Approaches to Quantum Cosmology

Abstract

Different proposals for the wave function of the universe are analyzed, with an emphasis on various forms of the tunneling proposal. The issues discussed include the equivalence of the Lorentzian path integral and outgoing-wave proposals, the definitions of the outgoing waves and of superspace boundaries, topology change and the corresponding modification of the Wheeler-DeWitt equation. Also discussed are the "generic" boundary conditions and the third quantization approach.

38 pages

Cited by in corpus (163)

• Reconstructing the Universe
• Cosmological term as a source of mass
• Lorentzian Quantum Cosmology
• No smooth beginning for spacetime
• Semiclassical Universe from First Principles
• Making Predictions in Eternally Inflating Universe
• Dark energy perturbations and cosmic coincidence
• Tunneling wave function of the universe
• Operator ordering and consistency of the wavefunction of the Universe
• The wave function discord
• Quantum state of the multiverse
• Closed String Tachyon Condensation and Worldsheet Inflation
• Dynamical Vacuum in Quantum Cosmology
• Tunneling cosmological state revisited: Origin of inflation with a non-minimally coupled Standard Model Higgs inflaton
• Universes inside a $\Lambda$ black hole
• Cosmology with a Nonlinear Born-Infeld type Scalar Field
• Collapse of simple harmonic universe
• Tunneling in quantum cosmology: numerical study of particle creation
• Spontaneous creation of the universe from nothing
• de Sitter Fractional Quantum Cosmology
• Can we predict $\Lambda$ for the Non-SUSY sector of the Landscape ?
• Tunneling wave function of the universe II: the backreaction problem
• Ostrogradski approach for the Regge-Teitelboim type cosmology
• Group field cosmology: a cosmological field theory of quantum geometry
• Self-Adjoint Wheeler-DeWitt Operators, the Problem of Time and the Wave Function of the Universe
• Applications of a New Proposal for Solving the "Problem of Time" to Some Simple Quantum Cosmological Models
• Wave Function of a Brane-like Universe
• Cosmological Measures without Volume Weighting
• Susskind's Challenge to the Hartle-Hawking No-Boundary Proposal and Possible Resolutions
• Instantons and unitarity in quantum cosmology with fixed four-volume
• String Tension between de Sitter vacua and Curvature Corrections
• Effective equations in quantum cosmology
• Jackiw-Teitelboim Gravity in the Second Order Formalism
• Deformation quantization of cosmological models
• Why the Universe Started from a Low Entropy State
• The no-boundary proposal in biaxial Bianchi IX minisuperspace
• Islands in the Lambda-sea: An alternative cosmological model
• Causal continuity in degenerate spacetimes
• Two dimensional Nearly de Sitter gravity
• The no-boundary measure in string theory: Applications to moduli stabilization, flux compactification, and cosmic landscape
• Cosmological ${\alpha }^{\prime }$-corrections from the functional renormalization group
• In defence of the `Tunneling' wave function of the Universe
• Scalar field quantum cosmology: a Schrödinger picture
• Birth of the Universe from the Landscape of String Theory
• Toward inflation models compatible with the no-boundary proposal
• A model Universe with variable space dimension: its dynamics and wave function
• CFT driven cosmology and the DGP/CFT correspondence
• WKB Approaches to Restore Time in Quantum Cosmology: Predictions and Shortcomings
• Equivalence of the Chern-Simons state and the Hartle-Hawking and Vilenkin wave-functions
• Quantum cosmology and eternal inflation
• The Bianchi Type I minisuperspace model
• Singularities in a Scalar Field Quantum Cosmology
• Study of the Inflationary Spectrum in the Presence of Quantum Gravity Corrections
• Bianchi-I classical and quantum spinor cosmology with signature change
• Dynamical interpretation of the wavefunction of the universe
• Multiverse in the Third Quantized Horava-Lifshits Theory of Gravity
• No-boundary measure and preference for large e-foldings in multi-field inflation
• Morse index and causal continuity. A criterion for topology change in quantum gravity
• Wavefunction of the Universe on the Landscape
• Jackiw-Teitelboim and Kantowski-Sachs quantum cosmology
• Quantum modified Regge-Teitelboim cosmology
• Lorentzian path integral for quantum tunneling and WKB approximation for wave-function
• A phase space description of the FLRW quantum cosmology in Ho$\check{\mathrm{r}}$ava-Lifshitz type gravity
• Quantum cosmology of a conformal multiverse
• A Fly in the SOUP
• The real Chern-Simons wave function
• Quantum Cosmology of Generalized Two--Dimensional Dilaton Gravity Models
• Time reparameterization in Bianchi type I spinor cosmology
• A contextual Planck parameter and the classical limit in quantum cosmology
• Third quantization of $f(R)$-type gravity
• Symmetric-Bounce Quantum State of the Universe
• Large-N Expansion as Semiclassical Approximation to the Third-Quantized Theory
• Creation of entangled universes avoids the big bang singularity
• A generalized Hartle-Hawking wavefunction
• Quantum cosmology of a dynamical Lambda
• Hamiltonian formalism in Friedmann cosmology and its quantization
• Quantum Cosmology of Classically Constrained Gravity
• Configuration space for quantum gravity in a locally regularized path integral
• The Density Matrix Deformation in Physics of the Early Universe and Some of its Implications
• Gauge-noninvariance of quantum cosmology and vacuum dark energy
• No-boundary wave function for two-field inflation
• Third quantization: modeling the universe as a 'particle' in a quantum field theory of the minisuperspace
• Third quantization of $f(R)$-type gravity II - General $f(R)$ case -
• Period-doubling bifurcation in strongly anisotropic Bianchi I quantum cosmology
• Open inflation from quantum cosmology with a strong nonminimal coupling
• A Matter Scalar Field in a Closed Universe
• Riemann-Cartan gravity with dynamical signature
• Quantum Birth of a Hot Universe
• Quantum analysis of the recent cosmological bounce in the comoving Hubble length
• The Consistent Result of Cosmological Constant From Quantum Cosmology and Inflation with Born-Infeld Scalar Field
• Quantum torsion and a Hartle-Hawking "beam''
• Resonant structure of space-time of early universe
• From Big Crunch to Big Bang: A Quantum String Cosmology Perspective
• A cosmological viewpoint on the correspondence between deformed phase-space and canonical quantization
• No-Bang Quantum State of the Cosmos
• Semiclassical limit problems with concurrent use of several clocks in quantum cosmology
• Probabilistic Evolutionary Process: a possible solution to the problem of time in quantum cosmology and creation from nothing
• The structure and interpretation of cosmology: Part II - The concept of creation in inflation and quantum cosmology
• Perdurance of multiply connected de Sitter space
• Birth of the Universe from the Multiverse
• Extended particle models based on hollow singular hypersurfaces in general relativity: Classical and quantum aspects of charged textures
• Spacetime and Planck mass generation from scale-invariant degenerate gravity
• Unimodular Hartle-Hawking wave packets and their probability interpretation
• A fully quantum method of determination of penetrability and reflection coefficients in quantum FRW model with radiation
• Holographic Tunneling Wave Function
• Classical and statistical limits of the quantum singular oscillator
• Compactification, topology change and surgery theory
• Path Integrals in Quadratic Gravity
• The Quantum Collapse and the Birth of a New Universe
• Unitary and Vilenkin's wave functions
• Quantum Cosmology with Dynamical Vacuum in a Minimal-Length Scenario
• Gravitational Collapse via Wheeler-DeWitt Equation
• Birth of the Universe from the Multiverse, MG13
• Inflation of small true vacuum bubble by quantization of Einstein-Hilbert action
• Restoring Time Dependence into Quantum Cosmology
• Wheeler-DeWitt equation rejects quantum effects of grown-up universes as a candidate for dark energy
• Before spacetime: A proposal of a framework for multiverse quantum cosmology based on three cosmological conjectures
• Periodic Bounce for Nucleation Rate at Finite Temperature in Minisuperspace Models
• Quantum Field Theory in a Topology Changing Universe
• Is spacetime absolutely or just most probably Lorentzian?
• Wheeler-DeWitt equation and the late gravitational collapse: effects of factor ordering and the tunneling scenario
• Wave Function of the Universe from a Matrix Valued First-Order Formalism
• Nucleation of ${}^{(4)}R$ Brane Universes
• Novel Complete Non-compact Symmetries for the Wheeler-DeWitt Equation in a Wormhole Scalar Model and Axion-Dilaton String Cosmology
• Quantum cosmology of the flat universe via closed real-time path integral
• Wave function of the Universe in the early stage of its evolution
• Operator Ordering Ambiguity and Third Quantization
• Aspects of quantum gravity
• Detection of Particles Under Potential Barrier
• Gauge Group and Topology Change
• Testing the problem of time with cold atoms
• Classical and quantum evolution of non-isentropic hot singular layers in finite-temperature general relativity
• Quantum Mechanics from General Relativity and the Quantum Friedmann Equation
• A hidden constraint on the Hamiltonian formulation of relativistic worldlines
• De Sitter Quantum Mechanics and Inflationary Matrix Cosmology of Self-tuned Universe
• Bohmian Quantum Cosmology from the Wheeler-DeWitt Equation
• Kinetic dominance and the wavefunction of the universe
• Localization on the Landscape and Eternal Inflation
• Monte Carlo simulation of cosmologies with dust
• Quantum Cosmology With Conformally Invariant Scalar Field
• Radiation fluid singular hypersurfaces with de Sitter interior as models of charged extended particles in general relativity
• New Exact Supersymmetric Wave Functions for a Massless Scalar Field and Axion-Dilaton String Cosmology in a FRWL Metric
• Holographic vacuum energy regularization and corrected entropy of de Sitter space
• Tunneling in a quantum field theory on a compact one-dimensional space
• On the interpretation of quantum cosmology
• Complex time route to quantum backreaction
• Does Cosmology require Hermiticity in Quantum Mechanics?
• An accelerated closed universe
• Nucleation at finite temperature beyond the superminispace model
• Evolution of thin-wall configurations of texture matter
• Quantum Cosmology
• Quantum Uncertainty as an Intrinsic Clock
• Repeated measurements on non-replicable systems and their consequences for Unruh-DeWitt detectors
• Linking the Baum-Hawking-Coleman Mechanism with Unimodular Gravity and Vilenkin's Probability Flux
• Hubble tension problem encompassed by phase-space quantum cosmology
• Quantum method of determination of penetrability in FRW model with radiation
• Mini-Superspace Universality and No-Scale Quantum Cosmology
• Signs and Cosmology
• Novel phenomena of the Hartle-Hawking wave function
• The Quantum and Statistical Theory of Early Universe and Its Possible Applications to Cosmology
• Quantum Phase Space Description of a Cosmological Minimal Massive Bigravity Model
• Universe Decay, Inflation and the Large Eigenvalue of the Cosmological Constant Seesaw
• Dynamic quantum theory of large additional dimensions for non-massive particles