The European Physical Journal H最新文献

Robert A. Millikan (1868–1953) was the second American to win the Nobel Prize in physics. At the peak of his influence, no scientist save Einstein was more admired by the American public. Millikan, the head of the California Institute of Technology (Caltech) during its first 24 years, oversaw its rapid growth into one of the leading scientific institutions of the world. However, in response to demands for social justice following the murder of George Floyd, Caltech launched an investigation into Millikan. Caltech reached a decision to strip Millikan of honors (such as the library named after him), following accusations from various sources that he was a sexist, racist, xenophobic, antisemitic, pro-eugenic Nazi sympathizer. In short, Caltech threw the book at him. This article analyzes two accusations against Millikan. The first of these accusations was published in Nature: that he collaborated to deprive Japanese Americans of their rights during their forced relocation to internment camps during the Second World War. An examination of original historical sources will show that this accusation is false. On the contrary, Millikan actively campaigned during the war to promote the rights of Japanese Americans. This article traces the stages of misrepresentation that led to current false beliefs about Millikan. In view of Millikan’s extraordinary position in American science, this misrepresentation is a cautionary tale. The article also treats Caltech’s central accusation against Millikan: he lent his name to “a morally reprehensible eugenics movement” that had been scientifically discredited in his time. The article considers the statements purporting to show that eugenics movement had been denounced by the scientific community by 1938. In a reversal of Caltech’s claims, all three of Caltech’s scientific witnesses against eugenics—including two Nobel laureates—were actually pro-eugenic to varying degrees. This article concludes that Millikan’s beliefs fell within acceptable scientific norms of his day.

Perturbative expansions have played a peculiarly central role in quantum field theory, not only in extracting empirical predictions but also in investigations of the theory’s mathematical and conceptual foundations. This paper brings the special status of QFT perturbative expansions into focus by tracing the history of mathematical physics work on perturbative QFT and situating a contemporary approach, perturbative algebraic QFT, within this historical context. Highlighting the role that perturbative expansions have played in foundational investigations helps to clarify the relationships between the formulations of QFT developed in mathematical physics and high-energy phenomenology.

The Italian theorist Gian-Carlo Wick is well known for his work in mathematical physics. Nevertheless, working with Fermi’s group in Rome in the 1930s, he took on several behind-the-scenes roles that resulted in important papers in neutron physics. He clarified Fermi’s methodology for calculating neutron slowing down probabilities; using transport theory, he provided a comprehensive general method for calculating the neutron scattering albedo; and with an insight into the way, neutron scattering could yield information about lattice dynamics, he formulated the first theory of inelastic thermal neutrons scattering in crystalline materials. This work and his contributions are not well known today. We discuss its physical essence, its relevance to neutron physics, and its subsequent impact in later work.

This paper analyzes the effective field theory perspective on modern physics through the lens of the quantum theory of gravitational interaction. The historical part argues that the search for a theory of quantum gravity stimulated the change in outlook that characterizes the modern approach to the standard model of particle physics and general relativity. We present some landmarks covering a long period, i.e., from the beginning of the 1930s until 1994, when, according to Steven Weinberg, the modern bottom–up approach to general relativity began. Starting from the first attempt to apply the quantum field theory techniques to quantize Einstein’s theory perturbatively, we explore its developments and interaction with the top–down approach encoded by string theory. In the last part of the paper, we focus on this last approach to describe the relationship between our modern understanding of string theory and effective field theory in today’s panorama. To this end, the non-historical part briefly explains the modern concepts of moduli stabilization and Swampland to understand another change in focus that explains the present framework where some string theorists move.

This paper analyzes the physics of the famous 1940 Frisch–Peierls memorandum, which examined the possibility of creating a nuclear weapon utilizing a fast-neutron chain reaction with uranium-235. While Frisch and Peierls’ estimate of the critical mass was far too low, their analysis was fundamentally sound. I also survey the role of the memorandum in the overall history of wartime nuclear developments, and its prescient predictions of aspects of the Cold War.

A gas–hydrate method of CO₂ gas storage is one of the modern technologies for reducing it emissions into the atmosphere. The breakup of gas bubbles by a shock wave is an actual area of scientific and technological research. However, it is less known that such research began in the late 1950s in the USSR by Prof. Vladilen F. Minin. The paper presents the main discoveries related to the destruction of gas bubbles in a liquid under the influence of a shock wave made more than 60 years ago. Looking back: Study the past to understand the present.

Over the last 70 years, Feynman diagrams have played an essential role in the development of many theoretical predictions derived from the standard model Lagrangian. In fact, today they have become an essential and seemingly irreplaceable tool in quantum field theory calculations. In this article, we propose to explore the development of computational methods for Feynman diagrams with a special focus on their automation, drawing insights from both theoretical physics and the history of science. From the latter perspective, the article particularly investigates the emergence of computer algebraic programs, such as the pioneering SCHOONSCHIP, REDUCE, and ASHMEDAI, designed to handle the intricate calculations associated with Feynman diagrams. This sheds light on the many challenges faced by physicists when working at higher orders in perturbation theory and reveal, as exemplified by the test of the validity of quantum electrodynamics at the turn of the 1960s and 1970s, the indispensable necessity of computer-assisted procedures. In the second part of the article, a comprehensive overview of the current state of the algorithmic evaluation of Feynman diagrams is presented from a theoretical point of view. It emphasizes the key algorithmic concepts employed in modern perturbative quantum field theory computations and discusses the achievements, ongoing challenges, and potential limitations encountered in the application of the Feynman diagrammatic method. Accordingly, we attribute the enduring significance of Feynman diagrams in contemporary physics to two main factors: the highly algorithmic framework developed by physicists to tackle these diagrams and the successful advancement of algebraic programs used to process the involved calculations associated with them.

Nucleon transfer reactions have played a fundamental role in understanding the single-particle components, shell structure and collective properties of atomic nuclei. The conventional distorted wave Born approximation (DWBA) envisioned the nucleon transfer reaction as a one-step process, which proceeds directly from the ground state of the target nucleus to a state of the residual nucleus. The coupled channels Born approximation (CCBA) and coupled reaction channels (CRC) theories evolved because a number of nucleon transfer reaction cross sections could not be reconciled within the DWBA. These coupled channels models revealed that, in addition to the “one-step” process of the DWBA, “multi-step” nucleon transfer processes involving accessary pathways can participate in populating the final nuclear state. In the CCBA, the auxiliary pathways involved inelastic excitations of the target and/or residual nucleus, whereas, in the CRC, the pathways included sequential nucleon transfer passing through nuclear states of an intermediate partition. Coherent addition of contributions from one-step and multi-step nucleon transfer processes resulted in dramatic alterations in reaction cross sections, which were experimentally confirmed. The CCBA and CRC linked the structure of the nuclei participating in a reaction to modalities of nucleon transfer arising during the relative motion between the interacting ions. These complementary theories inexorably changed physicists’ interpretations of nucleon transfer reactions and, in doing so, heralded in the new field of direct heavy-ion reactions.

As members of the Virgo Collaboration—one of the large scientific collaborations that explore the universe of gravitational waves together with the LIGO Scientific Collaboration and the KAGRA Collaboration—we became aware of biased citation practices that exclude Virgo, as well as KAGRA, from achievements that collectively belong to the wider LIGO/Virgo/KAGRA Collaboration. Here, we frame these practices in the context of Merton’s “Matthew effect”, extending the reach of this well-studied cognitive bias to include large international scientific collaborations. We provide qualitative evidence of its occurrence, displaying the network of links among published papers in the scientific literature related to Gravitational Wave science. We note how the keyword “LIGO” is linked to a much larger number of papers and variety of subjects than the keyword “Virgo”. We support these qualitative observations with a quantitative study based on a year-long monitoring of the relevant literature, where we scan all new preprints appearing in the arXiv electronic preprint database. Over the course of one year, we identified all preprints failing to assign due credits to Virgo. As a further step, we undertook positive actions by asking the authors of problematic papers to correct them. Here, we also report on a more in-depth investigation which we performed on problematic preprints that appeared in the first three months of the period under consideration, checking how frequently their authors reacted positively to our request and corrected their papers. Finally, we measure the global impact of papers classified as problematic and observe that, thanks to the changes implemented in response to our requests, the global impact (measured as the number of citations of papers which still contain Virgo visibility issues) was halved. We conclude the paper with general considerations for future work in a wider perspective.