Quantum quench and coherent–incoherent dynamics of Ising chains interacting with dissipative baths
Abstract
The modular path integral methodology is used to extend the well-known spin-boson dynamics to finite-length quantum Ising chains, where each spin is coupled to a dissipative harmonic bath. The chain is initially prepared in the ferromagnetic phase where all spins are aligned, and the magnetization is calculated with spin–spin coupling parameters corresponding to the paramagnetic phase, mimicking a quantum quench experiment. The observed dynamics is found to depend significantly on the location of the tagged spin. In the absence of a dissipative bath, the time evolution displays irregular patterns that arise from multiple frequencies associated with the eigenvalues of the chain Hamiltonian. Coupling of each spin to a harmonic bath leads to smoother dynamics, with damping effects that are stronger compared to those observed in the spin-boson model and more prominent in interior spins, a consequence of additional damping from the spin environment. Interior spins exhibit a transition from underdamped oscillatory to overdamped monotonic dynamics as the temperature, spin–bath, or spin–spin coupling is increased. In addition to these behaviors, a new dynamical pattern emerges in the evolution of edge spins with strong spin–spin coupling at low and intermediate temperatures, where the magnetization oscillates either above or below the equilibrium value.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 15, 2021
- Source ID
- 10.1063/5.0066891
Entities
People
- Nancy Makri
- Reshmi Dani
Organizations
- Air Force Office of Scientific Research
- Division of Chemistry
- University of Illinois Urbana–Champaign