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Quantum reservoir probing of quantum phase transitions
Kaito Kobayashi1, Yukitoshi Motome2
1Department of Applied Physics, University of Tokyo, Tokyo, Japan. kaito-kobayashi92@g.ecc.u-tokyo.ac.jp.
Nature Communications
|April 25, 2025
Summary
Local quantum quenches can now detect quantum phase transitions. Quantum reservoir probing (QRP) extracts localized excitations, revealing phase boundaries even in complex quantum spin systems.
Area of Science:
- Quantum Many-Body Physics
- Condensed Matter Physics
Background:
- Quantum phase transitions (QPTs) are critical phenomena in quantum many-body systems.
- Identifying QPTs in equilibrium systems presents significant theoretical and experimental challenges.
- Existing dynamical detection protocols rely on global quantum quenches and global excitations.
Purpose of the Study:
- To introduce a novel method for detecting quantum phase transitions using local quantum quenches.
- To demonstrate the efficacy of quantum reservoir probing (QRP) in analyzing localized excitations.
- To show that this framework can precisely delineate phase boundaries near quantum critical points.
Main Methods:
- Implementing local quantum quenches to induce localized out-of-equilibrium excitations.
- Utilizing the quantum reservoir probing (QRP) framework to isolate the effects of local quenches.
- Analyzing single-site observables to detect changes in quantum phases.
Main Results:
- Local quantum quenches and QRP can effectively detect quantum phase transitions.
- The impact of local quenches varies across different quantum phases.
- Quantum fluctuations near critical points suppress local quench effects, aiding phase boundary delineation.
- This method successfully identified QPTs in integrable and non-integrable quantum spin systems, including topological QPTs.
Conclusions:
- Local quantum quenches combined with QRP offer a powerful and versatile tool for detecting quantum phase transitions.
- This approach overcomes limitations of global quench methods by focusing on localized dynamics.
- The framework is applicable to various quantum systems and transition types, including topological transitions.
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