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Related papers: Oscillations in the Primordial Bispectrum: Mode Ex…

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Fourier series multiscale method, a concise and efficient analytical approach for multiscale computation, will be developed out of this series of papers. In the seventh paper, the usual structural analysis of beams on an elastic foundation…

Numerical Analysis · Mathematics 2023-01-04 Weiming Sun , Zimao Zhang

Normal-mode oscillation frequencies computed from stellar models differ from those which would be measured from stars with identical interior structures, because of modelling errors in the near-surface layers. These frequency differences…

Solar and Stellar Astrophysics · Physics 2021-10-20 J. M. Joel Ong , Sarbani Basu , Ian W. Roxburgh

We explore the use of galaxy bispectra with multitracer technique as a possible probe of primordial non-Gaussianities. We forecast future constraints on non-linearity parameters, $f_{\rm NL}^{\rm eq}$ and $f_{\rm NL}^{\rm orth}$, which…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-12 Daisuke Yamauchi , Shuichiro Yokoyama , Keitaro Takahashi

Primordial gravitational waves could be non-Gaussian, just like primordial scalar perturbations. Although the tensor two-point function has thus-far remained elusive, the three-point function could, in principle, be large enough to be…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-14 Oliver H. E. Philcox , Maresuke Shiraishi

Primordial oscillatory features in the power spectrum of curvature perturbations are sensitive probes of the dynamics of the early Universe and can provide insights beyond the standard inflationary scenario. While these features have been…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-09 Mario Ballardini , Nicola Barbieri

This paper proposes a novel, rigorous and simple Fourier-transformation approach to study resonances in a perfectly conducting slab with finite number of subwavelength slits of width $h\ll 1$. Since regions outside the slits are variable…

Numerical Analysis · Mathematics 2020-12-29 Jiaxin Zhou , Wangtao Lu

Universal conductance fluctuations are usually observed in the form of aperiodic oscillations in the magnetoresistance of thin wires as a function of the magnetic field B. If such oscillations are completely random at scales exceeding…

Disordered Systems and Neural Networks · Physics 2021-12-28 I. M. Suslov

It is shown that there exists a possibility of amplification of amplitudes of quantum pion modes with low momenta in the late time of chiral phase transition by using the Gaussian wave functional approximation in the O(4) linear sigma…

High Energy Physics - Phenomenology · Physics 2009-11-10 K. Watanabe , Y. Tsue , S. Nishiyama

We explore the use of the bispectrum for understanding quasiperiodic oscillations. The bispectrum is a statistic which probes the relations between the relative phases of the Fourier spectrum at different frequencies. The use of the…

High Energy Astrophysical Phenomena · Physics 2015-05-27 Thomas J. Maccarone , Philip Uttley , Michiel van der Klis , Rudy Wijnands , Paolo S. Coppi

There is a class of physical filtration processes where the input is adequately modeled by a continuous periodic function f (x) of bounded variation over its period, and the output depends only on certain harmonics of the Fourier expansion…

General Mathematics · Mathematics 2024-12-17 Vladimir Sluchak

The classical Fourier analysis of a time signal, in the discrete sense, provides the frequency content of signal under the assumption of periodicity. Although the original signal can be exactly recovered using an inverse transform, the time…

Fluid Dynamics · Physics 2026-01-06 Vilas J. Shinde

We calculate the bispectrum, B_g(k_1,k_2,k_3), Fourier transform of the three-point function of density peaks (e.g., galaxies), using two different methods: the Matarrese-Lucchin-Bonometto formula and the locality of galaxy bias. The…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-28 Donghui Jeong , Eiichiro Komatsu

We study the magnetospheric activity in the polar cap region of pulsars under stellar oscillations. The toroidal oscillation of the star propagates into the magnetosphere, which provides additional voltage due to unipolar induction, changes…

High Energy Astrophysical Phenomena · Physics 2015-01-27 Meng-Xiang Lin , Ren-Xin Xu , Bing Zhang

A small deviation from scale invariance in the form of oscillations in the primordial correlation spectra has been predicted by various cosmological models. In this paper we review a recently developed method to search for these features in…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-22 P. Daniel Meerburg , David N. Spergel , Benjamin D. Wandelt

Firstly, bilinear Fourier Restriction estimates --which are well-known for free waves-- are extended to adapted spaces of functions of bounded quadratic variation, under quantitative assumptions on the phase functions. This has applications…

Analysis of PDEs · Mathematics 2018-04-12 Timothy Candy , Sebastian Herr

Frequency dependence of pulsar linear polarization is investigated by simulations of emission and propagation processes. Linearly polarized waves are generated through curvature radiation by relativistic particles streaming along curved…

High Energy Astrophysical Phenomena · Physics 2015-06-23 P. F. Wang , C. Wang , J. L. Han

If time-dependent disruptions from slow-roll occur during inflation, the correlation functions of the primordial curvature perturbation should have scale-dependent features, a case which is marginally supported from the cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-04 Jinn-Ouk Gong , Gonzalo A. Palma , Spyros Sypsas

We introduce a quasinormal mode theory of mechanical open-cavity modes for optomechanical resonators, and demonstrate the importance of using a generalized (complex) effective mode volume and the phase of the quasinormal mode. We first…

Optics · Physics 2020-12-16 Al-Waleed El-Sayed , Stephen Hughes

This paper aims to study existence condition of possible bursting oscillations generated by low frequency excitation of a nonlinear vibratory system in the presence of parametric excitation. Slow-fast dissection technique and numerical…

Dynamical Systems · Mathematics 2025-07-22 Sobhan Mohammadi , Keegan J. Moore

The pseudo-spectral method is proposed for following the evolution of density and velocity fluctuations at the weakly non-linear stage in the expanding universe with a good accuracy. In this method, the evolution of density and velocity…

Astrophysics · Physics 2017-02-01 Naoteru Gouda