In a groundbreaking study published in Physical Review Letters, researchers have unveiled the first experimental observation of non-Hermitian edge burst in quantum dynamics. This exciting discovery sheds light on the unique behavior of non-Hermitian systems, which play a crucial role in understanding real-world systems characterized by dissipation, environmental interactions, or gain-and-loss mechanisms. Unlike Hermitian systems, non-Hermitian systems exhibit new physics phenomena such as boundary localization, which can have significant applications in photonics and condensed matter physics.
The Motivation Behind the Study
The co-authors of the study, including Prof. Wei Yi from the University of Science and Technology of China, Prof. Zhong Wang from Tsinghua University, and Prof. Peng Xue from Beijing Computational Science Research Center, shared their motivations for exploring non-Hermitian systems. Prof. Xue highlighted the discovery of the non-Hermitian skin effect (NHSE) as a key incentive for their research. The term NHSE was coined in an earlier study by Prof. Wang and his colleague, sparking their interest in uncovering dynamic phenomena with extreme sensitivity to boundaries in non-Hermitian systems.
Unlike Hermitian systems where operators are equal to their Hermitian conjugates, non-Hermitian systems have complex eigenvalues that lead to distinctive phenomena like the NHSE. In NHSE, eigenstates accumulate at the edges or boundaries of the system, a behavior not observed in bulk properties of Hermitian systems. These effects are typically seen in open systems with gain or loss in energy, known as the Hamiltonian.
Previous studies have focused on static aspects of non-Hermitian systems, such as energy spectra. However, the researchers in this study delved into the real-time dynamics of non-Hermitian systems to understand how edge dynamics evolve over time. By utilizing a one-dimensional quantum walk setup with photons, the team introduced probabilistic movement through quantum coin flips, simulating real-world systems where the Hamiltonian evolves over time.
The researchers used optical tools like beam splitters, wave plates, and beam displacers to study the edge dynamics in non-Hermitian systems. By introducing photon loss at the boundary using partially polarizing beam splitters, they were able to measure the occurrence of loss at different positions and times, providing insight into the dynamics of the edge. They found that the non-Hermitian edge burst only occurs when two specific conditions are met: the presence of the NHSE and the closing of the imaginary gap in the energy spectrum.
The experimental observation of non-Hermitian edge burst opens new avenues for research in the field of quantum dynamics. The researchers believe that the spatial and spectral sensitivity of the edge burst could lead to innovations in localized light harvesting or quantum sensing. The findings pave the way for studying real-time dynamics in non-Hermitian topological systems and hint at the presence of universal scaling relations in non-Hermitian systems.
The discovery of non-Hermitian edge burst in quantum dynamics represents a significant milestone in understanding the interplay between topological physics and dynamical phenomena. The researchers’ work not only expands our knowledge of non-Hermitian systems but also offers practical implications for applications in photonics and other wave-based fields. Moving forward, further research in this area could unlock new possibilities for harnessing light or particles at specific locations, with broad implications for various scientific disciplines.