scholarly journals Dynamical tadpoles and Weak Gravity Constraints

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Alessandro Mininno ◽  
Angel M. Uranga
Keyword(s):  
Quantum Gravity ◽  
Compact Spaces ◽  
Consistency Conditions ◽  
Dynamical Nature ◽  
Explicit Realization ◽  
String Models ◽  
Weak Gravity

Abstract Non-supersymmetric string models are plagued with tadpoles for dynamical fields, which signal uncanceled forces sourced by the vacuum. We argue that in certain cases, uncanceled dynamical tadpoles can lead to inconsistencies with quantum gravity, via violation of swampland constraints. We describe an explicit realization in a supersymmetric toroidal Z2 × Z2 orientifold with D7-branes, where the dynamical tadpole generated by displacement of the D7-branes off its minimum leads to violation of the axion Weak Gravity Conjecture. In these examples, cancellation of dynamical tadpoles provides consistency conditions for the configuration, of dynamical nature (as opposed to the topological conditions of topological tadpoles, such as RR tadpole cancellation in compact spaces). We show that this approach provides a re-derivation of the Z-minimization criterion for AdS vacua giving the gravitational dual of a-maximization in 4d $$ \mathcal{N} $$ N = 1 toric quiver SCFTs.

scholarly journals The UV fate of anomalous U(1)s and the Swampland

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Nathaniel Craig ◽  
Isabel Garcia Garcia ◽  
Graham D. Kribs
Keyword(s):  
Quantum Gravity ◽  
Gauge Theories ◽  
Critical Size ◽  
Gauge Coupling ◽  
Low Energy ◽  
Gravitational Anomaly ◽  
Light Vector ◽  
Energy Theory ◽  
The Cost ◽  
Weak Gravity

Abstract Massive U(1) gauge theories featuring parametrically light vectors are suspected to belong in the Swampland of consistent EFTs that cannot be embedded into a theory of quantum gravity. We study four-dimensional, chiral U(1) gauge theories that appear anomalous over a range of energies up to the scale of anomaly-cancelling massive chiral fermions. We show that such theories must be UV-completed at a finite cutoff below which a radial mode must appear, and cannot be decoupled — a Stückelberg limit does not exist. When the infrared fermion spectrum contains a mixed U(1)-gravitational anomaly, this class of theories provides a toy model of a boundary into the Swampland, for sufficiently small values of the vector mass. In this context, we show that the limit of a parametrically light vector comes at the cost of a quantum gravity scale that lies parametrically below MP1, and our result provides field theoretic evidence for the existence of a Swampland of EFTs that is disconnected from the subset of theories compatible with a gravitational UV-completion. Moreover, when the low energy theory also contains a U(1)3 anomaly, the Weak Gravity Conjecture scale makes an appearance in the form of a quantum gravity cutoff for values of the gauge coupling above a certain critical size.

scholarly journals Loop quantum gravity on non-compact spaces

2000 ◽  
Vol 577 (3) ◽  
pp. 529-546 ◽  
Author(s):  
Matthias Arnsdorf ◽  
Sameer Gupta
Keyword(s):  
Quantum Gravity ◽  
Loop Quantum Gravity ◽  
Compact Spaces

scholarly journals Axion experiments to algebraic geometry: Testing quantum gravity via the Weak Gravity Conjecture

2016 ◽  
Vol 25 (12) ◽  
pp. 1643005 ◽  
Author(s):  
Ben Heidenreich ◽  
Matthew Reece ◽  
Tom Rudelius
Keyword(s):  
Field Theory ◽  
Algebraic Geometry ◽  
Quantum Gravity ◽  
General Nature ◽  
Quantum Field ◽  
Gauge Groups ◽  
Common Features ◽  
Conformal Field ◽  
Pure Mathematics ◽  
Weak Gravity

Common features of known quantum gravity theories may hint at the general nature of quantum gravity. The absence of continuous global symmetries is one such feature. This inspired the Weak Gravity Conjecture, which bounds masses of charged particles. We propose the Lattice Weak Gravity Conjecture, which further requires the existence of an infinite tower of particles of all possible charges under both abelian and nonabelian gauge groups and directly implies a cutoff for quantum field theory. It holds in a wide variety of string theory examples and has testable consequences for the real world and for pure mathematics. We sketch some implications of these ideas for models of inflation, for the QCD axion (and LIGO), for conformal field theory, and for algebraic geometry.

scholarly journals Large N gauge theories with a dense spectrum and the weak gravity conjecture

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Prarit Agarwal ◽  
Jaewon Song
Keyword(s):  
Gauge Theory ◽  
General Theory ◽  
Quantum Gravity ◽  
Gauge Theories ◽  
Degree Of Freedom ◽  
Large N ◽  
The Matrix ◽  
Weak Gravity

Abstract We find large N gauge theories containing a large number of operators within a band of low conformal dimensions. One of such examples is the four-dimensional $$ \mathcal{N} $$ N = 1 supersymmetric SU(N) gauge theory with one adjoint and a pair of fundamental/anti-fundamental chiral multiplets. This theory flows to a superconformal theory in the infrared upon a superpotential coupling with gauge singlets. The gap in the low-lying spectrum scales as 1/N and the central charges scale as O(N1) contrary to the usual O(N2) scaling of ordinary gauge theory coming from the matrix degree of freedom. We find the AdS version of the Weak Gravity Conjecture (WGC) holds for this theory, although it cannot be holographically dual to supergravity. This supports the validity of WGC in a more general theory of quantum gravity.

scholarly journals Quantum corrections in 4d N = 1 infinite distance limits and the weak gravity conjecture

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Daniel Klaewer ◽  
Seung-Joo Lee ◽  
Timo Weigand ◽  
Max Wiesner
Keyword(s):  
Quantum Gravity ◽  
Weak Coupling Limit ◽  
Quantum Corrections ◽  
Classical Level ◽  
Four Dimensions ◽  
Weakly Coupled ◽  
The Masses ◽  
Perturbative Corrections ◽  
Weak Gravity ◽  
Kaluza Klein

Abstract We study quantum corrections in four-dimensional theories with N = 1 supersymmetry in the context of Quantum Gravity Conjectures. According to the Emergent String Conjecture, infinite distance limits in quantum gravity either lead to decompactification of the theory or result in a weakly coupled string theory. We verify this conjecture in the framework of N = 1 supersymmetric F-theory compactifications to four dimensions including perturbative α′ as well as non-perturbative corrections. After proving uniqueness of the emergent critical string at the classical level, we show that quantum corrections obstruct precisely those limits in which the scale of the emergent critical string would lie parametrically below the Kaluza-Klein scale. Limits in which the tension of the asymptotically tensionless string sits at the Kaluza-Klein scale, by contrast, are not obstructed.In the second part of the paper we study the effect of quantum corrections for the Weak Gravity Conjecture away from the strict weak coupling limit. We propose that gauge threshold corrections and mass renormalisation effects modify the super-extremality bound in four dimensions. For the infinite distance limits in F-theory the classical super-extremality bound is generically satisfied by a sublattice of states in the tower of excitations of an emergent heterotic string. By matching the F-theory α′-corrections to gauge threshold corrections of the dual heterotic theory we predict how the masses of this tower must be renormalised in order for the Weak Gravity Conjecture to hold at the quantum level.

scholarly journals A conjecture on the minimal size of bound states

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Ben Freivogel ◽  
Thomas Gasenzer ◽  
Arthur Hebecker ◽  
Sascha Leonhardt
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Black Holes ◽  
Quantum Gravity ◽  
Bound States ◽  
Bound State ◽  
Quantum Field ◽  
Minimal Size ◽  
Sharp Form ◽  
Weak Gravity

We conjecture that, in a renormalizable effective quantum field theory where the heaviest stable particle has mass mm, there are no bound states with radius below 1/m1/m (Bound State Conjecture). We are motivated by the (scalar) Weak Gravity Conjecture, which can be read as a statement forbidding certain bound states. As we discuss, versions for uncharged particles and their generalizations have shortcomings. This leads us to the suggestion that one should only constrain rather than exclude bound objects. In the gravitational case, the resulting conjecture takes the sharp form of forbidding the adiabatic construction of black holes smaller than 1/m1/m. But this minimal bound-state radius remains non-trivial as M_\mathrm{P}\to \inftyMP→∞, leading us to suspect a feature of QFT rather than a quantum gravity constraint. We find support in a number of examples which we analyze at a parametric level.

scholarly journals Supersymmetry breaking, brane dynamics and Swampland conjectures

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Ivano Basile
Keyword(s):  
Supersymmetry Breaking ◽  
Effective Charge ◽  
Qualitative Agreement ◽  
Heterotic String ◽  
The Other ◽  
String Amplitude ◽  
String Models ◽  
Weak Gravity

Abstract We investigate interactions between branes of various dimensions, both charged and uncharged, in three non-supersymmetric string models. These include the USp(32) and U(32) orientifold projections of the type IIB and type 0B strings, as well as the SO(16)×SO(16) projection of the exceptional heterotic string. The resulting ten-dimensional spectra are free of tachyons, and the combinations of branes that they contain give rise to rich and varied dynamics. We compute static potentials for parallel stacks of branes in three complementary regimes: the probe regime, in which one of the two stacks is parametrically heavier than the other, the string-amplitude regime, in which both stacks are light, and the holographic regime. Whenever comparisons are possible, we find qualitative agreement despite the absence of supersymmetry. For charged branes, our analysis reveals that the Weak Gravity Conjecture is satisfied in a novel way via a renormalization of the effective charge-to-tension ratio.

scholarly journals A proof of the weak gravity conjecture

2017 ◽  
Vol 26 (12) ◽  
pp. 1742004 ◽  
Author(s):  
Shahar Hod
Keyword(s):  
Quantum Gravity ◽  
Second Law Of Thermodynamics ◽  
Fundamental Aspect ◽  
Second Law ◽  
Consistent Theory ◽  
Generalized Second Law ◽  
Self Consistent ◽  
Proper Mass ◽  
Weak Gravity ◽  
Charge Formula

The weak gravity conjecture suggests that, in a self-consistent theory of quantum gravity, the strength of gravity is bounded from above by the strengths of the various gauge forces in the theory. In particular, this intriguing conjecture asserts that in a theory describing a [Formula: see text] gauge field coupled consistently to gravity, there must exist a particle whose proper mass is bounded (in Planck units) by its charge: [Formula: see text]. This beautiful and remarkably compact conjecture has attracted the attention of physicists and mathematicians over the last decade. It should be emphasized, however, that despite the fact that there are numerous examples from field theory and string theory that support the conjecture, we still lack a general proof of its validity. In the present paper, we prove that the weak gravity conjecture (and, in particular, the mass–charge upper bound [Formula: see text]) can be inferred directly from Bekenstein’s generalized second law of thermodynamics, a law which is widely believed to reflect a fundamental aspect of the elusive theory of quantum gravity.

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