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SUMMARY:Alejandro Cabo-Bizet (King's College)
DTSTART;VALUE=DATE-TIME:20200604T140000Z
DTEND;VALUE=DATE-TIME:20200604T150000Z
DTSTAMP;VALUE=DATE-TIME:20200812T043143Z
UID:HEPTUW/1
DESCRIPTION:Title: On the large N limit of the 4d N=1 superconformal index
\nby Alejandro Cabo-Bizet (King's College) as part of HEP seminars TU Wien
(Vienna)\n\n\nAbstract\nThe large N limit of the 4d N=1 superconformal in
dex is\nargued to be determined by competition among complex eigenvalue\nc
onfigurations. At least some of these configurations correspond to\nembedd
ings of abelian discrete groups of order N upon a 2-torus. Via\nthe princi
ples of AdS/CFT correspondence one of these configurations\nmaps to a regu
lar Wick-rotated section of a supersymmetric rotating and\nelectrically ch
arged Lorentzian AdS5 black hole. After an introduction\nto the problem\,
that will include a survey over the analytic frame that\nallows us to quan
tify the competition among elements of a sub-family of\nthese complex eige
nvalue configurations\, I will end with an\ninterpretation of our results
for SU(N) N=4 SYM\, and a comparison with\nrecently reported numerical stu
dies.\n
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SUMMARY:Miguel Montero (Harvard U.)
DTSTART;VALUE=DATE-TIME:20200618T140000Z
DTEND;VALUE=DATE-TIME:20200618T150000Z
DTSTAMP;VALUE=DATE-TIME:20200812T043143Z
UID:HEPTUW/2
DESCRIPTION:Title: Nothing is certain in string compactifications\nby Migu
el Montero (Harvard U.) as part of HEP seminars TU Wien (Vienna)\n\n\nAbst
ract\nA bubble of nothing is a spacetime instability where a compact dimen
sion collapses. After nucleation\, it expands at the speed of light\, leav
ing "nothing" behind. There are a couple of robust mechanisms that can pre
vent the existence of a bubble: Either it is not energetically favourable
to produce them\, or there is a topological obstruction to their existenc
e. The latter is often the case with SUSY-preserving boundary conditions.
I will explain how to understand the topological obstruction in detail us
ing bordism\, which will show that it is very generically absent even for
a SUSY-compatible spin structure. As a proof of principle\, we construct a
nd embed in string theory an explicit bubble of nothing for a T3 with comp
letely periodic (SUSY-compatible) spin structure. There is a dynamical ob
struction due to a positive energy theorem which is circumvented by highe
r-derivative corrections. Our model can be embedded in string theory. Our
techniques can be used to construct a plethora of bubbles of nothing for
spaces of interest like CY6's\, G2 manifolds\, or Sasaki-Einstein manifold
s. We will explain how to study and circumvent the topological and dynamic
al obstruction in these cases. Avoiding the dynamical obstruction means av
oiding a modified energy condition which might be related to the Weak Grav
ity Conjecture. Our results lend support to the conjecture that any \nnon
-supersymmetric vacuum of quantum gravity is ultimately unstable.\n
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BEGIN:VEVENT
SUMMARY:Charles Marteau
DTSTART;VALUE=DATE-TIME:20200625T140000Z
DTEND;VALUE=DATE-TIME:20200625T150000Z
DTSTAMP;VALUE=DATE-TIME:20200812T043143Z
UID:HEPTUW/3
DESCRIPTION:Title: New boundary conditions for AdS2\nby Charles Marteau as
part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nWe describe new boun
dary conditions for AdS2 in Jackiw-Teitelboim gravity. The asymptotic symm
etry group is enhanced to Diff(S1)āCā(S1) whose breaking to SL(2\,R)Ć
U(1) controls the near-AdS2 dynamics. The action reduces to a boundary ter
m which is a generalization of the Schwarzian theory. It can be interprete
d as the coadjoint action of the warped Virasoro group. We show that this
theory is holographically dual to the complex SYK model. We compute the Eu
clidean path integral and derive its relation to the random matrix ensembl
e of Saad\, Shenker and Stanford. We study the flat space version of this
action\, and show that the corresponding path integral also gives an ensem
ble average\, but of a much simpler nature. We explore some applications t
o near-extremal black holes.\n
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BEGIN:VEVENT
SUMMARY:Hiroshi Ooguri (Caltech & Kavli IPMU)
DTSTART;VALUE=DATE-TIME:20200709T140000Z
DTEND;VALUE=DATE-TIME:20200709T150000Z
DTSTAMP;VALUE=DATE-TIME:20200812T043143Z
UID:HEPTUW/5
DESCRIPTION:Title: Testing Swampland Conjectures\nby Hiroshi Ooguri (Calte
ch & Kavli IPMU) as part of HEP seminars TU Wien (Vienna)\n\n\nAbstract\nO
ver the last fourteen years\, a variety of swampland conditions have been
proposed with various degrees of rigor. In this talk\, I will discuss test
s of some of these conjectures that do not rely on specific string theory
constructions. They include constraints on symmetry\, strength of gravitat
ional couplings\, cobordism between theories\, and issues with lower dimen
sional theories.\n
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