Real-space spectral functions of three-dimensional billion-size topological non-Hermitian matter with tensor networks
The work develops a tensor-network framework to calculate spectral functions for three-dimensional non-Hermitian systems with over one billion lattice sites. By combining matrix product operators and a non-Hermitian kernel polynomial method, the researchers successfully resolved corner modes in a 3D higher-order topological insulator. This demonstrates the method's scalability for studying complex, large non-Hermitian quantum matter.