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The effective action in quantum general relativity is strongly dependent on the gauge-fixing and parametrization of the quantum metric. As a consequence, in the effective approach to quantum gravity, there is no possibility to introduce the…

High Energy Physics - Theory · Physics 2020-10-28 Breno L. Giacchini , Tibério de Paula Netto , Ilya L. Shapiro

We generalize and extend the stochastic path integral formalism and action principle for continuous quantum measurement introduced in [A. Chantasri, J. Dressel and A. N. Jordan, Phys. Rev. A {\bf 88}, 042110 (2013)], where the optimal…

Quantum Physics · Physics 2015-09-23 Areeya Chantasri , Andrew N. Jordan

Loop Quantum Gravity (LQG) is a non-perturbative attempt at quantization of a classical phase space description of gravity in terms of $SU(2)$ connections and electric fields. As emphasized recently [1], on this phase space, classical…

General Relativity and Quantum Cosmology · Physics 2021-07-07 Madhavan Varadarajan

An heuristic semiclassical procedure that incorporates quantum gravity induced corrections in the description of photons and spin 1/2 fermions is reviewed. Such modifications are calculated in the framework of loop quantum gravity and they…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Luis Urrutia

We study quantum interference effects due to electron motion on a three-dimensional cubic lattice in a continuously-tunable magnetic field of arbitrary orientation and magnitude. These effects arise from the interference between magnetic…

Mesoscale and Nanoscale Physics · Physics 2009-10-28 Yeong-Lieh Lin , Franco Nori

We consider the effective theory of perturbative quantum gravity coupled to a point particle, quantizing fluctuations of both the gravitational field and the particle's position around flat space. Using a recent relational approach to…

High Energy Physics - Theory · Physics 2022-02-02 M. B. Fröb , C. Rein , R. Verch

We implement the proof of principle for the quantum walk of one ion in a linear ion trap. With a single-step fidelity exceeding 0.99, we perform three steps of an asymmetric walk on the line. We clearly reveal the differences to its…

Quantum Physics · Physics 2015-05-13 H. Schmitz , R. Matjeschk , Ch. Schneider , J. Glueckert , M. Enderlein , T. Huber , T. Schaetz

We derive the quantum effective action up to second order in gradients and up to two-loop order for an interacting scalar field theory. This expansion of the effective action is useful to study problems in cosmological settings where…

High Energy Physics - Theory · Physics 2024-09-17 Sofia Canevarolo , Tomislav Prokopec

In this paper, we introduce and motivate the studies of Quantum Weyl Gravity (also known as Conformal Gravity). We discuss some appealing features of this theory both on classical and quantum level. The construction of the quantum theory is…

High Energy Physics - Theory · Physics 2021-07-16 Lesław Rachwał , Stefano Giaccari

We study the semiclassical expansion of the effective action for a Regge state-sum model and its dependence on the choice of the path-integral measure and the spectrum of the edge lengths. If the positivity of the edge lengths is imposed in…

General Relativity and Quantum Cosmology · Physics 2014-05-15 Aleksandar Mikovic

We provide a detailed analysis of the disk path integral of timelike Liouville theory, conceived as a tractable and precise toy-model quantum cosmology in two dimensions. Disk path integrals with the insertion of matter field operators,…

High Energy Physics - Theory · Physics 2026-04-14 Dionysios Anninos , Thomas Hertog , Joel Karlsson

Much like the action, diffeomorphism invariance can be used to fix the form of the path integral measure in quantum gravity. Moreover, since there is a redundancy between what constitutes "the action" and what constitutes "the measure" one…

High Energy Physics - Theory · Physics 2025-03-06 Alfio Bonanno , Kevin Falls , Renata Ferrero

We calculate the quantum corrections to the classical action of a particle with coordinate-dependent mass. The result is made self-consistent by a variational approach, thus making it applicable to strong-couplings and singular potentials.…

Quantum Physics · Physics 2007-05-23 M. E. S. Borelli , H. Kleinert

As part of a wider study of coherent states in (loop) quantum gravity, we introduce a modification to the standard construction, based on the recently introduced (non-commutative) flux representation. The resulting quantum states have some…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Daniele Oriti , Roberto Pereira , Lorenzo Sindoni

The field-theoretic one-loop effective action in a static scalar background depending nontrivially on a single spatial coordinate is related, in the proper-time formalism, to the trace of the evolution kernel (or heat kernel) for an…

High Energy Physics - Theory · Physics 2009-11-07 Chanju Kim , O-Kab Kwon , Choonkyu Lee

The present paper is the companion of [1] in which we proposed a scheme that tries to derive the Quantum Field Theory (QFT) on Curved Spacetimes (CST) limit from background independent Quantum General Relativity (QGR). The constructions of…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Hanno Sahlmann , Thomas Thiemann

We present a new method for constructing operators in loop quantum gravity. The construction is an application of the general idea of "coherent state quantization", which allows one to associate a unique quantum operator to every function…

General Relativity and Quantum Cosmology · Physics 2015-11-18 Emanuele Alesci , Andrea Dapor , Jerzy Lewandowski , Ilkka Makinen , Jan Sikorski

The computation of one-loop corrections to the $\gamma^\star Q_+ q$ and $gR_+g$ effective vertices in the framework of gauge-invariant effective theory for Multi-Regge processes in QCD is reviewed. Due to consistent implementation of the…

High Energy Physics - Phenomenology · Physics 2019-05-29 Maxim Nefedov

Statistics of classical Hamiltonian random walk of particle colliding with atoms of ideal gas is considered from viewpoint of earlier suggested exact pseudo-quantum path integral representation of the problem, and qualitative agreement is…

Statistical Mechanics · Physics 2013-11-14 Yu. E. Kuzovlev

An important aspect in defining a path integral quantum theory is the determination of the correct measure. For interacting theories and theories with constraints, this is non-trivial, and is normally not the heuristic "Lebesgue measure"…

General Relativity and Quantum Cosmology · Physics 2011-01-06 Jonathan Engle , Muxin Han , Thomas Thiemann