Search results for "Philosophy of physics"
showing 10 items of 19 documents
The Stern-Gerlach experiment revisited
2016
The Stern-Gerlach-Experiment (SGE) of 1922 is a seminal benchmark experiment of quantum physics providing evidence for several fundamental properties of quantum systems. Based on today's knowledge we illustrate the different benchmark results of the SGE for the development of modern quantum physics and chemistry. The SGE provided the first direct experimental evidence for angular momentum quantization in the quantum world and thus also for the existence of directional quantization of all angular momenta in the process of measurement. It measured for the first time a ground state property of an atom, it produced for the first time a `spin-polarized' atomic beam, it almost revealed the electr…
Riemann’s Result and Consequences for Physics and Philosophy
2020
Riemann commented on his main result as follows: “The common character of those manifolds whose curvature is constant may also be expressed thus: that figures may be viewed in them without stretching. For clearly figures could not be arbitrarily shifted and turned around in them if the curvature at each point were not the same in all directions at one point as at another, and consequently the same constructions can be made from it; whence it follows that in aggregates with constant curvature, figures may have any arbitrary position given them. The measure-relations of these manifolds depend only on the value of the curvature, and in relation to the analytic expression it may be remarked tha…
Journeys from quantum optics to quantum technology
2017
Sir Peter Knight is a pioneer in quantum optics which has now grown to an important branch of modern physics to study the foundations and applications of quantum physics. He is leading an effort to develop new technologies from quantum mechanics. In this collection of essays, we recall the time we were working with him as a postdoc or a PhD student and look at how the time with him has influenced our research.
Classical and relativistic n-body problem: from Levi-Civita to the most advanced interplanetary missions
2022
The n-body problem is one of the most important issue in Celestial Mechanics. This article aims to retrace the historical and scientific events that led the Paduan mathematician, Tullio Levi-Civita, to deal with the problem first from a classic and then a relativistic point of view. We describe Levi-Civita's contributions to the theory of relativity focusing on his epistolary exchanges with Einstein, on the problem of secular acceleration and on the proof of Brillouin's cancellation principle. We also point out that the themes treated by Levi-Civita are very topical. Specifically, we analyse how the mathematical formalism used nowadays to test General Relativity can be found in Levi-Civita'…
Teaching gauge theory to first year students
2020
One of the biggest revelations of 20th century physics, is virtually unheard of outside the inner circles of particle physics. This is the gauge theory, the foundation for how all physical interactions are described and a guiding principle for almost all work on new physics theories. Is it not our duty as physicists to try and spread this knowledge to a wider audience? Here, two simple gauge theory models are presented that should be understandable without any advanced mathematics or physics and it is demonstrated how they can be used to show how gauge symmetries are used to construct the standard model of particle physics. This is also used to describe the real reason we need the Higgs fie…
Textbook myths about early atomic models
2022
Most physics textbooks at college and university level introduce quantum physics in a historical context. However, the textbook version of this history does not match the actual history. In this article, the first in a series of articles looking at the textbook description of the quantum history, we follow an exceptional student through her endeavors to understand the early atomic models that led up to the work of Niels Bohr. We experience her disappointment when she discovers that the description of the famous atomic model by Thomson, is a mere caricature with almost no trace of Thomson's work and that the supposedly important radiative instability of Rutherford's atoms, is not there at al…
The dawning of the theory of equilibrium figures: a brief historical account from the 17th through the 20th century
2014
A brief but complete historical survey of the theory of equilibrium figures from its early origins, dating back to 17th-century, until the latest 20th-century developments, with a view towards its applications, is carried out.
Einstein's Washington Manuscript on Unified Field Theory
2020
In this note, we point attention to and briefly discuss a curious manuscript of Einstein, composed in 1938 and entitled "Unified Field Theory," the only such writing, published or unpublished, carrying this title without any further specification. Apparently never intended for publication, the manuscript sheds light both on Einstein's modus operandi as well as on the public role of Einstein's later work on a unified field theory of gravitation and electromagnetism.
The early historical roots of Lee-Yang theorem
2014
A deep and detailed historiographical analysis of a particular case study concerning the so-called Lee-Yang theorem of theoretical statistical mechanics of phase transitions, has emphasized what real historical roots underlie such a case study. To be precise, it turned out that some well-determined aspects of entire function theory have been at the primeval origins of this important formal result of statistical physics.
An historical prolegomenon to the occurrence of the resonance dual models: the Watson-Sommerfeld transform
2015
We would like to discuss, within the inherent historical context, upon one of the main works of fundamental physics which has led to the formulation of the early resonance dual models prior to string theory. In fact, we shall focus on certain aspects of the fundamental Tullio Regge work of 1959, to be precise, on certain mathematical methods handled by him to pursue his original intentions mainly motivated to prove some double dispersion relations into the framework of non-relativistic potential scattering.