[Paper Review] Parametric Resonance and Dark Matter Axion-Like Particles

Ariel Arza, Paola Arias+1 more|arXiv (Cornell University)|Jun 8, 2015

Dark Matter and Cosmic Phenomena3 references3 citations

TL;DR

This paper investigates how a time-varying external magnetic field can induce parametric resonance in axion-like particles, the proposed dark matter candidate. The resonance amplifies the local dark matter field amplitude quadratically with magnetic field strength, potentially increasing the local energy density by up to two orders of magnitude under realistic experimental conditions.

ABSTRACT

We study the local effects of an external time-dependent magnetic field on axion-like particles assuming they are all the dark matter of the universe. We find that under suitable conditions the amplitude of the dark matter field can resonate parametrically. The resonance depends on the velocity of the axion-like particles and scales quadratically with the strength} of the external magnetic field, $\fracρ{ρ_{DM}} \sim {B_0}^3$. By considering typical experimental benchmark values, we find the resonance could amplify around two orders of magnitude the local energy density stored in the dark matter condensate.

Motivation & Objective

• To examine the impact of an external time-dependent magnetic field on axion-like particles assumed to constitute all dark matter.
• To determine whether parametric resonance can occur in such a system under realistic astrophysical or laboratory conditions.
• To quantify the amplification of the local dark matter field amplitude due to resonance effects.
• To assess the detectability of such resonance effects using current experimental benchmarks.

Proposed method

• Modeling axion-like particles as a coherent scalar field coupled to an external time-varying magnetic field.
• Applying the framework of parametric resonance in quantum field theory to the oscillating dark matter field.
• Using the equation of motion for the scalar field in the presence of a time-dependent coupling to the magnetic field.
• Deriving the growth rate of field amplitude as a function of magnetic field strength and particle velocity.
• Scaling the resonance condition with respect to the dark matter energy density and external field amplitude.
• Evaluating the amplification factor using typical experimental values for magnetic field strength and particle velocity.

Experimental results

Research questions

• RQ1 Can a time-varying external magnetic field induce parametric resonance in axion-like particles that are the sole dark matter component?
• RQ2 How does the resonance amplitude scale with the strength and frequency of the external magnetic field?
• RQ3 What is the maximum possible amplification of the local dark matter energy density due to this resonance mechanism?
• RQ4 Under what velocity and field strength conditions is the resonance effect most pronounced?
• RQ5 Can this resonance effect be detectable with current or near-future experimental setups?

Key findings

• Parametric resonance can significantly amplify the amplitude of the axion-like dark matter field when exposed to a time-varying external magnetic field.
• The resonance effect scales quadratically with the magnetic field strength, leading to a ∼B₀³ dependence in the energy density amplification.
• For typical experimental benchmark values, the local dark matter energy density can be amplified by up to two orders of magnitude.
• The resonance is velocity-dependent, meaning only axion-like particles with specific velocities experience maximal amplification.
• The mechanism suggests a potential pathway to enhance detectability of axion-like dark matter in terrestrial experiments.
• The results indicate that resonant enhancement could make otherwise sub-threshold dark matter signals observable in sensitive detectors.