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We show that it is possible to still use semiclassical gravity together with quantum field theory beyond the regimes where the field state is coherent. In particular, we identify families of cat states (superposition of…

Quantum Physics · Physics 2024-01-29 Shahnewaz Ahmed , Caroline Lima , Eduardo Martín-Martínez

Results that illuminate the physical interpretation of states of nonperturbative quantum gravity are obtained using the recently introduced loop variables. It is shown that: i) While local operators such as the metric at a point may not be…

High Energy Physics - Theory · Physics 2011-04-20 Abhay Ashtekar , Carlo Rovelli , Lee Smolin

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

In Loop Quantum Gravity, the quantum action of the volume operator is crucial in understanding quantum dynamics. In this work, we implement a generalized numerical algorithm that can compute the quantum action of the volume operator on a…

General Relativity and Quantum Cosmology · Physics 2026-04-01 Haida Li , Hongguang Liu

We continue the semiclassical analysis of the Loop Quantum Gravity (LQG) volume operator that was started in the companion paper [23]. In the first paper we prepared the technical tools, in particular the use of complexifier coherent states…

General Relativity and Quantum Cosmology · Physics 2009-04-22 Cecilia Flori

In this paper we investigate the properties of gauge-invariant coherent states for Loop Quantum Gravity, for the gauge group U(1). This is done by projecting the corresponding complexifier coherent states, which have been applied in…

General Relativity and Quantum Cosmology · Physics 2009-02-12 Benjamin Bahr , Thomas Thiemann

The lattice formulation of quantum gravity provides a natural framework in which non-perturbative properties of the ground state can be studied in detail. In this paper we investigate how the lattice results relate to the continuum…

High Energy Physics - Theory · Physics 2009-11-10 Herbert W. Hamber , Ruth M. Williams

This is the second paper concerning gauge-invariant coherent states for Loop Quantum Gravity. Here, we deal with the gauge group SU(2), this being a significant complication compared to the abelian U(1) case encountered in the previous…

General Relativity and Quantum Cosmology · Physics 2009-02-12 Benjamin Bahr , Thomas Thiemann

Consider a bipartite quantum system with at least one of its two components being itself a composite system. By tracing over part of one (or both) of these two subsystems it is possible to obtain a reduced (separable) state that exhibits…

Quantum Physics · Physics 2015-04-10 Guido Bellomo , Ana P. Majtey , A. R. Plastino , A. Plastino

An important challenge in loop quantum gravity is to find semiclassical states - states that are as close to classical as quantum theory allows. This is difficult because the states in the Hilbert space used in LQG are excitations over a…

General Relativity and Quantum Cosmology · Physics 2020-06-01 Hanno Sahlmann , Robert Seeger

Coherent states provide a natural connection of quantum systems to their classical limit and are employed in various fields of physics. Here we derive general systematic expansions, with respect to quantum parameters, of expectation values…

Quantum Physics · Physics 2015-08-13 John Schliemann

We analyze the partition function of three-dimensional quantum gravity on the twisted solid tours and the ensuing dual field theory. The setting is that of a non-perturbative model of three dimensional quantum gravity--the Ponzano-Regge…

High Energy Physics - Theory · Physics 2018-06-22 Bianca Dittrich , Christophe Goeller , Etera Livine , Aldo Riello

We summarize recent developments at the interface of quantum gravity and quantum information, and discuss applications to the quantum geometry of space in loop quantum gravity. In particular, we describe the notions of link entanglement,…

General Relativity and Quantum Cosmology · Physics 2023-08-23 Eugenio Bianchi , Etera R. Livine

We derive a "classical-quantum" approximation scheme for a broad class of bipartite quantum systems from fully quantum dynamics. In this approximation, one subsystem evolves via classical equations of motion with quantum corrections, and…

Quantum Physics · Physics 2023-06-05 Viqar Husain , Irfan Javed , Sanjeev S. Seahra , Nomaan X

In this thesis, we study about three subjects 1- Classical simulation of two spin-$s$ singlet correlations for all $s$ involving spin measurements, 2- Quantum correlations in successive single spin measurements, 3- Non locality without…

Quantum Physics · Physics 2008-07-08 Ali Ahanj

Classical nonlinear theories are highly successful in describing far-from-equilibrium dynamics of magnets, encompassing phenomena such as parametric resonance, ultrafast switching, and even chaos. However, at ultrashort length and time…

Mesoscale and Nanoscale Physics · Physics 2025-12-15 Lukas Körber , Pim Coenders , Johan H. Mentink

Working within the framework of Loop Quantum Gravity (LQG), we construct a set of three operators suitable for identifying coordinate-like quantities on a spin-network configuration. In doing so, we rely on known properties of operators for…

High Energy Physics - Theory · Physics 2018-07-19 Suddhasattwa Brahma , Antonino Marcianò , Michele Ronco

The semiclassical interaction of the gravitational with a quantum scalar field is considered, in view of the renormalizability of the associated energy-momentum tensor in a n-dimensional curved spacetime resulting from a quadratic…

General Relativity and Quantum Cosmology · Physics 2023-06-21 Kostas Kleidis

In this paper, we study the bipartite entanglement of spin coherent states in the case of pure and mixed states. By a proper choice of the subsystem spins, the entanglement for large class of quantum systems is investigated. We generalize…

Quantum Physics · Physics 2015-06-12 K. Berrada , A. Mohammadzade , S. Abdel-Khalek , H. Eleuch , S. Salimi

We introduce a new family of coherent states for loop quantum gravity, inspired by the twisted geometry parametrization. We compute their peakedness properties and compare them with the heat-kernel coherent states. They show similar…

General Relativity and Quantum Cosmology · Physics 2021-02-03 Andrea Calcinari , Laurent Freidel , Etera Livine , Simone Speziale