山西大学激光光谱研究所

2025-03-01
In a periodic driven time-dependent system, a time dislocation topological lattice was successfully constructed by introducing time shifts in different spatial regions. Research has found that time dislocations can induce boundary and corner states with topological protection properties; Although the coupling of the entire lattice presents a uniform distribution in space, localized topological boundary states appear at the time interface within the system. Developed topological invariants for characterizing temporal dislocation topological states and proved the topological protection properties of temporal dislocation topological boundary states. This study expands the research scope of topological boundary states from the traditional spatial dimension to the temporal dimension, providing a new degree of freedom for exploring novel topological states and their quantum control.

2025-02-05
The research team has broken through the research paradigm of photon Anderson localized phase transition in the traditional disorder dimension (as shown on the left side of Figure a, which is characterized by the synchronous occurrence of localized extended state phase transition in all eigenstates when the disorder intensity of the system is below the critical value), and for the first time achieved photon Anderson phase transition in the energy dimension in an optical waveguide lattice. The research results include: as the disorder intensity decreases, it was found that the eigenstates in the intermediate eigenenergy range undergo localized extended state phase transitions first, while the eigenstates in the low-energy and high-energy regions still remain localized (as shown on the right side of Figure a); The intrinsic energy critical point of localized extension phase transition was directly measured, and it was observed that photon Anderson localization exhibits very different non-equilibrium quantum dynamic behaviors.

2025-1-19
The research team has discovered for the first time a concise and elegant physical connection between chiral quantum dynamics and Loschmidt echoes, that is, the amplitude of Loschmidt at time t is equal to the chiral center at time t/2. Using this physical connection, the research team further discovered that chiral quantum dynamics can directly detect topological localized density of states. This method is powerful and can simultaneously reveal the energy spectrum and spatial distribution topological characteristics of topological boundary states. This method also has universality, not only applicable to statically balanced topology systems, but also to periodically driven non-equilibrium topology systems. The research team has demonstrated that the local density of states in non-equilibrium topology can directly detect and reveal the unique topological characteristics of non-equilibrium topological states, including periodic topological quasi spectra and topological patterns, providing a new means for non-equilibrium topology detection.