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Astronomy & Astrophysics
Nils A. Nilsson
Summary: In this study, we investigate the effects of explicit spacetime-symmetry breaking on primordial tensor fluctuations using an effective-field theory for Lorentz/CPT violation. Our findings show that despite the symmetry breaking, the graviton remains massless, but the propagation speed of tensor modes is modified. We also derive a constraint on the coefficient determining the symmetry breaking based on recent measurements of the speed of gravity. Additionally, due to the symmetry breaking, the de-Sitter phase is altered, resulting in a slow oscillation of the power spectrum during the inflationary epoch. Furthermore, we observe that while the primordial tensor power spectrum maintains scale invariance, its amplitude is modified. Moreover, we find that the modes which become subhorizon during radiation domination experience a phase shift proportional to the coefficient for Lorentz violation.
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Astronomy & Astrophysics
Fabien Besnard, Christian Brouder
Summary: We investigate the 1-loop renormalization group flow of two models based on a generalization of noncommutative geometry, with one found to be predictive and compatible with experiments in a small parameter space while the other is not.
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Astronomy & Astrophysics
Mikhail Shaposhnikov, Andrey Shkerin, Sebastian Zell
Summary: The proposed model combines the Standard Model with gravity by utilizing nonminimal coupling and the Palatini formulation. It achieves electroweak symmetry breaking and incorporates inflation without introducing additional degrees of freedom beyond the SM and graviton. By relating inflationary parameters to collider experiment data, it addresses the hierarchy problem and opens up the possibility of calculating the Higgs mass.
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Physics, Fluids & Plasmas
Lucas Kluge, Jacob Schewe
Summary: Human migration is often studied using gravity models or radiation models, but both have limitations. Research shows that the radiation model systematically underestimates long-range moves in domestic migration data, while the traditional gravity model performs well for large distances. The universal opportunity model is proposed as an extension of the radiation model, showing improved fit for long-range moves but requiring additional parameters.
Article
Astronomy & Astrophysics
Rui Niu, Tao Zhu, Wen Zhao
Summary: The successful detection of gravitational waves provides a new avenue for exploring the nature of gravity. This study focuses on Lorentz symmetry during the propagation of gravitational waves. Bayesian inference on the waveform data reveals no evidence of Lorentz violation.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
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Mathematics, Applied
Mark Pollicott, Benedict Sewell
Summary: This paper presents concrete examples of Anosov diffeomorphisms of T2.
Article
Multidisciplinary Sciences
Nicolo Masi
Summary: This article proposes a new criterion for extending the Standard Model of particle physics based on the automorphism groups of main Cayley-Dickson algebras, leading to an enlargement of the color sector and the emergence of an additional ensemble of massive G(2)-gluons separated from the particle dynamics of the Standard Model.
SCIENTIFIC REPORTS
(2021)
Article
Astronomy & Astrophysics
N. Furey, M. J. Hughes
Summary: Reframing certain well-known particle models in terms of normed division algebras leads to two new results for BSM physics. Firstly, we identify a sequence of complex structures that induce a cascade of breaking symmetries. Secondly, we provide an explicit demonstration of left-right symmetric Higgs representations stemming from quaternionic triality.
Article
Physics, Particles & Fields
Hugues Beauchesne, Yevgeny Kats
Summary: The paper investigates how the Mirror Twin Higgs could be modified to be compatible with current cosmological constraints without explicit Z(2) breaking. It presents two simple models, one that can solve the N-eff problem and bring the abundance of mirror atoms to an allowed level, and another that leads to mirror neutron dark matter.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Physics, Particles & Fields
Alessandro D. A. M. Spallicci, Jose A. Helayel-Neto, Martin Lopez-Corredoira, Salvatore Capozziello
Summary: The paper discusses the different factors contributing to the red shift z, including the massiveness of photons and LSV fields, as well as an explanation for the discrepancy between the luminosity and red shift distances of SNeIa in cosmology.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Astronomy & Astrophysics
Katsuki Aoki, Shinji Mukohyama, Ryo Namba
Summary: In a Lorentz-breaking background, a class of multi-field scalar-field theories imposes consistency conditions on its effective theory of a single field, demonstrating an example of order-unity violation of a naively applied positivity bound when a large hierarchy exists between the masses of the lightest field and the others.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Mohsen Khodadi, Marco Schreck
Summary: This paper assesses modified cosmological settings based on the gravitational Standard-Model Extension (SME). It focuses on the Hubble tension (HT) between observational determinations of the Hubble parameter via Cosmic Microwave Background (CMB) and Type Ia supernovae. Two recently introduced cosmological models involving local Lorentz and diffeomorphism violation are considered as potential descriptions of the pre-CMB era. However, these models are found not suitable for fixing the HT. The paper demonstrates the novel possibility of refining our description of the early Universe through exploiting this discrepancy.
PHYSICS OF THE DARK UNIVERSE
(2023)
Article
Geography
Yue Dong, Peng Cheng, Xuesong Kong
Summary: This study uses a dual-scale coupling approach to identify the restructuring direction of rural settlements in Tingzu Town, Hubei Province, China. At the village scale, a population-land-industry evaluation index system is constructed to calculate the development potential of villages. The advanced gravity model is used to measure the intervillage connections, and clustering is applied to divide the village groups. At the patch scale, kernel density estimation and accessibility analysis are used to identify the spatial distribution characteristics of rural settlements. The study proposes four types of restructuring directions for rural settlements and determines the strategies for each type based on the influence scope of central villages and the development needs of rural settlements.
JOURNAL OF RURAL STUDIES
(2022)
Article
Astronomy & Astrophysics
Jin-Tao Yao, Xin Li
Summary: This paper investigates the closed orbits of the axial symmetric Finslerian extension of a Schwarzschild black hole and finds that a rational Finslerian parameter is necessary for closed orbits.
Article
Mechanics
Didier Clamond
Summary: This study presents an explicit expression for the Dirichlet-Neumann operator for surface water waves and demonstrates its applicability. The findings of this study are not limited to water waves and can be adapted to many other problems with similar mathematical formulations.
JOURNAL OF FLUID MECHANICS
(2022)
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Astronomy & Astrophysics
Robert Bluhm
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Multidisciplinary Sciences
Robert Bluhm
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Robert Bluhm, Nolan L. Gagne, Robertus Potting, Arturs Vrublevskis
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Robert Bluhm, Shu-Hong Fung, V. Alan Kostelecky
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Robert Bluhm, Hannah Bossi, Yuewei Wen
Proceedings Paper
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R. Bluhm
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Astronomy & Astrophysics
Robert Bluhm
INTERNATIONAL JOURNAL OF MODERN PHYSICS D
(2007)
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Astronomy & Astrophysics
R Bluhm, VA Kostelecky
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Instruments & Instrumentation
R Bluhm
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
(2004)
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Physics, Multidisciplinary
R Bluhm
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Astronomy & Astrophysics
R Bluhm, VA Kostelecky, CD Lane, N Russell
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Physics, Multidisciplinary
R Bluhm