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Dynamical quantum phase transitions in systems with broken-symmetry phases
1Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, 6020 Innsbruck, Austria and Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria.
Physical Review Letters
|November 29, 2014
Summary
Dynamical quantum phase transitions in Loschmidt echoes control order parameter dynamics after quantum quenches. This study links microscopic probabilities to macroscopic properties, offering experimental avenues with ultracold gases.
Area of Science:
- Quantum physics
- Condensed matter theory
- Statistical mechanics
Background:
- Dynamical quantum phase transitions (DQPTs) are a key feature of non-equilibrium quantum systems.
- Loschmidt echoes measure the sensitivity of quantum states to Hamiltonian perturbations.
- Broken-symmetry phases exhibit complex dynamics following quantum quenches.
Purpose of the Study:
- To establish a direct connection between Loschmidt echoes and order parameter dynamics in systems undergoing quantum quenches.
- To link microscopic quantum probabilities to macroscopic dynamical properties.
- To explore the role of DQPTs in controlling non-equilibrium dynamics.
Main Methods:
- Exact diagonalization was employed for numerical simulations.
- The study focused on quantum quenches in the XXZ spin chain model.
- Initial Néel states were used as a starting point for the quenches.
Main Results:
- A direct relationship was established between Loschmidt echoes and the order parameter's time evolution.
- Dynamical quantum phase transitions were shown to govern the non-equilibrium dynamics.
- The study demonstrated how microscopic probabilities dictate macroscopic behavior.
Conclusions:
- Loschmidt echoes provide a powerful tool to understand and control non-equilibrium dynamics in quantum systems.
- The findings pave the way for experimental verification using ultracold atomic gases in optical lattices.
- This work deepens the understanding of quantum phase transitions in driven systems.
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