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Related papers: Loop contribution to inflationary magnetic field

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Cosmological observables of the primordial universe are encoded in the late-time field-theoretic wavefunction. For shift-symmetric scalars in de Sitter, a good approximation for many inflationary models, the wavefunction must be purely real…

High Energy Physics - Theory · Physics 2026-03-11 Alexander Farren , Ciaran McCulloch , Enrico Pajer , Xi Tong

A formalism based on the fermionic functional-renormalization-group approach to interacting electron models defined on a lattice is presented. One-loop flow equations for the coupling constants and susceptibilities in the particle-particle…

Strongly Correlated Electrons · Physics 2024-08-21 Lucas Désoppi , Nicolas Dupuis , Claude Bourbonnais

In this paper we revisit and extend a previous analysis where the possible relevance of quantum gravity effects in a cosmological setup was studied. The object of interest are non-local (logarithmic) terms generated in the effective action…

General Relativity and Quantum Cosmology · Physics 2008-11-26 J. A. Cabrer , D. Espriu

We introduce a streamlined method for evaluating in-in loop integrals using dimensional regularization for diagrams with an arbitrary number of external legs and vertices, which complements earlier work and facilitates the extraction of the…

High Energy Physics - Theory · Physics 2026-05-15 Guillermo Ballesteros , Jesús Gambín Egea , Flavio Riccardi

We calculate the power spectrum of vacuum fluctuations of a generic scalar field in a quantum cosmological setting that is manifestly singularity-free. The power spectrum is given in terms of the usual scale invariant spectrum plus scale…

Astrophysics · Physics 2007-05-23 S. Hofmann , O. Winkler

We present an analysis of the one-loop contribution from left- and right-handed fermions to the static electromagnetic properties of an arbitrarily charged no self-conjugate vector boson $V$. Particular emphasis is given to the case of a no…

High Energy Physics - Phenomenology · Physics 2009-11-10 G. Tavares-Velasco , J. J. Toscano

Precise cosmological data from WMAP and forthcoming CMB experiments motivate the study of the quantum corrections to the slowroll inflationary parameters.We find the quantum (loop) corrections to the equations of motion of the classical…

Astrophysics · Physics 2009-11-10 D. Boyanovsky , H. J. de Vega , N. G. Sanchez

In this work we explore the effects that a possible primordial magnetic field can have on the inflaton effective potential, taking as the underlying model a warm inflation scenario, based on global supersymmetry with a new-inflation-type…

High Energy Physics - Phenomenology · Physics 2022-08-11 Gabriella Piccinelli , Angel Sánchez

We calculate the two-loop corrections in primordial power spectrum in models of single field inflation incorporating an intermediate USR phase employed for PBHs formation. Among the total eleven one-particle irreducible Feynman diagrams, we…

High Energy Physics - Phenomenology · Physics 2024-12-16 Hassan Firouzjahi

The one-loop effective potential of a thermodynamic fermion loop under constant magnetic field is studied. As expected, it can be interpreted literally as a discretized sum of $(D-2)$-dimensional energy density above the Dirac sea.…

High Energy Physics - Theory · Physics 2009-10-30 H-T. Sato

We compute the one loop fermion self-energy for massless Dirac + Einstein in the presence of a locally de Sitter background. We employ dimensional regularization and obtain a fully renormalized result by absorbing all divergences with BPHZ…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Shun-Pei Miao , R. P. Woodard

We consider a massless and minimally coupled self interacting quantum scalar field theory in the inflationary de Sitter background of dimension four. The self interaction potential is taken to be either quartic, $\lambda \phi^4/4!$, or…

High Energy Physics - Theory · Physics 2024-08-13 Sourav Bhattacharya , Sudesh Kumar

Using the one-loop Coleman-Weinberg effective potential, we derive a general analytic expression for all the derivatives of the effective potential with respect to any number of classical scalar fields. The result is valid for a…

High Energy Physics - Phenomenology · Physics 2016-07-29 José Eliel Camargo-Molina , António P. Morais , Roman Pasechnik , Marco O. P. Sampaio , Jonas Wessén

We commence the evaluation of the one- and two-loop binding corrections to the $g factor for an electron in a hydrogenlike system of order alpha^2 (Z alpha)^5 and consider diagrams with closed fermion loops. The one-loop vacuum-polarization…

High Energy Physics - Phenomenology · Physics 2009-09-26 U. D. Jentschura

We compute the one loop graviton contribution to the self-energy of a very light fermion on a locally de Sitter background. This result can be used to study the effect that a small mass has on the propagation of fermions through the sea of…

General Relativity and Quantum Cosmology · Physics 2015-06-05 S. P. Miao

We consider a vectorial, asymptotically free gauge theory and analyze the effect of higher-loop corrections to the beta function on the evolution of the theory from the ultraviolet to the infrared. We study the case in which the theory…

High Energy Physics - Phenomenology · Physics 2011-03-22 Thomas A. Ryttov , Robert Shrock

We include the single graviton loop contribution to the linearized Einstein equation. Explicit results are obtained for one loop corrections to the propagation of gravitational radiation. Although suppressed by a minuscule loop-counting…

General Relativity and Quantum Cosmology · Physics 2022-06-27 L. Tan , N. C. Tsamis , R. P. Woodard

We investigate the imprints on the angular power spectra of cosmological perturbations of a pre-inflationary bounce phase, as described by the hybrid and dressed metric approaches to loop quantum cosmology. For this purpose, we derive a new…

General Relativity and Quantum Cosmology · Physics 2026-05-15 Almudena Guillén , Kai Langer , Guillermo A. Mena Marugán , Niklas Rodenbücher , Antonio Vicente-Becerril

We study loop corrections to correlation functions of inflationary perturbations. Previous calculations have found that the two-point function can have a logarithmic running of the form log(k/mu), where k is the wavenumber of the…

High Energy Physics - Theory · Physics 2010-12-09 Leonardo Senatore , Matias Zaldarriaga

My project computed the one loop fermion self-energy for massless Dirac + Einstein in the presence of a locally de Sitter background. I employed dimensional regularization and obtain a fully renormalized result by absorbing all divergences…

High Energy Physics - Theory · Physics 2007-05-23 Shun-Pei Miao