Researchers at the University of East Anglia have discovered a new method of using quantum light to observe quantum sound. The study, published in the Physical Review Letters, explores the quantum-mechanical relationship between light particles (photons) and vibrations in molecules. This discovery could enhance our understanding of how light and matter interact at a molecular level, and could have implications for quantum technologies and biological systems. The research also delves into the ongoing debate in chemical physics about whether energy transfer processes within molecules are fundamentally quantum-mechanical or classical. The team also studied correlations in the light emitted from a molecule placed in a laser field, revealing quantum behaviour. The research suggests that when a molecule exchanges phonons (quantum-mechanical particles of sound) with its environment, it produces a recognisable signal in the photon correlations.
Introduction
Researchers at the University of East Anglia, including Dr Magnus Borgh, Ben Humphries, and Dr Garth Jones, have proposed a new method of using quantum light to ‘see’ quantum sound. The study, published in Physical Review Letters, explores the interaction between light particles (photons) and vibrations in molecules. The findings could enhance understanding of light and matter interactions at a molecular level, and potentially advance quantum technologies and biological systems. The team also suggests that their research could inspire the development of new techniques to detect individual sound particles (phonons) directly.
Quantum Light Used to ‘See’ Quantum Sound
Dr Magnus Borgh from the University’s School of Physics explained the ongoing debate in chemical physics about the nature of processes where energy from particles of light is transferred within molecules. The question is whether these processes are fundamentally quantum-mechanical or classical. Molecules are complex systems that are constantly vibrating, and these vibrations could potentially affect any quantum-mechanical processes in the molecule.
Quantum Optics Techniques for Investigating Molecular Systems
The researchers suggest that techniques from quantum optics, a field of physics that studies the quantum nature of light and its interactions with matter on the atomic scale, could provide a way to investigate genuine quantum effects directly in molecular systems. Quantum behaviour can be revealed by studying correlations in the emitted light from a molecule placed in a laser field. These correlations answer the question of how likely it is that two photons are emitted very close together.
Phonons and Photon Correlations
Ben Humphries, a PhD student in theoretical chemistry at the University of East Anglia, explained that their research shows that when a molecule exchanges phonons – quantum-mechanical particles of sound – with its environment, this produces a recognisable signal in the photon correlations. While photons are routinely created and measured in laboratories worldwide, individual quanta of vibrations, which are the corresponding particles of sound, phonons, cannot generally be similarly measured.
Investigating the World of Quantum Sound in Molecules
The new findings provide a toolbox for investigating the world of quantum sound in molecules. The researchers have also computed correlations between photon and phonons. Dr Garth Jones, from the University’s School of Chemistry, expressed hope that their paper could inspire the development of new experimental techniques to detect individual phonons directly.
Publication of the Research
The research, titled ‘Phonon Signatures in Photon Correlations’, has been published in the journal Physical Review Letters. The method of research was an experimental study, and the subject of research was not applicable. The article was published on 3rd October 2023.
Dr Magnus Borgh from UEA’s School of Physics said: “There is a long-standing controversy in chemical physics about the nature of processes where energy from particles of light is transferred within molecules. Are they fundamentally quantum-mechanical or classical? Molecules are complex and messy systems, constantly vibrating. How do these vibrations affect any quantum-mechanical processes in the molecule? These processes are typically investigated using techniques that rely on polarisation – the same property of light used in sunglasses to reduce reflections. But this is a classical phenomenon. Techniques from quantum optics, the field of physics that studies the quantum nature of light and its interactions with matter on the atomic scale, can offer a way to investigate genuine quantum effects directly in molecular systems.”
“Ben Humphries, PhD student in theoretical chemistry, at UEA said: “Our research shows that when a molecule exchanges phonons – quantum-mechanical particles of sound – with its environment, this produces a recognisable signal in the photon correlations.”
“Lead researcher Dr Garth Jones, from UEA’s School of Chemistry, said: “We have also computed correlations between photon and phonons. It would be very exciting if our paper could inspire the development of new experimental techniques to detect individual phonons directly,” he added.
Quick Summary
Researchers at the University of East Anglia have proposed a method of using quantum light to ‘see’ quantum sound, potentially enhancing understanding of light and matter interactions at a molecular level. The study, which could inspire the development of new techniques to detect individual phonons (particles of sound), may have implications for quantum technologies and biological systems.”
- Researchers at the University of East Anglia have proposed a new method of using quantum light to observe quantum sound, according to a paper published in the Physical Review Letters.
- The study explores the quantum-mechanical relationship between vibrations and particles of light, or photons, in molecules.
- The findings could enhance understanding of light and matter interactions at the molecular level and could have implications for quantum technologies and biological systems.
- Dr Magnus Borgh and Dr Garth Jones from UEA’s School of Physics and School of Chemistry respectively, along with PhD student Ben Humphries, are involved in the research.
- The team used techniques from quantum optics to investigate quantum effects in molecular systems.
- The research suggests that when a molecule exchanges phonons (quantum-mechanical particles of sound) with its environment, it produces a recognisable signal in the photon correlations.
- The team hopes their work could inspire the development of new experimental techniques to detect individual phonons directly.
