Results 151 to 160 of about 77,468 (282)
Mimicking Symmetry‐Breaking Einstein Ring by Optical Lens
Advanced Photonics Research, Volume 6, Issue 6, June 2025.This article uses an optical lens to emulate the gravitational lensing effect and observe the Einstein ring (ER) patterns. The symmetry‐breaking ER, i.e., Einstein cross, is observed utilizing a rotation‐symmetry‐breaking hemi‐ellipsoid lens. Deformed Einstein cross patterns induced by noncollinearly alignment of the light source–lens–observer are ...
Jun‐Liang Duan +5 more
wiley +1 more source
Properties of Fluctuating States in Loop Quantum Cosmology
Mathematics, 2019 In loop quantum cosmology, the values of volume fluctuations and correlations determine whether the dynamics of an evolving state exhibits a bounce. Of particular interest are states that are supported only on either the positive or the negative part of ...
Martin Bojowald
doaj +1 more source
Non-Gaussian features from the inverse volume corrections in loop quantum cosmology
, 2012 In this paper we study the non-Gaussian features of the primordial fluctuations in loop quantum cosmology with the inverse volume corrections. The detailed analysis is performed in the single field slow-roll inflationary models.
A. Ashtekar +7 more
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Report on the session Loop Quantum Gravity: Cosmology and Black Holes of\n the 16th Marcel Grossmann Meeting [PDF]
, 2021 Jorge Pullin, Parampreet Singh
openalex +1 more source
Singular Electromagnetics: From Phase Singularities to Optical Skyrmions and Beyond
Advanced Physics Research, Volume 4, Issue 5, May 2025.Singular electromagnetics/optics studies multidimensional topological defects of electromagnetic fields (also known as optical singularities), including phase and polarization singularities, 3D singularities (e.g., optical skyrmions, merons, hopfions, knots, links, and Möbius strips), and even higher‐dimensional singularities.
Jie Yang +3 more
wiley +1 more source
Uniqueness of measures in loop quantum cosmology [PDF]
Journal of Mathematical Physics, 2015 In Ashtekar and Campiglia [Classical Quantum Gravity 29, 242001 (2012)], residual diffeomorphisms have been used to single out the standard representation of the reduced holonomy-flux algebra in homogeneous loop quantum cosmology (LQC). We show that, in the homogeneous isotropic case, unitarity of the translations with respect to the extended ℝ-action (
openaire +2 more sources
Spin-foam model for gravity coupled to massless scalar field
, 2018 A spin-foam model is derived from the canonical model of Loop Quantum Gravity coupled to a massless scalar field. We generalized to the full theory the scheme first proposed in the context of Loop Quantum Cosmology by Ashtekar, Campiglia and Henderson ...
Kisielowski, Marcin, Lewandowski, Jerzy
core +1 more source
Dynamical coherent states and physical solutions of quantum cosmological bounces
, 2007 A new model is studied which describes the quantum behavior of transitions through an isotropic quantum cosmological bounce in loop quantum cosmology sourced by a free and massless scalar field.
A. Ashtekar +7 more
core +1 more source
Universe, 2018 The understanding of black holes in loop quantum gravity is becoming increasingly accurate. This review focuses on the possible experimental or observational consequences of the underlying spinfoam structure of space-time.
Aurélien Barrau +2 more
doaj +1 more source
Some conceptual issues in loop quantum cosmology
, 2016 Loop quantum gravity is a mature theory. To proceed to explicit calculations in cosmology, it is necessary to make assumptions and simplifications based on the symmetries of the cosmological setting. Symmetry reduction is especially critical when dealing
Barrau, Aurélien, Bolliet, Boris
core +3 more sources