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We consider $P(\phi^I,X^{IJ})$ theories of multi-field inflation and ask the question of how to define the adiabatic and entropy perturbations, widely used in calculating the curvature and isocurvature power spectra, in this general…

General Relativity and Quantum Cosmology · Physics 2017-01-25 Chris Longden

After introducing gauge-invariant cosmological perturbation theory we give an improved set of governing equations for multiple fluids including energy transfer. Having defined adiabatic and entropic perturbations we derive the…

Astrophysics · Physics 2007-05-23 Karim A. Malik

We theoretically study nonadiabatic corrections for charge pumping in a noninteracting electron model of a single-level quantum dot. We derive a formula for the velocity limit of parameter driving to realize adiabatic pumping and illustrate…

Mesoscale and Nanoscale Physics · Physics 2022-06-15 Masahiro Hasegawa , Takeo Kato

Non-adiabatic pressure perturbations naturally occur in models of inflation consisting of more than one scalar field. The amount of non-adiabatic pressure present at the end of inflation can have observational consequences through changes…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-30 Ian Huston , Adam J. Christopherson

We study the out of equilibrium dynamics of inflationary phase transitions and compute the resulting spectrum of metric perturbations relevant to observation. We show that simple single field models of inflation may produce an adiabatic…

Astrophysics · Physics 2016-11-03 D. Cormier , R. Holman

We review some recent progress in the extraction of inflationary observables in loop quantum cosmology. Inverse-volume quantum corrections induce a growth of power in the large-scale cosmological spectra and are constrained by observations.

General Relativity and Quantum Cosmology · Physics 2012-05-23 Gianluca Calcagni

We reconsider fluctuations of Affleck-Dine (AD) field in a D-term inflation model. Contrary to the previous analysis, we find that the spectrum of the adiabatic fluctuations is almost scale invariant even if the AD field has a large initial…

High Energy Physics - Phenomenology · Physics 2014-11-17 Masahiro Kawasaki , Fuminobu Takahashi

We calculate one-loop correction to the two-point functions of curvature perturbation in single-field inflation generated by cubic self-interaction. Incorporating the observed red-tilted spectrum of curvature perturbation, the relevant…

High Energy Physics - Theory · Physics 2022-07-05 Jason Kristiano , Jun'ichi Yokoyama

We generalize the perturbations theory of loop quantum cosmology to a hydrodynamical form and define an effective curvature perturbation on an uniform density hypersurfaces $\zeta_e$. As in the classical cosmology, $\zeta_e$ should be…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Yu Li , Jian-Yang Zhu

We perform a thorough computation of the one-loop corrections from both scalar and tensor degrees of freedom to the power spectrum of curvature fluctuations for non-canonical Lagrangians in single-field inflation. We consider models…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-27 Nicola Bartolo , Emanuela Dimastrogiovanni , Alberto Vallinotto

In the inflationary scenario of loop quantum cosmology in the presence of inverse-volume corrections, we give analytic formulas for the power spectra of scalar and tensor perturbations convenient to compare with observations. Since…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Martin Bojowald , Gianluca Calcagni , Shinji Tsujikawa

We study inflation for a quantum scalar electrodynamics model in curved space-time and for higher-derivative quantum gravity (QG) coupled with scalar electrodynamics. The corresponding renormalization-group (RG) improved potential is…

High Energy Physics - Theory · Physics 2017-03-15 Ratbay Myrzakulov , Sergei Odintsov , Lorenzo Sebastiani

An analysis of the decoherence of quantum fluctuations shows that production of classical adiabatic density perturbations may not take place in models of power-law inflation with power 1< p < 3. Some consequences for models of extended…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Milan Mijic

In Dirac-Born-Infeld inflation, changes in the sound speed that transiently break the slow roll approximation lead to features in the power spectrum. We develop and test the generalized slow roll approximation for calculating such effects…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-18 V Miranda , Wayne Hu , Peter Adshead

We show explicitly some exciting features of double-inflation: (i) it can often lead to strongly correlated adiabatic and entropy (isocurvature) power spectra. (ii) The two-field slow-roll consistency relations can be violated when the…

Astrophysics · Physics 2009-11-07 Shinji Tsujikawa , David Parkinson , Bruce A. Bassett

I review the standard analysis of adiabatic scalar and tensor perturbations produced by slow-roll inflation driven by a single scalar field, before going on to discuss recent work on the role of non-adiabatic modes during and after…

Astrophysics · Physics 2007-05-23 David Wands

We study the one-loop corrections in power spectrum of long gravitational waves induced from small scale modes in the models of single field inflation undergoing a phase of ultra-slow-roll (USR). We show that the spectrum of long tensor…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-05 Hassan Firouzjahi

We obtain the effective inflaton potential during slow roll inflation by including the one loop quantum corrections to the energy momentum tensor from scalar curvature and tensor perturbations as well as quantum fluctuations from light…

Astrophysics · Physics 2009-11-13 D. Boyanovsky , H. J. de Vega , N. G. Sanchez

Loop quantum cosmology is a symmetry-reduced application of loop quantum gravity. The theory predicts a bounce for the universe at the Planck scale and resolves the singularity of standard cosmology. The dynamics is also governed by an…

General Relativity and Quantum Cosmology · Physics 2024-06-27 Abolhassan Mohammadi

We analyze the spectrum of density perturbations generated in models of the recently discovered "D-cceleration" mechanism of inflation. In this scenario, strong coupling quantum field theoretic effects sum to provide a DBI-like action for…

High Energy Physics - Theory · Physics 2009-11-10 Mohsen Alishahiha , Eva Silverstein , David Tong