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We consider two-dimensional quantum gravity endowed with a positive cosmological constant and coupled to a conformal field theory of large and positive central charge. We study cosmological properties at the classical and quantum level. We…

High Energy Physics - Theory · Physics 2025-03-05 Dionysios Anninos , Chiara Baracco , Beatrix Mühlmann

Phase Space is the framework best suited for quantizing superintegrable systems--systems with more conserved quantities than degrees of freedom. In this quantization method, the symmetry algebras of the hamiltonian invariants are preserved…

Quantum Physics · Physics 2009-10-02 Cosmas K Zachos , Thomas L Curtright

Symplectic quantization is a functional approach to quantum field theory that allows sampling of quantum fluctuations directly in Minkowski space time by means of a Hamiltonian dynamics in an intrinsic time $\tau$ which samples a…

High Energy Physics - Lattice · Physics 2026-05-28 Francesco Scardino , Martina Giachello , Giacomo Gradenigo

In this work, we investigate the quantum Brownian motion of a point charge arising as a consequence of two fluctuating point-like boundaries. The study considers Dirichlet, Neumann, and mixed boundary conditions imposed on a real massless…

High Energy Physics - Theory · Physics 2025-08-22 Eliza M. B. Guedes , Herondy Mota

The spatially flat Friedman-Robertson-Walker (FRW) cosmological model with a massless scalar field in loop quantum cosmology admits a description in terms of a completely solvable model. This has been used to prove that: i) the quantum…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Alejandro Corichi , Edison Montoya

In this paper, we develop a quantum theory of homogeneously curved tetrahedron geometry, by applying the combinatorial quantization to the phase space of tetrahedron shapes defined in arXiv:1506.03053. Our method is based on the relation…

General Relativity and Quantum Cosmology · Physics 2023-11-17 Muxin Han , Chen-Hung Hsiao , Qiaoyin Pan

The physics of the inflationary universe requires the study of the out of equilibrium evolution of quantum fields in curved spacetime. We present the evolution for both the geometry and the matter (described by the quantum inflaton field)…

Astrophysics · Physics 2007-05-23 D. Boyanovsky , D. Cormier , H. J. de Vega , R. Holman , S. P. Kumar

We compute the quantum circuit complexity of the evolution of scalar curvature perturbations on expanding backgrounds, using the language of squeezed vacuum states. In particular, we construct a simple cosmological model consisting of an…

High Energy Physics - Theory · Physics 2020-05-22 Arpan Bhattacharyya , Saurya Das , S. Shajidul Haque , Bret Underwood

Within the framework of loop quantum cosmology, there exists a semi-classical regime where spacetime may be approximated in terms of a continuous manifold, but where the standard Friedmann equations of classical Einstein gravity receive…

General Relativity and Quantum Cosmology · Physics 2009-11-10 James E. Lidsey

The five-dimensional loop quantum Kaluza-Klein cosmology is constructed based on the symmetric reduction of the connection formulation of the full theory. Through semiclassical analysis, the effective scalar constraint for the cosmological…

General Relativity and Quantum Cosmology · Physics 2026-02-20 Shengzhi Li , Yongge Ma , Faqiang Yuan , Xiangdong Zhang

We present a systematic study of the cosmological dynamics resulting from an effective Hamiltonian, recently derived in loop quantum gravity using Thiemann's regularization and earlier obtained in loop quantum cosmology (LQC) by keeping the…

General Relativity and Quantum Cosmology · Physics 2018-04-25 Bao-Fei Li , Parampreet Singh , Anzhong Wang

We analyze the size and evolution of quantum fluctuations of cosmologically relevant geometric observables, in the context of the effective relational cosmological dynamics of GFT models of quantum gravity. We consider the fluctuations of…

General Relativity and Quantum Cosmology · Physics 2021-09-23 Luca Marchetti , Daniele Oriti

We quantize a flat cosmological model in the context of $f(T)$ theory of modified gravity using the Dirac's quantization approach for Hamiltonian constraint systems. In this regard, first we obtain the Wheeler-DeWitt equation as the…

General Relativity and Quantum Cosmology · Physics 2019-08-05 F. Darabi , K. Atazadeh

Quantum--mechanical operators corresponding to canonical momentum and position of a point--like particle, which follow from the quantum field theory in the general Riemannian space-time, satisfy generally to a deformation of the canonical…

General Relativity and Quantum Cosmology · Physics 2007-05-23 E. A. Tagirov

We study the phase space structure and the quantization of a pointlike particle in 2+1 dimensional gravity. By adding boundary terms to the first order Einstein Hilbert action, and removing all redundant gauge degrees of freedom, we arrive…

General Relativity and Quantum Cosmology · Physics 2016-08-31 Hans-Juergen Matschull , Max Welling

We study the evolution of cosmological perturbations in a non-singular bouncing cosmology with a bounce phase which has superimposed oscillations of the scale factor. We identify length scales for which the final spectrum of fluctuations…

High Energy Physics - Theory · Physics 2018-02-14 Robert Brandenberger , Qiuyue Liang , Rudnei O. Ramos , Siyi Zhou

Determining the physical Hilbert space is often considered the most difficult but crucial part of completing the quantization of a constrained system. In such a situation it can be more economical to use effective constraint methods, which…

Mathematical Physics · Physics 2009-12-04 Martin Bojowald , Artur Tsobanjan

We study QED$_2$ in de Sitter space as a minimal interacting gauge theory in which cosmological expansion directly competes with quantum dynamics. In cosmic time, the hopping redshifts as $1/a(t)$ while the electric term grows as $g^2…

High Energy Physics - Theory · Physics 2026-04-06 Kazuki Ikeda , Yaron Oz

The global symmetry data of a $D$-dimensional absolute quantum field theory can sometimes be packaged in terms of a $(D+1)$-dimensional bulk system obtained by extending along an interval, with a relative QFT$_D$ at one end and suitable…

High Energy Physics - Theory · Physics 2025-12-23 Jonathan J. Heckman , Max Hübner , Chitraang Murdia

We consider warped compactifications in (4+d)-dimensional theories, with four dimensional de Sitter dS_4 vacua (with Hubble parameter H) and with a compact internal space. After introducing a gauge-invariant formalism for the generic metric…

High Energy Physics - Theory · Physics 2010-11-19 Carlo Contaldi , Lev Kofman , Marco Peloso