Magnetic monopoles form an inspiring chapter of theoretical physics, covering a variety of surprising subjects. We review their role in nonabelian gauge theories. An exposé of exquisite physics derived from a hypothetical particle species, because the fact remains that in spite of ever more tempting arguments from theory, monopoles have never reared their head in experiment. For many relevant p...

Certain magnetic recording applications call for a large number of sequences whose differences do not include certain disallowed binary patterns. We show that the number of such sequences increases exponentially with their length and that the growth rate, or capacity, is the logarithm of the joint spectral radius of an appropriately defined set of matrices. We derive a new algorithm for determi...

Despite 180 years of theory on magnetism, it appears that the practice of calculating forces on magnetic media is ambiguous, as illustrated by a recent article by Casperson [1]. Potentially troubling issues include: Which field B or H should be used? This issue was raised by Einstein [2, 3, 4, 5] who gave a now-nonstandard answer, which has no doubt prolonged this debate. Should the total field...

We calculate the magnetic moments of the pentaquark states from different models and compare our results with predictions of other groups. PACS number: 12.39.Mk, 14.20.-C, 12.39.-x

Magnetic nanoparticles (NPs) show interesting size/shape-dependent magnetism and magnetic transition from ferromagnetism to superparamagnetism. Such unique nanomagnetism has been studied extensively in the hope to optimize magnetic NPs for future magnetic data storage, energy storage and biomedicine applications. To achieve any of these application goals, the size, composition, shape and surfac...

Experiments with polarized ion beams in storage rings can provide new testing grounds of fundamental physics. A feasible experiment for the search of space-parity nonconservation effects in He-like Eu and an experiment to search for time-reversal noninvariance with bare high-Z polarized nuclei have been proposed. Both goals can be achieved provided a polarized one-electron ion beam will be avai...

An analytical model for the read back signal is derived for perpendicular and longitudinal magnetic recording. The model captures the contribution of a single bit rather than the contribution of a bit transition which makes it applicable to patterned media as well as continuous media. It is based on the law of Biot–Savart and separates the contribution of the magnetic media from the head sensit...