The European Physical Journal H最新文献

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.

The article delves into the intriguing disagreement among historians of science regarding the origin of the idea of universal gravity. Prominent researchers of the genesis of Newton's Principia did not believe that he could have come up with this idea in 1666, after observing a falling apple, as he claimed. On the other hand, prominent biographers of Newton did believe. The proposed key to solving this paradox is a thought experiment described in Newton's manuscript, ‘The System of the World,’ which preceded the creation of his ‘Principia.’ According to the proposed ‘subjunctive’ scenario, it was possible to come from the motion of a projectile to the concept of universal gravity, relying only on the knowledge and skills of Galileo in 1611.

Reasoning by analogies permeates theoretical developments in physics and astrophysics, motivated by the unreachable nature of many phenomena at play. For example, analogies have been used to understand black hole physics, leading to the development of a thermodynamic theory for these objects and the discovery of the Hawking effect. The latter, which results from quantum field theory on black hole space-times, changed the way physicists approached this subject: what had started as a mere aid to understanding becomes a possible source of evidence via the research programme of “analogue gravity” that builds on analogue models for field effects. Some of these analogue models may and can be realised in the laboratory, allowing experimental tests of field effects. Here, we present a historical perspective on the connection between the Hawking effect and analogue models. We also present a literature review of current research, bringing history and contemporary physics together. We argue that the history of analogue gravity and the Hawking effect is divided into three distinct phases based on how and why analogue models have been used to investigate fields in the vicinity of black holes. Furthermore, we find that modern research signals a transition to a new phase, where the impetus for the use of analogue models has surpassed the problem they were originally designed to solve.

The formulation of a measurement theory for relativistic quantum field theory (QFT) has recently been an active area of research. In contrast to the asymptotic measurement framework that was enshrined in QED, the new proposals aim to supply a measurement framework for measurements in local spacetime regions. This paper surveys episodes in the history of quantum theory that contemporary researchers have identified as precursors to their own work and discusses how they laid the groundwork for current approaches to local measurement theory for QFT.

The simple story line that ‘Gell-Mann and Zweig invented quarks in 1964 and the quark model was generally accepted after 1968 when deep inelastic electron scattering experiments at SLAC showed that they are real’ contains elements of the truth, but is not true. This paper describes the origins and development of the quark model until it became generally accepted in the mid-1970s, as witnessed by a spectator and some-time participant who joined the field as a graduate student in October 1964. It aims to ensure that the role of Petermann is not overlooked, and Zweig and Bjorken get the recognition they deserve, and to clarify the role of Serber.

David Bohm has often been considered unable to understand the meaning of the quantum revolution as well as its radical metaphysical implications. Similarly, his pilot-wave theory was negatively portrayed as an attempt to restore a classical and deterministic Weltanschauung. Against this background, the aim of this paper is twofold: in the first place, it will be argued that the accusations of dogmatism advanced by several eminent physicists contra Bohm show a biased understanding of his works. Referring to this, two case studies will be discussed: the Bohm–Pauli correspondence, and the difficult relationship between the former and Leon Rosenfeld, a fervent supporter of Bohr’s philosophy of complementarity. These examples indicate that the opposition to the pilot-wave approach was for the most part not based on scientific grounds. In the second place, I will reconstruct and analyze the evolution of Bohm’s philosophical reflections about ontology, scientific realism and pluralism studying private correspondences as well as his main works in the fifties culminated in the book Causality and Chance in Modern Physics. Underlining the originality of Bohm’s thoughts, it will be concluded that his perspective can be characterized as a form of internal realism.