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The cosmological constant problem represents a profound conflict between quantum field theory and general relativity. Unimodular gravity offers a compelling starting point by de-gravitating the vacuum energy of the Standard Model, but this…

High Energy Physics - Phenomenology · Physics 2025-11-18 David E. Kaplan , Surjeet Rajendran

We propose a proper definition of the vacuum expectation value of the stress energy tensor $\langle 0 | T_{\mu\nu} |0 \rangle$ for integrable quantum field theories in two spacetime dimensions, which is the analog of the cosmological…

High Energy Physics - Theory · Physics 2024-03-04 André LeClair

We provide a consistency relation between cosmological observables in general relativity with the cosmological constant. Breaking of this relation at any redshift would imply the breakdown of the hypothesis of the cosmological constant as…

Astrophysics · Physics 2009-06-23 Takeshi Chiba , Takashi Nakamura

Einstein-Hilbert action is supplemented by Gauss-Bonnet squared term, its phase-space structure is constructed and canonical quantization is performed. Resolution of a contradiction that emerges in the process, requires the presence of…

General Relativity and Quantum Cosmology · Physics 2019-08-19 Abhik Kumar Sanyal , Chandramouli Sarkar

Both Stefan-Boltzmann law and the Casimir effect, in a universe described by the FRW metric with zero curvature, are calculated. These effects are described by Thermo Field Dynamics (TFD). The gravitational energy-momentum tensor is defined…

General Relativity and Quantum Cosmology · Physics 2022-04-20 A. F. Santos , S. C. Ulhoa , E. P. Spaniol , Faqir C. Khanna

The idea that the cosmological term, Lambda, should be a time dependent quantity in cosmology is a most natural one. It is difficult to conceive an expanding universe with a strictly constant vacuum energy density, namely one that has…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Joan Sola

It is shown that topological changes in space-time are necessary to make General Relativity compatible with the Newtonian limit and to solve the hierarchy of the fundamental interactions. We detail how topology and topological changes…

General Relativity and Quantum Cosmology · Physics 2012-12-10 M. D. Maia

We use general arguments to examine the energy scales for which a quantum coherent description of gravitating quantum energy units is necessary. The cosmological dark energy density is expected to decouple from the Friedman-Lemaitre energy…

Astrophysics · Physics 2007-05-23 James V. Lindesay , H. Pierre Noyes

The $q$-theory approach to the cosmological constant problem is reconsidered. The new observation is that the effective classical $q$-theory gets modified due to the backreaction of quantum-mechanical particle production by spacetime…

High Energy Physics - Theory · Physics 2016-09-13 F. R. Klinkhamer , G. E. Volovik

We develop a new model for the Universe based on two key assumptions: first, the inertial energy of the Universe is a constant, and second, the total energy of a particle, the inertial plus the gravitational potential energy produced by the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Hossein Shojaie , Mehrdad Farhoudi

Lord Kelvin believed that the electromagnetic aether must also generate gravity. Presently, we have no methods to determine the density of the electromagnetic aether, or we say the $\Omega(1)$ substratum. Thus, we also suppose that vacuum…

General Physics · Physics 2022-09-22 Xiao-Song Wang

We outline the evaluation of the cosmological constant in the framework of the standard field-theoretical treatment of vacuum energy and discuss the relation between the vacuum energy problem and the gauge-group spontaneous symmetry…

General Relativity and Quantum Cosmology · Physics 2008-11-26 A. A. Andrianov , F. Cannata , P. Giacconi , A. Yu. Kamenshchik , R. Soldati

Shortly the vacuum component of the Universe from the geometry point of view and from the point of view of the standard model of physics of elementary particles is discussed. Some arguments are given to the calculated value of the…

Astrophysics · Physics 2009-12-15 V. Burdyuzha , G. Vereshkov

The exact solution of the Hamiltonian constraint in canonical gravity and the resultant reduction of Einstein's theory reveal the synergy between gravitation and the intrinsic cosmic clock of our expanding universe. Intrinsic Time…

General Relativity and Quantum Cosmology · Physics 2023-11-27 Chopin Soo

An additional variation of the Einstein-Hilbert action with respect to the Planck mass provides a constraint on the average Ricci scalar that prevents vacuum energy from gravitating. Consideration of the evolution of the inhomogeneous…

General Relativity and Quantum Cosmology · Physics 2019-09-18 Lucas Lombriser

We discuss the main myths related to the vacuum energy and cosmological constant, such as: ``unbearable lightness of space-time''; the dominating contribution of zero point energy of quantum fields to the vacuum energy; non-zero vacuum…

General Relativity and Quantum Cosmology · Physics 2008-11-26 G. E. Volovik

Assuming the existence of a cosmological constant depending on time, we study the evolution of this field in a local region of spacetime. Solving the standard equations of Einstein Relativity in the weak field approximation we find two…

General Relativity and Quantum Cosmology · Physics 2015-12-09 Elmo Benedetto , Antonio Feoli , Liberato Pizza

The cosmological constant $\Lambda$ is a free parameter in Einstein's equations of gravity. We propose to fix its value with a boundary condition: test particles should be free when outside causal contact, e.g. at infinity. Under this…

General Physics · Physics 2019-05-24 Enrique Gaztanaga

At the level of the Planck scale, the spacetime metric has to be considered a quantum variable. Conformal quantum fluctuations of the metric tensor are studied here. They lead to an extra term in the Einstein equations which can be…

Astrophysics · Physics 2007-05-23 Alex H. Blin

It is traced out a parallel between the cosmological constant problem and the polymer physics. The time evolution of the universe world line is compared with the growing of a polymer chain. An equivalent Flory free energy and a modification…

General Relativity and Quantum Cosmology · Physics 2011-08-31 Paulo Roberto Silva
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