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We report a new strategy to remove the reflections resulted from the finite embedded transformation-optical design by proposing an impedance-tunable coordinate transformation, on which the functions of impedance coefficients can be derived…

Optics · Physics 2015-06-18 Jun Cao , Lifa Zhang , Senlin Yan , Xiaohan Sun

Radiative transfer in curved spacetimes has become increasingly important to understanding high-energy astrophysical phenomena and testing general relativity in the strong field limit. The equations of radiative transfer are physically…

Astrophysics · Physics 2009-11-13 Avery E. Broderick

Three thought experiments demonstrate that under certain circumstances electromagnetic fields have to be attenuated or amplified multiplicatively in order not to violate the conservation of energy. Modulation of radiation by means other…

Classical Physics · Physics 2016-11-14 Joerg Fricke

The widespread use of GPS devices has driven advances in spatiotemporal data mining, enabling machine learning models to simulate human decision making and generate realistic trajectories, addressing both data collection costs and privacy…

Machine Learning · Computer Science 2025-10-09 Zhiyang Zhang , Ningcong Chen , Xin Zhang , Yanhua Li , Shen Su , Hui Lu , Jun Luo

Spatial coordinate transformation is used as a reliable tool to control electromagnetic fields. In this paper, we derive the permeability and permittivity tensors of a metamaterial able to transform an isotropically radiating source into a…

Classical Physics · Physics 2009-06-03 Paul-Henri Tichit , Shah Nawaz Burokur , Andre de Lustrac

The emission spectrum of a dipole embedded in a semi-infinite photonic crystal is calculated. For simplicity we study the case in which the dielectric function is sinusoidally modulated only along the direction perpendicular to the boundary…

Condensed Matter · Physics 2009-10-31 A. G. Galstyan , M. E. Raikh , Z. V. Vardeny

While controlling particle diffusion in a confined geometry is a popular approach taken by both natural and artificial systems, it has not been widely adopted for controlling light transport in random media, where wave interference effects…

Optics · Physics 2016-01-06 Raktim Sarma , Alexey Yamilov , Seng Fatt Liew , Mikhael Guy , Hui Cao

This paper presents the general theory of canonical transformations of coordinates in quantum mechanics. First, the theory is developed in the formalism of phase space quantum mechanics. It is shown that by transforming a star-product, when…

Mathematical Physics · Physics 2015-06-11 Maciej Blaszak , Ziemowit Domanski

The Drexhage effect, caused by interference between a dipole and its image formed in a substrate, modifies the local density of optical states of quantum emitters which can either enhance or suppress their spontaneous emission rate…

Optics · Physics 2025-04-23 Sandeep Kumar Chamoli , Mohamed ElKabbash

One of the main applications of electromagnetic metasurfaces (MSs) is to tailor spatial field distributions. The radiation pattern of a given source can be desirably modified upon reflection on an MS having proper spatial modulation of its…

It has recently been shown theoretically that the time-dependent heat conduction equation is form-invariant under curvilinear coordinate transformations. Thus, in analogy to transformation optics, fictitious transformed space can be mapped…

Materials Science · Physics 2013-05-14 Robert Schittny , Muamer Kadic , Sebastien Guenneau , Martin Wegener

The atmospheres of planets (including Earth) and the outer layers of stars have often been treated in radiative transfer as plane-parallel media, instead of spherical shells, which can lead to inaccuracy, e.g. limb darkening. We give an…

Statistical Mechanics · Physics 2009-11-11 Michael J. Caola

4 emitters broadcasting an increasing electromagnetic signal generate a system of relativistic coordinates for the space-time, called emission coordinates. Their physical realization requires an apparatus similar to the one of the Global…

General Relativity and Quantum Cosmology · Physics 2016-08-16 José María Pozo

An extremely simple single-trace transmission example shows how an extended source formulation of full waveform inversion can produce an optimization problem without spurious local minima ("cycle skipping"). The data consist of a single…

Geophysics · Physics 2020-04-03 William W. Symes

Quantitative thermodynamical, dynamical and magnetic properties of the solar and stellar plasmas are obtained by interpreting their emergent non-polarized and polarized spectrum. This inference requires the selection of a set of spectral…

Solar and Stellar Astrophysics · Physics 2016-05-25 A. Asensio Ramos , J. de la Cruz Rodriguez , M. J. Martinez Gonzalez , A. Pastor Yabar

Limited-diffraction beams are a class of waves that may be localized in space and time. Theoretically, these beams are propagation invariant and can propagate to an infinite distance without spreading. In practice, when these beams are…

General Physics · Physics 2011-11-10 Jian-yu Lu

We propose and investigate an "interface-flattening" transformation, hinging upon Transformation Optics (T.O.) techniques, to facilitate the rigorous analysis of electromagnetic (EM) fields radiated by sources embedded in tilted,…

Computational Physics · Physics 2016-02-17 Kamalesh Sainath , Fernando L. Teixeira

In a recent article [A. Kurcz et al., Phys. Rev. A 81, 063821 (2010)] we predicted an energy concentrating mechanism in composite quantum systems. Its result is a non-zero stationary state photon emission rate even in the absence of…

Quantum Physics · Physics 2015-05-20 Almut Beige , Antonio Capolupo , Andreas Kurcz , Emilio Del Giudice , Giuseppe Vitiello

We show that a unified and maximally generalized approach to spatial transformation design is possible, one that encompasses all second order waves, rays, and diffusion processes in anisotropic media. Until the final step, it is unnecessary…

Classical Physics · Physics 2018-05-04 Paul Kinsler , Martin W. McCall

A perfectly collimated beam can be spread out by multiple scattering, creating a speckle pattern and increasing the etendue of the system. Standard optical systems conserve etendue, and thus are unable to reverse the process by transforming…

Optics · Physics 2021-07-23 Alba M. Paniagua-Diaz , William L. Barnes , Jacopo Bertolotti