scholarly journals An introduction to kinks in $\varphi^4$-theory

2021 ◽  
Author(s):  
Mariya Lizunova ◽  
Jasper van Wezel
Keyword(s):  
Undergraduate Students ◽  
Particle Physics ◽  
Topological Defects ◽  
Resonant Scattering ◽  
Theoretical Physics ◽  
Topological Classification ◽  
Condensed Matter Theory ◽  
Matter Theory ◽  
Quantitative Understanding ◽  
The Rich

As a low-energy effective model emerging in disparate fields throughout all of physics, the ubiquitous \varphi^4φ4-theory is one of the central models of modern theoretical physics. Its topological defects, or kinks, describe stable, particle-like excitations that play a central role in processes ranging from cosmology to particle physics and condensed matter theory. In these lecture notes, we introduce the description of kinks in \varphi^4φ4-theory and the various physical processes that govern their dynamics. The notes are aimed at advanced undergraduate students, and emphasis is placed on stimulating qualitative insight into the rich phenomenology encountered in kink dynamics. The appendices contain more detailed derivations, and allow enquiring students to also obtain a quantitative understanding. Topics covered include the topological classification of stable solutions, kink collisions, the formation of bions, resonant scattering of kinks, and kink-impurity interactions.

Wilsonian Renormalization in the 1970s

2021 ◽  
Vol 51 (5) ◽  
pp. 605-633
Author(s):  
Julia Harriet Menzel
Keyword(s):  
United States ◽  
Renormalization Group ◽  
Particle Physics ◽  
Condensed Matter ◽  
Social Institutions ◽  
The United States ◽  
Theoretical Physics ◽  
Condensed Matter Theory ◽  
Summer Schools ◽  
The Cold War

This paper examines the history of the renormalization group, a cornerstone of contemporary theoretical physics, focusing on the work of Kenneth Wilson (winner of the 1982 Nobel Prize in physics) and affiliated scholars in the 1970s. In particular, it reconstructs how studies of the renormalization group led to formative interactions between two distinct branches of physics, namely particle physics and condensed matter theory. Instead of explaining such intellectual coordination as the result of material and conceptual exchanges, as in Peter Galison’s widely influential discussion of the “trading zone,” my analysis emphasizes the pedagogical labor, social institutions, and political economic conditions that gave the renormalization group its mediating power. To that end, I show how early lectures and fast circulating pre-prints on the renormalization group created a population of physicists in the United States conversant in the rudiments of both condensed matter and particle theory. I then root the formation of a transatlantic network of renormalization group enthusiasts in the geopolitics of the Cold War, showing that the spread of Wilsonian ideas was made possible by a liberal internationalist program of academic exchanges and summer schools sponsored by the US state department and NATO. Finally, I argue that sharp cuts to basic science funding in the United States pushed young physicists seeking jobs in the 1970s to work across specializations, which visibly impacted how renormalization group ideas were interpreted and used—often against the objections of their original progenitors.

Models of Strongly Interacting Quantum Matter

2019 ◽  
pp. 241-420
Author(s):  
Hans-Peter Eckle
Keyword(s):  
Particle Physics ◽  
Magnetic Moments ◽  
Selection Criterion ◽  
Quantum Matter ◽  
Strongly Interacting ◽  
Condensed Matter Theory ◽  
Matter Theory ◽  
Rabi Model ◽  
Fermionic Systems ◽  
The One

This chapter introduces a select number of models of strongly interacting quantum many-particle physics and examines their basic properties. These models represent Bosonic and Fermionic systems as well as systems where magnetic moments, i.e. spins, interact. The main selection criterion has been the existence of a variant of the model that is quantum integrable using Bethe ansatz methods. After studying the Bose fluid, the Landau Fermi liquid, and the one-dimensional concept of the Luttinger liquid, it reviews some of the major models of condensed matter theory, including the Hubbard model describing itinerant magnetism, the Heisenberg model describing localized magnetism, and the Kondo model describing the interaction of a magnetic impurity and band electrons. It also presents the Rabi model and some of its descendants in order to describe the interaction of light and quantum matter in quantum optics.

scholarly journals Wavefront dislocations reveal the topology of quasi-1D photonic insulators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Clément Dutreix ◽  
Matthieu Bellec ◽  
Pierre Delplace ◽  
Fabrice Mortessagne
Keyword(s):  
Local Density ◽  
Topological Defects ◽  
Wave Functions ◽  
Topological Classification ◽  
Local Density Of States ◽  
Topological Phase Transition ◽  
Interference Fringes ◽  
Classical Wave ◽  
Phase Singularities

AbstractPhase singularities appear ubiquitously in wavefields, regardless of the wave equation. Such topological defects can lead to wavefront dislocations, as observed in a humongous number of classical wave experiments. Phase singularities of wave functions are also at the heart of the topological classification of the gapped phases of matter. Despite identical singular features, topological insulators and topological defects in waves remain two distinct fields. Realising 1D microwave insulators, we experimentally observe a wavefront dislocation – a 2D phase singularity – in the local density of states when the systems undergo a topological phase transition. We show theoretically that the change in the number of interference fringes at the transition reveals the topological index that characterises the band topology in the insulator.

scholarly journals GEORGE KEITH BATCHELOR 8 March 1920–30 March 2000 Founding Editor, Journal of Fluid Mechanics, 1956

2000 ◽  
Vol 421 ◽  
pp. 1-14 ◽  
Author(s):  
HERBERT E. HUPPERT
Keyword(s):  
Fluid Mechanics ◽  
International Organizations ◽  
Solid Mechanics ◽  
Applied Mathematics ◽  
Fluid Flows ◽  
Theoretical Physics ◽  
Founding Editor ◽  
Number Of Factors ◽  
Quantitative Understanding ◽  
The Subject

George Batchelor was one of the giants of fluid mechanics in the second half of the twentieth century. He had a passion for physical and quantitative understanding of fluid flows and a single-minded determination that fluid mechanics should be pursued as a subject in its own right. He once wrote that he ‘spent a lifetime happily within its boundaries’. Six feet tall, thin and youthful in appearance, George's unchanging attire and demeanour contrasted with his ever-evolving scientific insights and contributions. His strongly held and carefully articulated opinions, coupled with his forthright objectivity, shone through everything he undertook.George's pervasive influence sprang from a number of factors. First, he conducted imaginative, ground-breaking research, which was always based on clear physical thinking. Second, he founded a school of fluid mechanics, inspired by his mentor G. I. Taylor, that became part of the world renowned Department of Applied Mathematics and Theoretical Physics (DAMTP) of which he was the Head from its inception in 1959 until he retired from his Professorship in 1983. Third, he established this Journal in 1956 and actively oversaw all its activities for more than forty years, until he relinquished his editorship at the end of 1998. Fourth, he wrote the monumental textbook An Introduction to Fluid Dynamics, which first appeared in 1967, has been translated into four languages and has been relaunched this year, the year of his death. This book, which describes the fundamentals of the subject and discusses many applications, has been closely studied and frequently cited by generations of students and research workers. It has already sold over 45 000 copies. And fifth, but not finally, he helped initiate a number of international organizations (often European), such as the European Mechanics Committee (now Society) and the biennial Polish Fluid Mechanics Meetings, and contributed extensively to the running of IUTAM, the International Union of Theoretical and Applied Mechanics. The aim of all of these associations is to foster fluid (and to some extent solid) mechanics and to encourage the development of the subject.

scholarly journals Will Saudi's 2030 Vision Raise the Students’ Awareness to National Literature? Saudi Literature and Identity

2021 ◽  
Vol 15 ◽  
pp. 95-105
Author(s):  
Mubarak Altwaiji ◽  
Majed Alenezi ◽  
Sajeena Gayathrri ◽  
Ebrahim Mohammed Alwuraafi ◽  
Maryam Naif Alanazi
Keyword(s):  
National Identity ◽  
Undergraduate Students ◽  
Narrative Analysis ◽  
National Literature ◽  
Cultural Issues ◽  
Social Constructs ◽  
Northern Border ◽  
History Of ◽  
The Rich ◽  
Modern Identity

Forming national identity is placed on top of the seven aspects of High-Impact Educational Practices (HIEPs) in Northern Border University. Similarly, the concept of academic awareness to national literature has been one of the main challenges to national literature in the Middle East. Just as the strong presence of national identity in Saudi’s 2030 vision has initiated re-evaluations of how national identity is shaped, Saudi novel has similar concerns that inform social constructs of national identity through overarching themes and comprehensive representations of cultural issues. This study investigates the ways in which two Saudi novelists interrogate the intertwined issues shared by 2030 vision and national novel which address the archetypal Saudi identity: first, that the construction of modern identity requires much cultural openness with the world; second, that construction of Saudi identity needs exclusion of otherness; and third, that national identity depends on the rich history of two historical regions – Najd and Hijaz - that binds identity to a unified territory. The study focuses on how these novels give visibility to issues that are at the core of 2030 vision’s social and cultural aspect such as life style, appearance behaviours, attitudes, accepting differences and willingness to work and volunteer. Drawing on this narrative analysis, the study advocates for the utility of introducing national novel for undergraduate students to help them perceive identity as a position and support their identity enactment.

scholarly journals A Study of University Students in Japan: Learning and Application of Academic English Writing

2021 ◽  
Author(s):  
◽  
James Graham McKinley
Keyword(s):  
Undergraduate Students ◽  
Academic Writing ◽  
Social Constructivist ◽  
Academic English ◽  
Writing Classes ◽  
Writer Identity ◽  
Writing Courses ◽  
English Writing ◽  
Written Texts ◽  
The Rich

<p>This study investigated Japanese first and second year undergraduate students learning English academic writing in their compulsory English composition courses in a Japanese university. The thesis takes a social constructivist approach to investigate the aspects of critical argument and writer identity in these students’ classes and their writing.  The data for the study include classroom observations and teacher and student interviews, all conducted monthly throughout the academic year-long course. In total there were six courses, four teachers, and sixteen student participants. The observations were analyzed using an adapted version of Ivanič’s (2004) Discourses of Writing framework, which focused on aspects of identity construction in the writing classroom. The linguistic data included a selection of one major piece of writing from each student, analyzed using an adapted Appraisal framework within Systemic Functional Linguistics (Martin, 1997; 2000). In order to maintain a focus on writer identity in the analysis, Clark and Ivanič’s (1997) selves were identified through this analysis. In addition, the texts were analyzed for use of Casanave’s (2002) writing game strategies, in order to further establish the students’ approaches in writing their texts. The objective was not to generalize about how Japanese students learn to write academic English, but rather to provide, from a social constructivist, Western researcher’s perspective, an analysis of what happened in these students’ writing classes and how it affected their writing for those classes.  Teachers’ general practices in the observed courses mainly focused on two aspects of writing: 1) as a communicative act (writing for a reader), and 2) as an exercise in critical thinking (developing a thesis). These two aspects emerged from the observation and interview data collection. The four teachers used very different approaches in designing their courses, and the students in the same classes responded in different ways, mostly depending on their ability to understand their teachers’ intentions and to form appropriate academic identities in an attempt to meet their teachers’ expectations. The analysis of the students’ written texts revealed that students often did not meet the teachers’ expectations of writing objectively and using a genre-appropriate voice as students often resorted to the same authorial voice to push their thesis.  This investigation was designed to inform pedagogic practices for university teachers of academic English and curriculum designers in Japan to establish effective English writing courses. The rich description of classroom practices and resulting written texts and the focus on differences in cultural expectations between teachers and students provide significant contributions to this area of inquiry. The main pedagogical suggestions are standardizing course objectives and goals, assigning more reading as a part of writing, and teaching students how to write authoritatively.</p>

Introduction

2021 ◽  
pp. 1-7
Author(s):  
Andrew Zangwill
Keyword(s):  
State Physics ◽  
Solid State ◽  
Symmetry Breaking ◽  
Particle Physics ◽  
Popular Media ◽  
Theoretical Physics ◽  
Solid State Physics ◽  
Scientific Enterprise ◽  
Big Ideas ◽  
Rules Of The Game

This chapter provides an overview of Anderson’s career and contrasts his speciality, the physics of the very many (solid-state physics), with the areas of physics that tend to appear in popular media—the physics of the very small (particle physics) and the physics of the very distant (astrophysics and cosmology). It compares Anderson’s physics skills to those of a chess grandmaster. The number of pieces (atoms and electrons) is so large that merely knowing the microscopic rules of the game is not enough to gain real understanding. There is a focus on the big ideas Anderson brought to the table—symmetry breaking, emergence, and complexity—and also his great interest in the cultural and political aspects of physics. The goal of the book is to help readers understand the magician-like skills Anderson brought to theoretical physics and the effect these had on his students, coworkers, community, and on scientific enterprise.

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