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Context. Recently our ability to study stars using asteroseismic techniques has increased dramatically, largely through the use of space based photometric observations. Work has also been done using ground based spectroscopic observations…

Solar and Stellar Astrophysics · Physics 2018-10-03 Jesper Schou

We investigate the phenomenology of a Standard Model extension incorporating an inert scalar doublet and a gauged $U(1)_{B-L}$ symmetry. Our analysis reveals regions of the parameter space that support strong first-order phase transitions,…

High Energy Physics - Phenomenology · Physics 2025-05-14 Indra Kumar Banerjee , Ujjal Kumar Dey , Shaaban Khalil

Recent investigations of the pseudospectrum in black hole spacetimes have shown that quasinormal mode frequencies suffer from spectral instabilities. This phenomenon may severely affect gravitational-wave spectroscopy and limit precision…

General Relativity and Quantum Cosmology · Physics 2023-03-13 Valentin Boyanov , Kyriakos Destounis , Rodrigo Panosso Macedo , Vitor Cardoso , José Luis Jaramillo

We report for the first time on triadic resonances in a rotating convection system. Using direct numerical simulations, we find that convective modes in a rotating spherical fluid can excite a pair of inertial modes whose frequencies and…

Fluid Dynamics · Physics 2020-12-30 Yufeng Lin

The asteroseismic analysis of stellar power density spectra is often computationally expensive. The models used in the analysis may use several dozen parameters to accurately describe features in the spectra caused by oscillation modes and…

Solar and Stellar Astrophysics · Physics 2023-08-23 M. B. Nielsen , G. R. Davies , W. J. Chaplin , W. H Ball , J. M. J. Ong , E. Hatt , B. P. Jones , M. Logue

We give insight into the critical problem of an open resonator that is subject to a perturbation outside of its cavity region. We utilize the framework of quasinormal modes (QNMs), which are the natural mode solutions to the open boundary…

Optics · Physics 2024-04-12 Sebastian Franke , Juanjuan Ren , Stephen Hughes

We analyze the passage to a continuum limit of the mode spectrum of primordial perturbations around flat cosmological spacetimes in Quantum Cosmology, showing that this limit can be reached even if one starts by considering a finite…

General Relativity and Quantum Cosmology · Physics 2021-11-04 Beatriz Elizaga Navascués , Guillermo A. Mena Marugán

We advocate a compressed sensing strategy that consists of multiplying the signal of interest by a wide bandwidth modulation before projection onto randomly selected vectors of an orthonormal basis. Firstly, in a digital setting with random…

Information Theory · Computer Science 2012-03-13 Gilles Puy , Pierre Vandergheynst , Rémi Gribonval , Yves Wiaux

Despite more and more observational data, stellar acoustic oscillation modes are not well understood as soon as rotation cannot be treated perturbatively. In a way similar to semiclassical theory in quantum physics, we use acoustic ray…

Solar and Stellar Astrophysics · Physics 2011-09-16 M. Pasek , B. Georgeot , F. Lignieres , D. R. Reese

The Baryon Acoustic Oscillations (BAO) are features in the matter power spectrum on scales of order 100-150 h^{-1} Mpc that promise to be a powerful tool to constrain and test cosmological models. The BAO have attracted such attention that…

Cosmology and Nongalactic Astrophysics · Physics 2014-01-14 Geraint Pratten , Dipak Munshi

Spherical confinement in 3D harmonic, quartic and other higher oscillators of even order is studied. The generalized pseudospectral method is employed for accurate solution of relevant Schr\"odinger equation in an \emph{optimum,…

Atomic Physics · Physics 2015-06-22 Amlan K. Roy

We revisit the problem of constraining steps in the inflationary potential with cosmological data. We argue that a step in the inflationary potential produces qualitatively similar oscillations in the primordial power spectrum,…

Astrophysics · Physics 2008-11-26 Jan Hamann , Laura Covi , Alessandro Melchiorri , Anze Slosar

In a previous paper [1] it was discussed the viability of functional analysis using as a basis a couple of generic functions, and hence vectorial decomposition. Here we complete the paradigm exploiting one of the analysis methodologies…

Numerical Analysis · Computer Science 2013-11-26 Sossio Vergara

Sonography techniques use multiple transducer elements for tissue visualization. Signals detected at each element are sampled prior to digital beamforming. The sampling rates required to perform high resolution digital beamforming are…

Information Theory · Computer Science 2013-07-25 Tanya Chernyakova , Yonina C. Eldar

Computationally efficient numerical methods for high-order approximations of convolution integrals involving weakly singular kernels find many practical applications including those in the development of fast quadrature methods for…

Numerical Analysis · Mathematics 2018-10-10 Akash Anand , Awanish Kumar Tiwari

Primordial magnetic fields lead to non-Gaussian signals in the cosmic microwave background (CMB) even at the lowest order, as magnetic stresses and the temperature anisotropy they induce depend quadratically on the magnetic field. In…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-17 Pranjal Trivedi , Kandaswamy Subramanian , T. R. Seshadri

(Abridged) High-order terms in the post-Newtonian (PN) expansions of various quantities for compact binaries exhibit a combinatorial increase in complexity, including ever-increasing numbers of transcendentals. Here we consider the…

General Relativity and Quantum Cosmology · Physics 2014-07-30 Nathan K. Johnson-McDaniel

We study cosmological tensor perturbations on a quantized background within the hybrid quantization approach. In particular, we consider a flat, homogeneous and isotropic spacetime and small tensor inhomogeneities on it. We truncate the…

General Relativity and Quantum Cosmology · Physics 2016-06-07 Florencia Benítez Martínez , Javier Olmedo

We demonstrate autoparametric excitation of two distinct sub-harmonic mechanical modes by the same driven mechanical mode corresponding to different drive frequencies within its resonance dispersion band. This experimental observation is…

Pattern Formation and Solitons · Physics 2017-10-11 Adarsh Ganesan , Cuong Do , Ashwin Seshia

The upcoming launch of the first space based X-ray polarimeter in $\sim 40$ years will provide powerful new diagnostic information to study accreting compact objects. In particular, analysis of rapid variability of the polarisation degree…

High Energy Astrophysical Phenomena · Physics 2017-08-30 Adam Ingram , Tom Maccarone