Results 111 to 120 of about 178,240 (316)

Towards a spin foam model description of black hole entropy

, 2008
We propose a way to describe the origin of black hole entropy in the spin foam models of quantum gravity. This stimulates a new way to study the relation of spin foam models and loop quantum gravity.Comment: 5 pages, 1 ...
Corichi A, Domagala M, Freidel L, J Manuel García-Islas, Kloster S, Manuel Garcia-Islas J, Tamaki T, Tanaka T Tamaki T   +7 more
core   +1 more source

Robust Reinforcement Learning Control Framework for a Quadrotor Unmanned Aerial Vehicle Using Critic Neural Network

Advanced Intelligent Systems, Volume 7, Issue 3, March 2025.
Quadrotor unmanned aerial vehicle control is critical to maintain flight safety and efficiency, especially when facing external disturbances and model uncertainties. This article presents a robust reinforcement learning control scheme to deal with these challenges.
Yu Cai, Yefeng Yang, Tao Huang, Boyang Li   +3 more
wiley   +1 more source

Gravitational action for a massive Majorana fermion in 2d quantum gravity

Journal of High Energy Physics
We compute the gravitational action of a free massive Majorana fermion coupled to two-dimensional gravity on compact Riemann surfaces of arbitrary genus. The structure is similar to the case of the massive scalar.
Corinne de Lacroix, Harold Erbin, Vincent Lahoche   +2 more
doaj   +1 more source

Quantum gravity fluctuations in the timelike Raychaudhuri equation

Journal of High Energy Physics, 2023
We consider a timelike geodesic congruence in the presence of perturbative quantum fluctuations of the spacetime metric. We calculate the change in the volume of a bundle of geodesics due to such fluctuations and thereby obtain a quantum-gravitationally ...
Sang-Eon Bak, Maulik Parikh, Sudipta Sarkar, Francesco Setti   +3 more
doaj   +1 more source

Generalised Wick Transform in Dimensionally Reduced Gravity

, 2003
In the context of canonical quantum gravity, we study an alternative real quantisation scheme, which is arising by relating simpler Riemannian quantum theory to the more complicated physical Lorentzian theory - the generalised Wick transform.
Ashtekar A, Ashtekar A, Ashtekar A, Barbero G J F, Bruno Hartmann, Ezawa K, Hartmann B, Jacek Wi niewski, Louko J, Nakahara M, Romano J D, Rovelli C, Thiemann T, Wi?niewski J   +13 more
core   +1 more source

Quantum Gravity and Causal Structures: Second Quantization of Conformal Dirac Algebras [PDF]

, 2015
It is postulated that quantum gravity is a sum over causal structures coupled to matter via scale evolution. Quantized causal structures can be described by studying simple matrix models where matrices are replaced by an algebra of quantum mechanical ...
Bonezzi, R., Corradini, O., Latini, E., Waldron, A.   +3 more
core   +2 more sources

Consistency of matter models with asymptotically safe quantum gravity [PDF]

, 2014
We discuss the compatibility of quantum gravity with dynamical matter degrees of freedom. Specifically, we present bounds we obtained in [1] on the allowed number and type of matter fields within asymptotically safe quantum gravity. As a novel result, we
P. Donà, A. Eichhorn, R. Percacci
semanticscholar   +1 more source

Sound‐Based Assembly of Magnetically Actuated Soft Robots Toward Enhanced Release of Extracellular Vesicles

Advanced Intelligent Systems, Volume 7, Issue 3, March 2025.
Magnetic soft robots offer promise in biomedicine due to their wireless actuation and rapid response, but current fabrication methods are complex and have limited cellular compatibility. A new, contactless bioassembly strategy using hydrodynamic instabilities is introduced, enabling customizable, centimeter‐scale robots.
Wei Gao, Riccardo Tognato, Micaela Natta, Elena Della Bella, Alessandro Cianciosi, Tiziano Serra   +5 more
wiley   +1 more source

Tree-level scattering amplitudes in nonlocal field theories

Journal of High Energy Physics, 2021
We prove in two ways that, for a special class of nonlocal field theories consistent with linear and non-linear stability at the classical level, and with unitarity and super-renormalizability or finiteness at the quantum level, the n-point tree-level ...
Leonardo Modesto, Gianluca Calcagni
doaj   +1 more source

Noncomputability arising in dynamical triangulation model of four-dimensional Quantum Gravity [PDF]

Communications in Mathematical Physics, 1993
Computations in Dynamical Triangulation Models of Four-Dimensional Quantum Gravity involve weighted averaging over sets of all distinct triangulations of compact four-dimensional manifolds. In order to be able to perform such computations one needs an algorithm which for any given $N$ and a given compact four-dimensional manifold $M$ constructs all ...
Nabutovsky, A., Ben-Av, R.
openaire   +3 more sources