Results 111 to 120 of about 52,296 (249)

Christian Bohr. Discoverer of Homotropic and Heterotopic Allostery

Acta Physiologica, Volume 241, Issue S734, July 2025.
ABSTRACT This essay recounts and revisits the scientific contributions of Christian Bohr, highlighting his pivotal role in discovering allostery about 120 years ago. Bohr's meticulous experimentation led to identifying two distinct forms of allostery: homotropic (single‐ligand) and heterotropic (multi‐ligand), the latter widely recognized as the Bohr ...
Niels Bindslev
wiley   +1 more source

Loop Quantum Cosmology

Living Reviews in Relativity, 2005
Quantum gravity is expected to be necessary in order to understand situations where classical general relativity breaks down. In particular in cosmology one has to deal with initial singularities, i.e., the fact that the backward evolution of a classical
Bojowald Martin
doaj  

Emergent Horizons in the Laboratory

, 2010
The concept of a horizon known from general relativity describes the loss of causal connection and can be applied to non-gravitational scenarios such as out-of-equilibrium condensed-matter systems in the laboratory.
Barcelo C, Barcelo C, Barceló C, Birrell N D, Fulling S A, Gullstrand A, Lemaître G, Misner C M, Painlevé P, Queisser F, Ralf Schützhold, Retzker A Cirac J I Plenio M B Reznik B, Schützhold R, Schützhold R Uhlmann M, Uhlmann M, Volovik G E   +15 more
core   +1 more source

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, Wen Xiao, Minyong Guo, Tong Liu, Huanyang Chen, Jin‐Hui Chen   +5 more
wiley   +1 more source

Granice fizyki w kosmologii

Zagadnienia Filozoficzne w Nauce, 2015
The message is that physics has an „outward bound” of scientific inquiry in the field of cosmology. I present it in the historical development. Physics and astronomy, developing since the seventeenth century, inherited from the early Greek philosophers ...
Leszek M. Sokołowski
doaj  

Bogolyubov Quasiparticles in Constrained Systems

, 1999
The paper is devoted to the formulation of quantum field theory for an early universe in General Relativity considered as the Dirac general constrained system.
Bogoliubov N N, Chernikov N A, Dirac P A M, Dirac P A M, Faddeev L D, Grib A A, Gyngazov L N, Henneaux M, Hoyle F, Kodama H, Kuchar K, Lichnerowicz A, Maxwell J C, Narlikar J V, Penrose R, Pervushin V N, Pervushin V N, Review of particle physics Olive K A, V I Smirichinski, V N Pervushin, Vladimirov Yu S, Weyl H, Zel'dovich Ya B, Zelmanov A L, Zelmanov A L   +24 more
core   +2 more sources

Asymptotic Expansions Relating to the Distribution of the Product of Correlated Normal Random Variables

Studies in Applied Mathematics, Volume 154, Issue 6, June 2025.
ABSTRACT Asymptotic expansions are derived for the tail distribution of the product of two correlated normal random variables with nonzero means and arbitrary variances, and more generally the sum of independent copies of such random variables. Asymptotic approximations are also given for the quantile function.
Robert E. Gaunt, Zixin Ye
wiley   +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, Juanna Jiang, Jiafu Wang, Xuezhi Zheng   +3 more
wiley   +1 more source

Unitary evolution and cosmic acceleration in Loop Quantum Cosmology

Physics Letters B
Loop quantum cosmology was shown to interpolate between de Sitter and FLRW Universe phases through a bounce by including Euclidean and Lorentzian terms of the Hamiltonian constraint with weight one -that corresponding to classical General Relativity ...
Omar Gallegos, Tonatiuh Matos, Hugo A. Morales-Técotl   +2 more
doaj   +1 more source

Relational Motivation for Conformal Operator Ordering in Quantum Cosmology

, 2009
Operator-ordering in quantum cosmology is a major as-yet unsettled ambiguity with not only formal but also physical consequences. We determine the Lagrangian origin of the conformal invariance that underlies the conformal operator-ordering choice in ...
Anderson, Edward
core   +1 more source