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Related papers: Parity-violation in bouncing cosmology

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We calculate the power spectrum of cosmological perturbations originated from quantum vacuum fluctuations in bouncing scenarios proposed in Ref.~\cite{chamseddine2014cosmology} in the framework of mimetic cosmology. We show that all…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-02 Idaiane L. Machado , Dêivid R. da Silva , Nelson Pinto-Neto

Scenario bouncing can give the cosmology singularity problem a possible way out. Finding a solution for the universe's bouncing model requires proper estimation of the state equation. We present two such state equations that give us the…

General Relativity and Quantum Cosmology · Physics 2020-12-29 C. Swastik , P K Suresh , Barun Maity

We show that, in the presence of a string gas, simple higher-derivative modifications to the effective action for gravity can lead to bouncing and cyclic cosmological models. The modifications bound the expansion rate and avoid…

High Energy Physics - Theory · Physics 2009-11-06 Brian Greene , Daniel Kabat , Stefanos Marnerides

We present a model of non-relativistic gravitational theory which is power-counting renormalizable in 3+1 dimensional spacetime. When applied to cosmology, the relativity-violation terms lead to a dark radiation component, which can give…

High Energy Physics - Theory · Physics 2009-11-13 Yi-Fu Cai , Emmanuel N. Saridakis

In this paper, we analyze the modified $f(\mathcal{R})$ gravity models in Friedmann--Lema\^{\i}tre--Robertson--Walker (FLRW) background. The actions of bouncing cosmology are studied under consideration of different viable models in…

General Relativity and Quantum Cosmology · Physics 2021-02-18 M. Ilyas , W. U. Rahman

We show (in a completely analytical and exact manner) that an efficient magnetic field amplification method is operative during the bounce in a time-dependent gauge coupling model. The cosmological magnetic fields so generated have…

Astrophysics · Physics 2010-10-27 J. M. Salim , N. Souza , S. E. Perez Bergliaffa , T. Prokopec

In bouncing cosmology, the primordial fluctuations are generated in a cosmic contraction phase before the bounce into the current expansion phase. For a nonsingular bounce, curvature and anisotropy grow rapidly during the bouncing phase,…

General Relativity and Quantum Cosmology · Physics 2013-10-30 BingKan Xue , David Garfinkle , Frans Pretorius , Paul J. Steinhardt

Optimal simultaneous control of position and momentum can be achieved by maximizing the probabilities of finding their experimentally observed values within two well-defined intervals. The assumption that particles move along straight lines…

Quantum Physics · Physics 2017-09-06 Holger F. Hofmann

Massive particles produced during the cosmic inflation can imprint in the primordial non-Gaussianities as characteristic oscillating functions of various momentum ratios, known as cosmological collider signals. We initiate a study of the…

High Energy Physics - Theory · Physics 2023-04-27 Zhehan Qin , Zhong-Zhi Xianyu

We investigate non-singular bounce and cyclic cosmological evolutions in a universe governed by the extended nonlinear massive gravity, in which the graviton mass is promoted to a scalar-field potential. The extra freedom of the theory can…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-05 Yi-Fu Cai , Caixia Gao , Emmanuel N. Saridakis

Recent measurements of the 4-point correlation function in large-scale galaxy surveys have found apparent evidence of parity violation in the distribution of galaxies. This cannot happen via dynamical gravitational effects in general…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-04 Pritha Paul , Chris Clarkson , Roy Maartens

The parity-time symmetry (PT symmetry) breaking phenomenon is investigated in a coupled nanobeam cavity system. An exceptional point is observed during the tuning of the relation of the gain/loss and coupling strength of the closely placed…

Optics · Physics 2015-12-01 Senlin Zhang , Zhengdong Yong , Yuguang Zhang , Sailing He

We show that tunneling through quantum dots can be completely dominated by states quantized on stable bouncing-ball orbits. The fingerprints of bouncing-ball tunneling are sequences of Coulomb blockade peaks with strongly correlated peak…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Gregor Hackenbroich , Rafael A. Mendez

Nuclear parity violation is studied with polarized neutrons in the photodisintegration of the deuteron at low energies. A pionless effective field theory with di-baryon fields is used for the investigation. Hadronic weak interactions are…

Nuclear Theory · Physics 2015-05-30 J. W. Shin , S. -I. Ando , C. H. Hyun , S. W. Hong

Bouncing cosmologies offer an alternative to inflation by resolving the initial singularity through a contracting phase followed by a bounce into expansion. In many such models, the contracting phase is dominated by a single matter…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-30 Sandro D. P. Vitenti , Nelson Pinto-Neto , Patrick Peter , Luiz Felipe Demétrio

We examine the nature of the cosmological Big Bounce transition within the loop geometry underlying loop quantum cosmology at classical and quantum levels. Our canonical quantization method is an alternative to the standard loop quantum…

General Relativity and Quantum Cosmology · Physics 2009-09-24 Przemyslaw Malkiewicz , Wlodzimierz Piechocki

We propose a novel mechanism in which an external oscillatory wave modulates the mass-squared term of a scalar potential, periodically switching its sign. As a result of this "potential oscillation," the vacuum transitions between…

High Energy Physics - Phenomenology · Physics 2025-07-31 Yechan Kim , Hye-Sung Lee

Self-oscillations underlie many natural phenomena such as heartbeat, ocean waves, and the pulsation of variable stars. From pendulum clocks to the behavior of animal groups, self-oscillation is one of the keys to the understanding of…

The effect of vacuum polarization on the parity violating asymmetry in the elastic electron-nucleus scattering is considered. Calculations are performed in the high-energy approximation with an exact account for the electric field of the…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. I. Milstein , O. P. Sushkov

Weak interactions cause small parity-violating energy differences between left- and right-handed chiral systems. Although normally tiny, these effects may be significantly enhanced during collective phenomena such as phase transitions. We…

High Energy Physics - Phenomenology · Physics 2025-09-30 V. V. Flambaum