物理学史与哲学

We report on the retrieval of the last missing papers of the "Senatore folder", given by Majorana to one student of his in Naples in 1938, just before his disappearance. The mentioned manuscript is conserved at the Domus Galilaeana in Pisa…

Great opportunities arise for teaching physics, astronomy, and their histories when new discoveries are made that involve concepts accessible to students at every level. Such an opportunity currently exists thanks to the fact that notes…

Julian Schwinger's influence on Twentieth Century science is profound and pervasive. Of course, he is most famous for his renormalization theory of quantum electrodynamics, for which he shared the Nobel Prize with Richard Feynman and…

Semiclassical oscillation of the electron through the nucleus of the H atom yields both the exact energy and the correct orbital angular momentum for l=0 quantum states. Similarly, electron oscillation through the nuclei of H2+ accounts for…

In the centennial of Ettore Majorana's birth (1906-1938?), we re-examine some aspects of his fundamental scientific production in atomic and molecular physics, including a not well known short communication. There, Majorana critically…

A brief recollection is made of the many scientific collaborations of Bologna with colleagues from Developing Countries. In particular are discussed in detail the collaborations in some recent Astroparticle Physics experiments.

The goal of this report is to provide an up to date account of results on the quantum nature of the big bang, obtained in loop quantum cosmology. They suggest a radical modification of the paradigm provided by general relativity for the…

According to Dirac's theory of the positron, an electromagnetic field tends to create pairs of particles which leads to a change of Maxwell's equations in the vacuum. These changes are calculated in the special case that no real electrons…

The role mathematics plays within physics has been of sustained interest for physicists as well as for philosophers and historians of science. We explore this topic by tracing the role the mathematical structure associated with SU(2) has…

In this short note, a brief overview with a critical appraisal of the acclaimed singularity theorems, the most genuine post-Einsteinian result of General Relativity, is presented.

We show that a number of apparently separate extravagant Majorana's actions, including those connected with his disappearance are united by the invariant of behavior. It is based on "carrying into life" the principles of quantum theory. We…

Professor A. K. Raychaudhuri suddenly passed away on 18th June 2005. I have attempted to give a glimpse of his life and work, and more specifically his role as a great teacher and inspiring force to three generations of students of the…

An account is given on the first studies on the physics of ammonia, focusing on the infrared spectra of that molecule. Relevant contributions from several authors, in the years until 1932, are pointed out, discussing also an unknown study…

After some recollections of the early bubble chamber times, a brief overview of the golden age of the field is made, including its legacy and the use of bubble chamber events for the popularization of science.

This is a translation of an inaugural speech given originally in Dutch in 1998. The topic of that speech, intended for a general audience, was what is now called "The Anthropic Landscape of String Theory".

An account is given of some topical unpublished work by Ettore Majorana, revealing his very deep intuitions and skilfulness in Theoretical Physics. The relevance of the quite unknown results obtained by him is pointed out as well.

It is said that Einstein's conceptual base for the theory of relativity was the philosophy formulated by Immanuel Kant. Then, is it possible to see how Kant played a role in Einstein's thinking without reading Kant's books? This question…

The coming into light of the neutron is discussed. It is remarked that some experiments had already suggested that the penetrating radiation from beryllium had an electromagnetic component, before Joliot-Curies suggested the beryllium…

Omission of Bohr's second postulate permits a derivation of spectral intensity. The transition amplitudes serve as upper bounds to quantum mechanical matrix elements. They also provide insight into the latter in terms of Sommerfeld ellipses…

We give, for the first time, the English translation of a manuscript by Ettore Majorana, which probably corresponds to the text for a seminar delivered at the University of Naples in 1938, where he lectured on Theoretical Physics. Some…