Dolphin cognitive capabilities have been explored by investigating their neural anatomy, their social behavior in the wild, and by analysis of their complex vocalizations used for communication and environmental perception. After a brief introduction to dolphin hearing, sounds, and neurophysiology, and an even briefer discussion of sound propagation in the ocean, an analysis is given of some representative vocalizations. It is also shown that Mathematica offers a tool for easily synthesizing dolphin-like sounds that could be as basis for constructing a pidgin type language for human-dolphin communication.
It has been suggested that the north-polar hexagon found on Saturn is an unusual Rossby wave. If this is to be the case, one must not only explain how a Rossby wave can be hexagonal in shape, albeit with curved corners, but also why it is hexagonal rather than in the form of some other polygon. It is likely that a spectrum of Rossby waves with different amplitudes and wavelengths resulting from the velocity profile of the hexagonal jet is responsible for its shape.
Link for Saturn video (3rd slide):
This book takes the reader from some elementary ideas about groups to the essence of the Standard Model of particle physics along a relatively straight and intuitive path. Groups alone are first used to arrive at a classical analog of the Dirac equation. Using elementary quantum mechanics, this analog can be turned into the actual Dirac equation, which governs the motion of the quarks and leptons of the Standard Model. After introduction to the gauge principle, the groups introduced in the beginning of the book are used to give an introduction to the Standard Model. The idea is to give an Olympian view of this evolution, one that is often missing when absorbing the detailed subject matter of the Standard Model as presented in an historical approach to the subject.
Published by World Scientific:
The chiral anomaly is a purely quantum mechanical phenomenon that has a long history dating back to the late 1960s. Surprisingly, it has recently made a macroscopic appearance in condensed matter physics. A brief introduction to the relevant features of this anomaly is given and it is shown that its appearance in condensed matter systems must involve force-free magnetic fields, which may help explain the long current relaxation times in Dirac and Weyl semimetals.
Canadian Journal of Physics: Published on the web 13 March 2017, 10.1139/cjp
The published version is available here:
The idea that particles are the basic constituents of all matter dates back to ancient times and formed the basis of physical thought well into modern times. The debate about whether light was a wave or a stream of particles also lasted until relatively recently. It was the advent of de Broglie’s work and its implications that revolutionized the concept of an elementary particle–but unfortunately did not banish the idea of a point particle despite its difficulties in both classical and quantum physics. Some of these problems are discussed in this essay, which covers chiral oscillations, Penrose’s “zigzag” picture of particles satisfying the Dirac equation, and some ideas derived from string theory.
This essay examines our fundamental conceptions of time, spacetime, the asymmetry of time, and the motion of a quantum mechanical particle. The concept of time has multiple meanings and these are often confused in the literature and must be distinguished if any light is to be thrown on this age-old issue. The asymmetry of time also has different meanings that depend on context—although the fundamental time asymmetry is associated with the expansion of the universe. These and related issues are discussed in both classical and quantum mechanical contexts.
(This version has been expanded and reorganized)
The Einstein field equations have no known and acceptable interior solution that can be matched to an exterior Kerr field. In particular, there are no interior solutions that could represent objects like the Earth or other rigidly rotating astronomical bodies. It is shown here that there exist closed surfaces upon which the frame-dragging angular velocity and the red-shift factor for the Kerr metric are constant. These surfaces could serve as a boundary between rigidly rotating sources for the Kerr metric and the Kerr external field.
In the December 2013 issue of Physics Today David Kramer tells us—in an article titled A nuclear bomb worth more than its weight in gold?—that “some critics of the B-61 life extension program question whether the program is necessary.” And, “Representative John Garamendi (D-CA) questioned why the B-83, a newer bomb that officials acknowledge won’t need a life extension for at least 10 years, shouldn’t replace the B-61”. Strangely enough the article omits the principal reason why the administration may think the B-61 is worth more than its weight in gold.
The article appears in Physics & Society 6 Feb 2014. The link is:
The MS with better quality figures and equations is available here: P&S-EPW-nid
The late 19th century and the beginning of the 20th brought with it a revolution in the scientific understanding of the universe around us, one whose effects are still being felt around the world as it forces people to change their ideas about the universe and the place of human beings within it. Even a conceptual understanding of the early origin of the universe requires an introductory knowledge of quantum mechanics. Unfortunately, the attempt to reconcile quantum mechanics with concepts brought over from classical mechanics has led to much confusion especially among non-physicists and students of physics. This essay is an attempt to address some of this wide spread confusion.
It is the purpose of this essay to take the reader from some elementary ideas about groups to the essence of the Standard Model of particle physics along a relatively straight and intuitive path. The idea is to give an Olympian view of this evolution, one that is often missing when absorbing the detailed subject matter of the Standard Model as presented in an historical approach to the subject.
p.58: First equation should read
p. 59: Line after 2nd equation from the bottom of the page should read, “This corresponds to a right-handed spinor and, for spin 1/2 is designated (1/2, 0).”
The end of the last line should read, ” . . . is designated by (0, 1/2).”