scholarly journals Semiclassical limit problems with concurrent use of several clocks in quantum cosmology

2021 ◽  
Vol 104 (12) ◽  
Author(s):  
Bruno Alexandre ◽  
João Magueijo
Keyword(s):  
Quantum Cosmology ◽  
Semiclassical Limit ◽  
Limit Problems ◽  
Concurrent Use

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.

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

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

384-P: Impact of Concurrent Use of Oral Antidiabetes Agents with Insulin in the Real-World Hospital Setting

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 384-P
Author(s):  
BHARGAVI PATHAM ◽  
SOUMYA CHIKERMANE ◽  
AISHA VADHARIYA ◽  
MICHAEL L. JOHNSON ◽  
ARCHANA R. SADHU
Keyword(s):  
Real World ◽  
Hospital Setting ◽  
The Real ◽  
Concurrent Use

Interaction between Traditional Chinese Medicine and Anticoagulant/Antiplatelet Drugs

2019 ◽  
Vol 20 (9) ◽  
pp. 701-713 ◽  
Author(s):  
Jiajia Li ◽  
Qing Liang ◽  
GuangChun Sun
Keyword(s):  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Drug Interactions ◽  
Adverse Reactions ◽  
Bleeding Risk ◽  
Antiplatelet Drugs ◽  
Pharmacokinetic Studies ◽  
Drug Databases ◽  
Concurrent Use ◽  
Anticoagulant Drugs

Background: Traditional Chinese medicine (TCM) has been used for medical purposes since the ancient time and has gradually gained recognition worldwide. Nowadays, patients with thrombus presiding to anticoagulant/ antiplatelet drugs prefer taking TCM. However, an increasing number of studies on herb–drug interactions have been shown. Nevertheless, findings are frequently conflicting and vague. In this review, we discuss the herb–drug interactions between TCM and anticoagulant/antiplatelet drugs to provide guidance on concomitant ingestion with anticoagulant/antiplatelet drugs. Methods: We undertook a structured search of medicine and drug databases for peer-reviewed literature using focused review questions. Results: Danshen, Ginkgo, Ginger, H. Perforatum, SMY and Puerarin injection had directional regulation effects on the efficacy of anticoagulant drugs by altering the CYPs, pharmacokinetic indexs and hemorheological parameters. H. Perforatum inhibited the efficacy of Clopidogrel by enhancing the CYP3A4 activity and Ginkgo increased the efficacy of Ticlopidine. Additionally, Renshen, the formulae except SMY and injections except Puerarin injection could increase or decrease the efficacy of anticoagulant/antiplatelet drugs via regulating the CYPs, platelet aggregation, hemorheological parameters and others. Conclusion: Some cases have reported that TCMs may increase the bleeding risk or has no effect on coagulation when anticoagulant/antiplatelet drugs are concurrently used. However, pharmacokinetic studies have presented either consistent or slightly varying results. So it is difficult to ascertain whether the concurrent use of TCM may increase or reduce the pharmacologic effects of anticoagulant/antiplatelet drugs with adverse reactions. Therefore, herb–drug interactions of TCM and anticoagulant/antiplatelet drugs should be further explored and defined.

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