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Related papers: Fermions in Quantum Gravity

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The gapless fermionic excitations in superfluid 3He-A have the "relativistic" spectrum close to the gap nodes. This allowed us to model the modern cosmological scenaria of baryogenesis and magnetogenesis. The same massless fermions induce…

Condensed Matter · Physics 2009-09-25 G. E. Volovik

We argue that two-dimensional dilaton gravity models can all be derived from an analog of Jacobson's covariant version of the first law of thermodynamics. We then specialize to the JT gravity model and couple it to massless fermions. This…

High Energy Physics - Theory · Physics 2022-05-17 Tom Banks , Patrick Draper , Bingnan Zhang

The main principle of affine quantum gravity is the strict positivity of the matrix \{\hat g_{ab}(x)\} composed of the spatial components of the local metric operator. Canonical commutation relations are incompatible with this principle,…

General Relativity and Quantum Cosmology · Physics 2010-03-15 John R. Klauder

Quantum gravity corrections to the behavior of matter, such as Higgs bosons and fermions, are notoriously difficult to calculate. The standard tools of quantum field theory often break down, producing infinite results that spoil our…

General Physics · Physics 2025-09-22 Sebastián Alí Sacasa-Céspedes

We study the cosmology of a quadratic metric-compatible torsionful gravity theory in the presence of a perfect hyperfluid. The gravitational action is an extension of the Einstein-Cartan theory given by the usual Einstein-Hilbert…

General Relativity and Quantum Cosmology · Physics 2021-10-07 Damianos Iosifidis , Lucrezia Ravera

Loop Quantum Gravity faces challenges in constructing a well-defined Hamiltonian constraint and understanding the quantum notion of time. In this paper these issues are studied by quantizing the $U(1)^3$ model, a simplified system…

General Relativity and Quantum Cosmology · Physics 2024-12-02 Sepideh Bakhoda , Yongge Ma

Fermion fields are fundamental for the description of nature and also fit very naturally into the framework of loop quantum gravity. Motivated partially by proposals to use gravitationally mediated entanglement of matter as a witness for…

General Relativity and Quantum Cosmology · Physics 2025-08-07 Hanno Sahlmann , Martin Zeiß

Fermions on a cylinder coupled to gravity and gauge fields are examined by studying the geometric action associated with the symmetries of such a system. The gauge coupling constant is shown to be constrained and the effect of gravity on…

High Energy Physics - Theory · Physics 2009-10-28 R. P. Lano , V. G. J. Rodgers

We study perturbative noncommutative quantum gravity by expanding the gravitational field about a fixed classical background. A calculation of the one loop gravitational self-energy graph reveals that only the non-planar graviton loops are…

High Energy Physics - Theory · Physics 2009-10-31 J. W. Moffat

We present a detailed Hamiltonian treatment of an inhomogeneous fermionic perturbation propagating on a closed FLRW spacetime quantized via LQC. Expanding the fermion in spinor harmonics on spatial 3-sphere and truncating at quadratic…

General Relativity and Quantum Cosmology · Physics 2025-10-02 Yaser Tavakoli , Ahad K. Ardabili , Sara Mosaddegh

A new symmetric Hamiltonian constraint operator is proposed for loop quantum gravity, which is well defined in the Hilbert space of diffeomorphism invariant states up to non-planar vertices with valence higher than three. It inherits the…

General Relativity and Quantum Cosmology · Physics 2015-12-04 Jinsong Yang , Yongge Ma

Using the Cartan formulation of General Relativity, we construct a well defined lattice-regularized theory capable to describe large non-perturbative quantum fluctuations of the frame field (or the metric) and of the spin connection. To…

High Energy Physics - Theory · Physics 2011-09-02 Dmitri Diakonov

The problem of finding the quantum theory of the gravitational field, and thus understanding what is quantum spacetime, is still open. One of the most active of the current approaches is loop quantum gravity. Loop quantum gravity is a…

General Relativity and Quantum Cosmology · Physics 2016-10-19 Carlo Rovelli

There must exist a reformulation of quantum field theory which does not refer to classical time. We propose a pre-quantum, pre-spacetime theory, which is a matrix-valued Lagrangian dynamics for gravity, Yang-Mills fields, and fermions. The…

General Physics · Physics 2022-02-16 Tejinder P. Singh

We apply the method of flow equations to describe quantum systems subject to a time-periodic drive with a time-dependent envelope. The driven Hamiltonian is expressed in terms of its constituent Fourier harmonics with amplitudes that may…

Quantum Physics · Physics 2022-01-12 Viktor Novičenko , Giedrius Žlabys , Egidijus Anisimovas

This thesis deals with the systematic treatment of quantum-mechanical systems in post-Newtonian gravitational fields. Starting from clearly spelled-out assumptions, employing a framework of geometric background structures defining the…

General Relativity and Quantum Cosmology · Physics 2020-10-07 Philip K. Schwartz

Within loop quantum gravity we construct a coarse-grained approximation for the Einstein-Maxwell theory that yields effective Maxwell equations in flat spacetime comprising Planck scale corrections. The corresponding Hamiltonian is defined…

High Energy Physics - Theory · Physics 2009-11-07 Jorge Alfaro , Hugo A. Morales-Técotl , Luis F. Urrutia

We derive the quantum Einstein equations (which are the quantum generalisation of the Einstein equations of classical gravity) from Bohmian quantum gravity. Bohmian quantum gravity is a non-classical geometrodynamics (in the ADM formalism)…

General Relativity and Quantum Cosmology · Physics 2020-08-11 Detlef Dürr , Ward Struyve

New results from the new variables/loop representation program of nonperturbative quantum gravity are presented, with a focus on results of Ashtekar, Rovelli and the author which greatly clarify the physical interpretation of the quantum…

High Energy Physics - Theory · Physics 2007-05-23 Lee Smolin

In the presence of spacetime boundaries, diffeomorphisms in gravitational theories can become physical and acquire non-vanishing Noether charges. These charges obey an algebra which, within the extended phase-space formalism, faithfully…

High Energy Physics - Theory · Physics 2026-03-24 Ludovic Varrin