Testing the Weak Equivalence Principle Using Optical and Near-infrared Crab Pulses<\/a><\/p>\n\n\n\nThe Astrophysical Journal 861, 66 (2018)<\/p>\n\n\n\n
Abstract<\/h2>\n\n\n\n
The Weak Equivalence Principle states that the geodesics of a test particle in a gravitational field are independent of the particle\u2019s constitution. To constrain violations of the Weak Equivalence Principle, we use the one-meter telescope at Table Mountain Observatory near Los Angeles to monitor the relative arrival times of pulses from the Crab Pulsar in the optical (\u03bb \u2248 585 nm) and near-infrared (\u03bb \u2248 814 nm) using an instrument that detects single photons with nanosecond-timing resolution in those two bands. The infrared pulse arrives slightly before the visible pulse. Our three analysis methods give delays with statistical errors of \u0394tobs = 7.41 \u00b1 0.58, 0.4 \u00b1 3.6, and 7.35 \u00b1 4.48 microseconds (at most 1\/4000 of the pulsar period). We attribute this discrepancy to systematic error from the fact that the visible and infrared pulses have slightly different shapes. Whether this delay emerges from the pulsar, is caused by passing through wavelength-dependent media, or is caused by a violation of the equivalence principle, unless there is a fine-tuned cancellation among these, we set the first upper limit on the differential post-Newtonian parameter at these wavelengths of \u0394\u03b3 < 1.07 \u00d7 10\u221210 (3\u03c3). This result falls in an unexplored region of parameter space and complements existing limits on equivalence-principle violation from fast radio bursts, gamma-ray bursts, as well as previous limits from the Crab.\n<\/p>\n","protected":false},"excerpt":{"rendered":"
Calvin Leung, Beili Hu, Sophia Harris, Amy Brown, Jason Gallicchio*, and Hien Nguyen Testing the Weak Equivalence Principle Using Optical […]<\/p>\n","protected":false},"author":1,"featured_media":0,"template":"","publication_author":[16],"class_list":["post-6450","physics_publications","type-physics_publications","status-publish","hentry","publication_author-gallicchio"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/physics_publications\/6450","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/physics_publications"}],"about":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/types\/physics_publications"}],"author":[{"embeddable":true,"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/users\/1"}],"wp:attachment":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/media?parent=6450"}],"wp:term":[{"taxonomy":"publication_author","embeddable":true,"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/publication_author?post=6450"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}