Finite time path field theory and quantum spin chain quenches – nonperturbative approach

Our recent work [1,2] on newly revealed type of universal behavior of Loschmidt echo that emerges in exponentially short time scale for an important class of quench protocols is presented in this context, with relevance to potential technological applications in relation to spin chains. They are specially related to topologically frustrated spin chains, i.e. antiferromagnetic spin chains with periodic boundary conditions and an odd number of spins. Topological frustration induces delocalized domain wall excitations and our findings about the universal behaviour of a large class of local, global and disorder quenches with different types of perturbation switching on protocols, both sudden and non-sudden, containing the sudden quench as a special case, imply the robustness of related quantum technology concepts. This work reveals noperturbative aspects of the problem relevant for strong perturbations.

[1] Kuić, D.; Knapp, A.; Šaponja-Milutinović, D. Finite Time Path Field Theory Perturbative Methods for Local Quantum Spin Chain Quenches. Universe 2024, 10, 384.
[2] Kuić, D.; Knapp, A.; Šaponja-Milutinović, D. Finite Time Path Field Theory and a New Type of Universal Quantum Spin Chain Quench Behavior. Universe 2025, 11, 230.