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相关论文: Universe on Extremely Small Spacetime Scales: Quan…

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We extend the treatment of quantum cosmology to a manifold with torsion. We adopt a model of Einstein-Cartan-Sciama-Kibble compatible with the cosmological principle. The universe wavefunction will be subject to a $\mathcal{PT}$-symmetric…

广义相对论与量子宇宙学 · 物理学 2020-12-22 Ammar Kasem , Shaaban Khalil

There are not many tools to quantitatively monitor the emergence of classical geometric features from a quantum spacetime, whose microscopic structure may be a highly quantum-fluctuating "spacetime foam". To improve this situation, we…

高能物理 - 理论 · 物理学 2023-05-10 R. Loll , A. Silva

We present a brief history of the construction of models of the universe, followed by calculations of quantitative characteristics of basic geometric and kinematic properties of the Standard Cosmological Model ($\Lambda$CDM). Using the…

广义相对论与量子宇宙学 · 物理学 2026-04-23 D. I. Nagirner , S. G. Jorstad , A. V. Dementyev

We propose a method to construct quantum theory of matter fields in a topology changing universe. Analytic continuation of the semiclassical gravity of a Lorentzian geometry leads to a non-unitary Schr\"{o}dinger equation in a Euclidean…

高能物理 - 理论 · 物理学 2009-10-31 Sang Pyo Kim

The laws of thermodynamics in the expanding universe are formulated within the quasi-metric framework. Since the quasi-metric cosmic expansion does not directly influence momenta of material particles, so that the expansion directly cools…

广义相对论与量子宇宙学 · 物理学 2025-01-14 Dag Østvang

Using Relativistic Quantum Geometry we study back-reaction effects of space-time inside the causal horizon of a static de Sitter metric, in order to make a quantum thermodynamical description of space-time. We found a finite number of…

广义相对论与量子宇宙学 · 物理学 2020-01-08 Juan Ignacio Musmarra , Mauricio Bellini

The standard cosmological model supposes that the dominant matter component changes in the course of the evolution of the universe. We study the homogeneous and isotropic universe with non-zero cosmological constant in the epoch when the…

宇宙学与河外天体物理 · 物理学 2012-03-16 V. E. Kuzmichev , V. V. Kuzmichev

Suppose the usual description of spacetime as a 4-dimensional manifold with a Lorentzian metric breaks down at Planck energies. Can we still construct sensible theoretical models of the universe? Are they testable? Do they lead to a…

广义相对论与量子宇宙学 · 物理学 2007-05-23 Fotini Markopoulou

In the late 1990s, observations of type Ia supernovae led to the astounding discovery that the universe is expanding at an accelerating rate. The explanation of this anomalous acceleration has been one of the great problems in physics since…

综合物理 · 物理学 2015-11-09 Wun-Yi Shu

A low matter density decaying vacuum cosmology is proposed on the assumption that the universe's radius is a complex quantity \hat{R} if it is regarded as having a zero energy-momentum tensor. But we find that when the radius is real, it…

广义相对论与量子宇宙学 · 物理学 2008-11-26 Moncy V. John , K. Babu Joseph

We explain how quantum gravity can be defined by quantizing spacetime itself. A pinpoint is that the gravitational constant G = L_P^2 whose physical dimension is of (length)^2 in natural unit introduces a symplectic structure of spacetime…

高能物理 - 理论 · 物理学 2014-11-21 Hyun Seok Yang

Theories based on General Relativity or Quantum Mechanics have taken a leading position in macroscopic and microscopic Physics, but fail when used in the other extremity. Thus, we try to establish a new structure of united theory based on…

综合物理 · 物理学 2014-04-14 Chang-kai Zhang

Familiar textbook quantum mechanics assumes a fixed background spacetime to define states on spacelike surfaces and their unitary evolution between them. Quantum theory has changed as our conceptions of space and time have evolved. But…

广义相对论与量子宇宙学 · 物理学 2008-06-09 James B. Hartle

The properties which give quantum mechanics its unique character - unitarity, complementarity, non-commutativity, uncertainty, nonlocality - derive from the algebraic structure of Hermitian operators acting on the wavefunction in complex…

量子物理 · 物理学 2022-09-14 Tim Palmer

In this paper a new small parameter associated with the density matrix deformation (density pro-matrix)studied in previous works of the author is introduced into the Generalized Quantum Mechanics (GQM), i.e. quantum mechanics involving…

高能物理 - 理论 · 物理学 2009-11-10 A. E. Shalyt-Margolin

We perform large-scale cosmological simulations that solve Einstein's equations directly via numerical relativity. Starting with initial conditions sampled from the cosmic microwave background, we track the emergence of a cosmic web without…

宇宙学与河外天体物理 · 物理学 2019-03-27 Hayley J. Macpherson , Daniel J. Price , Paul D. Lasky

A free massless scalar field is coupled to homogeneous and isotropic loop quantum cosmology. The coupled model is investigated in the vicinity of the classical singularity, where discreteness is essential and where the quantum model is…

广义相对论与量子宇宙学 · 物理学 2009-11-07 Martin Bojowald , Franz Hinterleitner

We consider a model in which the universe is the direct product of a (3+1)-dimensional Friedmann, Robertson-Walker (FRW) space and a compact hyperbolic manifold (CHM). Standard Model fields are confined to a point in the CHM (i.e. to a…

高能物理 - 理论 · 物理学 2008-11-26 Glenn D. Starkman , Dejan Stojkovic , Mark Trodden

We discuss phenomenology of quantum vacuum. Phenomenology of macroscopic systems has three sources: thermodynamics, topology and symmetry. Thermodynamics of the self-sustained vacuum allows us to treat the problems related to the vacuum…

其他凝聚态物理 · 物理学 2013-09-13 G. E. Volovik

We propose a heuristic model of the universe as a growing quasicrystal projected from a higher-dimensional lattice. This quasicrystalline framework offers a novel perspective on cosmic expansion, where the intrinsic growth dynamics…

综合物理 · 物理学 2025-02-04 Marcelo Maciel Amaral , Aman Yadav