Exact path integrals on half-line in quantum cosmology with a fluid clock and aspects of operator ordering ambiguity
arXiv:2501.11680 · doi:10.1007/JHEP05(2025)128
Abstract
We perform half-line path integral quantization of flat, homogeneous cosmological models containing a perfect fluid acting as an internal clock, in a dimensional minisuperspace setup. We also discuss certain classes of operator ordering ambiguity inherent in such quantization procedures and argue that a particular ordering prescription in the quantum theory can preserve two symmetries, namely arbitrary lapse rescalings and general covariance, which are already present at the classical level. As a result of this imposition, a large class of quantum Hamiltonians differing by operator ordering produces the same inner products between quantum states. This imposition of the two symmetries of the classical minisuperspace models leads to a unique prescription for writing the quantum Hamiltonian for minisuperspace dimension . Interestingly, in the case of , the lapse rescaling symmetry is lost in the quantum theory, leading to an essentially ambiguous description of the canonical theory. We provide general proof of this in the context of both canonical quantization and path integrals. We supply concrete examples to validate our findings further.
References in corpus (36)
- Quantum Gravity: a Progress Report
- A Quantum Gravity Extension of the Inflationary Scenario
- Lorentzian Quantum Cosmology
- Theory of cosmological perturbations in an anisotropic universe
- Time and a physical Hamiltonian for quantum gravity
- The Trinity of Relational Quantum Dynamics
- Quantum cosmology: a review
- Quantum cosmological perfect fluid models
- No smooth beginning for spacetime
- Cosmology without inflation
- Quantum field theory on a cosmological, quantum space-time
- No Rescue for the No Boundary Proposal
- The Real No-Boundary Wave Function in Lorentzian Quantum Cosmology
- A non inflationary model with scale invariant cosmological perturbations
- Tunneling wave function of the universe
- Tensor Perturbations in Quantum Cosmological Backgrounds
- Factor ordering in standard quantum cosmology
- Singularity avoidance for collapsing quantum dust in the Lemaitre-Tolman-Bondi model
- Damped perturbations in the no-boundary state
- Spontaneous creation of the universe from nothing
- Singularity avoidance in Bianchi I quantum cosmology
- Tunneling wave function of the universe II: the backreaction problem
- WKB Approaches to Restore Time in Quantum Cosmology: Predictions and Shortcomings
- Dynamical interpretation of the wavefunction of the universe
- Unavoidable shear from quantum fluctuations in contracting cosmologies
- Dynamics of primordial fields in quantum cosmological spacetimes
- Primordial gravitational waves in a quantum model of big bounce
- Big Bang Singularity Resolution In Quantum Cosmology
- Elimination of cosmological singularities in quantum cosmology by suitable operator orderings
- Inflation of small true vacuum bubble by quantization of Einstein-Hilbert action
- Analyzing the influence of graviton fluctuations on the inflationary spectrum with a Kuchař-Torre clock
- Infrared signatures of quantum bounce in a minisuperspace analysis of Lema\^ıtre-Tolman-Bondi dust collapse
- Ambiguous power spectrum from a quantum bounce
- Analyzing quantum gravity spillover in the semiclassical regime
- A formalism for the ambiguities of the Wheeler-DeWitt equation
- Imprints of the operator ordering ambiguity on the dynamics of perfect fluid dominated quantum universe