Professor Chen Feng's team at the School of Physics has made important progress in the study of quantum Zeno effect and dynamical quantum control. They proposed a new method for realizing optical Zeno effect in an integrated photonics system and using Zeno dynamics to control system evolution. The related paper titled "Engineering of Zeno Dynamics in Integrated Photonics" was published in the international physics authoritative journal Physical Review Letters. Professor Chen Feng is the corresponding author of the paper, and PhD students Liu Quancheng and Liu Weijie are co-first authors. Shandong University is the first author institute and corresponding author institute.

Measurement is a fundamental scientific problem in quantum mechanics and also plays an important role in quantum technology. Unlike the classical world, observation of a quantum system will change its state. In the classical world, measurement only extracts physical quantities, and measuring the speed of a car does not affect its operation. However, if it is a quantum car, its operation will be changed by measurement and collapse to the measured eigenstate. The Zeno effect shows that if a quantum system is rapidly and frequently measured, its evolution will be frozen, which provides the possibility of using measurement to control the system. However, simply freezing the evolution of a system cannot provide more possibilities for its control. How to use the Zeno effect to achieve more control over the system, even complete control, is an important scientific problem and also has potential application prospects.

Professor Chen Feng's team and collaborators proposed a novel method for achieving periodic rapid measurement of the observed system in an integrated optical system and proposed a new theoretical model - quantum Zeno slicing. This method can realize multidimensional control of the system by designing different Zeno dynamics processes, providing a new way to control system evolution using the Zeno effect. In the experiment, the researchers used the optical waveguide array (photonic lattice) to make reasonable analogies and correspondences between the optical waveguide mode and different quantum states and mapped the time evolution of the system into the spatial extension of the optical system, and implemented the measurement process using pre-designed interrupted waveguides. Under strong measurement, the researchers successfully realized the Zeno effect and Zeno dynamics in the optical system and verified the relationship between them. Based on this, using the quantum Zeno slicing method, the researchers generated a series of different Zeno subspaces in the optical system through different projection measurement processes, achieved dynamic slicing of the system's original Hilbert space, enhanced the complexity of the system evolution, and thus achieved complete control of the system evolution.

This research demonstrates a new and scalable experimental method for realizing the Zeno effect and controlling Zeno dynamics in the optical waveguide array. At the same time, the quantum Zeno slicing model provides a new way for using the Zeno effect to achieve further quantum state control and quantum information processing, which is of great significance for a deeper understanding of the Zeno effect and the development of information technology based on the Zeno effect.

This research was supported by Professor Klaus Ziegler (University of Augsburg, Germany), the National Natural Science Foundation of China, the Major Basic Research Project of Natural Science Foundation of Shandong Province, the Taishan Scholar Climbing Program of Shandong Province, and the State Key Laboratory of Crystal Materials.

Figure (a) Optical Zeno effect | Figure (b) Implementation of Zeno dynamics slicing in the optical waveguide array.

Link to the paper：https://doi.org/10.1103/PhysRevLett.130.103801