scholarly journals ON THE COSMOLOGICAL CONSTANT PROBLEM

1996 ◽  
Vol 05 (04) ◽  
pp. 433-440 ◽  
Author(s):  
DHURJATI PRASAD DATTA
Keyword(s):  
Cosmological Constant ◽  
Mechanical Model ◽  
Vacuum Energy ◽  
Quantum Mechanical ◽  
Cosmological Constant Problem ◽  
Molecular Physics ◽  
Simple Quantum ◽  
Time Formalism ◽  
Oppenheimer Approximation ◽  
The Universe

A simple quantum mechanical model of a closed interacting system is studied following the intrinsic time formalism developed recently, on the basis of the modified Born-Oppenheimer approximation. Apart from shedding further insights into the recent results on a possible nongravitating vacuum energy in the universe, the study also offers potentially interesting possibilities even in atomic/molecular physics.

scholarly journals The cosmological constant of emergent spacetime in the Newtonian approximation

2020 ◽  
Vol 29 (13) ◽  
pp. 2050093
Author(s):  
J. C. Castro-Palacio ◽  
P. Fernández de Córdoba ◽  
J. M. Isidro
Keyword(s):  
Cosmological Constant ◽  
Quantum Mechanical ◽  
Nonrelativistic Quantum ◽  
Expectation Value ◽  
Simple Quantum ◽  
Emergent Spacetime ◽  
Nonrelativistic Quantum Mechanics ◽  
The Given ◽  
The Universe ◽  
Matter Fields

We present a simple quantum-mechanical estimate of the cosmological constant of a Newtonian Universe. We first mimic the dynamics of a Newtonian spacetime by means of a nonrelativistic quantum mechanics for the matter contents of the Universe (baryonic and dark) within a fixed (i.e. nondynamical) Euclidean spacetime. Then we identify an operator that plays, on the matter states, a role analogous to that played by the cosmological constant. Finally, we prove that there exists a quantum state for the matter fields, in which the above-mentioned operator has an expectation value equal to the cosmological constant of the given Newtonian Universe.

scholarly journals INTRINSICALLY QUANTUM-MECHANICAL GRAVITY AND THE COSMOLOGICAL CONSTANT PROBLEM

2011 ◽  
Vol 26 (32) ◽  
pp. 2375-2389 ◽  
Author(s):  
PHILIP D. MANNHEIM
Keyword(s):  
Cosmological Constant ◽  
Conformal Symmetry ◽  
Zero Point ◽  
Dynamical Symmetry ◽  
Matter Field ◽  
Quantum Mechanical ◽  
Conformal Invariant ◽  
Cosmological Constant Problem ◽  
The Universe ◽  
Matter Fields

We propose that gravity be intrinsically quantum-mechanical, so that in the absence of quantum mechanics the geometry of the universe would be Minkowski. We show that in such a situation gravity does not require any independent quantization of its own, with it being quantized simply by virtue of its being coupled to the quantized matter fields that serve as its source. We show that when the gravitational and matter fields possess an underlying conformal symmetry, the gravitational field and fermionic matter-field zero-point fluctuations cancel each other identically. Then, when the fermions acquire mass by a dynamical symmetry breaking procedure that induces a cosmological constant in such conformal theories, the zero-point fluctuations readjust so as to cancel the induced cosmological constant identically. The zero-point vacuum problem and the cosmological constant vacuum problems thus mutually solve each other. We illustrate our ideas in a completely solvable conformal-invariant model, namely two-dimensional quantum Einstein gravity coupled to a Nambu–Jona-Lasinio self-consistent fermion.

scholarly journals TIME, VACUUM ENERGY, AND THE COSMOLOGICAL CONSTANT

2009 ◽  
Vol 18 (14) ◽  
pp. 2265-2268 ◽  
Author(s):  
VIQAR HUSAIN
Keyword(s):  
Quantum Gravity ◽  
Cosmological Constant ◽  
Vacuum Energy ◽  
Cosmological Constant Problem ◽  
Problem Of Time ◽  
The Relationship

We describe a link between the cosmological constant problem and the problem of time in quantum gravity. This arises from examining the relationship between the cosmological constant and vacuum energy in light of nonperturbative formulations of quantum gravity.

scholarly journals On The Symmetry of The Universe

2020 ◽  
Author(s):  
Engel Roza
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Thermodynamic Equilibrium ◽  
Vacuum Energy ◽  
Quantum Mechanical ◽  
Baryonic Matter ◽  
Time Uncertainty ◽  
Matter Effect ◽  
Mechanical Interpretation ◽  
The Universe

It is shown that the Lambda component in the cosmological Lambda-CDM model can be conceived as vacuum energy, consisting of gravitational particles subject to Heisenberg’s energy-time uncertainty. These particles can be modelled as elementary polarisable Dirac-type dipoles (“darks”) in a fluidal space at thermodynamic equilibrium, with spins that are subject to the Bekenstein-Hawking entropy. Around the baryonic kernels, uniformly distributed in the universe, the spins are polarized, thereby invoking an increase of the effective gravitational strength of the kernels. It explains the dark matter effect to the extent that the numerical value of Milgrom’s acceleration constant can be assessed by theory. Non-polarized vacuum particles beyond the baryonic kernels compose the dark energy. The result is a quantum mechanical interpretation of gravity in terms of quantitatively established shares in baryonic matter, dark matter and dark energy, which correspond with the values of the Lambda-CDM model..

scholarly journals The nature of the gravitational vacuum

2019 ◽  
Vol 28 (14) ◽  
pp. 1944005
Author(s):  
Samir D. Mathur
Keyword(s):  
Black Hole ◽  
String Theory ◽  
Cosmological Constant ◽  
Mass Formula ◽  
Vacuum Energy ◽  
Planck Scale ◽  
Cosmological Constant Problem ◽  
Horizon Radius ◽  
Number Formula ◽  
Gravitational Vacuum

The vacuum must contain virtual fluctuations of black hole microstates for each mass [Formula: see text]. We observe that the expected suppression for [Formula: see text] is counteracted by the large number [Formula: see text] of such states. From string theory, we learn that these microstates are extended objects that are resistant to compression. We argue that recognizing this ‘virtual extended compression-resistant’ component of the gravitational vacuum is crucial for understanding gravitational physics. Remarkably, such virtual excitations have no significant effect for observable systems like stars, but they resolve two important problems: (a) gravitational collapse is halted outside the horizon radius, removing the information paradox, (b) spacetime acquires a ‘stiffness’ against the curving effects of vacuum energy; this ameliorates the cosmological constant problem posed by the existence of a planck scale [Formula: see text].

scholarly journals WHY THERE IS SOMETHING SO CLOSE TO NOTHING: TOWARDS A FUNDAMENTAL THEORY OF THE COSMOLOGICAL CONSTANT

2007 ◽  
Vol 22 (10) ◽  
pp. 1797-1818 ◽  
Author(s):  
VISHNU JEJJALA ◽  
DJORDJE MINIC
Keyword(s):  
Quantum Theory ◽  
String Theory ◽  
Cosmological Constant ◽  
Vacuum Energy ◽  
Uncertainty Relation ◽  
Space Time ◽  
Large Size ◽  
Minkowski Space Time ◽  
The Universe ◽  
Canonical Quantum

The cosmological constant problem is turned around to argue for a new foundational physics postulate underlying a consistent quantum theory of gravity and matter, such as string theory. This postulate is a quantum equivalence principle which demands a consistent gauging of the geometric structure of canonical quantum theory. We argue that string theory can be formulated to accommodate such a principle, and that in such a theory the observed cosmological constant is a fluctuation about a zero value. This fluctuation arises from an uncertainty relation involving the cosmological constant and the effective volume of space–time. The measured, small vacuum energy is dynamically tied to the large "size" of the universe, thus violating naive decoupling between small and large scales. The numerical value is related to the scale of cosmological supersymmetry breaking, supersymmetry being needed for a nonperturbative stability of local Minkowski space–time regions in the classical regime.

BLACK HOLE QUANTIZATION, THERMODYNAMICS AND COSMOLOGICAL CONSTANT

2004 ◽  
Vol 13 (05) ◽  
pp. 885-898
Author(s):  
LI XIANG
Keyword(s):  
Black Hole ◽  
Cosmological Constant ◽  
Vacuum Energy ◽  
Planck Scale ◽  
Additional Term ◽  
Logarithmic Correction ◽  
De Sitter ◽  
Horizon Area ◽  
Constant Distance ◽  
The Universe

Bekenstein argues that the horizon area of a black hole has a constant distance spectrum. We investigate the effects of such a discrete spectrum on the thermodynamics of a Schwarzchild black hole (SBH) and a Schwarzchild–de Sitter black hole (SdBH), in terms of the time-energy uncertainty relation and Stefan–Boltzman law. For the massive SBH, a negative and logarithmic correction to the Bekenstein–Hawking entropy is obtained, as well as other authors by using other methods. As to the minimal hole near the Planck scale, its entropy is no longer proportional to the horizon area, but is of order of the mass of the hole. This is similar to an excited stringy state. The vanishing heat capacity of such a minimal black hole implies that it may be a remnant as the ground state of the evaporating hole. The properties of a SdBH are similar to the SBH, except for an additional term of square area associated with the cosmological constant. In order to maintain the validity of the Bekenstein–Hawking formula, the cosmological constant is strongly limited by the size of the biggest black hole in the universe. A relation associated with the cosmological constant, Planck area and the Stefan–Boltzman constant is obtained. The cosmological constant is not only related to the vacuum energy, but is also related to the thermodynamics.

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