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V. Hnizdo

Publications and source records attributed to V. Hnizdo.

32 records · Page 2Linked to original sources
arXiv2004

On linear momentum in quasistatic electromagnetic systems

The analysis of Aguirregabiria, Hernandez, and Rivas [2004 Eur. J. Phys. 25, 555--567] of the electromagnetic linear momentum in quasistatic systems omits the presence of an equal and opposite hidden mechanical momentum in such systems. The existence of hidden mechanical momentum ensures that the action--reaction law holds for the forces between the charge- and current-carrying bodies of a quasistatic system, and thus the total mechanical momentum associated with the motion of such bodies in a closed quasistatic system is conserved.

physics.class-ph↗
arXiv2004

Potentials of a uniformly moving point charge in the Coulomb gauge

The Coulomb-gauge vector potential of a uniformly moving point charge is obtained by calculating the gauge function for the transformation between the Lorenz and Coulomb gauges. The expression obtained for the difference between the vector potentials in the two gauges is shown to satisfy a Poisson equation to which the inhomogeneous wave equation for this quantity can be reduced. The right-hand side of the Poisson equation involves an important but easily overlooked delta-function term that arises from a second-order partial derivative of the Coulomb potential of a point charge.

physics.class-ph↗
arXiv2003

Comment on `Vector potential of the Coulomb gauge'

The expression for the Coulomb-gauge vector potential in terms of the `instantaneous' magnetic field derived by Stewart [2003 Eur. J. Phys. 24, 519] by employing Jefimenko's equation for the magnetic field and Jackson's formula for the Coulomb-gauge vector potential can be proven much more simply.

physics.class-ph↗
arXiv2003

Comment on `About the magnetic field of a finite wire'

A flaw is pointed out in the justification given by Charitat and Graner [2003 Eur. J. Phys. vol. 24, 267] for the use of the Biot--Savart law in the calculation of the magnetic field due to a straight current-carrying wire of finite length.

physics.class-ph↗
arXiv2002

Response to Compagno and Persico

Some mathematically incorrect claims of Compagno and Persico in their reply (2002 J. Phys. A: Math. Gen. 35, 8965) to my comment on their recent paper on self-dressing and radiation reaction in classical electrodynamics are pointed out.

physics.class-ph↗
arXiv2002

Geometric factors in the Bohr--Rosenfeld analysis of the measurability of the electromagnetic field

The Geometric factors in the field commutators and spring constants of the measurement devices in the famous analysis of the measurability of the electromagnetic field by Bohr and Rosenfeld are calculated using a Fourier--Bessel method for the evaluation of folding integrals, which enables one to obtain the general geometric factors as a Fourier--Bessel series. When the space region over which the factors are defined are spherical, the Fourier--Bessel series terms are given by elementary functions, and using the standard Fourier-integral method of calculating folding integrals, the geometric factors can be evaluated in terms of manageable closed-form expressions.

math-ph↗
arXiv2002

Comment on 'Self-dressing and radiation reaction in classical electrodynamics'

Using the canonical formalism, Compagno and Persico [J. Phys. A: Math. Gen. 35 (2002) 3629--45] have calculated the 'radiation-reaction' force on a uniform spherical charge moving rigidly, slowly and slightly from its position at the time when the transverse electric field is assumed to vanish. This force is shown to result in the same time-averaged self-force as that which has been obtained by different means for the test charge of a Bohr--Rosenfeld field-measurement procedure and which Compagno and Persico claimed to be incorrect.

physics.class-ph↗
arXiv2002

Comment on "Limits of the measurability of the local quantum electromagnetic-field amplitude"

It is argued that the findings of a recent reanalysis by Compagno and Persico [Phys. Rev. A 57, 1595 (1998)] of the Bohr--Rosenfeld procedure for the measurement of a single space-time-averaged component of the electromagnetic field are incorrect when the field measurement time is shorter than that required for light to traverse the measurement's test body. To this end, the time-averaged "self-force" on the test body, assumed for simplicity to be of a spherical shape, is evaluated in terms of a one-dimensional quadrature for the general trajectory allowed for the test body by Compagno and Persico, and in closed form for the limiting steplike trajectory used by Bohr and Rosenfeld.

quant-ph↗
arXiv2000

The electromagnetic self-force on a charged spherical body slowly undergoing a small, temporary displacement from a position of rest

The self-force of classical electrodynamics on a charged "rigid" body of radius R is evaluated analytically for the body undergoing a slow (i.e., with a speed v<<c), slight (i.e., small compared to R), and temporary displacement from an initial position of rest. The results are relevant to the Bohr-Rosenfeld analysis of the measurability of the electromagnetic field, which has been the subject of a recent controversy.

math-ph↗
arXiv1994

A Microscopic T-Violating Optical Potential: Implications for Neutron-Transmission Experiments

We derive a T-violating P-conserving optical potential for neutron-nucleus scattering, starting from a uniquely determined two-body $ρ$-exchange interaction with the same symmetry. We then obtain limits on the T-violating $ρ$-nucleon coupling $\overline{g}_ρ$ from neutron-transmission experiments in $^{165}$Ho. The limits may soon compete with those from measurements of atomic electric-dipole moments.

nucl-th↗
arXiv1993

Optical-Model Description of Time-Reversal Violation

A time-reversal-violating spin-correlation coefficient in the total cross section for polarized neutrons incident on a tensor rank-2 polarized target is calculated by assuming a time-reversal-noninvariant, parity-conserving ``five-fold" interaction in the neutron-nucleus optical potential. Results are presented for the system $n + {^{165}{\rm Ho}}$ for neutron incident energies covering the range 1--20 MeV. From existing experimental bounds, a strength of $2 \pm 10$ keV is deduced for the real and imaginary parts of the five-fold term, which implies an upper bound of order $10^{-4}$ on the relative $T$-odd strength when compared to the central real optical potential.

nucl-th↗