scholarly journals A physical protocol for observers near the boundary to obtain bulk information in quantum gravity

2021 ◽  
Vol 10 (5) ◽  
Author(s):  
Chandramouli Chowdhury ◽  
Olga Papadoulaki ◽  
Suvrat Raju
Keyword(s):  
Quantum Gravity ◽  
Gauge Theories ◽  
Boundary Region ◽  
Low Energy ◽  
Back Reaction ◽  
Small Interval ◽  
Bulk State ◽  
Energy Theory ◽  
Theory Of Gravity ◽  
Entanglement Structure

We consider a set of observers who live near the boundary of global AdS, and are allowed to act only with simple low-energy unitaries and make measurements in a small interval of time. The observers are not allowed to leave the near-boundary region. We describe a physical protocol that nevertheless allows these observers to obtain detailed information about the bulk state. This protocol utilizes the leading gravitational back-reaction of a bulk excitation on the metric, and also relies on the entanglement-structure of the vacuum. For low-energy states, we show how the near-boundary observers can use this protocol to completely identify the bulk state. We explain why the protocol fails completely in theories without gravity, including non-gravitational gauge theories. This provides perturbative evidence for the claim that one of the signatures of holography - the fact that information about the bulk is also available near the boundary - is already visible in the low-energy theory of gravity.

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 Higgs Branch, Hyper-Kähler Quotient and Duality in SUSY N = 2 Yang–Mills Theories

1997 ◽  
Vol 12 (27) ◽  
pp. 4907-4931 ◽  
Author(s):  
I. Antoniadis ◽  
B. Pioline
Keyword(s):  
Moduli Space ◽  
Gauge Theories ◽  
Geometric Interpretation ◽  
Low Energy ◽  
Target Space ◽  
Field Theories ◽  
Yang Mills ◽  
Coulomb Phase ◽  
Supersymmetric Field Theories ◽  
Energy Theory

Low-energy limits of N = 2 supersymmetric field theories in the Higgs branch are described in terms of a nonlinear four-dimensional σ-model on a hyper-Kähler target space, classically obtained as a hyper-Kähler quotient of the original flat hypermultiplet space by the gauge group. We review in a pedagogical way this construction, and illustrate it in various examples, with special attention given to the singularities emerging in the low-energy theory. In particular, we thoroughly study the Higgs branch singularity of Seiberg–Witten SU(2) theory with Nf flavors, interpreted by Witten as a small instanton singularity in the moduli space of one instanton on ℝ4. By explicitly evaluating the metric, we show that this Higgs branch coincides with the Higgs branch of a U(1) N = 2 SUSY theory with the number of flavors predicted by the singularity structure of Seiberg–Witten's theory in the Coulomb phase. We find another example of Higgs phase duality, namely between the Higgs phases of U(Nc)Nf flavors and U(Nf-Nc)Nf flavors theories, by using a geometric interpretation due to Biquard et al. This duality may be relevant for understanding Seiberg's conjectured duality Nc ↔ Nf-Nc in N = 1 SUSY SU(Nc) gauge theories.

scholarly journals The Swampland Conjectures: A Bridge from Quantum Gravity to Particle Physics

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 273
Author(s):  
Mariana Graña ◽  
Alvaro Herráez
Keyword(s):  
Effective Field Theories ◽  
Quantum Gravity ◽  
Particle Physics ◽  
Effective Field ◽  
Low Energy ◽  
Field Theories ◽  
Neutrino Masses ◽  
Higgs Potential ◽  
Photon Mass ◽  
Effective Theories

The swampland is the set of seemingly consistent low-energy effective field theories that cannot be consistently coupled to quantum gravity. In this review we cover some of the conjectural properties that effective theories should possess in order not to fall in the swampland, and we give an overview of their main applications to particle physics. The latter include predictions on neutrino masses, bounds on the cosmological constant, the electroweak and QCD scales, the photon mass, the Higgs potential and some insights about supersymmetry.

scholarly journals Limits on quantum gravity effects from Swift short gamma-ray bursts

2017 ◽  
Vol 607 ◽  
pp. A121 ◽  
Author(s):  
M. G. Bernardini ◽  
G. Ghirlanda ◽  
S. Campana ◽  
P. D’Avanzo ◽  
J.-L. Atteia ◽  
...  
Keyword(s):  
Quantum Gravity ◽  
Gamma Ray ◽  
Lorentz Invariance ◽  
Spectral Energy Distribution ◽  
Gamma Ray Bursts ◽  
Low Energy ◽  
Energy Separation ◽  
Spectral Energy ◽  
Spectral Evolution ◽  
Short Grbs

The delay in arrival times between high and low energy photons from cosmic sources can be used to test the violation of the Lorentz invariance (LIV), predicted by some quantum gravity theories, and to constrain its characteristic energy scale EQG that is of the order of the Planck energy. Gamma-ray bursts (GRBs) and blazars are ideal for this purpose thanks to their broad spectral energy distribution and cosmological distances: at first order approximation, the constraints on EQG are proportional to the photon energy separation and the distance of the source. However, the LIV tiny contribution to the total time delay can be dominated by intrinsic delays related to the physics of the sources: long GRBs typically show a delay between high and low energy photons related to their spectral evolution (spectral lag). Short GRBs have null intrinsic spectral lags and are therefore an ideal tool to measure any LIV effect. We considered a sample of 15 short GRBs with known redshift observed by Swift and we estimate a limit on EQG ≳ 1.5 × 1016 GeV. Our estimate represents an improvement with respect to the limit obtained with a larger (double) sample of long GRBs and is more robust than the estimates on single events because it accounts for the intrinsic delay in a statistical sense.

scholarly journals NONCOMMUTATIVE OPEN STRING THEORIES AND THEIR DUALITIES

2001 ◽  
Vol 16 (04n06) ◽  
pp. 349-359 ◽  
Author(s):  
M. M. SHEIKH-JABBARI
Keyword(s):  
Open String ◽  
Low Energy ◽  
Duality Group ◽  
Critical Limit ◽  
Quantum Theories ◽  
Open Strings ◽  
Energy Theory ◽  
String Theories

The recently found noncritical open string theories is reviewed. These open strings, noncommutative open string theories (NCOS), arise as consistent quantum theories describing the low energy theory of D-branes in a background electric B-field in the critical limit. Focusing on the D3-brane case, we construct the most general (3+1) NCOS, which is described by four parameters. We study S- and T-dualities of these theories and argue the existence of a U-duality group.

scholarly journals Standard model and graviweak unification with (super)renormalizable gravity. Part I: Visible and invisible sectors of the universe

2015 ◽  
Vol 30 (09) ◽  
pp. 1550044 ◽  
Author(s):  
L. V. Laperashvili ◽  
H. B. Nielsen ◽  
A. Tureanu
Keyword(s):  
Standard Model ◽  
Quantum Gravity ◽  
Consistent Theory ◽  
Invariant Model ◽  
Higher Derivative ◽  
Self Consistent ◽  
Renormalizable Theory ◽  
Theory Of Gravity ◽  
Higgs Fields ◽  
The Universe

We develop a self-consistent Spin (4, 4)-invariant model of the unification of gravity with weak SU(2) gauge and Higgs fields in the visible and invisible sectors of our universe. We consider a general case of the graviweak unification, including the higher-derivative super-renormalizable theory of gravity, which is a unitary, asymptotically-free and perturbatively consistent theory of the quantum gravity.

scholarly journals Renormalizable and Unitary Model of Quantum Gravity

Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1334
Author(s):  
S. A. Larin
Keyword(s):  
Quantum Theory ◽  
Quantum Gravity ◽  
Curvature Tensor ◽  
Relativistic Quantum ◽  
Dimensional Regularization ◽  
Graviton Propagator ◽  
Unitary Model ◽  
Theory Of Gravity ◽  
Made In

We consider R + R 2 relativistic quantum gravity with the action where all possible terms quadratic in the curvature tensor are added to the Einstein-Hilbert term. This model was shown to be renormalizable in the work by K.S. Stelle. In this paper, we demonstrate that the R + R 2 model is also unitary contrary to the statements made in the literature, in particular in the work by Stelle. New expressions for the R + R 2 Lagrangian within dimensional regularization and the graviton propagator are derived. We demonstrate that the R + R 2 model is a good candidate for the fundamental quantum theory of gravity.

Sign in / Sign up

Export Citation Format

Share Document