Constraining CPT-odd electromagnetic chiral parameters with pulsar timing

Abstract

The arrival time of electromagnetic signals traveling in chiral cosmic media is investigated in the context of Maxwell-Carroll-Field-Jackiw electrodynamics. Considering the interstellar medium (ISM) as a cold, ionized, chiral plasma, we derive the time delay between two traveling signals, expressed in terms of a modified dispersion measure (DM) which receives additional contribution from the chiral parameters. Faraday rotation angle is also addressed in this chiral plasma scenario, yielding modified rotation measures (RM). Using DMs data from five pulsars, we establish constraints on the chiral parameter magnitude at the order of $10^{-23}$ -- $10^{-22}$ GeV. On the other hand, the Faraday rotation retrieved from RM measurements implied upper constraints as tight as $10^{-36}$ GeV.