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In about half of Seyfert galaxies, the X-ray emission is absorbed by an optically thin, ionized medium, the so-called "Warm Absorber", whose origin and location is still a matter of debate. The aims of this paper is to put more constraints…

The microwave absorption and noise caused by quantum two-level systems (TLS) dramatically suppress the coherence in Josephson junction qubits that are promising candidates for a quantum information applications. Microwave absorption by TLSs…

Mesoscale and Nanoscale Physics · Physics 2018-07-04 Alexander L. Burin , Andrii O. Maksymov

The far-infrared absorption of triangular and square two-dimensional quantum dots is studied by means of time simulations of the density oscillations within the time-dependent local-spin-density approximation. The absorption is spatially…

Mesoscale and Nanoscale Physics · Physics 2016-08-16 Manuel Valín-Rodríguez , Antonio Puente , Llorenç Serra

The properties of the Lyman-$\alpha$ absorptions observed in the spectra of QSOs are reviewed: the distribution of column densities and Doppler widths, the redshift evolution, the ``inverse effect'', the clustering. By interpreting the…

Astrophysics · Physics 2007-05-23 S. Cristiani

We realized and experimentally tested a conceptually new kind of electrically thin absorbers of electromagnetic waves. The idea is to utilize a single layer of precisely designed meta-atoms. This allows one to design an absorber with…

Soon after the first QSO was identified, Gunn & Peterson searched for the expected characteristic absorption trough on the blueward side of Lya in the spectrum of the QSO due to an Intergalactic Medium (IGM). They failed to find it, placing…

Astrophysics · Physics 2007-05-23 Yu Zhang , Avery Meiksin , Peter Anninos , Michael L. Norman

More than half of the volume of our Universe is occupied by cosmic voids. The lensing magnification effect from those under-dense regions is generally thought to give a small dimming contribution: objects on the far side of a void are…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-18 Krzysztof Bolejko , Chris Clarkson , Roy Maartens , David Bacon , Nikolai Meures , Emma Beynon

The necessary and sufficient condition for the absence of particle horizons in a big bang Friedmann-Robertson-Walker universe is provided. It happens to be a "smooth big bang" initial condition: the proper time derivative of the expansion…

General Relativity and Quantum Cosmology · Physics 2019-11-11 Carles Bona

Recently, inhomogeneous generalisations of the Friedmann-Lemaitre-Robertson-Walker cosmological models have gained interest in the astrophysical community and are more often employed to study cosmological phenomena. However, in many papers…

Cosmology and Nongalactic Astrophysics · Physics 2011-10-17 Krzysztof Bolejko , Marie-Noëlle Célérier , Andrzej Krasiński

The absorption feature in the global spectrum is likely the first 21 cm observable from the cosmic dawn, which provides valuable insights into the earliest history of structure formation. We run a set of high-resolution hydrodynamic…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-23 Yidong Xu , Bin Yue , Xuelei Chen

The equation for temporary evolution of spectral energy of collisionless Alfven waves is derived in framework of weak turbulence theory. The main nonlinear processes for such conditions are induced scattering and two quantum absorption of…

Astrophysics · Physics 2009-10-31 V. N. Zirakashvili

Absorption of light is directly associated with dissipative processes in a material. In suitably tailored resonators, a specific level of dissipation can support coherent perfect absorption, the time-reversed analogue of lasing, which…

Optics · Physics 2017-10-26 Denis G Baranov , Alex Krasnok , Andrea Alù

Here we embark on a thorough investigation of the magneto-optical absorption in semiconducting {\em spherical} quantum dots characterized by a confining harmonic potential and an applied magnetic field in the symmetric gauge. This is done…

Mesoscale and Nanoscale Physics · Physics 2016-04-13 Manvir S. Kushwaha

Epitaxially-grown quantum well and quantum dot solar cells suffer from weak light absorption, strongly limiting their performance. Light trapping based on optical resonances is particularly relevant for such devices to increase light…

Applied Physics · Physics 2023-11-10 Maxime Giteau , Yusuke Oteki , Kento Kitahara , Naoya Miyashita , Ryo Tamaki , Yoshitaka Okada

Since the first detection of gravitational waves in 2015, gravitational-wave astronomy has emerged as a rapidly advancing field that holds great potential for studying the cosmos, from probing the properties of black holes to testing the…

General Relativity and Quantum Cosmology · Physics 2023-05-17 Anna Liu , Isaac C. F. Wong , Samson H. W. Leong , Anupreeta More , Otto A. Hannuksela , Tjonnie G. F. Li

We consider the gravitational analogue of Lyman-alpha absorption lines in astronomical spectroscopy. If Einstein gravity with minimally coupled matter is valid up to the Planck scale, quantum bound states absorb gravitons of a specific…

High Energy Physics - Theory · Physics 2020-02-12 Andrea Palessandro , Martin S. Sloth

We introduce an absorption imaging technique for ultracold gases that suppresses interference fringes and coherence-induced artifacts by reducing the transverse spatial coherence of the imaging light. The method preserves the narrow…

Quantum Gases · Physics 2026-02-16 Julia Fekete , Poppy Joshi , Peter Krüger , Fedja Oručević

The effect of gravitational wave of cosmological wavelength on the gravitational lensing is investigated. When the source, deflector, and observer are aligned in a highly symmetric configuration, an Einstein ring will be observed by the…

General Relativity and Quantum Cosmology · Physics 2021-11-04 Wenshuai Liu

Wave-mechanical effects in gravitational lensing have long been predicted, and with the discovery of populations of compact transients such as gravitational wave events and fast radio bursts, may soon be observed. We present an observer's…

High Energy Astrophysical Phenomena · Physics 2023-04-04 Calvin Leung , Dylan Jow , Prasenjit Saha , Liang Dai , Masamune Oguri , Léon V. E. Koopmans

In a universe where, according to the standard cosmological models, some 97% of the total mass-energy is still "missing in action" it behooves us to spend at least a little effort critically assessing and exploring radical alternatives.…

General Relativity and Quantum Cosmology · Physics 2017-11-28 Matt Visser