[Paper Review] Quantum damping of neutron-antineutron oscillations

B. O. Kerbikov|arXiv (Cornell University)|Apr 24, 2017

Atomic and Subatomic Physics Research3 citations

TL;DR

This paper applies the density matrix formalism and Bloch equations to model neutron-antineutron oscillations, showing that environmental decoherence suppresses oscillatory behavior in trapped neutrons, nuclear systems, and quasi-free propagation—making observation of oscillations highly unlikely in free neutron experiments.

ABSTRACT

We propose a new approach based on the density matrix formalism and Bloch equation to the problem of neutron-antineutron oscillations. We consider three strategies that are designed to search for oscillations: experiments with trapped neutrons, oscillations in nuclei, and quasi-free propagation. Decoherence induced by the interaction with the environment makes the time evolution non-oscillating in all three cases. It is shown that there is little hope to observe oscillating behavior in experiments with free neutrons.

Motivation & Objective

• To investigate the feasibility of observing neutron-antineutron oscillations under realistic experimental conditions.
• To analyze how environmental interactions affect the coherence of neutron-antineutron oscillations.
• To evaluate three experimental strategies: trapped neutrons, oscillations in nuclei, and quasi-free propagation.
• To determine whether oscillatory behavior can persist despite decoherence effects.

Proposed method

• Uses the density matrix formalism to describe the quantum state of neutrons and antineutrons.
• Applies the Bloch equation to model the time evolution of the density matrix under environmental interactions.
• Models decoherence effects as interactions with the environment that suppress quantum coherence.
• Considers three experimental setups: trapped neutrons, bound states in nuclei, and quasi-free propagation.
• Analyzes the time evolution of the density matrix to detect oscillatory behavior.
• Assesses the survival probability of neutrons to identify damping of oscillations.

Experimental results

Research questions

• RQ1 Can neutron-antineutron oscillations be observed in experiments with trapped neutrons despite environmental decoherence?
• RQ2 How do interactions within nuclei affect the coherence and oscillatory nature of neutron-antineutron transitions?
• RQ3 To what extent does quasi-free propagation preserve oscillatory behavior in the presence of environmental coupling?
• RQ4 What is the role of decoherence in suppressing oscillations across different experimental configurations?

Key findings

• Decoherence induced by environmental interactions leads to non-oscillatory time evolution in all three experimental strategies.
• The survival probability of neutrons does not exhibit oscillatory behavior due to decoherence effects.
• There is little hope of observing oscillating behavior in experiments with free neutrons due to strong decoherence.
• Oscillations are damped in nuclear environments due to interactions that break quantum coherence.
• The density matrix and Bloch equation framework successfully captures the suppression of oscillations.
• The results suggest that current experimental approaches based on free or weakly bound neutrons are unlikely to detect oscillations.