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Related papers: Possible polarisation and spin dependent aspects o…

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Spatially nonhomogeneously spin polarized nuclei are proposed as a new mechanism to monitor electron states in a nanostructure, or as a means to createn and, if necessary, reshape such nanostructures in the course of the experiment. We…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 V. Fleurov , V. A. Ivanov , F. M. Peeters , I. D. Vagner

New covariant theories of emergent modified gravity exist not only in spherically symmetric models, as previously found, but also in polarized Gowdy systems that have a local propagating degree of freedom. Several explicit versions are…

General Relativity and Quantum Cosmology · Physics 2024-12-04 Martin Bojowald , Erick I. Duque

The questions of describing observables and observation in quantum gravity appear to be centrally important to its physics. A relational approach holds significant promise, and a classification of different types of relational observables…

High Energy Physics - Theory · Physics 2025-06-13 Steven B. Giddings

Inhomogeneities are introduced in loop quantum cosmology using regular lattice states, with a kinematical arena similar to that in homogeneous models considered earlier. The framework is intended to encapsulate crucial features of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Martin Bojowald

We propose a new polymerization scheme for scalar fields coupled to gravity. It has the advantage of being a (non-bijective) canonical transformation of the fields and therefore ensures the covariance of the theory. We study it in detail in…

General Relativity and Quantum Cosmology · Physics 2022-10-11 Florencia Benítez , Rodolfo Gambini , Jorge Pullin

We present a line by line derivation of canonical quantum mechanics stemming from the compatibility of the statistical geometry of distinguishable observations with the canonical Poisson structure of Hamiltonian dynamics. This viewpoint can…

High Energy Physics - Theory · Physics 2017-08-23 Djordje Minic , Chia-Hsiung Tze

I shall discuss some "conditions of possibility" of a quantum theory of gravity, stressing the need for solutions to some of fundamental problems confronting any attempt to apply some method of quantization to the field equations of general…

General Relativity and Quantum Cosmology · Physics 2007-05-23 John Stachel

The covariance of loop quantum gravity studies of spherically symmetric space-times has recently been questioned. This is a reasonable worry, given that they are formulated in terms of slicing-dependent variables. We show explicitly that…

General Relativity and Quantum Cosmology · Physics 2022-02-21 Rodolfo Gambini , Javier Olmedo , Jorge Pullin

We construct perturbative quantum gravity in a generally covariant way. In particular our construction is background independent. It is based on the locally covariant approach to quantum field theory and the renormalized Batalin-Vilkovisky…

Mathematical Physics · Physics 2015-11-30 Romeo Brunetti , Klaus Fredenhagen , Katarzyna Rejzner

Quantum gravity places important consistency conditions on low-energy effective field theory, such as the absence of global symmetries. These may have important consequences in the search for particle physics beyond the Standard Model. We…

High Energy Physics - Phenomenology · Physics 2022-03-16 Patrick Draper , Isabel Garcia Garcia , Matthew Reece

The representation theory of non-centrally extended Lie algebras of Noether symmetries, including spacetime diffeomorphisms and reparametrizations of the observer's trajectory, has recently been developped. It naturally solves some…

General Relativity and Quantum Cosmology · Physics 2007-05-23 T. A. Larsson

We investigate a quantum geometric space in the context of what could be considered an emerging effective theory from Quantum Gravity. Specifically we consider a two-parameter class of twisted Poincar\'e algebras, from which Lie-algebraic…

Mathematical Physics · Physics 2017-05-26 Cesar A. Aguillón , Albert Much , Marcos Rosenbaum , J. David Vergara

Loop quantum gravity in its Hamiltonian form relies on a connection formulation of the gravitational phase space with three key properties: 1.) a compact gauge group, 2.) real variables, and 3.) canonical Poisson brackets. In conjunction,…

General Relativity and Quantum Cosmology · Physics 2024-12-09 Norbert Bodendorfer , Konstantin Eder , Xiangdong Zhang

We consider the implications of some simple assumptions about the nature of the quantum theory of gravity which are plausible for a class of possible theories I have been attempting to construct. The simple assumptions turn out to have…

High Energy Physics - Theory · Physics 2007-05-23 Louis Crane

Contrary to the expected behavior, we show the existence of non-invertible deformations of Lie algebras which can generate invariants for the coadjoint representation, as well as delete cohomology with values in the trivial or adjoint…

High Energy Physics - Theory · Physics 2008-11-26 R. Campoamor-Stursberg

After a brief introduction, basic ideas of the quantum Riemannian geometry underlying loop quantum gravity are summarized. To illustrate physical ramifications of quantum geometry, the framework is then applied to homogeneous isotropic…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Abhay Ashtekar

Various theories of spinning particles are interpreted as realizing elements of an underlying geometric theory. Classical particles are described by trajectories on the Poincare group. Upon quantization an eleven-dimensional Kaluza-Klein…

Quantum Physics · Physics 2007-05-23 Ludger Hannibal

It is generally believed that a full-fledged theory of quantum gravity should exhibit background independence and diffeomorphism invariance. In its most general form, the latter comprises field redefinitions, which are diffeomorphisms in…

High Energy Physics - Theory · Physics 2023-01-25 Roberto Casadio , Alexander Kamenshchik , Iberê Kuntz

Homogeneous time-dependent solutions of massive gravity generalise the plane wave solutions of the linearised Fierz-Pauli equations for a massive spin-two particle, as well as the Kasner solutions of General Relativity. We show that they…

High Energy Physics - Theory · Physics 2015-06-17 J. Mourad , D. A. Steer

The spin supplementary conditions are constraints on spin degrees of freedom in classical relativity which restricts physical degrees of freedom to rotations. It is argued that the equivalent constraints in quantum field theory are the…

High Energy Physics - Theory · Physics 2023-07-11 Jung-Wook Kim , Jan Steinhoff