Gravitational Microlensing by the Ellis Wormhole

TL;DR

This paper derives a method to analyze gravitational microlensing caused by Ellis wormholes, revealing distinctive light curve features and assessing the potential for detection in galactic surveys.

Contribution

It introduces a weak-field approximation for Ellis wormhole lensing and evaluates detection prospects using existing microlensing data.

Findings

Light curves show gutters of about 4% outside Einstein ring crossing times.

Magnification by Ellis wormholes is generally less than Schwarzschild lensing.

Detection is possible if wormholes are bound to the galaxy with certain size and density parameters.

Abstract

A method to calculate light curves of the gravitational microlensing of the Ellis wormhole is derived in the weak-field limit. In this limit, lensing by the wormhole produces one image outside the Einstein ring and one other image inside. The weak-field hypothesis is a good approximation in Galactic lensing if the throat radius is less than $10^{11} km$. The light curves calculated have gutters of approximately 4% immediately outside the Einstein ring crossing times. The magnification of the Ellis wormhole lensing is generally less than that of Schwarzschild lensing. The optical depths and event rates are calculated for the Galactic bulge and Large Magellanic Cloud fields according to bound and unbound hypotheses. If the wormholes have throat radii between 100 and $10^7 km$, are bound to the galaxy, and have a number density that is approximately that of ordinary stars, detection can be achieved by reanalyzing past data. If the wormholes are unbound, detection using past data is impossible.