We show that modifications of Einstein gravity during inflation could leave potentially measurable imprints on cosmological observables in the form of non-Gaussian perturbations. This is due to the fact that these modifications appear in the form of an extra field that could have nontrivial interactions with the inflaton. We show it explicitly for the case R+αR(2), where nearly scale-invariant non-Gaussianity at the level of f(NL) ≈ - (1 to 30) can be obtained, in a quasilocal configuration.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1103/PhysRevLett.113.161303 | DOI Listing |
Curr Biol
October 2024
Department of Biological Sciences, The National University of Singapore, Singapore 117543, Singapore; Mechanobiology Institute, The National University of Singapore, Singapore 117543, Singapore. Electronic address:
If you ever forget to water your houseplant, you may find its leaves getting soft and droopy - if you water it again in time, the leaves may stiffen, spring back up, and resist gravity. During this recovery, plant cells absorb water and build up an intracellular pressure, called turgor pressure, similar to inflating a balloon. Turgor pressure is an intrinsic component of plant physiology, and its biomechanical role as the 'hydroskeleton' is generally appreciated either statically in structural stability, like leaves resisting gravity, or dynamically in rapid motions, like Venus flytrap snapping, Mimosa closing, or stomatal opening.
View Article and Find Full Text PDFPhys Rev Lett
September 2024
Department of Physics and Astronomy, University of the Western Cape, Cape Town 7535, South Africa.
Recent measurements of the four-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 relativity. If such a violation arose from physics in the early Universe it could indicate important new physics beyond the standard model, and would be at odds with most models of inflation.
View Article and Find Full Text PDFBiomech Model Mechanobiol
December 2024
Solid Mechanics Laboratory, École Polytechnique/IPP/CNRS, Palaiseau, France.
Recent years have seen the development of multiple in silico lung models, notably with the aim of improving patient care for pulmonary diseases. These models vary in complexity and typically only consider the implementation of pleural pressure, a depression that keeps the lungs inflated. Gravity, often considered negligible compared to pleural pressure, has been largely overlooked, also due to the complexity of formulating physiological boundary conditions to counterbalance it.
View Article and Find Full Text PDFBiosystems
December 2024
OP Jindal Global University, Sonipat, 131001, India; CEASP, Fellow Jindal India Institute, USA.
We attempt in this article to formulate a conceptual and testable framework weaving Cosmos, Mind and Matter into a whole. We build on three recent discoveries, each requiring more evidence: i. The particles of the Standard Model, SU(3) × SU(2) × U(1), are formally capable of collective autocatalysis.
View Article and Find Full Text PDFPhys Rev Lett
August 2024
Department of Physics, University of Winnipeg, Winnipeg, Manitoba R3B 2E9, Canada.
We demonstrate that gravitational particle production of a massive, Abelian, vector (Proca) field during inflation in the presence of nonminimal coupling to gravity may suffer from an instability which leads to runaway production of high-momentum modes. This is untenable unless there is some mechanism to regulate the runaway. We discuss the parameter space of the particle mass and nonminimal couplings where such a runaway occurs and possible ways to tame the runaway.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!