Pulsar Polarization Arrays

TL;DR

This paper proposes pulsar polarization arrays (PPAs) as a new tool to detect ultralight axion-like dark matter through cosmic birefringence, leveraging large-scale correlations to probe fundamental physics.

Contribution

It introduces the concept of PPAs, extending pulsar timing arrays, and demonstrates their potential to detect ultralight ALDM via cosmic birefringence and Chern-Simons coupling.

Findings

PPAs can probe Chern-Simons coupling up to ~10^{-14}-10^{-17} GeV^{-1}

Potential to detect ALDM in the mass range ~10^{-27} to 10^{-21} eV

PPAs reveal large-scale correlations that are hard to mimic by local noise

Abstract

Pulsar timing arrays (PTAs) consisting of widely distributed and well-timed millisecond pulsars can serve as a galactic interferometer to measure gravitational waves. With the same data acquired for PTAs, we propose to develop pulsar polarization arrays (PPAs), to explore astrophysics and fundamental physics. As in the case of PTAs, PPAs are best suited to reveal temporal and spatial correlations at large scales that are hard to mimic by local noise. To demonstrate the physical potential of PPAs, we consider detection of ultralight axion-like dark matter (ALDM), through cosmic birefringence induced by its Chern-Simon coupling. Because of its tiny mass, the ultralight ALDM can be generated as a Bose-Einstein condensate, characterized by a strong wavy nature. Incorporating both temporal and spatial correlations of the signal, we show that PPAs have a potential to probe the Chern-Simon coupling up to $\sim 10^{-14}-10^{-17}$GeV$^{-1}$, with a mass range $\sim 10^{-27} - 10^{-21}$eV.