1,776 research outputs found
Observations on interfacing loop quantum gravity with cosmology
Indexación: Web of Science; Scopus.A simple idea of relating the loop quantum gravity (LQG) and loop quantum cosmology (LQC) degrees of freedom is introduced and used to define a relatively robust interface between these theories in context of toroidal Bianchi I model. The idea is an expansion of the construction originally introduced by Ashtekar and Wilson-Ewing and relies on explicit averaging of a certain subclass of spin networks over the subgroup of the diffeomorphisms remaining after the gauge fixing used in homogeneous LQC. It is based on the set of clearly defined principles and thus is a convenient tool to control the emergence and behavior of the cosmological degrees of freedom in studies of dynamics in canonical LQG. The constructed interface is further adapted to isotropic spacetimes. Relating the proposed LQG-LQC interface with some results on black hole entropy suggests a modification to the area gap value currently used in LQC.https://journals.aps.org/prd/pdf/10.1103/PhysRevD.92.12402
Uniqueness of infrared asymptotics in Landau gauge Yang-Mills theory
We uniquely determine the infrared asymptotics of Green functions in Landau
gauge Yang-Mills theory. They have to satisfy both,
Dyson-Schwinger equations and functional renormalisation group equations.
Then, consistency fixes the relation between the infrared power laws of these
Green functions. We discuss consequences for the interpretation of recent
results from lattice QCD.Comment: 24 pages, 8 figure
Automating embedded analysis capabilities and managing software complexity in multiphysics simulation part I: template-based generic programming
An approach for incorporating embedded simulation and analysis capabilities
in complex simulation codes through template-based generic programming is
presented. This approach relies on templating and operator overloading within
the C++ language to transform a given calculation into one that can compute a
variety of additional quantities that are necessary for many state-of-the-art
simulation and analysis algorithms. An approach for incorporating these ideas
into complex simulation codes through general graph-based assembly is also
presented. These ideas have been implemented within a set of packages in the
Trilinos framework and are demonstrated on a simple problem from chemical
engineering
Benchmarking two-photon absorption with CC3 quadratic response theory, and comparison with density-functional response theory
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