A New Analytical Route to Higher-Winding Non-Hermitian Topological Phases
Topological phase transitions in non-Hermitian systems can be associated with spectral winding numbers and are often inferred from the energy spectrum. Beyond this conventional approach, Dr. Chen-Hsuan Hsu's team at the Institute of Physics has developed an efficient method for analytically determining phase boundaries and for computing topological invariants in one-dimensional non-Hermitian topological systems. By avoiding direct calculation of the energy spectrum, the approach provides a practical route to identifying higher-winding topological superconducting phases and robust Majorana zero modes. The method was demonstrated in several tight-binding models, including a highly complex system with more than 10 parameters. Even for a case with 10 parameters, analytical phase-boundary expressions containing more than 10,000 terms can be obtained, illustrating the potential of this approach for studying complex non-Hermitian quantum systems. In collaboration with Prof. Ken Shiozaki at Kyoto University, this work has been published in J. Appl. Phys. and selected as a Featured Article by the editors. Some of the numerical calculations in this work were carried out using computational resources provided by the Academia Sinica Grid Computing Centre (ASGC).
Journal Links: https://doi.org/10.1063/5.0344650