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Bending the web: exploring the impact of modified gravity on the density field and halo properties within the cosmic web Suhani Gupta, Simon Pfeifer, Punyakoti Ganeshaiah Veena, Wojciech A. Hellwing arXiv:2408.13219v1 Announce Type: new Abstract: This work investigates the impact of different Modified Gravity (MG) models on the large-scale structures (LSS) properties in relation to the cosmic web (CW), using N-body simulations of f(R) and nDGP models. We analyse the impact of the MG effect on the density field through density distribution and clustering statistics, and assess its influence on halo properties by examining the halo mass function and spin. We find that the PDFRead More →

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Gravitationally Misaligned Ultralight Dark Matter and Implications for Neutron Stars Hooman Davoudiasl arXiv:2408.12667v1 Announce Type: cross Abstract: We examine the possibility that dark matter (DM) may be an ultralight scalar that was misaligned via non-minimal coupling to gravity, in the early Universe. For a certain regime of scalar masses, gravitational effects in neutron stars could place interesting bounds on the viable parameter space of the model, even in the absence of non-gravitational interactions between DM and ordinary matter.arXiv:2408.12667v1 Announce Type: cross Abstract: We examine the possibility that dark matter (DM) may be an ultralight scalar that was misaligned via non-minimal coupling to gravity, in theRead More →

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A rapid multi-modal parameter estimation technique for LISA Charlie Hoy, Connor Weaving, Laura K. Nuttall, Ian Harry arXiv:2408.12764v1 Announce Type: cross Abstract: The Laser Interferometer Space Antenna (LISA) will observe gravitational-wave signals from a wide range of sources, including massive black hole binaries. Although numerous techniques have been developed to perform Bayesian inference for LISA, they are often computationally expensive; analyses often take at least $sim 1$ month on a single CPU, even when using accelerated techniques. Not only does this make it difficult to concurrently analyse more than one gravitational-wave signal, it also makes it challenging to rapidly produce parameter estimates for possible electromagneticRead More →

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Effective field theories of dissipative fluids with one-form symmetries Shreya Vardhan, Sav{s}o Grozdanov, Samuel Leutheusser, Hong Liu arXiv:2408.12868v1 Announce Type: cross Abstract: A system with a one-form global symmetry at finite temperature can be viewed as a dissipative fluid of string-like objects. In this work, we classify and construct the most general effective field theories for hydrodynamics of such string fluids, in a probe limit where the one-form charge density is decoupled from the energy-momentum tensor. We show that at leading order in the derivative expansion, there are two distinct types of diffusive transport in a string fluid depending on the discrete spacetime symmetries presentRead More →

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New series expansion method for the periapsis shift Akihito Katsumata, Tomohiro Harada, Kota Ogasawara, Hayami Iizuka arXiv:2408.12977v1 Announce Type: cross Abstract: We propose a new series expansion method for the periapsis shift. The method formulates the periapsis shift in various spacetimes analytically without using special functions and provides simple and highly accurate approximate formulae. We derive new series representations for the periapsis shift in the Kerr and the Chazy-Curzon spacetimes by using the method, where the expansion parameter is defined as the eccentricity divided by the non-dimensional quantity that vanishes in the limit of the innermost stable circular orbit. That is to say, the expansionRead More →

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Perturbations in $mathbf{O}(D,D)$ string cosmology from double field theory Stephen Angus, Shinji Mukohyama arXiv:2408.13032v1 Announce Type: cross Abstract: The low-energy limit of string theory contains additional gravitational degrees of freedom, a skew-symmetric tensor $B$-field and a scalar dilaton, that are not present in general relativity. Together with the metric, these three fields are naturally embedded in the $mathbf{O}(D,D)$-symmetric framework of double field theory. The $mathbf{O}(D,D)$ symmetry uniquely prescribes the interactions between the extended gravitational sector and other matter, leading to novel features beyond conventional string cosmology. In this work we present the equations of motion for linear perturbations around $mathbf{O}(D,D)$ string cosmological backgrounds in $D=4$Read More →

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Laser-Driven Proton-Only Acceleration in a Multicomponent Near-Critical-Density Plasma Y. Sakawa, H. Ishihara, S. N. Ryazantsev, M. A. Alkhimova, R. Kumar, O. Kuramoto, Y. Matsumoto, M. Ota, S. Egashira, Y. Nakagawa, T. Minami, K. Sakai, T. Taguchi, H. Habara, Y. Kuramitsu, A. Morace, Y. Abe, Y. Arikawa, S. Fujioka, M. Kanasaki, T. Asai, T. Morita, Y. Fukuda, S. Pikuz, T. Pikuz, Y. Ohira, L. N. K. Doehl, N. Woolsey, T. Sano arXiv:2408.13088v1 Announce Type: cross Abstract: An experimental investigation of collisionless shock ion acceleration is presented using a multicomponent plasma and a high-intensity picosecond duration laser pulse. Protons are the only accelerated ions when a near-critical-densityRead More →

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Quarkyonic equation of state with a momentum dependent interaction and neutron star structure K. Folias, Ch. C. Moustakidis arXiv:2408.13107v1 Announce Type: cross Abstract: The structure and basic properties of dense nuclear matter still remain one of the open problems of Physics. In particular, the composition of the matter that composes neutron stars is under theoretical and experimental investigation. Among the theories that have been proposed, apart from the classical one where the composition is dominated by hadrons, the existence or coexistence of free quark matter is a dominant guess. An approach towards this solution is the phenomenological view according to which the existence of quarkyonicRead More →

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A GPU-accelerated semi-coherent hierarchical search for stellar-mass binary inspiral signals in LISA Diganta Bandopadhyay, Christopher J. Moore arXiv:2408.13170v1 Announce Type: cross Abstract: Searching for gravitational waves from stellar-mass binary black holes with LISA remains a challenging open problem. Conventional template-bank approaches to the search are impossible due to the prohibitive number of templates that would be required. This paper continues the development of a hierarchical semi-coherent stochastic search, extending it to a full end-to-end pipeline that is then applied to multiple mock LISA data streams which include simulated noise. Particle swarm optimization is used as a stochastic search algorithm, tracking multiple maxima of a semi-coherentRead More →

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Stratified Resistive Tearing Instability Scott J. Hopper, Toby S. Wood, Paul J. Bushby arXiv:2408.13210v1 Announce Type: cross Abstract: Resistive tearing instabilities are common in fluids that are highly electrically conductive and carry strong currents. We determine the effect of stable stratification on the tearing instability under the Boussinesq approximation. Our results generalise previous work that considered only specific parameter regimes, and we show that the length scale of the fastest growing mode depends non-monotonically on the stratification strength. We confirm our analytical results by solving the linearised equations numerically, and we discuss whether the instability could operate in the solar tachocline.arXiv:2408.13210v1 Announce Type: cross Abstract:Read More →

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GA-NIFS: The core of an extremely massive proto-cluster at the Epoch of Reionization probed with JWST/NIRSpec Santiago Arribas, Michele Perna, Bruno Rodr’iguez Del Pino, Isabella Lamperti, Francesco D’Eugenio, Pablo G. P’erez-Gonz’alez, Gareth C. Jones, Alejandro Crespo, Mirko Curti, Seunghwan Lim, Javier ‘Alvarez-M’arquez, Andrew J. Bunker, Stefano Carniani, St’ephane Charlot, Peter Jakobsen, Roberto Maiolino, Hannah "Ubler, Chris J. Willott, Torsten B"oker, Jacopo Chevallard, Chiara Circosta, Giovanni Cresci, Nimisha Kumari, Eleonora Parlanti, Jan Scholtz, Giacomo Venturi, Joris Witstok arXiv:2312.00899v5 Announce Type: replace Abstract: The SPT0311-58 system resides in a massive dark matter halo at z ~ 6.9. It hosts two dusty galaxies (E and W) with aRead More →

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The Big Fringe Telescope. A 2.2 KILOMETER Telescope on the Cheap. And it Can Make Exoplanet “Movies”. Can a kilometer-scale telescope help conduct more efficient science, and specifically for the field of optical interferometry? This is what a recently submitted study hopes to address as a pair of researchers propose the Big Fringe Telescope (BFT), which is slated to comprise 16 telescopes 0.5-meter in diameter and will be equivalent to a telescope at 2.2 kilometers in diameter. What makes BFT unique is its potential to create real-time exoplanet “movies” like the movies featuring Venus transiting our Sun, along with significantly reduced construction costs compared toRead More →

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What Makes a Supercluster? By eye, it’s impossible to pick out the exact boundaries of the superclusters, which are among the largest structures in the universe. But that’s because they are not defined by their edges, but by the common motion of their components. The Milky Way galaxy was long thought to be a member of the Virgo supercluster, a complex, twisting branch containing over 100 individual galaxy groups and clusters stretching for more than a hundred million light-years. Astronomers arrived at that definition through some of the earliest galaxy surveys that attempted to map the nearby portions of the universe. Those early surveys wereRead More →

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Neutron Star Mergers Could Be Producing Quark Matter When neutron stars dance together, the grand smash finale they experience might create the densest known form of matter known in the Universe. It’s called “quark matter, ” a highly weird combo of liberated quarks and gluons. It’s unclear if the stuff existed in their cores before the end of their dance. However, in the wild aftermath a neutron-star merger, the strange conditions could free quarks and gluons from protons and neutrons. That lets them move around freely in the aftermath. So, researchers want to know how freely they move and what conditions might impede their motionRead More →

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Chinese Researchers Devise New Strategy for Producing Water on the Moon In the coming years, China and Roscosmos plan to create the International Lunar Research PStation (ILRSP), a permanent base in the Moon’s southern polar region. Construction of the base will begin with the delivery of the first surface elements by 2030 and is expected to last until about 2040. This base will rival NASA’s Artemis Program, which will include the creation of the Lunar Gateway in orbit around the Moon and the various surface elements that make up the Artemis Base Camp. In addition to the cost of building these facilities, there are manyRead More →

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Is Science Slowing Down? Paradoxically, even though we produce more scientific output than ever before – each year, researchers around the world publish millions of academic papers – the pace of scientific discovery is slowing down. There are several factors behind this general slow-down of scientific advancement, but the most important factor is the simple maturation of any field. As time goes on fields of science become more mature and sophisticated. This is a good thing, as we take small threads of newfound knowledge and develop them into full-fledged theories of the workings of the universe. But this process ironically slows the pace of futureRead More →

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China Proposes Magnetic Launch System for Sending Resources Back to Earth In his famous novel The Moon is a Harsh Mistress, Robert A. Heinlein describes a future lunar settlement where future lunar residents (“Loonies”) send payloads of wheat and water ice to Earth using an electromagnetic catapult. In this story, a group of Loonies conspire to take control of this catapult and threaten to “throw rocks at Earth” unless they recognize Luna as an independent world. Interestingly enough, scientists have explored this concept for decades as a means of transferring lunar resources to Earth someday. Given that space agencies are planning on sending missions toRead More →

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Professor proposes how a black hole in orbit around a planet could be a sign of an advanced civilization In 1971, English mathematical physicist and Nobel-prize winner Roger Penrose proposed how energy could be extracted from a rotating black hole. He argued that this could be done by building a harness around the black hole’s accretion disk, where infalling matter is accelerated to close to the speed of light, triggering the release of energy in multiple wavelengths. phys.org Go to SourceRead More →