BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Wall-crossing\, easy and smooth - Boris Pioline\, CERN and LPTHE
DTSTART:20150226T130000Z
DTEND:20150226T140000Z
UID:TALK58120@talks.cam.ac.uk
CONTACT:Joao Miguel Vieira Gomes
DESCRIPTION:The spectrum of BPS states in four-dimensional gauge theories 
 and string vacua with N=2 supersymmetry is well-known to be jump across ce
 rtain walls in moduli space\, where bound states can decay. In this talk I
  will survey how the discontinuity can be understood in terms of the super
 symmetric quantum mechanics of mutually non-local point particles. This ph
 ysical picture\nsuggests that\, at any point in moduli space\, the BPS spe
 ctrum can be viewed as a sum of bound states of absolutely stable `single-
 centered' constituents. This idea appears to be vindicated in the context 
 of quiver moduli spaces. Finally\, I shall explain how the discontinuous B
 PS indices can be combined into a `new' supersymmetric index\, a function 
 which sums up multi-particle state contributions and is continuous across 
 the wall.
LOCATION:Potter Room (first floor\, Pav. B)
END:VEVENT
END:VCALENDAR