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Quantum Accelerating Universe
Published in Xavier Oriols, Jordi Mompart, Applied Bohmian Mechanics, 2019
PedroF. González-Díaz, Alberto Rozas-Fernández
where we have restored the cosmic time t, using the notation of Refs. [90, 97], and [98], so that a suffix X or ϕ denotes a partial derivative with respect to X or ϕ, respectively, and now the last coupling term is Time dependent. Note that if we confine ourselves to the theory where a(t) accelerates in an exponential fashion and ϕ˙2 = 1, then the first term of this equation would vanish. Anyway, in terms of the energy density ρ for the scalar field ϕ, the above general equation becomes formally the same as that which was derived in Ref. [90]: () dρdN+3(1+w)ρ=−QρmdϕdN,
Galaxies at Radio Wavelengths
Published in Ronald L. Snell, Stanley E. Kurtz, Jonathan M. Marr, Fundamentals of Radio Astronomy, 2019
Ronald L. Snell, Stanley E. Kurtz, Jonathan M. Marr
CO emission has been detected in numerous submillimeter galaxies, so it is now possible to ask how the gas content of galaxies has changed over cosmic time. In Section 8.2.2, we discussed that local late-type or disk galaxies typically have a molecular gas mass about one-tenth that of their stellar mass. Surveys, such as that carried out by Roberto Decarli and collaborators21, have shown that at large redshifts, disk galaxies have molecular gas mass to stellar mass ratios ten times larger than local disk galaxies. Such gas-rich submillimeter galaxies are responsible for the ten-fold increase in the cosmic star formation rate density at redshifts between 2 and 3 as compared with today. Thus, as these submillimeter galaxies evolve with time, their gas is converted into stars, decreasing their gas mass leading to a decline in the star formation rate. Galaxies!molecular gasSubmillimeter galaxiesGalaxies!submillimeter galaxiesSubmillimeter galaxies!CO
Spherical metrics in general relativity
Published in Maricel Agop, Ioan Merches, Operational Procedures Describing Physical Systems, 2018
Indeed, making allowance for the relation cosmic time proper time [8] dtdτ=(1-v2v2-nn)-12 $$ \frac{{dt}}{{d\tau }} = ~(1 - \frac{{v^{2} }}{{v^{2} }} - \frac{n}{n})^{{ - \frac{1}{2}}} $$
On The Fractional Domain Analysis of HP TiO2 Memristor Based Circuits with Fractional Conformable Derivative
Published in Cogent Engineering, 2021
For the extension to fractional domain, all conventional derivatives within equation (8) must be replaced by the fractional ones where incommensurate orders have been assumed for more degree of freedom. Since the dimensional consistencies of the fractional derivatives, which are respected to t, have also been considered, the fractional time component parameter or the cosmic time (σ) (Gómez-Aguilar et al., 2012) must be included in the fractional derivative terms of the resulting system of FDEs. As a result, we have