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Inflation is now an accepted paradigm in standard cosmology, with its predictions consistent with observations of the cosmic microwave background. It lacks, however, a firm physical theory, with many possible theoretical origins beyond the…

Astrophysics · Physics 2009-01-16 Nishant Agarwal , Rachel Bean

In this paper, we investigate some consequences of multiple-field inflation for the cosmic microwave background radiation (CMB). We derive expressions for the amplitudes, the spectral indices and the derivatives of the indices of the CMB…

Astrophysics · Physics 2009-11-10 Bartjan van Tent

We present a numerical integration of the cosmological scalar perturbation equations in warm inflation. The initial conditions are provided by a discussion of the thermal fluctuations of an inflaton field and thermal radiation using a…

Astrophysics · Physics 2009-11-07 Lisa M. H. Hall , Ian G. Moss , Arjun Berera

In this letter, we propose a model of inflationary cosmology with a bounce preceded and study its primordial curvature perturbations. Our model gives rise to a primordial power spectrum with a feature of oscillation on large scales compared…

Astrophysics · Physics 2009-02-02 Yi-Fu Cai , Tao-tao Qiu , Jun-Qing Xia , Xinmin Zhang

We explore constraints on inflationary models employing data on large scale structure mainly from COBE temperature anisotropies and IRAS selected galaxy surveys, taking care not to apply linear perturbation theory to data in the non-linear…

Astrophysics · Physics 2009-12-30 R. K. Schaefer , Q. Shafi

We analyze a class of generalized inflationary models proposed in Ref. [1], known as $\beta$-exponential inflation. We show that this kind of potential can arise in the context of brane cosmology, where the field describing the size of the…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-15 M. A. Santos , M. Benetti , J. S. Alcaniz , F. A. Brito , R. Silva

Slow-roll of the inflaton field defines the standard dynamics of the inflationary epoch. However, the inflationary system deviates from slow-roll when it encounters an extremely flat region of the inflaton potential, and enters a phase…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-04 Sandip Biswas , Kaushik Bhattacharya , Suratna Das

We study the inflation process of universe based on the renormalizable quantum gravity formulated as a conformal field theory (CFT). We show that the power-law CFT spectrum approaches to that of the Harrison-Zel'dovich-Peebles type as the…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-18 Ken-ji Hamada , Shinichi Horata , Tetsuyuki Yukawa

The first year of observations by the Planck satellite mission shows that the cosmic microwave background (CMB) fluctuations are consistent with gaussian statistics in the primordial perturbations, a key prediction of the simplest models of…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-19 Ana Achucarro , Vicente Atal , Pablo Ortiz , Jesus Torrado

We revisit an inflationary scenario in which primordial inhomogeneities arise from a quantum collapse, a stochastic mechanism described in the context of quantum collapse theories in its continuous version and within semiclassical gravity.…

General Relativity and Quantum Cosmology · Physics 2026-03-04 María Pía Piccirilli , Gabriel León , Rosa-Laura Lechuga-Solis , Daniel Sudarsky

A particularly attractive feature of inflation is that quantum fluctuations in the inflaton field may have seeded inhomogeneities in the cosmic microwave background (CMB) and the formation of large-scale structure. In this paper, we…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-21 Fulvio Melia

We consider an additional fine-tuning problem which afflicts scalar-driven models of inflation. The problem is that successful reheating requires the inflaton be coupled to ordinary matter, and quantum fluctuations of this matter induces…

General Relativity and Quantum Cosmology · Physics 2019-05-22 Z. H. Liao , S. P. Miao , R. P. Woodard

Recently, the Planck 2013 results showed possible evidence for a dipolar power modulation of the CMB temperature fluctuations at low--(\ell) multipoles. This anomaly might imply certain deviations from statistical isotropy. To incorporate…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-24 Zhe Chang , Sai Wang

We construct a model of inflation based on a low-energy effective theory of spontaneously broken global scale invariance. This provides a shift symmetry that protects the inflaton potential from quantum corrections. Since the underlying…

High Energy Physics - Theory · Physics 2014-10-22 Csaba Csaki , Nemanja Kaloper , Javi Serra , John Terning

We explore the noncommutative effect on single field inflation and compare with WMAP five-year data. First, we calculate the noncommutative effect from the potential and dynamical terms, and construct the general form of modified power…

Astrophysics · Physics 2009-06-18 Hong-Guang Zhang , Jie Ren , Xin-He Meng

Oscillating massive fields in the primordial universe can be used as Standard Clocks. The ticks of these oscillations induce features in the density perturbations, which directly record the time evolution of the scale factor of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Xingang Chen , Mohammad Hossein Namjoo , Yi Wang

Noncommutative geometry can provide effective description of physics at very short distances taking into account generic effects of quantum gravity. Inflation amplifies tiny quantum fluctuations in the early universe to macroscopic scales…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-18 Tomi S. Koivisto , David F. Mota

Warm inflation is examined in a multi-field model. Solutions are obtained for expansion e-folds and scalar density perturbations. Nonequilibrium dynamics is restricted to a regime that is displaced only slightly from thermal equilibrium and…

High Energy Physics - Phenomenology · Physics 2009-10-31 Arjun Berera

Inflationary cosmology has made significant strides in understanding the physics driving the rapid expansion of the early universe. However, many inflation models with diverse potential shapes present analysis, comparison, and…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-25 Somnath Das , P K Suresh

We discuss ability of the harmonic pattern of peaks in the CMB angular power spectrum to test inflation. By studying robust features of alternate models, which must all be isocurvature in nature, we reveal signatures unique to inflation.…

Astrophysics · Physics 2007-05-23 Martin White , Wayne Hu
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