Quantum Sensing with Atom-Light Hybrid Interferometers

Project: Research

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Quantum interference is at the heart of the second quantum revolution that is currently under way and exploits the entanglement nature in atoms and photons for information processing with superior speed and transmission with unbreakable security. Whileclassical interferometric technique has been applied in gravitational wave detection with unprecedent precision, applications of quantum states of light to classical interferometers promise to give rise to even better sensitivity. Recently, we realized a novel type of quantum interferometer that is based on nonlinear interaction between waves. The interferometer is intrinsically quantum mechanical because of the quantum entanglement created in the nonlinear process. Compared to the traditional classical interferometers, it has a number of advantages, among which the most attractive is the coupling and interference of different waves. In this research program, we will study this new type of quantum interferometers but involve optical waves and atomic waves. Thus, the interferometers are sensitive to the phases of both waves. Our goal is to better understand the quantum nature of this newlyinvented interferometer, which is by itself a new paradigm in interferometry, and apply it to high precision measurement by using atoms as sensors but photons for detection. Here, we first study the quantum noise correlation between atom and light and use thiscorrelation to reduce the quantum noise in order to enhance the sensitivity of the interferometer. Then, we will use the hybrid interferometers for probing atom's internal state change under the influence of external magnetic and optical fields. The study ofmagnetic influence on atoms will lead to highly sensitive magnetometers with accuracy beyond classical limit by employing the quantum entanglement between atom and light. The effect of light fields on atomic phase change allows one to make quantum non-demolition measurement of photon number of the light field. This paves way to study the fundamental yet elusive quantum measurement process. The program can lead to new approaches in quantum interferometry and open up a new way for quantum control and manipulations of quantum states of atomic and optical systems. The program involves precision phase measurement and thus has practicalapplications in quantum metrology. Potential industrial transfer of the quantum technology will be possible for sensing applications. The experiments are performed on tabletops, which are the perfect platform for training next generation quantum physicists and preparing them for the second quantum revolution. 


Project number9043399
Grant typeGRF
Effective start/end date1/01/23 → …