Modelling and Analysis of Permanent Magnet Electrodynamic Suspension Systems

Rezaei, Hossein; Vaez‐Zadeh, Sadegh

doi:10.2528/pierm14032407

Cited by 9 publications

(11 citation statements)

References 10 publications

(13 reference statements)

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“…The above formula is the canonical implementation of the RVM for the present universe and it shows that it predicts a certain degree of dynamics for the vacuum energy density provided |ν| is small but not negligible, what is corroborated by the fitting values to the latest observations, where one finds ν ∼ 10 −3 -see e.g. [82][83][84].…”

Section: B Rvm For the Current Universesupporting

confidence: 57%

“…Let us emphasize that Occam's razor is preferred only if it works better, but sometimes additional assumptions can be more efficient. The idea of dynamical vacuum energy can be helpful for the study of our speeding up universe, and it proves competitive enough in the description of the overall cosmological data [77][78][79][80][81][82][83][84]. For this reason we shall focus on the thermodynamical aspects of the class of the dynamical vacuum models (DVMs) and particulary on the subclass of the running vacuum models (RVMs), which we will introduce in more detail in Sec.…”

Section: Dynamical Vacuum Modelsmentioning

confidence: 99%

“…the ΛCDM, see e.g. [77][78][79][80][81][82][83][84]. The RVM can also be extended such that it can also encompass the physics of inflation and its transition to the standard radiation epoch, see [70,71] and [67,72].…”

Section: Running Vacuum Modelsmentioning

confidence: 99%

“…Equilibrium is nevertheless approached in an asymptotic way. Interestingly enough, the recent and successful confrontation of the RVM against the overall cosmological data show that these models are competitive with those from the ΛCDM; and they render ν ∼ 10 −3 > 0 as the characteristic order of magnitude of the running vacuum parameter [77][78][79][80][81][82][83][84].…”

Section: Current Universementioning

confidence: 99%

“…Phenomenologically, the class of RVM models show very good consistency with the observational data, see Refs. [77][78][79][80][81][82][83][84][85][86]. Moreover, it has been shown that some tensions of the concordance ΛCDM model with the data can be alleviated with the option of dynamical vacuum or mimicking it, see e.g.…”

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confidence: 99%

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Particle and entropy production in the running vacuum universe

Peracaula

2020

Gen Relativ Gravit

128

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We study particle production and the corresponding entropy increase in the context of cosmology with dynamical vacuum. We focus on the particular form that has been called "running vacuum model" (RVM), which is known to furnish a successful description of the overall current observations at a competitive level with the concordance ΛCDM model. It also provides an elegant global explanation of the cosmic history from a non-singular initial state in the very early universe up to our days and further into the final de Sitter era. The model has no horizon problem and offers an alternative explanation for the early inflation and its graceful exit, as well as a powerful mechanism for generating the large entropy of the current universe. The energy-momentum tensor of matter is generally non-conserved in such context owing to particle creation or annihilation.We analyze general thermodynamical aspects of particle and entropy production in the RVM. We first study the entropy of particles in the comoving volume during the early universe and late universe. Then, in order to obtain a more physical interpretation, we pay attention to the entropy contribution from the cosmological apparent horizon, its interior and its surface. On combining the inner volume entropy with the entropy on the horizon, we elucidate with detailed calculations whether the evolution of the entropy of the RVM universe satisfies the Generalized Second Law of Thermodynamics. We find it is so and we prove that the essential reason for it is the existence of a positive cosmological constant.

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Section: B Rvm For the Current Universesupporting

confidence: 57%

Section: Dynamical Vacuum Modelsmentioning

confidence: 99%

Section: Running Vacuum Modelsmentioning

confidence: 99%

Section: Current Universementioning

confidence: 99%

mentioning

confidence: 99%

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Particle and entropy production in the running vacuum universe

Peracaula

2020

Gen Relativ Gravit

128

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Linear permanent magnet electrodynamic suspension system: Dynamic characteristics, magnetic-mechanical coupling and filed test

Shi,

Deng,

et al. 2024

Measurement

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Scalar field theory description of the running vacuum model: the vacuumon

Basilakos

Mavromatos

Peracaula

2019

J. Cosmol. Astropart. Phys.

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We investigate the running vacuum model (RVM) in the framework of scalar field theory. This dynamical vacuum model provides an elegant global explanation of the cosmic history, namely the universe starts from a non-singular initial de Sitter vacuum stage, it passes smoothly from an early inflationary era to a radiation epoch ("graceful exit") and finally it enters the dark matter and dark energy (DE) dominated epochs, where it can explain the large entropy problem and predicts a mild dynamical evolution of the DE. Within this phenomenologically appealing context, we formulate an effective classical scalar field description of the RVM through a field φ, called the vacuumon, which turns out to be very helpful for an understanding and practical implementation of the physical mechanisms of the running vacuum during both the early universe and the late time cosmic acceleration. In the early universe the potential for the vacuumon may be mapped to a potential that behaves similarly to that of the scalaron field of Starobinsky-type inflation at the classical level, whilst in the late universe it provides an effective scalar field description of DE. The two representations, however, are not physically equivalent since the mechanisms of inflation are entirely different. Moreover, unlike the scalaron, vacuumon is treated as a classical background field, and not a fully fledged quantum field, hence cosmological perturbations will be different between the two pictures of inflation.

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Modelling and Analysis of Permanent Magnet Electrodynamic Suspension Systems

Cited by 9 publications

References 10 publications

Particle and entropy production in the running vacuum universe

Particle and entropy production in the running vacuum universe

Linear permanent magnet electrodynamic suspension system: Dynamic characteristics, magnetic-mechanical coupling and filed test

Scalar field theory description of the running vacuum model: the vacuumon

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