Fluctuation energies in quantum cosmology

Abstract

Quantum fluctuations or other moments of a state contribute to energy expectation values and can imply interesting physical effects. In quantum cosmology, they turn out to be important for a discussion of density bounds and instabilities of initial-value problems in the presence of signature change in loop-quantized models. This article provides an effective description of these issues, accompanied by a comparison with existing numerical results and an extension to squeezed states. The comparison confirms that canonical effective methods are well-suited for computations of properties of physical states. As a side product, an example is found for a simple state in which quantum fluctuations can cancel holonomy modifications of loop quantum cosmology.

arXiv comment35 pages, 6 figures

References in corpus (39)

• Background Independent Quantum Gravity: A Status Report
• Quantum Nature of the Big Bang: Improved dynamics
• Black hole entropy in Loop Quantum Gravity
• Black hole entropy from Quantum Geometry
• Isotropic Loop Quantum Cosmology
• Anomaly-free scalar perturbations with holonomy corrections in loop quantum cosmology
• The Inverse Scale Factor in Isotropic Quantum Geometry
• Effective Equations of Motion for Quantum Systems
• Anomaly freedom in perturbative loop quantum gravity
• Deformed General Relativity and Effective Actions from Loop Quantum Gravity
• An effective approach to the problem of time
• On the Hamiltonian Constraint of Loop Quantum Cosmology
• Effective approach to the problem of time: general features and examples
• Loop quantum cosmology and inhomogeneities
• Large scale effective theory for cosmological bounces
• Numerical simulations of a loop quantum cosmos: robustness of the quantum bounce and the validity of effective dynamics
• On the regularization ambiguities in loop quantum gravity
• Quantum Gravity and Higher Curvature Actions
• Dynamical coherent states and physical solutions of quantum cosmological bounces
• Anomaly-free perturbations with inverse-volume and holonomy corrections in Loop Quantum Cosmology
• Effective Constraints for Relativistic Quantum Systems
• Effective Constraints for Quantum Systems
• Towards an Anomaly-Free Quantum Dynamics for a Weak Coupling Limit of Euclidean Gravity
• Effective relational dynamics of a nonintegrable cosmological model
• Quantum Cosmology: Effective Theory
• How quantum is the big bang?
• Constraint algebra in LQG reloaded : Toy model of a U(1)^{3} Gauge Theory I
• Effective equations for isotropic quantum cosmology including matter
• Physical time and other conceptual issues of QG on the example of LQC
• Discreteness corrections and higher spatial derivatives in effective canonical quantum gravity
• Harmonic cosmology: How much can we know about a universe before the big bang?
• Constraint algebra in LQG reloaded : Toy model of an Abelian gauge theory - II Spatial Diffeomorphisms
• The Dark Side of a Patchwork Universe
• Higher time derivatives in effective equations of canonical quantum systems
• Chimera: A hybrid approach to numerical loop quantum cosmology
• Poisson Geometry in Constrained Systems
• Factor ordering and large-volume dynamics in quantum cosmology
• Comparison between quantum and classical dynamics in the effective action formalism
• Effective Casimir Conditions and Group Coherent States

Cited by in corpus (12)

• Anomaly-free cosmological perturbations in effective canonical quantum gravity
• Some implications of signature-change in cosmological models of loop quantum gravity
• Information loss, made worse by quantum gravity?
• Protected $SL(2,\mathbb{R})$ Symmetry in Quantum Cosmology
• Time in quantum cosmology
• Covariance in self dual inhomogeneous models of effective quantum geometry: Spherical symmetry and Gowdy systems
• Effective constraint algebras with structure functions
• Effective Field Theory of Loop Quantum Cosmology
• Non-bouncing solutions in loop quantum cosmology
• Properties of fluctuating states in loop quantum cosmology
• Quantum Kasner transition in a locally rotationally symmetric Bianchi II universe
• Semiclassical study of the Mixmaster model: the quantum Kasner map