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Emergence of Objectivity for Quantum Many-Body Systems
1Institut National de Recherche en Informatique et en Automatique, 2 Rue Simone Iff, 75012 Paris, France.
Entropy (Basel, Switzerland)
|February 25, 2022
Summary
Quantum many-body systems can achieve objectivity even without environmental decoherence. New conditions ensure classicality for observers accessing only system fragments, even with imperfect measurements.
Area of Science:
- Quantum physics
- Many-body systems
- Foundations of quantum mechanics
Background:
- Objectivity in quantum mechanics is typically linked to environmental decoherence.
- Previous work established conditions for objectivity in pure states with ideal measurements.
- Limited observer access to quantum systems poses a challenge to establishing objective reality.
Purpose of the Study:
- To investigate the emergence of objectivity in quantum many-body systems without environmental decoherence.
- To extend existing results to mixed states, generalized measurements (POVMs), and imperfect outcome recordings.
- To establish conditions for full classicality for multiple observers with limited system access.
Main Methods:
- Extension of Reidel's (2017) framework for objectivity.
- Introduction of a novel condition on quantum states and measurements.
- Analysis of quantum many-body system evolutions and measurement outcome redundancy.
Main Results:
- Objectivity can emerge in isolated quantum many-body systems.
- The framework is generalized to mixed states, POVMs, and imperfect imprints.
- A new condition is introduced that guarantees full classicality for any number of observers.
Conclusions:
- Emergence of objectivity is possible without environmental decoherence.
- Redundant measurement outcomes in quantum many-body systems naturally lead to states satisfying the condition for classicality.
- This work provides a new perspective on quantum objectivity and classical emergence.
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