Results 11 to 20 of about 1,109,861 (332)
Four-Dimensional Spin Foam Perturbation Theory [PDF]
Symmetry, Integrability and Geometry: Methods and Applications, 2011 We define a four-dimensional spin-foam perturbation theory for the BF-theory with a B∧B potential term defined for a compact semi-simple Lie group G on a compact orientable 4-manifold M.
João Faria Martins, Aleksandar Mikovic
doaj +7 more sources
Spin foams and noncommutative geometry [PDF]
Classical and Quantum Gravity, 2010 We extend the formalism of embedded spin networks and spin foams to include topological data that encode the underlying three-manifold or four-manifold as a branched cover.
Domenic Denicola +2 more
core +8 more sources
Positivity of spin foam amplitudes [PDF]
Classical and Quantum Gravity, 2002 The amplitude for a spin foam in the Barrett-Crane model of Riemannian quantum gravity is given as a product over its vertices, edges and faces, with one factor of the Riemannian 10j symbols appearing for each vertex, and simpler factors for the edges ...
John C. Baez, J. Daniel Christensen
core +8 more sources
Feynman Propagator for Spin Foam Quantum Gravity [PDF]
Physical Review Letters, 2005 We link the notion causality with the orientation of the 2-complex on which spin foam models are based. We show that all current spin foam models are orientation-independent, pointing out the mathematical structure behind this independence.
Daniele Oriti
core +6 more sources
Operator Spin Foam Models [PDF]
Classical and Quantum Gravity, 2010 The goal of this paper is to introduce a systematic approach to spin foams. We define operator spin foams, that is foams labelled by group representations and operators, as the main tool.
Alesci E Bianchi E Magliaro E Perini C +33 more
core +5 more sources
Elucidating the Chirality-Induced Spin Selectivity Effect of Co-Doped NiO Deposited on Ni Foam for Highly Stable Zn-Air Batteries. [PDF]
ACS Appl Mater InterfacesThe urgent need to alleviate global warming and limit the consumption of fossil fuels has prompted the development of rechargeable Zn–air batteries (ZABs) considering their superior energy density, safety, and cost-effectiveness.
Park YS +13 more
europepmc +2 more sources
Spin Foam Vertex Amplitudes on Quantum Computer—Preliminary Results [PDF]
Universe, 2019 Vertex amplitudes are elementary contributions to the transition amplitudes in the spin foam models of quantum gravity. The purpose of this article is to make the first step towards computing vertex amplitudes with the use of quantum algorithms.
Jakub Mielczarek
doaj +2 more sources
Group field theories for all loop quantum gravity
New Journal of Physics, 2015 Group field theories represent a second quantized reformulation of the loop quantum gravity state space and a completion of the spin foam formalism. States of the canonical theory, in the traditional continuum setting, have support on graphs of arbitrary
Daniele Oriti +2 more
doaj +2 more sources
Causal Structure in Spin Foams
UniverseThe metric field of general relativity is almost fully determined by its causal structure. Yet, in spin foam models of quantum gravity, the role played by the causal structure is still largely unexplored.
Eugenio Bianchi, Pierre Martin-Dussaud
doaj +3 more sources
A new 2+1 coherent spin-foam vertex for quantum gravity [PDF]
Classical and quantum gravityWe propose an explicit spin-foam amplitude for Lorentzian gravity in three dimensions, allowing for both space- and time-like boundaries. The model is based on two main requirements: that it should be structurally similar to its well-known Euclidean ...
José Diogo de Figueiredo e Simão
semanticscholar +2 more sources