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The existence of a quantum bounce in isotropic spacetimes is a key result in loop quantum cosmology (LQC), which has been demonstrated to arise in all the models studied so far. In most of the models, the bounce has been studied using…

General Relativity and Quantum Cosmology · Physics 2017-06-20 Peter Diener , Brajesh Gupt , Parampreet Singh

We compute second-order quantum corrections, as quantum dispersions and correlations, to a cosmological model coupling a single scalar perturbation mode to a bouncing background within Loop Quantum Cosmology (LQC). Using an effective…

General Relativity and Quantum Cosmology · Physics 2026-05-19 Héctor Hernández Hernández , Hugo Morales Técotl , Gustavo Sánchez Herrera

We perform a detailed analysis of the behavior of coherent and squeezed states undergoing time evolution. We calculate time dependence of expectation values of position and momentum in coherent and squeezed states (which can be interpreted…

Quantum Physics · Physics 2018-02-14 Ziemowit Domański , Maciej Błaszak

A model for quantum gravity in one (time) dimension is discussed, based on Regge's discrete formulation of gravity. The nature of exact continuous lattice diffeomorphisms and the implications for a regularized gravitational measure are…

High Energy Physics - Theory · Physics 2009-10-28 Herbert W. Hamber , Ruth M. Williams

An important aspect in understanding the dynamics in the context of deparametrized models of LQG is to obtain a sufficient control on the quantum evolution generated by a given Hamiltonian operator. More specifically, we need to be able to…

General Relativity and Quantum Cosmology · Physics 2017-08-02 Mehdi Assanioussi , Jerzy Lewandowski , Ilkka Mäkinen

The realization of scalable fault-tolerant quantum computing is expected to hinge on quantum error-correcting codes. In the quest for more efficient quantum fault tolerance, a critical code parameter is the weight of measurements that…

Quantum Physics · Physics 2025-02-21 Austin Yubo He , Zi-Wen Liu

In this work we propose a new algorithm for the computation of statistical equilibrium quantities on a cubic lattice when both an energy and a statistical temperature are involved. We demonstrate that the pivot algorithm used in situations…

Statistical Mechanics · Physics 2021-06-15 Pavel Bělík , Eric Bibelnieks , Robert Laskowski , Aleksandr Lukanen , Douglas P. Dokken

We provide an analytical solution to the quantum dynamics of a flat Friedmann-Lema\^itre- Robertson-Walker model with a massless scalar field in the presence of a small and positive cosmological constant, in the context of Loop Quantum…

General Relativity and Quantum Cosmology · Physics 2020-02-06 Mercedes Martín-Benito , Rita B. Neves

The large-scale execution of quantum algorithms requires basic quantum operations to be implemented fault-tolerantly. The most popular technique for accomplishing this, using the devices that can be realised in the near term, uses…

Approximating ground and a fixed number of excited state energies, or equivalently low order Hamiltonian eigenvalues, is an important but computationally hard problem. Typically, the cost of classical deterministic algorithms grows…

Quantum Physics · Physics 2015-08-10 Stuart Hadfield , Anargyros Papageorgiou

Grover's unstructured search algorithm is one of the best examples to date for the superiority of quantum algorithms over classical ones. Its applicability, however, has been questioned by many due to its oracular nature. We propose a…

Quantum Physics · Physics 2017-08-21 Itay Hen

Affine quantum gravity involves (i) affine commutation relations to ensure metric positivity, (ii) a regularized projection operator procedure to accomodate first- and second-class quantum constraints, and (iii) a hard-core interpretation…

High Energy Physics - Theory · Physics 2009-11-10 John R. Klauder

Fluid flow simulations marshal our most powerful computational resources. In many cases, even this is not enough. Quantum computers provide an opportunity to speed up traditional algorithms for flow simulations. We show that lattice-based…

In this paper, we continue investigating the possible values of the pre-factors $\alpha$ and $\beta$ in the logarithmic corrected entropy-area relation based on cosmological stability arguments. In a previous study, we have investigated the…

General Relativity and Quantum Cosmology · Physics 2019-06-26 Nasr Ahmed , Sultan Z. Alamri

We present a family of algorithms, combining real-space renormalization methods and belief propagation, to estimate the free energy of a topologically ordered system in the presence of defects. Such an algorithm is needed to preserve the…

Quantum Physics · Physics 2015-05-14 Guillaume Duclos-Cianci , David Poulin

Loop Quantum Gravity is a background independent, nonperturbative approach to the quantization of General Relativity. Its application to models of interest in cosmology and astrophysics, known as Loop Quantum Cosmology, has led to new and…

General Relativity and Quantum Cosmology · Physics 2015-05-27 Guillermo A. Mena Marugan

Accurate time-dependent quantum dynamics of Coulombic systems on grid-based representations remains computationally demanding due to the singularity of the Coulomb potential, which necessitates extremely fine spatial grids to mitigate…

Quantum Physics · Physics 2026-03-04 Xiaoning Feng , Hans Hon Sang Chan , David P. Tew

While homogeneous cosmologies have long been studied in the group field theory (GFT) approach to quantum gravity, including a quantum description of cosmological perturbations is highly non-trivial. Here we apply a recent proposal for…

General Relativity and Quantum Cosmology · Physics 2025-11-18 Steffen Gielen , Lisa Mickel

The preparation of the ground state of a Hamiltonian $H$ with a large spectral radius has applications in many areas such as electronic structure theory and quantum field theory. Given an initial state with a constant overlap with the…

Quantum Physics · Physics 2024-06-05 Yulong Dong , Lin Lin

Classical algorithms for predicting the equilibrium geometry of strongly correlated molecules require expensive wave function methods that become impractical already for few-atom systems. In this work, we introduce a variational quantum…