scholarly journals Opacity and effective field theory in anti–de Sitter backgrounds

2019 ◽  
Vol 100 (9) ◽  
Author(s):  
Sylvain Fichet
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Field ◽  
De Sitter

scholarly journals Role of trans-Planckian modes in cosmology

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Arjun Berera ◽  
Suddhasattwa Brahma ◽  
Jaime R. Calderón
Keyword(s):  
Field Theory ◽  
Power Spectrum ◽  
Effective Field Theory ◽  
Effective Field ◽  
Inflationary Cosmology ◽  
De Sitter ◽  
Warm Inflation ◽  
Primordial Power Spectrum ◽  
Hubble Horizon

Abstract Motivated by the old trans-Planckian (TP) problem of inflationary cosmology, it has been conjectured that any consistent effective field theory should keep TP modes ‘hidden’ behind the Hubble horizon, so as to prevent them from turning classical and thereby affecting macroscopic observations. In this paper we present two arguments against the Hubble horizon being a scale of singular significance as has been put forward in the TP Censorship Conjecture (TCC). First, refinements of TCC are presented that allow for the TP modes to grow beyond the horizon while still keeping the de-Sitter conjecture valid. Second, we show that TP modes can turn classical even well within the Hubble horizon, which, as such, negates this rationale behind keeping them from crossing it. The role of TP modes is known to be less of a problem in warm inflation, because fluctuations start out usually as classical. This allows warm inflation to be more resilient to the TP problem compared to cold inflation. To understand how robust this is, we identity limits where quantum modes can affect the primordial power spectrum in one specific case.

nflation from the Persepective of Quantum Gravity

2020 ◽  
Vol 29 (11) ◽  
pp. 26-30
Author(s):  
Seoktae KOH ◽  
Jinn-Ouk GONG ◽  
Min-Seok SEO
Keyword(s):  
Field Theory ◽  
Quantum Gravity ◽  
Effective Field Theory ◽  
Model Building ◽  
Quantum Fluctuations ◽  
De Sitter Space ◽  
Effective Field ◽  
De Sitter ◽  
Space Model

A brief review on inflation is given from the quantum gravity perspective. Using the effective field theory, we discuss quantum fluctuations and how they evolve into classical perturbations. We then list some limitations on de Sitter space model building and unresolved issues of inflation theory, together with persepectives.

scholarly journals Cosmic Microwave Background from Effective Field Theory †

Universe ◽  
2019 ◽  
Vol 5 (6) ◽  
pp. 155
Author(s):  
Sayantan Choudhury
Keyword(s):  
Field Theory ◽  
Cosmic Microwave Background ◽  
Effective Field Theory ◽  
Vacuum State ◽  
Effective Field ◽  
De Sitter ◽  
Microwave Background ◽  
Slow Roll ◽  
Point Correlation ◽  
Single Field

In this work, we study the key role of generic Effective Field Theory (EFT) framework to quantify the correlation functions in a quasi de Sitter background for an arbitrary initial choice of the quantum vacuum state. We perform the computation in unitary gauge, in which we apply the St u ¨ ckelberg trick in lowest dimensional EFT operators which are broken under time diffeomorphism. In particular, using this non-linear realization of broken time diffeomorphism and truncating the action by considering the contribution from two derivative terms in the metric, we compute the two-point and three-point correlations from scalar perturbations and two-point correlation from tensor perturbations to quantify the quantum fluctuations observed in the Cosmic Microwave Background (CMB) map. We also use equilateral limit and squeezed limit configurations for the scalar three-point correlations in Fourier space. To give future predictions from EFT setup and to check the consistency of our derived results for correlations, we use the results obtained from all classes of the canonical single-field and general single-field P ( X , ϕ ) model. This analysis helps us to fix the coefficients of the relevant operators in EFT in terms of the slow-roll parameters and effective sound speed. Finally, using CMB observations from Planck we constrain all these coefficients of EFT operators for the single-field slow-roll inflationary paradigm.

scholarly journals Effective field theory of hairy black holes and their flat and de Sitter limits

2019 ◽  
Vol 100 (6) ◽  
Author(s):  
Sayan Chakrabarti ◽  
Sumeet Chougule ◽  
Debaprasad Maity
Keyword(s):  
Field Theory ◽  
Black Holes ◽  
Effective Field Theory ◽  
Effective Field ◽  
De Sitter ◽  
Hairy Black Holes

scholarly journals Resolving spacetime singularities in flux compactifications & KKLT

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Federico Carta ◽  
Jakob Moritz
Keyword(s):  
Field Theory ◽  
Flux Compactifications ◽  
Effective Field Theory ◽  
Bound States ◽  
Effective Field ◽  
Low Energy ◽  
De Sitter ◽  
Yang Mills ◽  
Type Iib String Theory ◽  
De Sitter Vacuum

Abstract In flux compactifications of type IIB string theory with D3 and seven-branes, the negative induced D3 charge localized on seven-branes leads to an apparently pathological profile of the metric sufficiently close to the source. With the volume modulus stabilized in a KKLT de Sitter vacuum this pathological region takes over a significant part of the entire compactification, threatening to spoil the KKLT effective field theory. In this paper we employ the Seiberg-Witten solution of pure SU(N) super Yang-Mills theory to argue that wrapped seven-branes can be thought of as bound states of more microscopic exotic branes. We argue that the low-energy worldvolume dynamics of a stack of n such exotic branes is given by the (A1, An−1) Argyres-Douglas theory. Moreover, the splitting of the perturbative (in α′) seven-brane into its constituent branes at the non-perturbative level resolves the apparently pathological region close to the seven-brane and replaces it with a region of $$ \mathcal{O} $$ O (1) Einstein frame volume. While this region generically takes up an $$ \mathcal{O} $$ O (1) fraction of the compactification in a KKLT de Sitter vacuum we argue that a small flux superpotential dynamically ensures that the 4d effective field theory of KKLT remains valid nevertheless.

Effective Field Theory in Particle Physics and Cosmology

2020 ◽  
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Particle Physics ◽  
Large Scale ◽  
Effective Field ◽  
Effective Theory ◽  
Soft Collinear Effective Theory ◽  
Multiple Length Scales ◽  
Cosmological Observations ◽  
Standard Models

Effective field theory (EFT) is a general method for describing quantum systems with multiple-length scales in a tractable fashion. It allows us to perform precise calculations in established models (such as the standard models of particle physics and cosmology), as well as to concisely parametrize possible effects from physics beyond the standard models. EFTs have become key tools in the theoretical analysis of particle physics experiments and cosmological observations, despite being absent from many textbooks. This volume aims to provide a comprehensive introduction to many of the EFTs in use today, and covers topics that include large-scale structure, WIMPs, dark matter, heavy quark effective theory, flavour physics, soft-collinear effective theory, and more.

The Fujita-Miyazawa force in the light of effective field theory

2008 ◽  
Author(s):  
Ulf-G. Meiβner ◽  
Hideyuki Sakai ◽  
Kimiko Sekiguchi ◽  
Benjamin F. Gibson
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Field

scholarly journals Towards Feynman rules for conformal blocks

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Sarah Hoback ◽  
Sarthak Parikh
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Hypergeometric Functions ◽  
Power Series Expansion ◽  
Effective Field ◽  
Conformal Block ◽  
Tree Level ◽  
Conformal Blocks ◽  
Simple Set ◽  
Feynman Rules

Abstract We conjecture a simple set of “Feynman rules” for constructing n-point global conformal blocks in any channel in d spacetime dimensions, for external and exchanged scalar operators for arbitrary n and d. The vertex factors are given in terms of Lauricella hypergeometric functions of one, two or three variables, and the Feynman rules furnish an explicit power-series expansion in powers of cross-ratios. These rules are conjectured based on previously known results in the literature, which include four-, five- and six-point examples as well as the n-point comb channel blocks. We prove these rules for all previously known cases, as well as two new ones: the seven-point block in a new topology, and all even-point blocks in the “OPE channel.” The proof relies on holographic methods, notably the Feynman rules for Mellin amplitudes of tree-level AdS diagrams in a scalar effective field theory, and is easily applicable to any particular choice of a conformal block beyond those considered in this paper.

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