History and Philosophy of Physics
The concepts of symmetry, symmetry breaking and gauge symmetries are discussed, their operational meaning being displayed by the observables {\em and} the (physical) states. For infinitely extended systems the states fall into physically…
The purpose of this work is to retrace the steps that were made by scientists of XX century, like Bohr, Schrodinger, Heisenberg, Pauli, Dirac, for the formulation of what today represents the modern quantum mechanics and that, within two…
We try to define "our world" by stating that "we live in the quantum 4-dimensional Minkowski space-time with the force-fields gauge group $SU_c(3) \times SU_L(2) \times U(1) \times SU_f(3)$ built-in from the outset". We begin by explaining…
A major question in philosophy of science involves the unreasonable effectiveness of mathematics in physics. Why should mathematics, created or discovered, with nothing empirical in mind be so perfectly suited to describe the laws of the…
"The Lord made me a very great favor in an imaginary vision" wrote Maria de Agreda in the seventeenth century, "His Majesty put me at the foot of a beautiful Ladder, and showed me I had to climb it." These words refer to the spiritual…
Recent theoretical progress in nonequilibrium thermodynamics, linking the physical principle of Maximum Entropy Production ("MEP") to the information-theoretical "MaxEnt" principle of scientific inference, together with conjectures from…
Superfluidity is a remarkable manifestation of quantum mechanics at the macroscopic level. This article describes the history of its discovery, which took place at a particularly difficult period of the twentieth century. A special emphasis…
Some erroneous and misleading statements in an article by J. Bernstein on Heisenberg's visit to Cracow during the war are corrected.
In summer 1923, a year after his lectures on the `New Foundation of Mathematics' and half a year before the republication of his two notes on the `Foundations of Physics,' Hilbert delivered a trilogy of lectures in Hamburg. In these…
Galileo's realization that nature is not scale invariant, motivating his subsequent discovery of scaling laws, is traced to two lectures he gave on the geography of Dante's Inferno.
John Bell's investigations in foundations of quantum mechanics, particle physics, and quantum field theory are recalled.
Wigner's "unreasonable effectiveness of mathematics" in physics can be understood as a reflection of a deep and unexpected unity between the fundamental structures of mathematics and of physics. Some of the history of evidence for this is…
I address a question recently raised by Simon Saunders [Phil. Sci. 80(2): 22-48 (2013)] concerning the relationship between the spacetime structure of Newton-Cartan theory and that of what I will call "Maxwell-Huygens spacetime". This…
It is argued that the concept of free will, like the concept of truth in formal languages, requires a separation between an object level and a meta-level for being consistently defined. The Jamesian two-stage model, which deconstructs free…
In the period 1968 - 1974 I was a graduate student and then a postdoc at Caltech and was involved with the developments of the quark and parton models. Most of this time I worked in close contact with Richard Feynman and thus was present…
Radio astronomy began with one array (Jansky's) and one paraboloid of revolution (Reber's) as collecting areas and has now reached the point where a large number of facilities are arrays of paraboloids, each of which would have looked…
The letter addresses misattribution of the discovery of the classical equation for spin motion in electromagnetic field, known as the BMT equation, named after Bargmann, Michel, and Telegdi. I argue that J. (or Ya.) Frenkel, along with L.…
Cosmology as an exact physical science is of new date, but it has long roots in the past. This essay is concerned with four important themes in the history of cosmological thought which, if taken together, offer a fairly comprehensive…
South America is a region which is free from nuclear weapons. However, this was not an inevitable development from the relationships among its countries. Indeed, regional rivalries between Brazil and Argentina, with military implications…
With reference to primary sources it is shown that key claims made regarding the history of the pilot wave theory in Quantum Theory at the Crossroads are not supported by the historical record. It is also argued that the association of de…