No-go theorems for ψ-epistemic models based on a continuity assumption

Area of Science:

• Quantum Mechanics
• Foundations of Physics
• Quantum Information Theory

Background:

• The fundamental nature of the quantum state (ψ) is debated: is it ontic (a real property) or epistemic (representing knowledge)?
• Understanding the quantum state's nature is crucial for interpreting quantum theory and developing quantum technologies.
• Previous work, like the Pusey-Barrett-Rudolph theorem, has explored constraints on ψ-ontic and ψ-epistemic models.

Purpose of the Study:

• To investigate the viability of epistemic interpretations of the quantum state within the framework of quantum theory.
• To derive constraints on ψ-epistemic models using minimal assumptions and a single quantum system.
• To present an argument distinct from existing proofs regarding the nature of the quantum state.

Main Methods:

• Assumed a natural continuity assumption for the quantum state.
• Employed a weak separability assumption for quantum systems.
• Developed a novel argument to test the consistency of epistemic interpretations with quantum theory.

Main Results:

• Demonstrated that epistemic interpretations of the quantum state lead to contradictions with quantum theory.
• Established a nontrivial constraint on ψ-epistemic models using only a single copy of the quantum system.
• Provided an argument that differs from the Pusey-Barrett-Rudolph proof.

Conclusions:

• Epistemic interpretations of the quantum state are incompatible with the principles of quantum theory.
• The findings significantly constrain the landscape of possible ψ-epistemic models.
• This research offers new insights into the fundamental interpretation of quantum mechanics.