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Upper bound on locally extractable energy from entangled pure state under feedback control.
Kanji Itoh1, Yusuke Masaki1, Hiroaki Matsueda1,2
1Tohoku University, Department of Applied Physics, Graduate School of Engineering, Sendai 980-8579, Japan.
Physical Review. E
|March 20, 2026
Summary
Researchers explored extracting energy from quantum entanglement using a novel effective thermodynamics. They established new bounds on extractable energy, linking it to quantum entanglement structure and consistent with information thermodynamics.
Area of Science:
- Quantum Information Science
- Thermodynamics
- Quantum Many-Body Systems
Background:
- Multipartite entangled pure states are crucial in quantum information.
- Extracting energy from quantum systems is a key challenge.
- Understanding the interplay between entanglement and thermodynamics is essential.
Purpose of the Study:
- To investigate locally extractable energy from multipartite entangled pure states.
- To introduce a new framework of effective thermodynamics based on entanglement.
- To derive bounds on extractable energy and explore their relation to entanglement structure.
Main Methods:
- Definition of an entanglement-based effective temperature.
- Derivation of an upper bound on extractable energy with feedback control.
- Formulation of a general bound dependent on the initial state and local Hamiltonian.
- Analysis of the connection to ordinary information thermodynamics.
Main Results:
- An effective thermodynamics framework was established.
- An upper bound on extractable energy was derived, analogous to the second law of information thermodynamics.
- A general bound explicitly relating extractable energy to entanglement structure was found.
- The derived bounds were shown to be achievable in a specific example.
Conclusions:
- The study provides a novel approach to energy extraction from quantum entangled states.
- The results offer explicit connections between quantum entanglement and thermodynamic energy limits.
- The findings are consistent with established principles of information thermodynamics.
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