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Category: physics – Page 55

Cosmological foundations revisited with Pantheon+

ABSTRACT. We reanalyse the Pantheon+ supernova catalogue to compare a cosmology with non-FLRW evolution, the timescape cosmology, with the standard Lambda cold dark matter (⁠|Lambda$|CDM) cosmology. To this end, we analyse the Pantheon+ for a geometric comparison between the two models. We construct a covariance matrix to be as independent of cosmology as possible, including independence from the FLRW geometry and peculiar velocity with respect to FLRW average evolution. This framework goes far beyond most other definitions of model independence. We introduce new statistics to refine Type Ia supernova (SNe Ia) light-curve analysis. In addition to conventional galaxy correlation functions used to define the scale of statistical homogeneity we introduce empirical statistics that enables refined analysis of the distribution biases of SNe Ia light-curve parameters |beta c$| and |alpha x_1$|⁠. For lower redshifts, the Bayesian analysis highlights important features attributable to the increased number of low-redshift supernovae, the artefacts of model-dependent light-curve fitting, and the cosmic structure through which we observe supernovae. This indicates the need for cosmology-independent data reduction to conduct a stronger investigation of the emergence of statistical homogeneity and to compare alternative cosmologies in light of recent challenges to the standard model. Dark energy is generally invoked as a place-holder for new physics. For the first time, we find evidence that the timescape cosmology may provide a better overall fit than |Lambda$|CDM and that its phenomenology may help disentangle other astrophysical puzzles. Our from-first-principles reanalysis of Pantheon|$+$| supports future deeper studies between the interplay of matter and non-linear spacetime geometry in a data-driven setting.

Nanoparticle technique gauges bite force in tiny C. elegans worms

A team of materials scientists, physicists, mechanical engineers, and molecular physiologists at Stanford University have developed a nanoparticle technique that can be used to measure force dynamics inside a living creature, such as Caenorhabditis elegans worms biting their food.

In their paper published in the journal Nature, the group describes how they used to excite luminescent nanocrystals in a way that allowed the energy levels of cells inside a C. elegans worm to be measured.

Andries Meijerink, with Utrecht University, has published a News & Views piece in the same journal issue, outlining the work done by the team in California.

How does a hula hoop master gravity? Mathematicians prove that body shape matters

Hula hooping is so commonplace that we may overlook some interesting questions it raises: “What keeps a hula hoop up against gravity?” and “Are some body types better for hula hooping than others?” A team of mathematicians explored and answered these questions with findings that also point to new ways to better harness energy and improve robotic positioners.

The results are the first to explain the physics and mathematics of hula hooping.

“We were specifically interested in what kinds of body motions and shapes could successfully hold the hoop up and what physical requirements and restrictions are involved,” explains Leif Ristroph, an associate professor at New York University’s Courant Institute of Mathematical Sciences and the senior author of the paper, which appears in the Proceedings of the National Academy of Sciences.

Observational evidence for cosmological coupling of black holes and its implications for an astrophysical source of dark energy

“The Universe Expands Beyond All Bounds”

The universe expands beyond all bounds, Black holes gain mass, where wonders surround. Curvature shifts like moonlight’s gleam, Adding new mass, no matter redeemed.

A new year dawns with lessons to share, Physics reveals a truth so rare. The cosmos vast, profound, and wide, Marks 2025 with knowledge as our guide.

The first endeavor of this brand-new year, Explains black hole growth without drawing near. Expanding space, a force untamed, Curvature energy, its role proclaimed.

Based on observed and verified research: arxiv.org/abs/2302.

Through our novel gravitational field theory: dx.doi.org/10.1016/j.astropartphys.2024.

Details await within the links above, Happy New Year 2025 to all with love! http://dx.doi.org/10.13140/RG.2.2.18170.

Continue reading “Observational evidence for cosmological coupling of black holes and its implications for an astrophysical source of dark energy” | >

Unlocking the Universe’s Hidden Secrets With Cutting-Edge Gravitational Wave Detectors

In a groundbreaking study, researchers have developed optical spring tracking to enhance signal clarity in gravitational-wave detectors, such as aLIGO.

This innovation could dramatically increase our understanding of cosmic events like black hole mergers, potentially unlocking secrets of the universe’s formation.

Revolutionary advances in gravitational wave detection.

Switchbacks: Solar Jets may hold the Key for Understanding Complete Magnetic Field Reversals

NASA’s Parker Solar Probe mission has detected magnetic distortions in solar wind, known as switchbacks. To better understand these phenomena, whose origins remain uncertain, a study was conducted by a network of collaborators. This study, published in the journal Astronomy & Astrophysics, reveals that solar jets can create similar disturbances without causing a complete reversal of the magnetic field.

NASA’s Parker Solar Probe mission revealed the presence of switchbacks, sudden and rapid reversals of the magnetic field in the solar wind. These peculiar phenomena, rarely observed near Earth, have captivated the scientific community due to their enigmatic origins. A leading theory suggests that switchbacks originate from solar jets, which are ubiquitous in the lower atmosphere of the sun.

To investigate their origins, a team of researchers from LPP, LPC2E, FSLAC, the University of Dundee and Durham University conducted 3D numerical simulations to replicate plasma behavior in the sun’s atmosphere. These simulations modeled solar jets and studied their propagation in solar wind.

The science behind your Christmas sweater: How friction shapes the form of knitted fabrics

A trio of physicists from the University of Rennes, Aoyama Gakuin University, and the University of Lyon have discovered, through experimentation, that it is friction between fibers that allows knitted fabrics to take on a given form. Jérôme Crassous, Samuel Poincloux, and Audrey Steinberger have attempted to understand the underlying mechanics involved in the forms of knitted garments. Their paper is published in Physical Review Letters.

The research team noted that while many of the factors that are involved in intertwined fabrics have been studied to better understand their characteristics (such as why sweaters keep people warm despite the gaps between stitches), much less is known about the form garments made using such techniques can take.

To learn more, they conducted experiments using a nylon yarn and a well-known Jersey knit stitch called the stockinette—a technique that involves forming interlocked loops using knitting needles. They knitted a piece of using 70×70 stitches and attached it to a biaxial tensile machine.

Researchers improve chaotic mapping for super-resolution image reconstruction

Super-resolution (SR) technology plays a pivotal role in enhancing the quality of images. SR reconstruction aims to generate high-resolution images from low-resolution ones. Traditional methods often result in blurred or distorted images. Advanced techniques such as sparse representation and deep learning-based methods have shown promising results but still face limitations in terms of noise robustness and computational complexity.

In a recent study published in Sensors, researchers from the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences proposed innovative solutions that integrate chaotic mapping into SR image process, significantly enhancing the image quality across various fields.

Researchers innovatively introduced circle chaotic mapping into the dictionary sequence solving process of the K-singular value decomposition (K-SVD) dictionary update . This integration facilitated balanced traversal and simplified the search for global optimal solutions, thereby enhancing the noise robustness of the SR reconstruction.

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