Weak Lensing Approximation of Wave-optics Effects from General Symmetric Lens Profiles

TL;DR

This paper introduces a new efficient method to approximate wave-optics effects caused by symmetric gravitational lens profiles, aiding in better lens modeling and dark matter research.

Contribution

The authors develop a novel framework for accurately approximating wave-optics effects in weak gravitational lensing with symmetric profiles, validated against numerical methods.

Findings

Method accurately recovers high- and low-frequency asymptotic behavior.

Framework enables improved lens reconstruction and delensing.

Provides a new probe for low-mass halos and dark matter properties.

Abstract

Gravitational lensing of electromagnetic (EM) waves has yielded many profound discoveries across fundamental physics, astronomy, astrophysics, and cosmology. Similar to EM waves, gravitational waves (GWs) can also be lensed. When their wavelength is comparable to the characteristic scale of the lens, wave-optics (WO) effects manifest as frequency-dependent modulations in the GW waveform. These WO features encode valuable information about the lensing system but are challenging to model, especially in the weak lensing regime, which has a larger optical depth than strong lensing. We present a novel and efficient framework to accurately approximate WO effects induced by general symmetric lens profiles. Our method is validated against numerical calculations and recovers the expected asymptotic behavior in both high- and low-frequency limits. Accurate and efficient modeling of WO effects in the weak lensing regime will enable improved lens reconstruction, delensing of standard sirens, and provide a unique probe to the properties of low-mass halos with minimal baryonic content, offering new insights into the nature of dark matter.