CANCELLED

HEP Theory Journal Club

Genuine Cosmic Hair

David Kastor

UMass Amherst

Inflationary expansion is expected to homogenize and isotropize the universe. Regarding isotropy, results known (inaccurately) as “cosmic no hair” theorems show, for example, that anisotropies decay exponentially in asymptotically future deSitter spacetimes (AFdS) and other systems with inflationary growth. We show that AFdS spacetimes nevertheless carry a form of “genuine” cosmic hair that characterizes their falloff to deSitter at future infinity, in much the same way that mass and angular momentum characterize the falloff of asymptotically flat spacetimes at spatial infinity. A Smarr formula further relates cosmic hair to early time behavior of the spacetime near a big bang singularity.