Interplay of topology and nonequilibrium conditions in low-dimensional quantum many-body systems: Interferometry and dynamical phase transitions

• Applicant: Professor Dr. Reinhold Egger
• Subject Area: Theoretical Condensed Matter Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 570117402

In the present proposal, we will advance theories describing the interplay of topology and nonequilibrium conditions in low-dimensional quantum many-body systems along several interrelated directions. First, we study Ising anyon tunneling signatures in the frequency-dependent charge conductance for a chiral Majorana interferometer with unequal path lengths and finite voltage bias. Ising anyons are paradigmatic examples for excitations with nontrivial braiding statistics that have so far not been detected in experiments but would be very useful for quantum information processing applications. To describe realistic Majorana interferometers harboring Ising anyons, fundamental technical advances are needed. We have already done preparatory studies ensuring that our ideas in that direction work out in principle. Armed with these tools, we propose and study multi-terminal chiral Majorana interferometers. Our theories are aimed at elucidating effects of fusion and braiding statistics of Ising anyons in transport experiments performed in such geometries. In addition, we will likely encounter novel types of strongly correlated local non-Fermi liquid fixed points that can be experimentally detected through the temperature dependence of the charge conductance tensor. In addition, we will study general classes of 1D topological many-body systems and investigate the occurrence and properties of topological dynamical phase transitions occuring after a sudden quantum quench of one or several control parameters. We will use the Lindblad master equation approach, but also plan to employ the theoretical techniques developed for chiral Majorana interferometers in order to identify topological dynamical phase transitions in those geometries beyond the approximations behind the Lindblad equation.

• DFG Programme: Research Grants