scholarly journals Chaos and semiclassical limit in quantum cosmology

1995 ◽  
Vol 51 (12) ◽  
pp. 6821-6828 ◽  
Author(s):  
Esteban Calzetta ◽  
Juan José Gonzalez
Keyword(s):  
Quantum Cosmology ◽  
Semiclassical Limit

scholarly journals Clock Time in Quantum Cosmology

Universe ◽  
2019 ◽  
Vol 5 (2) ◽  
pp. 66
Author(s):  
Marcello Rotondo ◽  
Yasusada Nambu
Keyword(s):  
Harmonic Oscillator ◽  
Quantum Cosmology ◽  
Schrodinger Equation ◽  
Semiclassical Limit ◽  
Cosmic Time ◽  
Wave Functions ◽  
Degree Of Freedom ◽  
Clock Time ◽  
Quantum Harmonic Oscillator ◽  
Flrw Universe

We consider the conditioning of the timeless solution to the Wheeler–DeWitt equation by a predefined matter clock state in the simple scenario of an FLRW universe. The resulting evolution of the geometrodynamical degree of freedom with respect to clock time is characterized by the “Berry connection” of the reduced geometrodynamical space, which relies on the coupling of the clock with the geometry. When the connection vanishes, the standard Schrödinger equation is obtained for the geometry with respect to clock time. When one considers environment-induced decoherence in the semiclassical limit, this condition is satisfied, and clock time coincides with cosmic time. Explicit results for the conditioned wave functions for minimal clocks made up of two quantum harmonic oscillator eigenstates are shown.

scholarly journals SYMMETRIES OF AXION–DILATON STRING COSMOLOGY

2005 ◽  
Vol 20 (07) ◽  
pp. 1441-1469 ◽  
Author(s):  
JNANADEVA MAHARANA
Keyword(s):  
Quantum Cosmology ◽  
Chaotic Behavior ◽  
Semiclassical Limit ◽  
Wave Functions ◽  
Duality Group ◽  
Duality Symmetry ◽  
Complete Set ◽  
The One ◽  
High Degree ◽  
Theory Technique

The axion–dilaton string effective action is expressed in Einstein frame metric in a manifestly S-duality invariant form. It is shown that the moduli can be redefined to describe surface of a (2+1)-dimensional pseudosphere. The classical cosmological solutions of axion–dilaton are revisited. The Wheeler–DeWitt equation for the system is exactly solved and complete set of eigenfunctions are presented. The wave function factorizes and the one depending on the moduli is obtained by appealing to the underlying S-duality symmetry. Axion and dilaton parametrize [Formula: see text], the S-duality group, and the Hamiltonian is expressed as a sum of the Ricci scalar and the Casimir of SU (1, 1). Therefore, the complete set of wave functions, depending on the moduli, is obtained from group theory technique. The evidence for the existence of a W-infinity algebra in axion–dilaton cosmology is presented and the origin of the algebra is primarily due to high degree of degeneracies in the wave functions. It is qualitatively argued that axion–dilaton quantum cosmology exhibits chaotic behavior in the semiclassical limit.

ON THE SEMICLASSICAL LIMIT OF LOOP QUANTUM COSMOLOGY

2012 ◽  
Vol 21 (09) ◽  
pp. 1250076 ◽  
Author(s):  
ALEJANDRO CORICHI ◽  
EDISON MONTOYA
Keyword(s):  
Coherent State ◽  
Quantum Cosmology ◽  
Coherent States ◽  
Semiclassical Limit ◽  
Loop Quantum Cosmology ◽  
Squeezed States ◽  
Gaussian States ◽  
Exactly Solvable ◽  
Spatial Topology ◽  
Frw Model

We consider a k = 0 Friedman–Robertson–Walker (FRW) model within loop quantum cosmology (LQC) and explore the issue of its semiclassical limit. The model is exactly solvable and allows us to construct analytical (Gaussian) coherent-state solutions for each point on the space of classical states. We propose physical criteria that select from these coherent states, those that display semiclassical behavior, and study their properties in the deep Planck regime. Furthermore, we consider generalized squeezed states and compare them to the Gaussian states. The issue of semiclassicality preservation across the bounce is studied and shown to be generic for all the states considered. Finally, we comment on some implications these results have, depending on the topology of the spatial slice. In particular, we consider the issue of the recovery, within our class of states, of a scaling symmetry present in the classical description of the system when the spatial topology is noncompact.

The semiclassical limit of the intermediate scattering function

1996 ◽  
Vol 89 (4) ◽  
pp. 1203-1207
Author(s):  
S. BONELLA ◽  
G. CICCOTTI ◽  
D.F. COKER
Keyword(s):  
Semiclassical Limit ◽  
Scattering Function ◽  
Intermediate Scattering Function

scholarly journals Bootstrapped Newtonian Cosmology and the Cosmological Constant Problem

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 358
Author(s):  
Roberto Casadio ◽  
Andrea Giusti
Keyword(s):  
Black Holes ◽  
Cosmological Constant ◽  
Quantum Cosmology ◽  
Quantum Physics ◽  
Gravitational Interaction ◽  
Newtonian Gravity ◽  
Cosmological Constant Problem ◽  
Newtonian Cosmology ◽  
Natural Solution ◽  
The Impact

Bootstrapped Newtonian gravity was developed with the purpose of estimating the impact of quantum physics in the nonlinear regime of the gravitational interaction, akin to corpuscular models of black holes and inflation. In this work, we set the ground for extending the bootstrapped Newtonian picture to cosmological spaces. We further discuss how such models of quantum cosmology can lead to a natural solution to the cosmological constant problem.

scholarly journals Decoherence in quantum cosmology at the onset of inflation

1999 ◽  
Vol 551 (1-2) ◽  
pp. 374-396 ◽  
Author(s):  
A.O Barvinsky ◽  
A.Yu Kamenshchik ◽  
C Kiefer ◽  
I.V Mishakov
Keyword(s):  
Quantum Cosmology

scholarly journals The Semiclassical Limit of the Gailitis Formula Applied to Electron Impact Broadening of Spectral Lines of Ionized Atoms

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 29
Author(s):  
Sylvie Sahal-Bréchot
Keyword(s):  
Electron Impact ◽  
Classical Limit ◽  
Semiclassical Limit ◽  
Spectral Lines ◽  
Stark Broadening ◽  
Feshbach Resonances

The present paper revisits the determination of the semi-classical limit of the Feshbach resonances which play a role in electron impact broadening (the so-called “Stark“ broadening) of isolated spectral lines of ionized atoms. The Gailitis approximation will be used. A few examples of results will be provided, showing the importance of the role of the Feshbach resonances.

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