出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We exploit recent polarimetric observations of the Crab Nebula in the hard X-ray band by INTEGRAL
to show that the absence of vacuum birefringence effects constrains O(E/M) Lorentz
violation in QED to the level |x | < 9×10−10 (at 3s CL). This tightens by more than three orders
of magnitude previous constraints. We also show that planned X-ray polarimeters have the
potential to probe |x | ∼ 10−16 by detecting polarization in active galaxies at red-shift ∼ 1.
