BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:UW-Madison-Physics-Events BEGIN:VEVENT SEQUENCE:0 UID:UW-Physics-Event-2294 DTSTART:20111108T220000Z DURATION:PT1H0M0S DTSTAMP:20260420T113918Z LAST-MODIFIED:20111025T142103Z LOCATION:Chamberlin 5280 SUMMARY:Massive gravitons and enhanced gravitational lensing\, Theory Seminar (High Energy/Cosmology)\, Mark Wyman\, University of Chicago DESCRIPTION:The mystery of dark energy suggests that there is new grav itational physics at low energies and on long length scales. On the ot her hand\, low mass degrees of freedom in gravity are strictly limited by observations within the solar system. A compelling way to resolve this apparent contradiction is to add a galilean-invariant scalar fie ld to gravity. Called galileons\, these scalars have strong self inter actions near overdensities\, like the solar system\, that suppress the ir effects on the motion of massive particles. These non-linearities are weak on cosmological scales\, permitting new physics to operate. E xtending galilean invariance to the coupling of galileons to stress-en ergy -- as was first done in the case of massive gravity -- can have a surprising phenomenological consequence: enhanced gravitational lensi ng. Weak lensing observations will be able to detect or constrain out this effect\, which is not well described by existing model independe nt tests of GR.
URL:https://www.physics.wisc.edu/events/?id=2294 END:VEVENT END:VCALENDAR