On the linear response of Bardeen–Cooper–Schrieffer superconductors I. clean superconductors

We calculate the linear response of a Bardeen–Cooper–Schrieffer superconductor to transverse and longitudinal electromagnetic radiation. Oscillations in the pair potential are also investigated. The order parameter and electric field of a point charge imbedded in a superconductor are also calculated. We assume a reasonable bare potential for the point charge. Finally, the linear response to the order parameter and magnetic vector potential is calculated for a reasonable model of a magnetic point dipole, again employing a more accurate model for the spin impurity than the usual delta-function approximation.

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On the calculus of Dirac delta function with some applications in classical electrodynamics

Revista Mexicana de Física E ◽

10.31349/revmexfise.18.020205 ◽

2021 ◽

Vol 18 (2 Jul-Dec) ◽

pp. 020205

Author(s):

Milan S. Kovacevic ◽

Miroslav R. Jovanovic ◽

Marko M. Milosevic

Keyword(s):

Charge Density ◽

Point Charge ◽

Delta Function ◽

Analytical Framework ◽

Dirac Delta Function ◽

Classical Electrodynamics ◽

Mathematical Tool ◽

Point Dipole ◽

Dirac Delta ◽

Physics Curriculum

The Dirac delta function is a concept that is useful throughout physics as a standard mathematical tool that appears repeatedly in the undergraduate physics curriculum including electrodynamics, optics, and quantum mechanics. Our analysis was guided by an analytical framework focusing on how students activate, construct, execute, and reflect on the Dirac delta function in the context of classical electrodynamics problems solving. It’s applications in solving the charge density associated with a point charge as well as electrostatic point dipole field, for more advanced situations to describe the charge density of hydrogen atom were presented.

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Space–time diagram approach in derivation of Lienard–Wiechert potential for a moving point charge

Canadian Journal of Physics ◽

10.1139/cjp-2013-0073 ◽

2013 ◽

Vol 91 (7) ◽

pp. 519-521

Author(s):

Biswaranjan Dikshit

Keyword(s):

Point Charge ◽

Scalar Potential ◽

Charged Particles ◽

Space Time ◽

Classical Electrodynamics ◽

Magnetic Vector Potential ◽

Time Diagram ◽

Magnetic Vector ◽

Electric And Magnetic Fields ◽

Diagram Approach

In classical electrodynamics, electric and magnetic fields at a point due to moving charges are calculated from the electric scalar potential and magnetic vector potential. For a moving point charge, this potential is known as Lienard–Wiechert potential and is derived in many different ways in textbooks. In this paper, we derive the retarded Lienard–Wiechert potential in a new graphical manner using space–time diagrams so that the derivation becomes more appealing and we can visualize the reason for the presence of an additional velocity-dependant factor in the denominator of the expression for the Lienard–Wiechert potential. The derivation is valid even for charged particles moving at relativistic speeds.

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A note on ”a note on the magnetic vector potential”

Journal of Electrical Engineering ◽

10.2478/jee-2018-0036 ◽

2018 ◽

Vol 69 (3) ◽

pp. 259-260

Author(s):

L’ubomír Šumichrast ◽

Rastislav Dosoudil

Keyword(s):

Vector Potential ◽

Point Charge ◽

Scalar Potential ◽

Short Paper ◽

Magnetic Vector Potential ◽

Magnetic Vector ◽

Rigorous Approach ◽

Alternative Approach ◽

Electromagnetic Field Theory ◽

Paper Author

Abstract In the recently published short paper author deals with the derivation of the scalar potential pertaining to the point charge as well as of the vector potential pertaining to the point current. He shows his alternative approach and compares it to the ”traditional” methods commonly used in textbooks. Here we want to show that use of the generalised functions (symbolic functions, distributions) in the domain of electromagnetic field theory provides more straightforward and more rigorous approach to the problem.

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