Nuclear Sciences & Technologies

EPJ H Highlight - How Einstein’s theory of gravitation experienced a Renaissance after World War II

alt
Einstein’s General Relativity’s place in history.

Journey into the post-war transformation leading to the return of General Relativity within physics

Einstein’s 1915 theory of gravitation, also known as General Relativity, is now considered one of the pillars of modern physics. It contributes to our understanding of cosmology and of fundamental interactions between particles. But that was not always the case. Between the mid-1920s and the mid-1950s, General Relativity underwent a period of stagnation, during which the theory was mostly considered as a stepping-stone for a superior theory. In a special issue of EPJ H just published, historians of science and physicists actively working on General Relativity and closely related fields share their views on the process, during the post-World War II era, in particular, which saw the “Renaissance” of General Relativity, following progressive transformation of the theory into a bona fidae physics theory.

Read more...

EPJ H Highlight - Historical account of how donut-shaped fusion plasmas managed to decrease adverse turbulence

alt
Toroidally shaped plasmas of the tokamak type offer a path to low turbulence. Credit: DJ Quietstorm / Fickr https://www.flickr.com/photos/
djquietstorm/4823366075/

Achieving fusion has become more realistic since plasma flow was identified as regulating turbulence in the 1980s

Fusion research has been dominated by the search for a suitable way of ensuring confinement as part of the research into using fusion to generate energy. In a recent paper published in EPJ H, Fritz Wagner from the Max Planck Institute for Plasma Physics in Germany, gives a historical perspective outlining how our gradual understanding of improved confinement regimes for what are referred to as toroidal fusion plasmas –- confined in a donut shape using strong magnetic fields-- have developed since the 1980s. He explains the extent to which physicists’ understanding of the mechanisms governing turbulent transport in such high-temperature plasmas has been critical in improving the advances towards harvesting fusion energy.

Read more...

EPJ H Highlight - The 1950s: the decade in which gravity physics became experimental

alt
Experimental tests from a hundred years ago that compare the gravitational accelerations of different kinds of material.

History shows experiments to be just as key as theory in gravity physics

In the 1950s and earlier, the gravity theory of Einstein's general relativity was largely a theoretical science. In a new paper published in EPJ H, Jim Peebles, a physicist and theoretical cosmologist who is currently the Albert Einstein Professor Emeritus of Science at Princeton University, New Jersey, USA, shares a historical account of how the experimental study of gravity evolved.

Read more...

EPJ H Highlight - Timeless thoughts on the definition of time

alt
The solar year was often determined as the interval between consecutive spring equinoxes when the sun is directly over the equator.

On the evolution of how we have defined time, time interval and frequency since antiquity

The earliest definitions of time and time-interval quantities were based on observed astronomical phenomena, such as apparent solar or lunar time, and as such, time as measured by clocks, and frequency, as measured by devices were derived quantities. In contrast, time is now based on the properties of atoms, making time and time intervals themselves derived quantities. Today’s definition of time uses a combination of atomic and astronomical time. However, their connection could be modified in the future to reconcile the divergence between the astronomic and atomic definitions. These are some of the observations made by Judah Levine, author of a riveting paper just published in EPJ H, which provides unprecedented insights into the nature of time and its historical evolution.

Read more...

EPJ H Editor Allan Franklin receives 2016 Abraham Pais Prize for History of Physics

alt
Prof. Allan Franklin

The Abraham Pais Prize for History of Physics is given annually to recognize outstanding scholarly achievements in the history of physics. Professor Allan Franklin, who is an Editor of EPJ H and author of the Springer book The Rise and Fall of the Fifth Force, receives the 2016 Abraham Pais Prize for History of Physics for "path-breaking historical analyses of the roles of experiment in physics and for explicating the nature of evidence and error in scientific argument".

Read more...

EPJ H Highlight - May the 5th force be with you

alt
Ephraim Fischbach, Purdue University Physics Professor
© Purdue University

Ephraim Fischbach revisits the wealth of research emerging from the quest for the fifth force, which he hypothesised in the 1980s as being a new fundamental force in nature

Discovering possible new forces in nature is no mean task. The discovery of gravity linked to Newton’s arguably apocryphal apple experiment has remained anchored in popular culture. In January 1986, Ephraim Fischbach, Physics Professor from Purdue University in West Lafayette, Indiana, had his own chance to leave his mark on collective memory. His work made the front page of the New York Times after he and his co-authors published a study uncovering the tantalising possibility of the existence of a fifth force in the universe. In an article published in EPJ H, Fischbach gives a personal account of how the existence of the gravity-style fifth force has stimulated an unprecedented amount of research in gravitational physics - even though its existence, as initially formulated, has not been confirmed by experiment.

Read more...

EPJ H Highlight - Penrose’s and Hawking’s early math award

alt

Find out how Roger Penrose and Stephen Hawking won recognition for their work on space time singularities back in the sixties, suggesting an initial start to the universe

In 1966, it was Roger Penrose who won the prestigious Adams prize for his essay: An Analysis of the Structure of Space Time. The Adams prize—named after the British mathematician John Couch Adams—is awarded each year by the Faculty of Mathematics at the University of Cambridge to a young, UK-based mathematician. At the same time, Stephen Hawking won an auxiliary to the Adams prize for an essay entitled Singularities and the Geometry of Spacetime, shortly after completing his PhD. A copy of the original submission has now been reproduced in EPJ H.

Read more...

EPJ H Highlight - All paths lead to Rome, even the path to condensed matter theory

alt
Carlo Di Castro. © 2004 Humboldt Prize

Italian physicist Carlo Di Castro shares his thoughts on the development of theoretical condensed matter physics in Rome from the 1960s until the beginning of this century.

Italian physicist Carlo Di Castro, professor emeritus at the University of Rome Sapienza, Italy, shares his recollections of how theoretical condensed matter physics developed in Rome, starting in the 1960s. Luisa Bonolis, a researcher at the Max Planck Institute for the History of Science in Berlin, Germany invited Di Castro to reflect upon his research career, which he did in an interview published in EPJ H.

In this unique document, Di Castro talks about his upbringing during the second World War. He also explains how this childhood experience later influenced his philosophy, which he aptly summarises as follows: “the fear of the unknown must be overcome through knowledge and reason.” Ultimately, this approach guided the career choices that led him to become a condensed matter physicist.

Read more...

EPJ H Highlight - Einstein’s forgotten model of the universe

alt
An image of the blackboard used in Einstein’s 2nd Rhodes lecture at Oxford in April 1931. © Museum of the History of Science, University of Oxford, UK

New insights into Einstein’s view of the cosmos from the translation and study of one of his least known papers

A paper published in EPJ H provides the first English translation and an analysis of one of Albert Einstein’s little-known papers, “On the cosmological problem of the general theory of relativity”. Published in 1931, it features a forgotten model of the universe, while refuting Einstein’s own earlier static model of 1917. In this paper, Einstein introduces a cosmic model in which the universe undergoes an expansion followed by a contraction. This interpretation contrasts with the monotonically expanding universe of the widely known Einstein-de Sitter model of 1932.

Read more...

EPJ H Highlight - Einstein’s conversion from a static to an expanding universe

alt
Einstein and Lemaître photographed around 1933. © Archives Lemaître, Université Catholique, Louvain

Albert Einstein accepted the modern cosmological view that the universe is expanding, only long after several of his contemporaries had demonstrated it with astrophysical observations

Until 1931, physicist Albert Einstein believed that the universe was static. An urban legend attributes this change of perspective to when American astronomer Edwin Hubble showed Einstein his observations of redshift in the light emitted by far away nebulae—today known as galaxies. But the reality is more complex. The change in Einstein’s viewpoint, in fact, resulted from a tortuous thought process. Now, in an article published in EPJ H, Harry Nussbaumer from the Institute of Astronomy at ETH Zurich, Switzerland, explains how Einstein changed his mind following many encounters with some of the most influential astrophysicists of his generation.

Read more...

Editors-in-Chief
G. Moutiers and A. Nicolas
ISSN: 2491-9292 (Electronic Edition)

© EDP Sciences

Conference announcements