Search

In this work, using a spherically symmetric metric, we investigate a minimally interacting holographic dark energy model within the framework of Saez-Ballester Theory. We predict that the dark energy component dominating the universe is of phantom type, which will lead the model universe to cosmic doomsday (big rip singularity). As big rip and holographic dark energy are incompatible with each other, we employ a higher dimensional scenario so that the cosmic doomsday is replaced by the de-Sitter phase. The model expands with a slow and uniform change of size during the early evolution, whereas the change becomes faster, agreeing with the present observation of the accelerated expansion. The present values of Hubble’s parameter and the dark energy EoS parameter are measured to be H = 67 and λ = − 1 . 00011 , which agree with the respective values H 0 = 67 . 36 ± 0 . 54 kms − 1 Mpc − 1 and λ = − 1 . 03 ± 0 . 03 of the most recent Planck 2018 result.

Today, two distinct camps exist in the Physics community: those who believe in the asymptotic safe gravity program for gravity, and those who don’t. Not many physicists are undecided, even if those who claim not to care. It is a polarizing topic, and nobody seems to ever be really convinced by the arguments of the others. Add to this, the existential threat potentially posed by asymptotic safety to the physicality of supersymmetry, supergravity, superstrings, M-Theory, and many of the popular GUTs and TOEs out there, and one can understand why the question of asymptotic safety of gravity is often either viewed as critical, or dismissed as irrelevant. Yet, the asymptotic safety program has claimed indications that gravity may be asymptotically safe. So far, none are definitive, and most are derided by the other camp. In the context of the multi-fold theory, we have shown that multi-fold gravity is asymptotically safe. Using arguments, that gravity is 2D at small scales, something agreed upon by most consistent theories of quantum gravity, we inferred that gravity is most probably asymptotically safe, even in non-muti-fold universes, and yet, we could manage to save superstrings as relevant around that 2D regime, while (mathematically) living in a tangent dual space. More recent results reinterpret the double copy duality and behavior of Yang Mills scattering to i) defined new AdS/CFT dualities, ii) encounter gravity as part of Yang Mills theory, iii) and encounter the multi-fold theory in both Yang Mills Actions, and in M-theory, through the AdS/CFT correspondence conjecture. Part of these previous works led us to announce that the AdS/CFT correspondence conjecture implies that General Relativity (GR) – based gravity is indeed asymptotically safe in a 4D spacetime. In the present paper, we detail such a non-perturbative derivation for GR-based gravity, and for GR-based gravity with. It does not require faith into evolution of time series, 2D processes, nor a priori multi-fold assumptions. In other words, the proof applies to Einstein gravity, in general, for conventional Physics, as well as for multi-fold universes. The paper also discusses considerations on why arguments, presented so far, against the asymptotic safety of gravity program would have been flawed, and, in particular, it shows how our proof is not affected by the Gribov ambiguity concerns, which does not apply to gravity + SM or SMG matter. Also supersymmetric matter are not asymptotically safe in 4D. Higher dimensions are also confirmed incompatible., Cite as: Stephane H Maes, (2022), "A Non-perturbative Proof of the Asymptotic Safety of 4D Einstein Gravity, With or Without Matter", https://doi.org/10.5281/zenodo.7953796, https://shmaesphysics.wordpress.com/2022/05/04/a-non-perturbative-proof-of-the-asymptotic-safety-of-4d-einstein-gravity-with-or-without-matter/, May 4, 2022.

The proposed book consists of two parts and is devoted to the systematic analysis of quantum mechanics and the modern theory of electromagnetic phenomena. Some inaccuracies of the application of mathematics in theoretical physics are discussed. This first part examines in detail the basic concepts of quantum mechanics, its apparatus, methods and applications and demonstrates their groundlessness, and often the internal inconsistency of the most common version of the Copenhagen interpretation of quantum mechanics. The book contains a critical analysis of the experiments underlying this theory. All this together proves that the generally accepted version of quantum mechanics is a temporary construction, and the creation of a new consistent theory of the microcosm is required. The book also discusses some alternative ideas applicable to the microcosm. This book may be useful for students, postgraduates, teachers, scientific and technical workers and anyone interested in the basics of physics. To the English version of the book. This is an English translation of the Russian version of the book. Quotations were also translated from Russian-language publications (therefore, for English-language works they are not a literal original, but they convey the essence of the quotations). However, references to pages or chapters have been corrected for the indicated English-language sources., {"references":["Artekha S.N. Criticism of the Foundations of the Relativity Theory, (Moscow: Editorial URSS, 2004, 224 p.)","Feynman R.P., R.B. Leighton, M. Sands, The Feynman Lectures on Physics, vol. 1, (Addison-Wesley Publishing Company, Massachusetts, 1963).","Landau L.D., E.M. Lifshits, Quantum mechanics. (Non-relativistic Theory), (Pergamon Press, Oxford, 1962).","Feynman R.P., R.B. Leighton, M. Sands, The Feynman Lectures on Physics, vol. 3, (Addison-Wesley Publishing Company, Massachusetts, 1963)."]}

We present the conceptual design and the physics potential of DarkSPHERE, a proposed 3 m in diameter spherical proportional counter electroformed underground at the Boulby Underground Laboratory. This effort builds on the R&D performed and experience acquired by the NEWS-G Collaboration. DarkSPHERE is primarily designed to search for nuclear recoils from light dark matter in the 0.05--10 GeV mass range. Electroforming the spherical shell and the implementation of a shield based on pure water ensures a background level below 0.01 dru. These, combined with the proposed helium-isobutane gas mixture, will provide sensitivity to the spin-independent nucleon cross-section of $2\times 10^{-41} (2\times 10^{-43})$ cm$^2$ for a dark matter mass of $0.1 (1)$ GeV. The use of a hydrogen-rich gas mixture with a natural abundance of $^{13}$C provides sensitivity to spin-dependent nucleon cross-sections more than two orders of magnitude below existing constraints for dark matter lighter than 1 GeV. The characteristics of the detector also make it suitable for searches of other dark matter signatures, including scattering of MeV-scale dark matter with electrons, and super-heavy dark matter with masses around the Planck scale that leave extended ionisation tracks in the detector., 18 pages, 13 figures

We explore an extension of the standard $\Lambda$CDM model by including an interaction between neutrinos and dark matter, and making use of the ground based telescope data of the Cosmic Microwave Background (CMB) from the Atacama Cosmology Telescope (ACT). An indication for a non-zero coupling between dark matter and neutrinos (both assuming a temperature independent and $T^2$ dependent cross-section) is obtained at the 1$\sigma$ level coming from the ACT CMB data alone and when combined with the Planck CMB and Baryon Acoustic Oscillations (BAO) measurements. This result is confirmed by both fixing the effective number of relativistic degrees of freedom in the early Universe to the Standard Model value of $N_{\rm eff}=3.044$, and allowing $N_{\rm eff}$ to be a free cosmological parameter. Furthermore, when performing a Bayesian model comparison, the interacting $\nu$DM (+$N_{\rm eff}$) scenario is mostly preferred over a baseline $\Lambda$CDM (+$N_{\rm eff}$) cosmology. The preferred value is then used as a benchmark and the potential implications of dark matter's interaction with a sterile neutrino are discussed., Comment: 18 pages, 11 figures, 5 tables

Considering possible solutions to the $S_8$ tension between the Planck cosmic microwave background (CMB) measurement and low-redshift probes, we extended the standard $\Lambda$CDM cosmological model by including decay of dark matter (DDM). We first tested the DDM model in which dark matter decays into a form of non-interacting dark radiation. Under this DDM model, we investigated the DDM's impacts on the Sunyaev Zel'dovich effect by varying the decay lifetime, $\Gamma^{-1}$, including the background evolution in cosmology and non-linear prescription in the halo mass function. We performed a cosmological analysis under the assumption of this extended cosmological model by combining the latest high-redshift Planck CMB measurement and low-redshift SZ measurement. Our result shows a preference for $\Gamma^{-1} \sim 200$ Gyr with a lower bound on the decay lifetime of $\sim$ 77 Gyr at 95% confidence level. However, the CMB data do not prefer this model, and the $S_8$ tension still remains. Additionally, we tested the other DDM model in which dark matter decays into warm dark matter and dark radiation. This model supports $\Gamma^{-1} \sim 204$ Gyr to resolve the $S_8$ tension with a lower bound on the decay lifetime of $\sim$ 47 Gyr at 95% confidence level.

Dr. Bert Sakmann (b. 1942) studied at the Universities of Tuebingen, Freiburg, Berlin, Paris, and Munich, graduating in 1967. Much of his professional life has been spent in various institutes of the Max Planck Society. In 1971, a British Council Fellowship took him to the Department of Biophysics of University College London to work with Bernard Katz (1911-2003). In 1974, he obtained his Ph.D. from the University of Goettingen and, with Erwin Neher (b. 1944) at the Max Planck Institute for Biophysical Chemistry, began work that would transform cellular biology and neuroscience, resulting in the 1991 Nobel Prize for Physiology or Medicine. In 2008, Dr. Sakmann returned to Munich, where he headed the research group "Cortical Columns in Silico" at the Max Planck Institute of Neurobiology in Martinsried. Here, their group discovered the cell-type specific sensory activation patterns in different layers of a column in the vibrissal area of rodents' somatosensory cortices.

In this paper we present the progress in development of a table-top version of the Kibble balance under the name Planck-Balance 2 (PB2). The PB2 is developed as a collaboration effort between the Technische Universität Ilmenau (TU Ilmenau) and Physikalisch-Technische Bundesanstalt (PTB) aiming for automatized mass calibration of the set of weights in the range from 1 mg to 100 g within the required uncertainties as stated by OIML recommendation R111 for weights of E2 class. We describe the design and the operational performance of the PB2 system in detail, the results of rigorous investigations of the error sources and subsequent improvements made since the beginning of the project in early 2017, the measurement data with the corresponding relative uncertainties and the preliminarily obtained uncertainty budget.

Loop diagrams with near-Planck energies create a strong external gravitational field, which slows down local processes for distant observers up to their freezing. Since Planck length is the gravitational radius of the system of quanta, the events of this and smaller scale cannot occur in finite world time t and do not contribute to the S-matrix. Consequently, gravitational time dilation, leading to a strong redshift of local frequencies, provides gravitational self-regularization of the loop diagrams. The loop corrections without gravity effects, cut off at Planck energy, give upper bounds for the corrections with gravity effects and this fact leads to simple rules of gravitational regularization. The corrections with quanta of gauge fields and gravitons are small, and the perturbation theory series converge. At pre-Planck energies, one-loop graviton contributions are sufficient, since the multi-loop ones are damped by high degrees of the relation “energy/Planck energy”. Scalar field with power-law growing corrections should be effective field. Non-linearity of fields enhances gravity and get faster freezing, which suppresses the high energy terms. Nonrenormalizable models are finite, but become consistent only when their loop corrections remain small on Planck scale and this occurs in quantum gravity. Gravitationally regularized Extended Standard Model (ESM), including gravitons and Standard Model with effective scalars, is renormalizable and finite, which simplifies its further generalization.

The first generation (Pop-III) stars can ionize 1-10% of the universe by $z=15$, when the metal-enriched (Pop-II) stars may contribute negligibly to the ionization. This low ionization tail might leave detectable imprints on the large-scale CMB E-mode polarization. However, we show that physical models for reionization are unlikely to be sufficiently extended to detect any parameter beyond the total optical depth through reionization. This result is driven in part by the total optical depth inferred by Planck, indicating a reionization midpoint around $z=8$, which in combination with the requirement that reionization completes by $z\approx 5.5$ limits the amplitude of an extended tail. To demonstrate this, we perform semi-analytic calculations of reionization including Pop-III star formation in minihalos with Lyman-Werner feedback. We find that standard Pop-III models need to produce very extended reionization at $z>15$ to be distinguishable at 2-$��$ from Pop-II-only models, assuming a cosmic variance-limited measurement of the low-$\ell$ EE power spectrum. However, we show that unless there is (1) a late-time quenching mechanism such as from strong X-ray feedback or (2) some other extreme Pop-III scenario, structure formation makes it quite challenging to produce high enough Thomson scattering optical depth from $z>15$, $��(z>15)$, and still be consistent with other observational constraints on reionization., 11 pages 4 figures + appendix

We solve for a system that emits acceleration radiation at two different temperatures. The equilibrium states occur asymptotically in Planck distributions and transition non-thermally. The model is simple enough to obtain a global solution for the radiation spectrum analytically. We present it as a potentially useful model for investigation of non-thermal vacuum acceleration radiation in the presence of final(initial) asymptotic thermodynamic horizon(less) states in equilibrium., Accepted to Astronomy Reports. 10 pages, 4 figures

The article describes the context and content of the November 1925 correspondence – so far overlooked by historians of physics – between Władysław (Ladislas) Natanson and Alfred Landé on Planck’s law and Bose statistics, and the effects of this interaction. The article publishes for the first time the transcription of two original letters in German and their translations into English.

The model reduction of a mesoscopic kinetic dynamics to a macroscopic continuum dynamics has been one of the fundamental questions in mathematical physics since Hilbert’s time. In this paper, we consider a diagram of the diffusion limit from the Vlasov–Poisson–Fokker–Planck (VPFP) system on a bounded interval with the specular reflection boundary condition to the Poisson–Nernst–Planck (PNP) system with the no-flux boundary condition. We provide a Deep Learning algorithm to simulate the VPFP system and the PNP system by computing the time-asymptotic behaviors of the solution and the physical quantities. We analyze the convergence of the neural network solution of the VPFP system to that of the PNP system via the Asymptotic-Preserving (AP) scheme. Also, we provide several theoretical evidence that the Deep Neural Network (DNN) solutions to the VPFP and the PNP systems converge to the a priori classical solutions of each system if the total loss function vanishes.

Along their long propagation from production to detection, neutrino states undergo quantum interference which converts their types, or flavours. High-energy astrophysical neutrinos, first observed by the IceCube Neutrino Observatory, are known to propagate unperturbed over a billion light years in vacuum. These neutrinos act as the largest quantum interferometer and are sensitive to the smallest effects in vacuum due to new physics. Quantum gravity (QG) aims to describe gravity in a quantum mechanical framework, unifying matter, forces and space-time. QG effects are expected to appear at the ultra-high-energy scale known as the Planck energy, $E_{P}\equiv 1.22\times 10^{19}$~giga-electronvolts (GeV). Such a high-energy universe would have existed only right after the Big Bang and it is inaccessible by human technologies. On the other hand, it is speculated that the effects of QG may exist in our low-energy vacuum, but are suppressed by the Planck energy as $E_{P}^{-1}$ ($\sim 10^{-19}$~GeV$^{-1}$), $E_{P}^{-2}$ ($\sim 10^{-38}$~GeV$^{-2}$), or its higher powers. The coupling of particles to these effects is too small to measure in kinematic observables, but the phase shift of neutrino waves could cause observable flavour conversions. Here, we report the first result of neutrino interferometry~\cite{Aartsen:2017ibm} using astrophysical neutrino flavours to search for new space-time structure. We did not find any evidence of anomalous flavour conversion in IceCube astrophysical neutrino flavour data. We place the most stringent limits of any known technologies, down to $10^{-42}$~GeV$^{-2}$, on the dimension-six operators that parameterize the space-time defects for preferred astrophysical production scenarios. For the first time, we unambiguously reach the signal region of quantum-gravity-motivated physics., Comment: The main text is 7 pages with 3 figures and 1 table. The Appendix includes 5 pages with 3 figures

The Internal Linear Combination (ILC) method has been extensively used to extract the cosmic microwave background (CMB) anisotropy map from foreground contaminated multi-frequency maps. However, the performance of simple ILC is limited and can be significantly improved by heavily constraint equations, dubbed cILC. The standard ILC and cILC works on the spin-0 field. Recently, a generalized version of ILC is developed to estimate polarization maps in which the quantity $Q \pm iU$ is combined at multiple frequencies using complex coefficients called Polarization ILC (PILC). A statistical moment expansion method has recently been developed for high precision modelling of the Galactic foregrounds. This paper develops a semi-blind component separation method combining the moment approach of foreground modelling with a generalized version of the PILC method for heavily constraint equations. The algorithm is developed in pixel space and performs for a spin-2 field. We employ this component separation technique in simultaneous estimation of Stokes $Q$, $U$ maps of the thermal dust at 353 GHz and synchrotron at 30 GHz over 78 % of the sky. We demonstrate the performance of the method on three sets of absolutely calibrated simulated maps at WMAP and planck frequencies with varying foreground models., Comment: 23 pages, 16 figures, Submitted to MNRAS

A family of generalised Planck (GP) laws is defined and its structural properties explored. Sometimes subject to parameter restrictions, a GP law is a randomly scaled gamma law; it arises as the equilibrium law of a perturbed version of the Feller mean reverting diffusion; the density functions can be decreasing, unimodal or bimodal; it is infinitely divisible. It is argued that the GP law is not a generalised gamma convolution. Characterisations are obtained in terms of invariance under random contraction of a weighted version of a related law. The GP law is a particular instance of equilibrium laws obtained from a recursion suggested by a genetic mutation-selection balance model. Some related infinitely divisible laws are exhibited.

An important route to testing General Relativity (GR) at cosmological scales is usually done by constraining modified gravity (MG) parameters added to the Einstein perturbed equations. Most studies have analyzed so far constraints on pairs of MG parameters, but here, we explore constraints on one parameter at a time while fixing the other at its GR value. This allows us to analyze various models while benefiting from a stronger constraining power from the data. We also explore which specific datasets are in tension with GR. We find that models with ($\mu=1$, $\eta$) and ($\mu$, $\eta=1$) exhibit a 3.9-$\sigma$ and 3.8-$\sigma$ departure from GR when using Planck18+SNe+BAO, while ($\mu$, $\eta$) shows a tension of 3.4-$\sigma$. We find no tension with GR for models with the MG parameter $\Sigma$ fixed to its GR value. Using a Bayesian model selection analysis, we find that some one-parameter MG models are moderately favored over $\Lambda$CDM when using all dataset combinations except Planck CMB Lensing and DES data. Namely, Planck18 shows a moderate tension with GR that only increases when adding any combination of RSD, SNe, or BAO. However, adding lensing diminishes or removes these tensions, which can be attributed to the ability of lensing in constraining the MG parameter $\Sigma$. The two overall groups of datasets are found to have a dichotomy when performing consistency tests with GR, which may be due to systematic effects, lack of constraining power, or modelling. These findings warrant further investigation using more precise data from ongoing and future surveys., Comment: 11 pages, 6 figures. Matches the published version on 06/24/2021. A Python wrapper for the system ISiTGR is also released with this paper and available at https://github.com/mishakb/ISiTGR

Dr. Wolf Singer (b. 1943) is one of Germany's most renowned brain researchers and neurophysiologists. His accomplishments in the creation of new research centers for neuroscience as well as his commitment to European scientific organizations for integrative brain research are highly valued as significant moments of advancement in the neurosciences. Before his appointment as a scientific member of the Max Planck Society and director at the Frankfurt Max Planck Institute for Brain Research, he gained deep insight into the chances and pitfalls of translational initiatives at the Max Planck Institute of Psychiatry in Munich. From the late 1950s onward, the institute adapted to emerging international trends and successfully integrated neurochemistry, neurophysiology, and neuroanatomy into the fledgling interdisciplinary field of neuroscience. This agenda of reorientation was an undertaking of Otto Detlev Creutzfeldt, Detlev Ploog, Gerd Peters, and Horst Jatzkewitz, among others. In the 1970s, Munich's laboratories attracted scientists from several countries in Europe and abroad. This article examines whether specific styles of conducting (neuro)science research existed in the Max Planck Society.

This paper investigates whether changes to late time physics can resolve the `Hubble tension'. It is argued that many of the claims in the literature favouring such solutions are caused by a misunderstanding of how distance ladder measurements actually work and, in particular, by the inappropriate use of a distance ladder H0 prior. A dynamics-free inverse distance ladder shows that changes to late time physics are strongly constrained observationally and cannot resolve the discrepancy between the SH0ES data and the base LCDM cosmology inferred from Planck. We propose a statistically rigorous scheme to replace the use of H0 priors, Comment: Expanded version following comments received on earlier astro-ph version

Within the $\Lambda$CDM model, measurements from recent Cosmic Microwave Background (CMB) and weak lensing (WL) surveys have uncovered a $\sim 3\sigma$ disagreement in the inferred value of the parameter $S_8 \equiv \sigma_8\sqrt{\Omega_m/0.3}$, quantifying the amplitude of late-time matter fluctuations. Before questioning whether the $S_8$ discrepancy calls for new physics, it is important to assess the view of measurements other than CMB and WL ones on the discrepancy. Here, we examine the role of measurements of the growth rate $f(z)$ in arbitrating the $S_8$ discrepancy, considering measurements of $f\sigma_8(z)$ from Redshift-Space Distortions (RSD). Our baseline analysis combines RSD measurements with geometrical measurements from Baryon Acoustic Oscillations (BAO) and Type Ia Supernovae (SNeIa), given the key role of the latter in constraining $\Omega_m$. From this combination and within the $\Lambda$CDM model we find $S_8 = 0.762^{+0.030}_{-0.025}$, and quantify the agreement between RSD+BAO+SNeIa and \textit{Planck} to be at the $2.2\sigma$ level: the mild disagreement is therefore compatible with a statistical fluctuation. We discuss combinations of RSD measurements with other datasets, including the $E_G$ statistic. This combination increases the discrepancy with \textit{Planck}, but we deem it significantly less robust. Our earlier results are stable against an extension where we allow the dark energy equation of state $w$ to vary. We conclude that, from the point of view of combined growth rate and geometrical measurements, there are hints, but no strong evidence yet, for the \textit{Planck} $\Lambda$CDM cosmology over-predicting the amplitude of matter fluctuations at redshifts $z \lesssim 1$. From this perspective, it might therefore still be premature to claim the need for new physics from the $S_8$ discrepancy., Comment: 13 pages, 1 table, 3 figures. Accepted for publication in MNRAS

This work focuses on a one-dimensional Poisson–Nernst–Planck system including small permanent charges for ionic flows with one cation and one anion through a membrane channel. Our main interest is to examine the qualitative properties of the individual fluxes with boundary layers that is more realistic for ion channel problem study. Our result shows that the individual fluxes depend sensitively on multiple system parameters such as permanent charges, channel geometry, boundary conditions (concentrations and potentials) and boundary layers. For the relatively simple setting and assumptions of the model in this work, we are able to characterize the different effects of the nonlinear interaction among these system parameters in detail and gain a better understanding of the internal dynamics of ionic flows through membrane channels. Our analysis indicates that the small positive permanent charge cannot strengthen the flux of cation while reduce that of anion. Critical electric potentials which play crucial roles in studying ionic flow properties are identified. Some can be estimated experimentally. Numerical simulations are further performed and numerical results are consistent with our analytical ones.

Distributions different from those predicted by equilibrium statistical mechanics are commonplace in a number of physical situations, such as plasmas and self-gravitating systems. The best strategy for probing these distributions and unavailing their origins consists in combining theoretical knowledge with experiments, involving both direct and indirect measurements, as those associated with dispersion relations. This paper addresses, in a quite general context, the signature of nonequilibrium distributions in dispersion relations. We consider the very general scenario of distributions corresponding to a superposition of equilibrium distributions, that are well-suited for systems exhibiting only local equilibrium, and discuss the general context of systems obeying the combination of the Schrödinger and Poisson equations, while allowing the Planck’s constant to smoothly go to zero, yielding the classical kinetic regime. Examples of media where this approach is applicable are plasmas, gravitational systems, and optical molasses. We analyse in more depth the case of classical dispersion relations for a pair plasma. We also discuss a possible experimental setup, based on spectroscopic methods, to directly observe these classes of distributions.

We analyse a quasi-one-dimensional Poisson–Nernst–Planck system for ionic flow through a membrane channel with nonzero but small permanent charge. The system includes three ion species, two cations with the same valences and one anion. The cross-sectional area of the channel is included in the system, which provides certain information of the geometry of the three-dimensional channel. This is critical for our analysis. We treat the model as a boundary value problem of a singularly perturbed system of differential equations. Under the framework of geometric singular perturbation theory, together with specific structures of the model, the existence and local uniqueness of solutions to the boundary value problem for small permanent charges is established. Furthermore, treating the permanent charge as a small parameter, via regular perturbation analysis, we are able to derive an approximation of the I–V (current–voltage) relations explicitly, from which the permanent charge and channel geometry effects on ionic flows are analysed in detail. Critical potentials are identified and their roles in characterising the ionic flow properties of interest are studied. Some critical potentials can be experimentally estimated, and this provides an efficient way to adjust the boundary pot to observe distinct dynamics of ionic flows. Mathematical analysis indicates that a short and narrow filter within which the permanent charge is confined is expected in order to optimise the effect of permanent charges. This is consistent with the typical structure of an ion channel.

We develop a set of numerical schemes for the Poisson--Nernst--Planck equations. We prove that our schemes are mass conservative, uniquely solvable and keep positivity unconditionally. Furthermore, the first-order scheme is proven to be unconditionally energy dissipative. These properties hold for various spatial discretizations. Numerical results are presented to validate these properties. Moreover, numerical results indicate that the second-order scheme is also energy dissipative, and both the first- and second-order schemes preserve the maximum principle for cases where the equation satisfies the maximum principle., Comment: 24 pages, 10 figures

Pinning down the total neutrino mass and the dark energy equation of state is a key aim for upcoming galaxy surveys. Weak lensing is a unique probe of the total matter distribution whose non-Gaussian statistics can be quantified by the one-point probability distribution function (PDF) of the lensing convergence. We calculate the convergence PDF on mildly non-linear scales from first principles using large-deviation statistics, accounting for dark energy and the total neutrino mass. For the first time, we comprehensively validate the cosmology-dependence of the convergence PDF model against large suites of simulated lensing maps, demonstrating its percent-level precision and accuracy. We show that fast simulation codes can provide highly accurate covariance matrices, which can be combined with the theoretical PDF model to perform forecasts and eliminate the need for relying on expensive N-body simulations. Our theoretical model allows us to perform the first forecast for the convergence PDF that varies the full set of $\Lambda$CDM parameters. Our Fisher forecasts establish that the constraining power of the convergence PDF compares favourably to the two-point correlation function for a Euclid-like survey area at a single source redshift. When combined with a CMB prior from Planck, the PDF constrains both the neutrino mass $M_\nu$ and the dark energy equation of state $w_0$ more strongly than the two-point correlation function., Comment: Accepted by MNRAS

This work is concerned with the stationary Poisson--Nernst--Planck equation with a large parameter which describes a huge number of ions occupying an electrolytic region. Firstly, we focus on the model with a single specie of positive charges in one-dimensional bounded domains due to the assumption that these ions are transported in the same direction along a tubular-like mircodomain. We show that the solution asymptotically blows up in a thin region attached to the boundary, and establish the refined "near-field" and "far-field" expansions for the solutions with respect to the parameter. Moreover, we obtain the boundary concentration phenomenon of the net charge density, which mathematically confirms the physical description that the non-neutral phenomenon occurs near the charged surface. In addition, we revisit a nonlocal Poisson--Boltzmann model for monovalent binary ions and establish a novel comparison for these two models.

We present a comparison of the physical properties of the ionized gas in the circumgalactic medium and intergalactic medium (IGM) at z ∼ 0 between observations and four cosmological hydrodynamical simulations: Illustris, TNG300 of the IllustrisTNG project, EAGLE, and one of the Magneticum simulations. For the observational data, we use the gas properties that are inferred from cross-correlating the Sunyaev–Zel’dovich effect (SZE) from the Planck CMB maps with haloes and large-scale structure. Both the observational and simulation results indicate that the integrated gas pressure in haloes deviates from the self-similar case, showing that feedback impacts haloes with $M_{500}\sim 10^{12\!-\!13}\, {\rm M_\odot }$. The simulations predict that more than half the baryons are displaced from haloes, while the gas fraction inferred from our observational data roughly equals the cosmic baryon fraction throughout the $M_{500}\sim 10^{12\!-\!14.5}\, {\rm M_\odot }$ halo mass range. All simulations tested here predict that the mean gas temperature in haloes is about the virial temperature, while that inferred from the SZE is up to one order of magnitude lower than that from the simulations (and also from X-ray observations). While a remarkable agreement is found for the average properties of the IGM between the observation and some simulations, we show that their dependence on the large-scale tidal field can break the degeneracy between models that show similar predictions otherwise. Finally, we show that the gas pressure and the electron density profiles from simulations are not well described by a generalized NFW profile. Instead, we present a new model with a mass-dependent shape that fits the profiles accurately.

Many late time approaches for the solution of the Hubble tension use late time smooth deformations of the Hubble expansion rate $H(z)$ of the Planck18/$\Lambda$CDM best fit to match the locally measured value of $H_0$ while effectively keeping the comoving distance to the last scattering surface and $\Omega_{0m} h^2$ fixed to maintain consistency with Planck CMB measurements. A well known problem of these approaches is that they worsen the fit to low $z$ distance probes. Here we show that another problem of these approaches is that they worsen the level of the $\Omega_{0m}-\sigma_8$ growth tension. We use the generic class of CPL parametrizations corresponding to evolving dark energy equation of state parameter $w(z)=w_0+w_1\frac{z}{1+z}$ with local measurements $H_0$ prior and identify the pairs $(w_0, w_1)$ that satisfy this condition. This is a generic class of smooth deformations of $H(z)$ that are designed to address the Hubble tension. We show that for these models the growth tension between dynamical probe data and CMB constraints is worse than the corresponding tension of the standard Planck18/$\Lambda$CDM model. We justify this feature using a full numerical solution of the growth equation and fit to the data, as well as by using an approximate analytic approach. The problem does not affect recent proposed solutions of the Hubble crisis involving a SnIa intrinsic luminosity transition at $z_t\simeq 0.01$., Comment: 7 pages, 5 figures. Published vesrion (MNRAS) doi.org/10.1093/mnras/stab1070. The numerical analysis files for the reproduction of the figures can be found in https://github.com/GeorgeAlestas/Growth-Hubble_Tension under the MIT license