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Stochastic Entropy Production Associated with Quantum Measurement in a Framework of Markovian Quantum State Diffusion
Claudia L Clarke1, Ian J Ford1
1Department of Physics and Astronomy and London Centre for Nanotechnology, University College London, Gower Street, London WC1E 6BT, UK.
Entropy (Basel, Switzerland)
|January 8, 2025
Summary
This study explores open quantum systems and their unpredictable evolution using quantum state diffusion. It introduces stochastic entropy production to quantify uncertainty, differing from standard entropy changes during measurement.
Area of Science:
- Quantum Physics
- Open Quantum Systems
- Quantum Information
Background:
- The evolution of open quantum systems is often unpredictable due to underspecified environmental details.
- Reduced density matrices project from the full system-environment state, leading to multiple possibilities.
Purpose of the Study:
- Investigate the dynamics of a two-level open quantum system using quantum state diffusion.
- Characterize the unpredictability and entropy production during continuous quantum measurement.
Main Methods:
- Employed a quantum state diffusion framework for analyzing open quantum systems.
- Simulated continuous quantum measurement of system observables by the environment.
- Analyzed stochastic entropy production and its relation to subjective uncertainty.
Main Results:
- Continuous measurement drives the system towards eigenstates, characterized by stochastic entropy production.
- Stochastic entropy production quantifies subjective uncertainty, distinct from von Neumann entropy.
- Simultaneous measurement of non-commuting observables leads to stationary probability distributions and zero further stochastic entropy production.
Conclusions:
- The quantum state diffusion framework provides insights into measurement dynamics and irreversible thermodynamics in quantum systems.
- Stochastic entropy production offers a novel way to understand uncertainty in open quantum systems.
- Transitions between stationary states under measurement changes result in finite mean stochastic entropy production.
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