Results 71 to 80 of about 45,346 (288)

Hidden Quantum Gravity in 3d Feynman diagrams

, 2006
In this work we show that 3d Feynman amplitudes of standard QFT in flat and homogeneous space can be naturally expressed as expectation values of a specific topological spin foam model.
Aristide Baratin, Baez J C, Baratin A, Barrett J W, Barrett J W Garcia-Islas J M Martins J F, Freidel L, Freidel L, Freidel L, Freidel L, Freidel L Livine E R, Freidel L Livine E R, Freidel L Louapre D, Freidel L Majid S, Freidel L Starodubtsev A, Laurent Freidel, Noui K, Oriti D, Perez A, Polyakov A M, Ponzano G, Regge T, Singer I M, Taylor Y U Woodward C T   +22 more
core   +1 more source

Spin foam models for quantum gravity [PDF]

Classical and Quantum Gravity, 2003
In this article we review the present status of the spin foam formulation of non-perturbative (background independent) quantum gravity. The article is divided in two parts. In the first part we present a general introduction to the main ideas emphasizing their motivations from various perspectives.
openaire   +3 more sources

Coarse graining methods for spin net and spin foam models [PDF]

New Journal of Physics, 2012
We undertake first steps in making a class of discrete models of quantum gravity, spin foams, accessible to a large scale analysis by numerical and computational methods. In particular, we apply Migdal-Kadanoff and Tensor Network Renormalization schemes to spin net and spin foam models based on finite Abelian groups and introduce `cutoff models' to ...
Dittrich, B., Eckert, F., Martin-Benito, M.   +2 more
openaire   +5 more sources

Flexible Leaf‐Like Fuel Cell From Plasmonic Janus Nanosheet

Advanced Functional Materials, EarlyView.
A flexible leaf‐like fuel cell is fabricated by conductive gold nanowire sponge‐supported plasmonic Janus nanosheet, which can generate a power of 8.93 mW cm⁻2 with less than 10% performance deterioration even being bent or twisted. Further assembly in a tree‐like layout demonstrates omnidirectional light harvesting capability and wind resistance ...
Yifeng Huang, Qianqian Shi, Siyuan Liu, Wenlong Cheng   +3 more
wiley   +1 more source

Decorated tensor network renormalization for lattice gauge theories and spin foam models

New Journal of Physics, 2016
Tensor network techniques have proved to be powerful tools that can be employed to explore the large scale dynamics of lattice systems. Nonetheless, the redundancy of degrees of freedom in lattice gauge theories (and related models) poses a challenge for
Bianca Dittrich, Sebastian Mizera, Sebastian Steinhaus   +2 more
doaj   +1 more source

Gravity as BF theory plus potential

, 2009
Spin foam models of quantum gravity are based on Plebanski's formulation of general relativity as a constrained BF theory. We give an alternative formulation of gravity as BF theory plus a certain potential term for the B-field.
Krasnov, Kirill
core   +1 more source

MEASUREMENTS AND INFORMATION IN SPIN FOAM MODELS [PDF]

International Journal of Modern Physics A, 2012
In the three-dimensional spin foam model of quantum gravity with a cosmological constant, there exists a set of observables associated with spin network graphs. A set of probabilities is calculated from these observables, and hence the associated Shannon entropy can be defined.
openaire   +3 more sources

Structured, Shaped, or Printed Single‐Atom Catalysts and Their Applications

Advanced Functional Materials, EarlyView.
This paper reviews the design and use of structured single‐atom catalysts, which integrate porous architectures with the exceptional reactivity of isolated catalytic sites. It explores fabrication strategies, advanced characterization methods, and support materials that enhance thermal stability, mechanical robustness, and operational efficiency of ...
Jiachengjun Luo, Hushan Chand, Rafael Luque, Alina M. Balu, Gianvito Vilé   +4 more
wiley   +1 more source

Loop quantum cosmology and spin foams

Physics Letters B, 2009
Loop quantum cosmology (LQC) is used to provide concrete evidence in support of the general paradigm underlying spin foam models (SFMs). Specifically, it is shown that: i) the physical inner product in the timeless framework equals the transition amplitude in the deparameterized theory; ii) this quantity admits a %convergent vertex expansion a la SFMs ...
Miguel Campiglia, Abhay Ashtekar, Adam Henderson   +2 more
openaire   +3 more sources

Intraoral Drug Delivery: Bridging the Gap Between Academic Research and Industrial Innovations

Advanced Functional Materials, EarlyView.
Intraoral drug delivery offers a promising route for systemic and localized therapies, yet challenges such as enzymatic degradation, limited permeability, and microbial interactions hinder efficacy. This figure highlights innovative strategies—mucoadhesive materials, enzyme inhibitors, and permeation enhancers—to overcome these barriers.
Soheil Haddadzadegan, Simona Summonte, Fabrizio Ricci, Matthias Sandmeier, Andreas Bernkop‐Schnürch   +4 more
wiley   +1 more source