Massive islands Geng, Hao; Karch, Andreas
The journal of high energy physics,
09/2020, Letnik:
2020, Številka:
9
Journal Article
Recenzirano
Odprti dostop
A
bstract
We comment on the role of the graviton mass in recent calculations of the Page curve using holographic ideas. All reliable calculations of the Page curve in more than 2+1 spacetime ...dimensions have been performed in systems with massive gravitons. A crucial ingredient in these calculations is the formation of islands, regions that contribute to the entropy of degrees of freedom located elsewhere. While most often simply ignored, it is indeed true that mass of the graviton does not appear to significantly affect the calculations that appeared in the literature. We use the freedom to change the graviton mass to give an extremely simple model of analytically tractable island formation in general dimensions. We do however note that if one attempts to take the limit of zero graviton mass, any contribution from the islands disappears. This raises the question to what extent entanglement islands can play a role in standard massless gravity.
Polyakov’s formulation of 2 d bosonic string theory Guillarmou, Colin; Rhodes, Rémi; Vargas, Vincent
Publications mathématiques. Institut des hautes études scientifiques,
12/2019, Letnik:
130, Številka:
1
Journal Article
A
bstract
We consider consequences of triviality of cobordism classes and anomaly cancellation in supergravity theories in
d >
6. We argue that this leads to the existence of certain defects which we ...call “I-folds” (a generalization of orientifolds). The requirement that compactifications to lower dimensions involving these defects be anomaly free leads to conditions on the higher dimensional theory. We show that in theories with 16 supercharges in
d >
6 this leads to restrictions on the rank of the allowed gauge groups and thus provides an explanation for the observed restrictions in known string theory constructions. In particular, in eight and nine dimensions the only solutions to our constraints are precisely the ones realized in string theory compactifications. We also use these techniques to place constraints on the global structure of the gauge group in eight and nine dimensions.
Supersymmetric Formula omitted, Formula omitted and asymptotically Formula omitted black hole solutions are studied in the context of non-minimal Formula omitted supergravity models involving three ...vector multiplets (STU-model) and Abelian gaugings of the universal hypermultiplet moduli space. Such models correspond to consistent subsectors of the Formula omitted and Formula omitted gauged maximal supergravities that arise from the reduction of 11D and massive IIA supergravity on Formula omitted spaces down to four dimensions. A unified description of all the models is provided in terms of a square-root prepotential and the gauging of a duality-hidden symmetry pair of the universal hypermultiplet. Some aspects of M-theory and massive IIA holography are mentioned in passing.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Low energy effective action of bosonic string theory possesses a kind of singular static solution which can be interpreted as a naked singularity. Based on the Hohm-Zwiebach action, the naked ...singularities could be smoothed out by introducing the complete Formula omitted corrections of string theory. In this paper, we present two sets of non-singular solutions, which are also regular everywhere in the Einstein frame. In the perturbative region Formula omitted, the solutions reduce to the perturbative results. Our result provides extra evidence for weak cosmic censorship conjecture (WCCC) from a viewpoint of string theory.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
7.
E‐String Theory on Riemann Surfaces Kim, Hee‐Cheol; Razamat, Shlomo S.; Vafa, Cumrun ...
Fortschritte der Physik,
January 2018, Letnik:
66, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We study compactifications of the 6d E‐string theory, the theory of a small E8 instanton, to four dimensions. In particular we identify N=1 field theories in four dimensions corresponding to ...compactifications on arbitrary Riemann surfaces with punctures and with arbitrary non‐abelian flat connections as well as fluxes for the abelian sub‐groups of the E8 flavor symmetry. This sheds light on emergent symmetries in a number of 4d N=1 SCFTs (including the ‘E7 surprise’ theory) as well as leads to new predictions for a large number of 4‐dimensional exceptional dualities and symmetries.
The authors investigate compactifications of the 6d E‐string theory, the theory of a small E8 instanton, to four dimensions. In particular, N=1 field theories in four dimensions are identified which correspond to compactifications on arbitrary Riemann surfaces with punctures and with arbitrary non‐abelian flat connections as well as fluxes for the abelian sub‐groups of the E8 flavor symmetry. This sheds light on emergent symmetries in a number of 4d N=1 SCFTs (including the ‘E7 surprise’ theory) as well as leads to new predictions for a large number of 4‐dimensional exceptional dualities and symmetries.
Stringy structure at the BPS bound Martinec, Emil J.; Massai, Stefano; Turton, David
The journal of high energy physics,
12/2020, Letnik:
2020, Številka:
12
Journal Article
Recenzirano
Odprti dostop
A
bstract
We explore the stringy structure of 1/2-BPS bound states of NS fivebranes carrying momentum or fundamental string charge, in the decoupling limits leading to little string theory and to
AdS
...3
/
CFT
2
duality. We develop an exact worldsheet description of these states using null-gauged sigma models, and illustrate the construction by deriving the closed-form solution sourced by an elliptical NS5-F1 supertube. The Calabi-Yau/Landau-Ginsburg correspondence maps this geometrical worldsheet description to a non-compact LG model whose superpotential is determined by the fivebrane source configuration. Singular limits of the 1/2-BPS configuration space result when the fivebrane worldvolume self-intersects, as can be seen from both sides of the CY/LG duality — on the Landau-Ginsburg side from the degeneration of the superpotential(s), and on the geometrical side from an analysis of D-brane probes. These singular limits are a portal to black hole formation via the condensation of the branes that are becoming massless, and thus exhibit in the gravitational bulk description the central actors in the non-gravitational dual theory underlying black hole thermodynamics.
A
bstract
When absorbing boundary conditions are used to evaporate a black hole in AdS/CFT, we show that there is a phase transition in the location of the quantum Ryu-Takayanagi surface, at ...precisely the Page time. The new RT surface lies slightly inside the event horizon, at an infalling time approximately the scrambling time
β/
2
π
log
S
BH
into the past. We can immediately derive the Page curve, using the Ryu-Takayanagi formula, and the Hayden-Preskill decoding criterion, using entanglement wedge reconstruction. Because part of the interior is now encoded in the early Hawking radiation, the decreasing entanglement entropy of the black hole is exactly consistent with the semiclassical bulk entanglement of the late-time Hawking modes, despite the absence of a firewall.
By studying the entanglement wedge of highly mixed states, we can understand the state dependence of the interior reconstructions. A crucial role is played by the existence of tiny, non-perturbative errors in entanglement wedge reconstruction. Directly after the Page time, interior operators can only be reconstructed from the Hawking radiation if the initial state of the black hole is known. As the black hole continues to evaporate, reconstructions become possible that simultaneously work for a large class of initial states. Using similar techniques, we generalise Hayden-Preskill to show how the amount of Hawking radiation required to reconstruct a large diary, thrown into the black hole, depends on both the energy and the entropy of the diary. Finally we argue that, before the evaporation begins, a single, state-independent interior reconstruction exists for any code space of microstates with entropy strictly less than the Bekenstein-Hawking entropy, and show that this is sufficient state dependence to avoid the AMPSS typical-state firewall paradox.
New boundary conditions for AdS3 Compère, Geoffrey; Song, Wei; Strominger, Andrew
The journal of high energy physics,
29/5, Letnik:
2013, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A
bstract
New chiral boundary conditions are found for quantum gravity with matter on AdS
3
. The associated asymptotic symmetry group is generated by a single right-moving U(1) Kac-Moody-Virasoro ...algebra with
. The Kac-Moody zero mode generates global left-moving translations and equals, for a BTZ black hole, the sum of the total mass and spin. The level is positive about the global vacuum and negative in the black hole sector, corresponding to ergosphere formation. Realizations arising in Chern-Simons gravity and string theory are analyzed. The new boundary conditions are shown to naturally arise for warped AdS
3
in the limit that the warp parameter is taken to zero.
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