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Scalar potential

About: Scalar potential is a research topic. Over the lifetime, 3642 publications have been published within this topic receiving 78868 citations. The topic is also known as: potential.


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TL;DR: In this paper, a 3D finite element (3D-FE) method for the computation of global distributions of 3D magnetic fields in electric machines containing permanent magnets is presented.
Abstract: A three dimensional finite element (3D-FE) method for the computation of global distributions of 3D magnetic fields in electric machines containing permanent magnets is presented. The formulation of this 3D-FE method including 3D permanent magnet modeling, which is based on a coupled magnetic vector potential-magnetic scalar potential (CMVP-MSP) approach, is given. The development of the necessary 3D-FE grids and algorithms for the application of the method to an example brushless DC motor, whose field is three dimensional due to the skewed permanent magnet mounts on its rotor, is also given here. A complete set of results of application of the method to the computation of the global 3D field distributions and associated motor parameters under no-load and load conditions are detailed in a companion paper. >

20 citations

Posted Content
TL;DR: In this article, the authors investigated the global behavior of scalar field cosmological models with very hard potential walls via the simple example of an exponentially steep potential well and found that the solutions exhibit a non-trivial oscillatory behavior in the approach to an initial space-time singularity.
Abstract: The global behavior of scalar field cosmological models with very hard potential walls is investigated via the simple example of an exponentially steep potential well. It is found that the solutions exhibit a non-trivial oscillatory behavior in the approach to an initial space-time singularity. This behavior can be interpreted as being due to the inability of the scalar field to negotiate the walls of the steep potential well.

20 citations

Journal ArticleDOI
TL;DR: In this article, the role of baryons for the structure of dense matter in the Gross-Neveu model was investigated within a variational calculation, and a trial ground state at finite baryon density was constructed, which breaks translational invariance.
Abstract: Within a variational calculation we investigate the role of baryons for the structure of dense matter in the Gross-Neveu model. We construct a trial ground state at finite baryon density which breaks translational invariance. Its scalar potential interpolates between widely spaced kinks and antikinks at low density and the value zero at infinite density. Its energy is lower than the one of the standard Fermi gas at all densities considered. This suggests that the discrete gamma_5 symmetry of the Gross-Neveu model does not get restored in a first order phase transition at finite density, at variance with common wisdom.

20 citations

Journal ArticleDOI
TL;DR: In this article, the electrokinematics theorem has been extended to any type of electromagnetic field and to quasi-relativistic quantum mechanics, in the case of many-particle systems for which, moreover, the probability current density is suitably computed.
Abstract: A recent electrokinematics theorem leads to a general equation that, through an arbitrary irrotational fieldF, connects the motion of the electric-charge carriers, the internal potential and the dielectric properties of a physical system with its external currents, voltages and powers. It has been proved for quasi-electrostatic fields,i.e. when the vector potential may be disregarded, and on the basis of classical mechanics. Here the theorem is extended to any type of electromagnetic field and to quasi-relativistic quantum mechanics, in the case of many-particle systems for which, moreover, the probability current density is suitably computed. The new equation so obtained, throughF, connects the external currents again with the internal electric permittivity and the scalar potential, in the same way as in the preceding approach, and with the carrier velocity that, however, has to be computed according to quantum mechanics. Moreover, it contains two new contributions, one deriving from the vector potential and the other from a current density arising from the electron spin. By means of proper choices ofF, new expressions of the external currents of the system are determined as functions of the motion of its internal carriers. In particular, the electrokinematics theorem is exploited to compute the output current in two-terminal nanoelectronic devices in which, owing to the small sizes, quantum effects cannot be disregarded. Finally, such results, when they are applied to the double-barrier tunnelling structures, allow us to show the splitting of the electron pulse into two uncorrelated pulses, and as a consequence, to obtain a possible shot noise suppression, up to fifty per cent of the full shot noise.

20 citations

Journal ArticleDOI
TL;DR: In this paper, a noncommutative version of the Brans-Dicke (BD) theory is introduced and the Hamiltonian equations of motion for a spatially flat Friedmann-Lema\^{\i}tre-Robertson-Walker universe filled with a perfect fluid.
Abstract: In this paper, we introduce a noncommutative version of the Brans-Dicke (BD) theory and obtain the Hamiltonian equations of motion for a spatially flat Friedmann-Lema\^{\i}tre-Robertson-Walker universe filled with a perfect fluid. We focus on the case where the scalar potential as well as the ordinary matter sector are absent. Then, we investigate gravity-driven acceleration and kinetic inflation in this noncommutative BD cosmology. In contrast to the commutative case, in which the scale factor and BD scalar field are in a power-law form, in the noncommutative case the power-law scalar factor is multiplied by a dynamical exponential warp factor. This warp factor depends on the noncommutative parameter as well as the momentum conjugate associated to the BD scalar field. We show that the BD scalar field and the scale factor effectively depend on the noncommutative parameter. For very small values of this parameter, we obtain an appropriate inflationary solution, which can overcome problems within BD standard cosmology in a more efficient manner. Furthermore, a graceful exit from an early acceleration epoch towards a decelerating radiation epoch is provided. For late times, due to the presence of the noncommutative parameter, we obtain a zero acceleration epoch, which can be interpreted as the coarse-grained explanation.

20 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202321
202238
2021137
2020149
2019147
2018147