# Probing Dynamical Gravity with the Polarization of Continuous Gravitational Waves

## TL;DR

This paper introduces new methods to detect and analyze the polarization content of continuous gravitational waves, enabling tests of general relativity and its alternatives using data from advanced detectors.

## Contribution

It presents a novel framework for identifying and constraining polarization modes in continuous gravitational wave signals, independent of specific models.

## Key findings

- Detectability threshold for polarization signals at strain $h\gtrsim 3\times10^{-27}$
- Detection of non-tensorial modes depends on their power, not tensorial strain strength
- Framework tested successfully on simulated data from advanced detectors

## Abstract

The direct detection of gravitational waves provides the opportunity to measure fundamental aspects of gravity which have never been directly probed before, including the polarization of gravitational waves. In the context of searches for continuous waves from known pulsars, we present novel methods to detect signals of any polarization content, measure the modes present and place upper-limits on the amplitude of non-tensorial components. This will allow us to obtain new model-independent, dynamical constraints on deviations from general relativity. We test this framework on multiple potential sources using simulated data from three advanced-era detectors at design sensitivity. We find that signals of any polarization will become detectable and distinguishable for characteristic strains $h\gtrsim 3\times10^{-27} \sqrt{1~{\rm yr}/T}$, for an observation time $T$. We also find that our ability to detect non-tensorial components depends only on the power present in those modes, irrespective of the strength of the tensorial strain.