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We extend a recently proposed framework, dubbed inflation by supersymmetry breaking, to hybrid inflation by introducing a waterfall field that allows to decouple the supersymmetry breaking scale in the observable sector from the inflation…

High Energy Physics - Theory · Physics 2025-12-16 Yermek Aldabergenov , Ignatios Antoniadis , Auttakit Chatrabhuti , Hiroshi Isono

Due to the non-stationarity of time series, the distribution shift problem largely hinders the performance of time series forecasting. Existing solutions either rely on using certain statistics to specify the shift, or developing specific…

Machine Learning · Computer Science 2025-02-10 Wei Fan , Shun Zheng , Pengyang Wang , Rui Xie , Kun Yi , Qi Zhang , Jiang Bian , Yanjie Fu

We analyze the flow into inflation for generic "single-clock" systems, by combining an effective field theory approach with a dynamical-systems analysis. In this approach, we construct an expansion for the potential-like term in the…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-15 Feraz Azhar , David I. Kaiser

We investigate the dynamics of homogeneous phase space for single-field models of inflation. Inflationary trajectories are formally attractors in phase space, but since in practice not all initial conditions lead to them, some degree of…

High Energy Physics - Theory · Physics 2014-11-20 Paul Franche , Rhiannon Gwyn , Bret Underwood , Alisha Wissanji

In the hope of avoiding model dependence of the cosmological observables, phenomenological parametrizations of Cosmic Inflation have recently been proposed. Typically, they are expressed in terms of two parameters associated with an…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-16 Jerome Martin , Christophe Ringeval , Vincent Vennin

We propose a model of inflation with a suitable potential for a single scalar field which falls in the wide class of hilltop inflation. We derive the analytical expressions for most of the physical quantities related to inflation and show…

High Energy Physics - Theory · Physics 2010-01-28 Barun Kumar Pal , Supratik Pal , B. Basu

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

In this paper we show that the dynamics associated with slow-roll models of inflation can be investigated through a method called deformation procedure. Using the latter, we explicitly derive an expression linking two slow-roll inflationary…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Jamilton Rodrigues , Marcos Souza

Recently, it has been found that complete resolution of the Hubble tension might point to a scale-invariant Harrison-Zeldovich spectrum of primordial scalar perturbation, i.e. $n_s=1$ for $H_0\sim 73$km/s/Mpc. We show that for well-known…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-14 Gen Ye , Jun-Qian Jiang , Yun-Song Piao

An appealing feature of inflationary cosmology is the presence of a phase-space attractor, "slow roll", which washes out the dependence on initial field velocities. We investigate the robustness of this property under backreaction from…

General Relativity and Quantum Cosmology · Physics 2021-04-05 Julien Grain , Vincent Vennin

We develop a theory of nonlinear cosmological perturbations on superhorizon scales for generic single-field inflation. Our inflaton is described by the Lagrangian of the form $W(X,\phi)-G(X,\phi)\Box\phi$ with…

General Relativity and Quantum Cosmology · Physics 2013-06-04 Yu-ichi Takamizu , Tsutomu Kobayashi

We propose a mechanism for generating an inflationary phase in the early universe without resorting to any type of scalar field(s). Instead, this accelerated expansion is driven by a dynamical "cosmological constant" in the framework of…

General Relativity and Quantum Cosmology · Physics 2022-03-18 Gabriel Leon

A new hybrid inflationary scenario in the context of $f(R,{\Box}R)$-gravity is proposed. Demanding the waterfall field to 'support the potential from below' [unlike the original proposal by Stewart in Phys. Lett. B345, 414 (1995)], we…

High Energy Physics - Theory · Physics 2011-03-18 Masao Iihoshi

We construct two simple effective field theory versions of {\it Hybrid Natural Inflation (HNI)} that illustrate the range of its phenomenological implications. The resulting inflationary sector potential, $V=\Delta^4(1+a\cos(\phi/f))$,…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 Graham G. Ross , Gabriel German , J. Alberto Vazquez

A wide variety of vacua, and their cosmological realization, may provide an explanation for the apparently anthropic choices of some parameters of particle physics and cosmology. If the probability on various parameters is weighted by…

High Energy Physics - Theory · Physics 2008-11-26 Lawrence J. Hall , Taizan Watari , T. T. Yanagida

We report on a new class of fast-roll inflationary models. In a huge part of its parameter space, inflationary perturbations exhibit quite unusual phenomena such as scalar and tensor modes freezing out at widely different times, as well as…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-30 Pascal M. Vaudrevange , Dmitry I. Podolsky , Glenn D. Starkman

With the growing consensus on simple power law inflation models not being favored by the PLANCK observation, dynamics for the non-standard form of the inflaton potential gain significant interest in the recent past. In this paper, we…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-08 Debaprasad Maity , Pankaj Saha

Fundamental formulae representing the density perturbation spectrums generated in inflationary scenarios are rigorously proved. Quantum fluctuations as initial conditions for structure generation in some inflationary era can be calculated…

Astrophysics · Physics 2008-11-26 J. Hwang

Einstein equations projected on to a black hole horizon gives rise to Navier-Stokes equations. Horizon-fluids typically possess unusual features like negative bulk viscosity and it is not clear whether a statistical mechanical description…

General Relativity and Quantum Cosmology · Physics 2016-03-23 Swastik Bhattacharya , S. Shankaranarayanan

We study an inflationary scenario with a vector impurity. We show that the universe undergoes anisotropic inflationary expansion due to a preferred direction determined by the vector. Using the slow-roll approximation, we find a formula to…

High Energy Physics - Phenomenology · Physics 2008-11-26 Sugumi Kanno , Masashi Kimura , Jiro Soda , Shuichiro Yokoyama
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