ten years because they are seen as a promising platform for new photovoltaic panels, new chemical platforms, and a new path for modern quantum technology.
“The ultrafast processes of photoactive molecules, such as electron transfer and energy redistribution, which are typically at the femtosecond scale (10–15 s), are of extensive importance for light-harvesting devices, energy conversion, and quantum computing,” said lead researcher Dr. Zhang Zhedong of CityU. Under the title “Multidimensional coherent spectroscopy for molecular polaritons,” the findings were published in the journal Physical Review Letters. Langevin method”
“The ultrafast processes of photoactive molecules, such as electron transfer and energy redistribution, which are typically at the femtosecond scale (10-15s), are extremely important for light-harvesting devices, energy conversion, and quantum computing,”
Dr. Zhang Zhedong, Assistant Professor of Physics at CityU,
However, there are many unanswered questions in the research on these processes. When short laser pulses are involved, the transient properties and ultrafast processes of molecules cannot be explained by the majority of existing theories about light-induced phases because these theories are constrained by time and energy scales. Dr. Zhang stated, “These impose a fundamental limit for investigating the light-induced phases of matter.”
Dr. Zhang and his colleagues created the world’s first quantum theory for the optical signals of the light-induced phases of molecules to address these issues. Through numerical simulations and mathematical analysis, the new theory explains the excited state dynamics and optical properties of molecules in real time, removing obstacles posed by previous theories and methods.
Ultrafast spectroscopy is combined with cutting-edge quantum electrodynamics in the new theory. It lays the groundwork for developing cutting-edge technological applications for lasers and material characterization by utilizing cutting-edge algebra to explain the nonlinear dynamics of molecules. As a result, it provides brand-new principles for quantum metrology and optical detection.
“The fact that the cooperative motion of a cluster of molecules exhibits a wave-like behavior that spreads over a distance is particularly fascinating about our new theory.” Traditional research was unable to accomplish this. Additionally, this collective motion can take place at room temperature as opposed to the previously required ultralow, cryogenic temperature. At room temperature, this suggests that precise control and sensing of particle motion may be possible. Dr. Zhang stated, “This may open new research frontiers, such as collective-driven chemistry, which could potentially transform the study of photochemistry.”
The next generation of light-harvesting and emitting devices, as well as laser operation and detection, are made simpler by the new quantum theory. Bright light emission may result from the coherence that emerges from the light-induced molecular cooperativity. Next-generation optical sensing and quantum metrology can benefit from the research’s spectroscopic probes of the light-induced phase of matter.
On a larger scale, the light-induced phases may make it possible for a wide range of novel light-based interdisciplinary applications like biological imaging, chemical catalysis control, and energy-efficient device designation for light-harvesting devices.
In the context of quantum entanglement, the researchers intend to investigate light-induced phases and their effect on quantum materials, as well as develop novel spectroscopic and detection methods.
More information: Zhedong Zhang et al, Multidimensional Coherent Spectroscopy of Molecular Polaritons: Langevin Approach, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.130.103001
