Various quantum gravity approaches that extend beyond the standard model predict Lorentz Invariance and Charge-Parity-Time Violation at energies approaching the Planck scale .
These models frequently predict a wavelength dependent speed of light , which would result in time delays between promptly emitted photons at different energies , as well as a wavelength-dependent rotation of the plane of linear polarization for photons resulting from vacuum birefringence .
Here , we describe a pilot program with an automated system of small telescopes that can simultaneously conduct high cadence optical photometry and polarimetry of Active Galactic Nuclei ( AGN ) in multiple passbands .
We use these observations as a proof-of-principle to demonstrate how such data can be used to test various Lorentz Violation models , including special cases of the Standard Model Extension ( SME ) .
In our initial campaign with this system , the Array Photo Polarimeter , we observed two AGN sources , including BL Lacertae at redshift z = 0.069 , and S5 B0716+714 at z = 0.31 .
We demonstrate that optical polarimetry with a broadband Luminance filter combined with simultaneous I _ { c } -band observations yields SME parameter constraints that are up to \sim 10 and \sim 30 times more sensitive than with a standard I _ { c } -band filter , for SME models with mass dimension d = 5 and d = 6 , respectively .
Using only a small system of telescopes with an effective 0.45 -m aperture , we further demonstrate d = 5 constraints for individual lines of sight that are within a factor of \sim 1 - 10 in sensitivity to comparable constraints from optical polarimetry with a 3.6 -m telescope .
Such an approach could significantly improve existing SME constraints via a polarimetric all-sky survey of AGN with multiple 1-meter class telescopes .