What's Happening?
Recent research led by Prof. Peng Xue from the Beijing Computational Science Research Center has delved into the realm of non-Hermitian quantum walks, uncovering dynamical quantum phase transitions (DQPTs)
under self-normal and biorthogonal bases. This study, published in Light: Science & Applications, marks the first comprehensive theoretical and experimental investigation comparing self-normal and biorthogonal DQPTs. The research highlights the unique time evolution behaviors in non-Hermitian systems, which differ from traditional closed quantum systems. By selecting different initial states, the researchers explored key physical quantities during various quench evolution processes, such as Loschmidt rate functions and dynamical topological order parameters. The study found that DQPTs only appear in the PT-symmetry-unbroken region and disappear in the broken region, existing only between distinct topological phases. The biorthogonal method was noted for its ability to better preserve system symmetry, offering advantages in non-Hermitian systems.
Why It's Important?
The exploration of non-Hermitian quantum walks and DQPTs is significant as it expands the framework of quantum mechanics, providing new insights into the dynamics of open quantum systems. This research has implications for high-sensitivity sensing, unidirectional optical devices, topological lasers, and quantum computing. By understanding the evolution of open systems, scientists can develop new quantum devices and enhance the theoretical foundations of quantum mechanics. The study's findings on the preservation of system symmetry through biorthogonal methods could lead to advancements in non-Hermitian topological theory and parity-time symmetry quantum mechanics, offering new approaches for investigating quantum dynamics.
What's Next?
Future research may focus on further exploring the differences between self-normal and biorthogonal DQPTs, particularly in relation to critical times and momenta. The experimental validation of theoretical predictions in one-dimensional discrete-time non-Hermitian quantum walks of single photons suggests potential for more precise parameter adjustments and the introduction of non-unitary dynamics. This could lead to greater controllability and flexibility in quantum experiments, paving the way for new discoveries in quantum mechanics and the development of innovative quantum devices.
Beyond the Headlines
The study of non-Hermitian quantum walks and DQPTs may have broader implications for understanding exotic physical phenomena in open systems, such as exceptional points and non-Hermitian topological effects. The introduction of biorthogonal bases offers solutions to challenges in non-Hermitian systems, such as probability conservation and dynamical descriptions. These advancements could influence the development of quantum technologies and contribute to the ongoing evolution of quantum mechanics as a field.
