Acoustic Oscillations Research Articles

Role of future SNIa data from rubin LSST in reinvestigating cosmological models

Abstract We study how future Type-Ia supernovae (SNIa) standard candles detected by the Vera C. Rubin Observatory (LSST) can constrain some cosmological models. We use a realistic three-year SNIa simulated dataset generated by the LSST Dark Energy Science Collaboration (DESC) Time Domain pipeline, which includes a mix of spectroscopic and photometrically identified candidates. We combine this data with Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillation (BAO) measurements to estimate the dark energy model parameters for two models – the baseline ΛCDM and Chevallier-Polarski-Linder (CPL) dark energy parametrization. We compare them with the current constraints obtained from joint analysis of the latest real data from the Pantheon SNIa compilation, CMB from Planck 2018 and BAO. Our analysis finds tighter constraints on the model parameters along with a significant reduction of correlation between H0 and σ8, 0. We find that LSST is expected to significantly improve upon the existing SNIa data in the critical analysis of cosmological models.

Exploring the deceleration parameter in f(T) gravity: A comprehensive analysis using parametrization techniques and observational data

In this paper, we employ parametrization techniques within the framework of [Formula: see text] gravity to investigate the deceleration parameter (DP), a key quantity characterizing the universe’s expansion dynamics. By analyzing the DP, we gain valuable insights into the nature of cosmic constituents and their impact on the universe’s evolution. We utilize a combination of observational data, including 31 Cosmic Chronometers (CC) measurements, 1048 Type Ia Supernovae (SNIa), 17 Baryon Acoustic Oscillation (BAO) measurements, Cosmic Microwave Background (CMB), 162 Gamma Ray Bursts (GRB), and 24 observations of compact radio quasars (Q). We employ the Markov chain Monte Carlo (MCMC) sampling technique to estimate the best-fit range of model parameters. Cosmological and cosmographic parameters are investigated, and their implications in the context of cosmology have been discussed. We also analyze the statefinder and [Formula: see text] diagnostic to gain deeper insights into the universe’s behavior. Furthermore, we conduct statistical analyses to compare our model with the standard [Formula: see text]CDM model. Our investigation also includes the study of physical parameters, providing comprehensive insights into the cosmological behavior within the [Formula: see text] gravity framework. The results and comparisons presented in this work contribute to a deeper understanding of the universe’s dynamics and provide valuable implications for the cosmological model under consideration.

On the nonlinear dynamic characteristics of forced acoustic oscillations in a heat-driven thermoacoustic engine

On the nonlinear dynamic characteristics of forced acoustic oscillations in a heat-driven thermoacoustic engine

A model-independent precision test of general relativity using bright standard sirens from ongoing and upcoming detectors

Abstract Gravitational waves (GWs) provide a new avenue to test Einstein’s General Relativity (GR) using the ongoing and upcoming GW detectors by measuring the redshift evolution of the effective Planck mass proposed by several modified theories of gravity. We propose a model-independent, data-driven approach to measure any deviation from GR in the GW propagation effect by combining multi-messenger observations of GW sources accompanied by EM counterparts, commonly known as bright sirens (Binary Neutron Star (BNS) and Neutron Star Black Hole systems (NSBH)). We show that by combining the GW luminosity distance measurements from bright sirens with the Baryon Acoustic Oscillation (BAO) measurements derived from galaxy clustering, and the sound horizon measurements from the Cosmic Microwave Background (CMB), we can make a data-driven reconstruction of deviation of the variation of the effective Planck mass (jointly with the Hubble constant) as a function of cosmic redshift. Using this technique, we achieve a precise measurement of GR with redshift (z) with a precision of approximately 7.9 % for BNSs at redshift z=0.075 and 10 % for NSBHs at redshift z=0.225 with 5 years of observation from LIGO-Virgo-KAGRA network of detectors. Employing Cosmic Explorer and Einstein Telescope for just 1 year yields the best precision of about 1.62 % for BNSs and 2 % for NSBHs at redshift z=0.5 on the evolution of the frictional term, and a similar precision up to z=1. This measurement can discover potential deviation from any kind of model that impacts GW propagation with ongoing and upcoming observations.

Dynamical System Approach and Thermodynamical Perspective of Hořava‐Lifshitz Gravity

AbstractThe authors have examined a Friedmann Robertson Walker cosmological model in Hořava‐Lifshitz gravity by using a dynamical system approach. A set of autonomous equations is derived and their solutions are calculated. The critical points from these equations and find the characteristics values with the analysis of the physical interpretation of the phase space for this system are assessed. Three stable critical points are found and the values of the physical parameters and the scale factor's expressions at each critical points are displayed in Tables 1, 2, and 3. A hybrid scale factor to develop the model, which results in a phase transition from deceleration to acceleration is used. The suitable values of the parameters are governed by applying the Monte Chain Monte Carlo method technique to the Hubble 46 and joint Hubble 46 and Baryon Acoustic Oscillations 15 datasets. In contrast to the negative behavior of pressure, the positive behavior of energy density and illustrate the Universe's acceleration epoch and the model is represented by the EoS parameter . The authors investigated that the energy conditions and their model violates the strong energy condition. Utilizing diagnostic test, it is found that the model represents phantom behavior. The thermodynamical perspective for the model is also examined. The model accurately explained the Universe's propagation history and fits well with contemporary cosmic data.

Time-resolved measurement of acoustic density fluctuations using a phase-shifting Mach-Zehnder interferometer.

Phase-shifting interferometry is one of the optical measurement techniques that improves accuracy and resolution by incorporating a controlled phase shift into conventional optical interferometry. In this study, a four-step phase-shifting interferometer is developed to measure the spatiotemporal distribution of acoustic density oscillations of the gas next to a rigid plate. The experimental apparatus consists of a polarizing Mach-Zehnder interferometer with a polarization camera capable of capturing four polarization directions in one shot image and it is used to measure the magnitude and the phase of density fluctuations through a duct of rectangular cross section connected to a loudspeaker. The results are compared with the well-established thermoacoustic theory describing the thermal coupling between acoustic oscillations and rigid boundaries, and the results show a very good agreement for various ratios of the (frequency-dependent) thermal boundary layer thickness to the plate spacing. This measurement technique could be advantageously employed to analyze more complex heat transfer processes involving the coupling of acoustic oscillations with rigid boundaries.

Self-calibrating BAO measurements in the presence of small displacement interlopers

Baryon Acoustic Oscillation (BAO) observations offer a robust method for measuring cosmological expansion. However, the BAO signal in a sample of galaxies can be diluted and shifted by interlopers — galaxies that have been assigned the wrong redshifts. Because of the slitless spectroscopic method adopted by the Roman and Euclid space telescopes, the galaxy samples resulting from single line detections will have relatively high fractions of interloper galaxies. Interlopers with a small displacement between true and false redshift have the strongest effect on the measured clustering. In order to model the BAO signal, the fraction of such interlopers and their clustering need to be accurately known. We introduce a new method to self-calibrate these quantities by shifting the contaminated sample towards or away from us along the line of sight by the interloper offset, and measuring the cross-correlations between these shifted samples. The contributions from the different components are shifted in scale in this cross-correlation compared to the auto-correlation of the contaminated sample, enabling the decomposition and extraction of the component terms. We demonstrate the application of the method using numerical simulations and show that an unbiased BAO measurement can be extracted. Unlike previous attempts to model the effects of contaminants, self-calibration allows us to make fewer assumptions about the form of the contaminants such as their bias.

The H 0 trouble: confronting non-thermal dark matter and phantom cosmology with the CMB, BAO, and Type Ia supernovae data

We have witnessed different values of the Hubble constant being found in the literature in the past years. Albeit, early measurements often result in an H 0 much smaller than those from late-time ones, producing a statistically significant discrepancy, and giving rise to the so-called Hubble tension. The trouble with the Hubble constant is often treated as a cosmological problem. However, the Hubble constant can be a laboratory to probe cosmology and particle physics models. In our work, we will investigate if the possibility of explaining the H 0 trouble using non-thermal dark matter production aided by phantom-like cosmology is consistent with the Cosmic Background Radiation (CMB) and Baryon Acoustic Oscillation (BAO) data. We performed a full Monte Carlo simulation using CMB and BAO datasets keeping the cosmological parameters Ω bh 2, Ω ch 2, 100θ, τopt , and w as priors and concluded that a non-thermal dark matter production aided by phantom-like cosmology yields at most H 0 = 70.5 km s-1 Mpc-1 which is consistent with some late-time measurements. However, if H 0 > 72 km s-1 Mpc-1 as many late-time observations indicate, an alternative solution to the Hubble trouble is needed. Lastly, we limited the fraction of relativistic dark matter at the matter-radiation equality to be at most 1%.

Observational bounds on extended minimal theories of massive gravity: new limits on the graviton mass

In this work, we derive for the first time observational constraints on the extended Minimal Theory of Massive Gravity (eMTMG) framework in light of Planck-CMB data, geometrical measurements from Baryon Acoustic Oscillation (BAO), Type Ia supernovae from the recent Pantheon+ samples, and also using the auto and cross-correlations cosmic shear measurements from KIDS-1000 survey. Given the great freedom of dynamics choice for the theory, we consider an observationally motivated subclass in which the background evolution of the Universe goes through a transition from a (positive or negative) value of the effective cosmological constant to another value. From the statistical point of view, we did not find evidence of such a transition, i.e. deviation from the standard ΛCDM behavior, and from the joint analysis using Planck + BAO + Pantheon+ data, we constrain the graviton mass to < 6.6 × 10-34 eV at 95% CL. We use KIDS-1000 survey data to constrain the evolution of the scalar perturbations of the model and its limits for the growth of structure predicted by the eMTMG scenario. In this case, we find small evidence at 95% CL for a non-zero graviton mass. We interpret and discuss these results in light of the current tension on the S 8 parameter. We conclude that, within the subclass considered, the current data are only able to impose upper bounds on the eMTMG dynamics. Given its potentialities beyond the subclass, eMTMG can be classified as a good candidate for modified gravity, serving as a framework in which observational data can effectively constrain (or confirm) the graviton mass and deviations from the standard ΛCDM behavior.

Exploring Universe acceleration through observational constraints via Hubble parameter reconstruction

In this article, we introduce an innovative parametric representation of the Hubble parameter, providing a model-independent means to explore the dynamics of an accelerating cosmos. The model's parameters are rigorously constrained through a Markov Chain Monte Carlo (MCMC) approach, leveraging a comprehensive dataset consisting of 31 data points from cosmic chronometers (CC), 1701 updated observations of Pantheon supernovae type Ia (SNeIa), and 6 data points from baryonic acoustic oscillations (BAO). Our analysis delves into the behavior of various cosmological parameters within the model, including the transition from a decelerating phase to an accelerating one, as well as the density parameters and the equation of state (EoS) parameter. The outcomes of our investigation reveal that the equation of state parameter aligns with characteristics reminiscent of the phantom model, supporting the prevailing understanding of our universe's current state of acceleration. This research contributes valuable insights into the ongoing cosmic expansion and underscores the utility of our novel parametric approach.

Thermoacoustic velocity and pressure oscillations in one-dimensional combustors with spatially varying heat sources and thermal distributions

In this work, an asymptotically based framework using a naturally occurring perturbation parameter is further developed in the context of a one-dimensional tube with an open–open end point configuration without and with a spatially variable heat source. This approach is shown to produce accurate predictions of not only pressure waveforms, as previously demonstrated, but also of velocity mode shapes and frequencies for arbitrary temperature distributions that mimic a wide variety of flow heating arrangements. These include those associated with a Rijke tube as well as other thermoacoustic sound-generation devices. The underlying formulation consists of two linearly coupled partial differential equations that can be solved simultaneously while using a Green's function to capture the thermoacoustically induced velocity. The strategy leading to accurate predictions of the thermoacoustic velocity is described and then applied to several representative cases. Results pertaining to the acoustic velocity and pressure are systematically discussed and compared to other models in the literature. Overall, we find the axially dependent thermal gain to have the most significant impact on the mode shape structure, frequencies, and nodal locations. For example, higher thermal gains lead to elevated wave propagation speeds in the downstream segment of the tube. As such, they cause the velocity nodes to gradually shift upstream with successive increases in the thermal gain. Moreover, due in part to a non-homogeneous pressure–temperature pumping term that appears exclusively in the acoustic velocity formulation, the main difference between the acoustic pressure and velocity oscillation frequencies can be directly attributed to specific derivatives of the spatially varying thermal profiles.

Measurement of the photometric baryon acoustic oscillations with self-calibrated redshift distribution

ABSTRACT We use a galaxy sample derived from the Dark Energy Camera Legacy Survey Data Release 9 to measure the baryonic acoustic oscillations (BAO). The magnitude-limited sample consists of 10.6 million galaxies in an area of 4974 deg2 over the redshift range of [0.6, 1]. A key novelty of this work is that the true redshift distribution of the photo-z sample is derived from the self-calibration method, which determines the true redshift distribution using the clustering information of the photometric data alone. Through the angular correlation function in four tomographic bins, we constrain the BAO scale dilation parameter α to be 1.025 ± 0.033, consistent with the fiducial Planck cosmology. Alternatively, the ratio between the comoving angular diameter distance and the sound horizon, DM/rs, is constrained to be 18.94 ± 0.61 at the effective redshift of 0.749. We corroborate our results with the true redshift distribution obtained from a weighted spectroscopic sample, finding very good agreement. We have conducted a series of tests to demonstrate the robustness of the measurement. Our work demonstrates that the self-calibration method can effectively constrain the true redshift distribution in cosmological applications, especially in the context of photometric BAO measurement.

Higgs inflation: Constraining the top quark mass and breaking the H0-σ8 correlation

Extending previous results, we explore aspects of the reheating mechanism for non-minimal Higgs inflation in the strong coupling regime. We constrain the radiative corrections for the inflaton's potential by considering the Coleman-Weinberg approximation and use the Renormalization Group Equations for the Higgs field to derive an upper limit on the top quark mass. Using the current Cosmic Microwave Background, Baryon Acoustic Oscillation, and Supernovae data, we obtain mt≤170.44 GeV, confirming the observational compatibility of the model with recent mt estimates reported by the CMS collaboration. We also analyze the breakdown of the well-known correlation involving the Hubble constant H0 and the clustering parameter σ8, which makes the model interesting in light of the cosmological tensions discussed over the last decade.

Assessment of technogenic acoustic background influence on y-spectrometer readings at registration of y-radiation spectra

The paper presents theoretical and experimental data determining the effect of acoustic perturbation on the readings of a γ-detector (CGS) with a working medium (high-pressure xenon gas) operating in the field of ionizing radiation. For this purpose, a chain of events is considered: an acoustic wave falls on the surface of the CGS, passes through and produces a perturbation in the gas which forms a non-uniformity of pressure distribution in the working medium. Exposure to ionising radiation leads to the formation of positive ions in the gas, the mobility of which is much lower than the mobility of free electrons, which are the main carriers in CGS. The experiments are carried out using an unmanned dosimetric complex BDK with a carrier in the form of (helicopter-type UAV) on which dosimetric equipment used for radiation control of the environment in conditions of its radioactive contamination is attached. Theoretical results obtained by solving the wave equation of sound wave passage in xenon filling the CGS are presented in the form of xenon density. The obtained data allowes us to obtain the radial distribution of the current density at different moments of the harmonic acoustic oscillation period. Experimental data demonstrated frequency characteristics of acoustic load and their amplitude values in different modes of UAV operation. The results of the research determine the recommendations that should be taken into account when using UAVs as carriers of dosimetric equipment in radiation monitoring of the environment. 

Baryon acoustic scale at zeff = 0.166 with the SDSS blue galaxies

ABSTRACT The baryon acoustic oscillations (BAOs) phenomenon provides a unique opportunity to establish a standard ruler at any epoch in the history of the evolving universe. The key lies in identifying a suitable cosmological tracer to conduct the measurement. In this study, we focus on quantifying the sound horizon scale of BAO in the Local Universe. Our chosen cosmological tracer is a sample of blue galaxies from the Sloan Digital Sky Survey (SDSS), positioned at the effective redshift $z_{{\rm eff}} = 0.166$. Utilizing Planck-CMB input values for redshift-to-distance conversion, we derive the BAO scale $s_{{\rm BAO}} = 100.28 ^{+10.79} _{-22.96}$ Mpc h−1 at the 1$\sigma$ confidence level. Subsequently, we extrapolate the BAO signal scale in redshift space: $\Delta z_{{\rm BAO}}(z_{\rm eff}=0.166)=0.0361^{+0.00262}_ {-0.0055}$. This measurement holds the potential to discriminate among dark energy models within the Local Universe. To validate the robustness of our methodology for BAO scale measurement, we conduct three additional BAO analyses using different cosmographic approaches for distance calculation from redshifts. These tests aim to identify possible biases or systematics in our measurements of $s_{{\rm BAO}}$. Encouragingly, our diverse cosmographic approaches yield results in statistical agreement with the primary measurement, indicating no significant deviations. Conclusively, our study contributes with a novel determination of the BAO scale in the Local Universe, at $z_{{\rm eff}} = 0.166$, achieved through the analysis of the SDSS blue galaxies cosmic tracer.

Lensing convergence and anisotropic dark energy in galaxy redshift surveys

Analyses of upcoming galaxy surveys will require careful modelling of relevant observables such as the power spectrum of galaxy counts in harmonic space Cℓ(z,z′). We investigate the impact of disregarding relevant relativistic effects by considering a model of dark energy including constant sound speed ceff2, constant equation of state w, and anisotropic stress sourced by matter perturbations π. Cosmological constraints were computed using cosmic microwave background anisotropies, baryon acoustic oscillations, supernovae type Ia, and redshift space distortions. Our results are consistent with w=−1, ceff2=1, and π=0. Then, a forecast for the performance of an Euclid-like galaxy survey was carried out also adding information from other probes. Here we show that, regardless of the galaxy survey configuration, neglecting the effect of lensing convergence will lead to substantial shifts in the galaxy bias b0 and the neutrino mass ∑mν. Shifts in the dark energy sound speed and anisotropic stress also appear, but they depend on the survey configuration and hence lack robustness. While neglecting lensing convergence also leads to a Hubble constant H0 moving downwards, the significance of the shift is not big enough to play a relevant part in the current H0 tension.

Coherent Oscillations in a SrRuO3/BiFeO3 Superlattice.

We investigated the ultrafast dynamics of a SrRuO3/BiFeO3 superlattice grown on a SrTiO3 substrate using a near infrared pump-probe technique at various temperatures. The superlattice exhibits a ferromagnetic order inherited from the SrRuO3 layer. The pump-induced changes in the reflectivity reveal periodic oscillations. We found that the oscillation frequency can be well explained by zone-folded acoustic phonon oscillations, whose dispersion depends on the sound velocity, density, and thickness within the supercell of each constituent layer. It is found that the observed oscillation frequency corresponds to the A1 mode, which suggests that oscillations are excited due to pump-induced expansion of the SrRuO3 layer that absorbs the pump photon. Temperature-dependent measurements reveal significant suppression of the oscillation amplitude in the ferromagnetic state. The suppressed amplitude is proportional to the square of the magnetization, M(T)2. This phenomenon can be attributed to a strong magnetostriction effect of SrRuO3 that suppresses lattice expansion upon pumping.

Breaking the baryon-dark matter degeneracy in a model-independent way through the Sunyaev-Zeldovich effect

In cosmological fits, it is common to fix the baryon density $ via the cosmic microwave background. We here constrain $ by means of a model-independent interpolation of the acoustic parameter from correlated baryonic acoustic oscillations. The proposed technique is used to alleviate the degeneracy between baryonic and dark matter abundances. We propose a model-independent Bézier parametric interpolation and applied it to intermediate-redshift data. We first interpolated the observational Hubble data to extract cosmic bounds over the (reduced) Hubble constant $h_0$ and interpolated the angular diameter distances, $D(z)$, of the galaxy clusters, inferred from the Sunyaev-Zel'dovich effect, to constrain the spatial curvature, $ Through the Hubble points and $D(z)$ determined in this way, we interpolated uncorrelated data of baryonic acoustic oscillations bounding the baryon $ and total matter $ densities, reinforcing the constraints on $h_0$ and $ with the same technique. Finally, to remove the matter sector degeneracy, we obtained $ by interpolating the acoustic parameter from correlated baryonic acoustic oscillations. Monte Carlo Markov chain simulations agree at $1$sigma confidence level with the flat Lambda CDM model and are roughly suitable at $1$sigma with its nonflat extension, while the Hubble constant appears in tension up to the $2$sigma confidence levels. Our method excludes very small extensions of the standard cosmological model, and on the Hubble tension side, seems to match local constraints slightly.

Cosmological Constraints on Neutrino Mass within Consistent Cosmological Models

Abstract Recently, the emergence of cosmological tension has raised doubts about the consistency of the ΛCDM model. In order to constrain the neutrino mass within a consistent cosmological framework, we investigate three massive neutrinos with normal hierarchy (NH) and inverted hierarchy (IH) in both the axion-like EDE (Axi-EDE) model and the AdS-EDE model. We use the joint datasets including cosmic microwave background (CMB) power spectrum from Planck 2018, Pantheon of type Ia supernova, baryon acoustic oscillation (BAO) and H0 data from SH0ES. For the νAxi-EDE model, we obtain Σmν, NH &lt; 0.152 eV and Σmν, IH &lt; 0.178 eV, while for the νAdS-EDE model, we find Σmν, NH &lt; 0.135 eV and Σmν, IH &lt; 0.167 eV. Our results exhibit a preference for the normal hierarchy in both the νAxi-EDE model and the νAdS-EDE model.

Cortical tracking of visual rhythmic speech by 5- and 8-month-old infants: Individual differences in phase angle relate to language outcomes up to 2years.

It is known that the rhythms of speech are visible on the face, accurately mirroring changes in the vocal tract. These low-frequency visual temporal movements are tightly correlated with speech output, and both visual speech (e.g., mouth motion) and the acoustic speech amplitude envelope entrain neural oscillations. Low-frequency visual temporal information ('visual prosody') is known from behavioural studies to be perceived by infants, but oscillatory studies are currently lacking. Here we measure cortical tracking of low-frequency visual temporal information by 5- and 8-month-old infants using a rhythmic speech paradigm (repetition of the syllable 'ta' at 2Hz). Eye-tracking data were collected simultaneously with EEG, enabling computation of cortical tracking and phase angle during visual-only speech presentation. Significantly higher power at the stimulus frequency indicated that cortical tracking occurred across both ages. Further, individual differences in preferred phase to visual speech related to subsequent measures of language acquisition. The difference in phase between visual-only speech and the same speech presented as auditory-visual at 6- and 9-months was also examined. These neural data suggest that individual differences in early language acquisition may be related to the phase of entrainment to visual rhythmic input in infancy. RESEARCH HIGHLIGHTS: Infant preferred phase to visual rhythmic speech predicts language outcomes. Significant cortical tracking of visual speech is present at 5 and 8months. Phase angle to visual speech at 8months predicted greater receptive and productive vocabulary at 24months.