Dynamically Induced Exceptional Phases in Quenched Interacting Semimetals

Area of Science:

• Condensed Matter Physics
• Quantum Dynamics
• Topological Phases of Matter

Background:

• Nonintegrable quantum systems exhibit complex behaviors when driven out of equilibrium.
• Critical points in phase diagrams are sensitive regions where novel phenomena can emerge.
• Non-Hermitian (NH) physics describes systems with gain or loss, offering new theoretical frameworks.

Purpose of the Study:

• To investigate the dynamical formation of exceptional degeneracies in quantum correlation functions.
• To explore the emergence of topologically robust non-Hermitian nodal phases in quenched systems.
• To identify observable signatures of these novel phases in dynamical processes.

Main Methods:

• Utilizing nonequilibrium Green's function methods.
• Employing the conserving second Born approximation for theoretical calculations.
• Analyzing quenched one- and two-dimensional nonintegrable systems near a critical point.

Main Results:

• Demonstrating the dynamical promotion of semimetallic points to topologically robust NH nodal phases.
• Predicting the emergence of these phases during coherent time evolution in equilibrating systems.
• Identifying distinct signatures in spectral functions and momentum distribution dynamics.

Conclusions:

• Exceptional degeneracies can dynamically form robust non-Hermitian nodal phases.
• These phases are a consequence of quantum dynamics near critical points.
• Observable signatures provide experimental avenues for detecting these novel topological phases.