scholarly journals How a four-dimensional de Sitter solution remains outside the swampland

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Keshav Dasgupta ◽  
Maxim Emelin ◽  
Mir Mehedi Faruk ◽  
Radu Tatar
Keyword(s):  
Effective Field Theory ◽  
Cosmic Censorship ◽  
Effective Field ◽  
Time Dependent ◽  
Quantum Corrections ◽  
De Sitter ◽  
Dimensional Solution ◽  
Moduli Stabilization ◽  
Local Quantum ◽  
Non Local

Abstract We argue that, in the presence of time-dependent fluxes and quantum corrections, four-dimensional de Sitter solutions should appear in the type IIB string landscape and not in the swampland. Our construction considers generic choices of local and non-local quantum terms and satisfies the no-go and the swampland criteria, the latter being recently upgraded using the trans-Planckian cosmic censorship. Interestingly, both time-independent Newton constant and moduli stabilization may be achieved in such backgrounds even in the presence of time-dependent fluxes and internal spaces. However, once the time-dependence is switched off, any four-dimensional solution with de Sitter isometries appears to have no simple effective field theory descriptions and is back in the swampland.

scholarly journals Effective field theory in time-dependent settings

2013 ◽  
Vol 2013 (2) ◽  
Author(s):  
Hael Collins ◽  
R. Holman ◽  
Andreas Ross
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Effective Field ◽  
Time Dependent

scholarly journals Axion hilltops, Kahler modulus quintessence and the swampland criteria

2019 ◽  
Vol 34 (28) ◽  
pp. 1950164 ◽  
Author(s):  
Maxim Emelin ◽  
Radu Tatar
Keyword(s):  
Degrees Of Freedom ◽  
Initial Conditions ◽  
Effective Field ◽  
Fine Tuning ◽  
De Sitter ◽  
Moduli Stabilization ◽  
Nonperturbative Effect ◽  
Initial Conditions Problem ◽  
Field Excursion ◽  
Hubble Time

We study the interplay among extrema of axion potentials, Kahler moduli stabilization and the swampland criteria. We argue that moving away from the minima of nonperturbatively generated axion potentials can lead to a runaway behavior of moduli that govern the couplings in the effective field theory. The proper inclusion of these degrees of freedom resolves the conflict between periodic axion potentials and the gradient de Sitter criterion, without the need to invoke the refined de Sitter criterion. We investigate the possibility of including this runaway direction as a model of quintessence that satisfies the swampland criteria. Using a single nonperturbative effect, the maximum along the axion direction provides such a runaway direction, which is unstable in the axion directions, sensitive to initial conditions and too steep to allow for a Hubble time of expansion without violating the field excursion criterion. Adding a second nonperturbative effect generates a saddle point in the potential satisfying the refined de Sitter criterion, which solves the steepness problem and improves the initial conditions problem although some fine-tuning remains required.

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.

scholarly journals The equivalence principle in a quantum world

2015 ◽  
Vol 24 (12) ◽  
pp. 1544013 ◽  
Author(s):  
N. E. J. Bjerrum-Bohr ◽  
John F. Donoghue ◽  
Basem Kamal El-Menoufi ◽  
Barry R. Holstein ◽  
Ludovic Planté ◽  
...  
Keyword(s):  
Quantum Gravity ◽  
Effective Field Theory ◽  
Equivalence Principle ◽  
Quantum Physics ◽  
Effective Field ◽  
Low Energy ◽  
Quantum Corrections ◽  
The Core ◽  
Modern Methods ◽  
Coordinate Invariance

We show how modern methods can be applied to quantum gravity at low energy. We test how quantum corrections challenge the classical framework behind the equivalence principle (EP), for instance through introduction of nonlocality from quantum physics, embodied in the uncertainty principle. When the energy is small, we now have the tools to address this conflict explicitly. Despite the violation of some classical concepts, the EP continues to provide the core of the quantum gravity framework through the symmetry — general coordinate invariance — that is used to organize the effective field theory (EFT).

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 Beryllium-9 in cluster effective field theory

2020 ◽  
Author(s):  
Elena Filandri ◽  
Paolo Andreatta ◽  
Carlo A. Manzata ◽  
Chen Ji ◽  
Win Leidemann ◽  
...  
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Ground State ◽  
Integral Transform ◽  
Scattering Length ◽  
Effective Field ◽  
Lorentz Integral Transform ◽  
Distance Dependence ◽  
Non Local ◽  
Potential Parameters

We study the ^99Be ground-state energy with non-local \alpha nαn and \alpha \alphaαα potentials derived from Cluster Effective Field Theory. The short-distance dependence of the interaction is regulated with a momentum cutoff. The potential parameters are fitted to reproduce the scattering length and effective range. We implement such potential models in a Non-Symmetrized Hyperspherical Harmonics (NSHH) code in momentum space. In addition we calculate ground-state energies of various alpha nuclei. Work is in progress on a calculation of the photodisintegration of ^99Be with the Lorentz Integral Transform (LIT) method.

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