Ashok Das – författare

This book explores urban informality in Asian cities and looks how the informal sector's contribution to inclusive and sustainable growth can be enhanced.While supporting the livelihoods of most of the developing world's urban poor, the informal sector also deprives them of basic services and social protection. Rendered vulnerable to socioeconomic threats, people in the urban informal sector have suffered disproportionately during the COVID-19 pandemic and face a highly uncertain future. The book explores informality's forms and constraints in Asian cities. It describes the pandemic's effects on the informal sector and how leveraging informal services can enable urban resilience. Drawing on interdisciplinary research, the book illustrates the transformative potential of urban planning and governance that addresses informality. It also details measures that could boost the informal sector's inclusive and sustainable growth potential.

This book discusses all three formalisms used in the study of finite temperature field theory, namely the imaginary time formalism, the closed time formalism and thermofield dynamics. Applications of the formalisms are worked out in detail. Gauge field theories and symmetry restoration at finite temperature are among the practical examples discussed in depth. The question of gauge dependence of the effective potential and the Nielsen identities are explained. The nonrestoration of some symmetries at high temperature (such as supersymmetry) and theories on nonsimply connected space-times are also described thoroughly. Other topics include (1+1)- and (2+1)-dimensional field theories at finite temperature and phase transitions, derivative expansion, linear response theory and the question of infrared divergences at finite temperature. In addition, examples of nonequilibrium phenomena are discussed with the disoriented chiral condensates as an illustration.This book is a very useful tool for graduate students, teachers and researchers in theoretical physics.

This unique book describes quantum field theory completely within the context of path integrals. With its utility in a variety of fields in physics, the subject matter is primarily developed within the context of quantum mechanics before going into specialized areas.All the existing chapters of the previous edition have been expanded for more clarity. The chapter on anomalies and the Schwinger model has been completely rewritten for better logical clarity. Two new chapters have been added at the request of students and faculty worldwide. The first describes Schwinger's proper time method with simple examples both at zero and at finite temperature while the second develops the idea of zeta function regularization with simple examples.This latest edition is a comprehensive and much expanded version of the original text.

This unique book describes quantum field theory completely within the context of path integrals. With its utility in a variety of fields in physics, the subject matter is primarily developed within the context of quantum mechanics before going into specialized areas.All the existing chapters of the previous edition have been expanded for more clarity. The chapter on anomalies and the Schwinger model has been completely rewritten for better logical clarity. Two new chapters have been added at the request of students and faculty worldwide. The first describes Schwinger's proper time method with simple examples both at zero and at finite temperature while the second develops the idea of zeta function regularization with simple examples.This latest edition is a comprehensive and much expanded version of the original text.

This book comprises the lectures of a two-semester course on quantum field theory, presented in a quite informal and personal manner. The course starts with relativistic one-particle systems, and develops the basics of quantum field theory with an analysis on the representations of the Poincaré group. Canonical quantization is carried out for scalar, fermion, Abelian and non-Abelian gauge theories. Covariant quantization of gauge theories is also carried out with a detailed description of the BRST symmetry. The Higgs phenomenon and the standard model of electroweak interactions are also developed systematically. Regularization and (BPHZ) renormalization of field theories as well as gauge theories are discussed in detail, leading to a derivation of the renormalization group equation. In addition, two chapters — one on the Dirac quantization of constrained systems and another on discrete symmetries — are included for completeness, although these are not covered in the two-semester course.This second edition includes two new chapters, one on Nielsen identities and the other on basics of global supersymmetry. It also includes two appendices, one on fermions in arbitrary dimensions and the other on gauge invariant potentials and the Fock-Schwinger gauge.

This book comprises the lectures of a two-semester course on quantum field theory, presented in a quite informal and personal manner. The course starts with relativistic one-particle systems, and develops the basics of quantum field theory with an analysis on the representations of the Poincaré group. Canonical quantization is carried out for scalar, fermion, Abelian and non-Abelian gauge theories. Covariant quantization of gauge theories is also carried out with a detailed description of the BRST symmetry. The Higgs phenomenon and the standard model of electroweak interactions are also developed systematically. Regularization and (BPHZ) renormalization of field theories as well as gauge theories are discussed in detail, leading to a derivation of the renormalization group equation. In addition, two chapters — one on the Dirac quantization of constrained systems and another on discrete symmetries — are included for completeness, although these are not covered in the two-semester course.This second edition includes two new chapters, one on Nielsen identities and the other on basics of global supersymmetry. It also includes two appendices, one on fermions in arbitrary dimensions and the other on gauge invariant potentials and the Fock-Schwinger gauge.

This book discusses all three formalisms used in the study of finite temperature field theory, namely the imaginary time formalism, the closed time formalism and thermofield dynamics. In addition, the finite temperature description on an arbitrary path in the complex t-plane is also described in detail. Gauge field theories and symmetry restoration at finite temperature are among the practical examples discussed in depth. The thermal operator representation relating the zero temperature Feynman graphs to the finite temperature ones are also explained in depth. Applications of the formalisms are worked out in detail. The consistent generalization of light-front field theories to finite temperature is systematically explained as well as the phenomenon of Unruh radiation. Cutting (Cutcosky) rules for the imaginary parts of amplitudes at finite temperature are discussed in careful detail and examples are worked out. Spontaneous and dynamical symmetry breaking and possible symmetry restoration at finite temperature are described. The question of gauge dependence of the effective potential as well as physical parameters (like mass) and the Nielsen identities are explained with examples. The methods for calculating effective actions at finite temperature are described with examples. The subtleties which arise at finite temperature are pointed out in detail also with examples. The nonrestoration of some of the symmetries at high temperature (such as supersymmetry) and theories on nonsimply connected space-times are described thoroughly. Examples of nonequilibrium phenomena are discussed with the disoriented chiral condensates as an illustration. Fluctuation-dissipation theorem is explained in detail and is worked out systematically for glassy materials. Several appendices are added at the end of some of the chapters to help the readers appreciate the discussions of the individual chapters.This book is a very useful tool for graduate students, teachers and researchers in theoretical physics.

This book discusses all three formalisms used in the study of finite temperature field theory, namely the imaginary time formalism, the closed time formalism and thermofield dynamics. In addition, the finite temperature description on an arbitrary path in the complex t-plane is also described in detail. Gauge field theories and symmetry restoration at finite temperature are among the practical examples discussed in depth. The thermal operator representation relating the zero temperature Feynman graphs to the finite temperature ones are also explained in depth. Applications of the formalisms are worked out in detail. The consistent generalization of light-front field theories to finite temperature is systematically explained as well as the phenomenon of Unruh radiation. Cutting (Cutcosky) rules for the imaginary parts of amplitudes at finite temperature are discussed in careful detail and examples are worked out. Spontaneous and dynamical symmetry breaking and possible symmetry restoration at finite temperature are described. The question of gauge dependence of the effective potential as well as physical parameters (like mass) and the Nielsen identities are explained with examples. The methods for calculating effective actions at finite temperature are described with examples. The subtleties which arise at finite temperature are pointed out in detail also with examples. The nonrestoration of some of the symmetries at high temperature (such as supersymmetry) and theories on nonsimply connected space-times are described thoroughly. Examples of nonequilibrium phenomena are discussed with the disoriented chiral condensates as an illustration. Fluctuation-dissipation theorem is explained in detail and is worked out systematically for glassy materials. Several appendices are added at the end of some of the chapters to help the readers appreciate the discussions of the individual chapters.This book is a very useful tool for graduate students, teachers and researchers in theoretical physics.

This book explores significant aspects of the New Urban Agenda in the Asia-Pacific region, and presents, from different contexts and perspectives, innovative interventions afoot for transforming the governance of 21st-century cities in two key areas: (i) urban planning and policy; and (ii) service delivery and social inclusion. Representing institutions across a wide geography, academic researchers and development practitioners from Asia, Australia, Europe, and North America have authored the chapters that lend the volume its distinctly diverse topical foci. Based on a wide range of cases and intriguing experiences, this collection is a uniquely valuable resource for everyone interested in the present and future of cities and urban regions in Asia-Pacific.

This book explores significant aspects of the New Urban Agenda in the Asia-Pacific region, and presents, from different contexts and perspectives, innovative interventions afoot for transforming the governance of 21st-century cities in two key areas: (i) urban planning and policy; and (ii) service delivery and social inclusion. Representing institutions across a wide geography, academic researchers and development practitioners from Asia, Australia, Europe, and North America have authored the chapters that lend the volume its distinctly diverse topical foci. Based on a wide range of cases and intriguing experiences, this collection is a uniquely valuable resource for everyone interested in the present and future of cities and urban regions in Asia-Pacific.

This book explores significant aspects of the New Urban Agenda in the Asia-Pacific region, and presents, from different contexts and perspectives, innovative interventions afoot for transforming the governance of 21st-century cities in two key areas: (i) urban planning and policy; and (ii) service delivery and social inclusion. Representing institutions across a wide geography, academic researchers and development practitioners from Asia, Australia, Europe, and North America have authored the chapters that lend the volume its distinctly diverse topical foci. Based on a wide range of cases and intriguing experiences, this collection is a uniquely valuable resource for everyone interested in the present and future of cities and urban regions in Asia-Pacific.

New Edition: Field Theory (3rd Edition)This unique book describes quantum field theory completely within the context of path integrals. With its utility in a variety of fields in physics, the subject matter is primarily developed within the context of quantum mechanics before going into specialized areas.Adding new material keenly requested by readers, this second edition is an important expansion of the popular first edition. Two extra chapters cover path integral quantization of gauge theories and anomalies, and a new section extends the supersymmetry chapter, where singular potentials in supersymmetric systems are described.

New Edition: Field Theory (3rd Edition)This unique book describes quantum field theory completely within the context of path integrals. With its utility in a variety of fields in physics, the subject matter is primarily developed within the context of quantum mechanics before going into specialized areas.Adding new material keenly requested by readers, this second edition is an important expansion of the popular first edition. Two extra chapters cover path integral quantization of gauge theories and anomalies, and a new section extends the supersymmetry chapter, where singular potentials in supersymmetric systems are described.

This book consists of the lectures for a two-semester course on quantum field theory, and as such is presented in a quite informal and personal manner. The course starts with relativistic one-particle systems, and develops the basics of quantum field theory with an analysis of the representations of the Poincaré group. Canonical quantization is carried out for scalar, fermion, Abelian and non-Abelian gauge theories. Covariant quantization of gauge theories is also carried out with a detailed description of the BRST symmetry. The Higgs phenomenon and the standard model of electroweak interactions are also developed systematically. Regularization and (BPHZ) renormalization of field theories as well as gauge theories are discussed in detail, leading to a derivation of the renormalization group equation. In addition, two chapters — one on the Dirac quantization of constrained systems and another on discrete symmetries — are included for completeness, although these are not covered in the two-semester course.

This book consists of the lectures for a two-semester course on quantum field theory, and as such is presented in a quite informal and personal manner. The course starts with relativistic one-particle systems, and develops the basics of quantum field theory with an analysis of the representations of the Poincaré group. Canonical quantization is carried out for scalar, fermion, Abelian and non-Abelian gauge theories. Covariant quantization of gauge theories is also carried out with a detailed description of the BRST symmetry. The Higgs phenomenon and the standard model of electroweak interactions are also developed systematically. Regularization and (BPHZ) renormalization of field theories as well as gauge theories are discussed in detail, leading to a derivation of the renormalization group equation. In addition, two chapters — one on the Dirac quantization of constrained systems and another on discrete symmetries — are included for completeness, although these are not covered in the two-semester course.

This book is a compilation of the lectures for a one-semester course on gravitation at the University of Rochester. Starting from a simple description of geometry, the topics are systematically developed to the big bang theory with a simple derivation of the cosmic background temperature. Several informative examples are worked out in detail as well.

This book is a compilation of the lectures for a one-semester course on gravitation at the University of Rochester. Starting from a simple description of geometry, the topics are systematically developed to the big bang theory with a simple derivation of the cosmic background temperature. Several informative examples are worked out in detail as well.

This set of lecture notes on quantum mechanics aims to teach, in a simple and straightforward manner, the basic theory behind the subject, drawing on examples from all fields of physics to provide both background as well as context.The self-contained book includes a review of classical mechanics and some of the necessary mathematics. Both the standard fare of quantum mechanics texts — the harmonic oscillator, the hydrogen atom, angular momentum as well as topics such as symmetry with a discussion on periodic potentials, the relativistic electron, spin and scattering theory are covered. Approximation methods are discussed with a view to applications; these include stationary perturbation theory, the WKB approximation, time dependent perturbations and the variational principle. Together, the seventeen chapters provide a very comprehensive introduction to quantum mechanics. Selected problems are collected at the end of each chapter in addition to the numerous exercises sprinkled throughout the text.The book is written in a simple and elegant style, and is characterized by clarity, depth and excellent pedagogical organization.

These lecture notes on electromagnetism have evolved from graduate and undergraduate EM theory courses given by the author at the University of Rochester, with the basics presented with clarity and his characteristic attention to detail.The thirteen chapters cover, in logical sequence, topics ranging from electrostatics, magnetostatics and Maxwell's equations to plasmas and radiation. Boundary value problems are treated extensively, as are wave guides, electromagnetic interactions and fields. This second edition comprises many of the topics expanded with more details on the derivation of various equations, particularly in the second half of the book that focuses on rather advanced topics.This set of lecture notes, written in a simple and lucid style and in a manner that is complementary to other texts on electromagnetism, will be a valuable addition to the physics bookshelf.

The book is intended for graduate students of theoretical physics (with a background in quantum mechanics) as well as researchers interested in applications of Lie group theory and Lie algebras in physics. The emphasis is on the inter-relations of representation theories of Lie groups and the corresponding Lie algebras.

The book is intended for graduate students of theoretical physics (with a background in quantum mechanics) as well as researchers interested in applications of Lie group theory and Lie algebras in physics. The emphasis is on the inter-relations of representation theories of Lie groups and the corresponding Lie algebras.

This book presents a comprehensive collection of research contributions from the National Conference on Modeling, Analysis, and Simulation (MAS 2024), held at the Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand, India, from 28–30 June 2024. It discusses the foundational and emerging topics vital to solving scientific and engineering challenges—ranging from mathematical modeling, dynamical systems, and mechanics of solids and fluids to advanced statistical approaches and the application of artificial intelligence, machine learning, and the Internet of Things. Emphasizing mathematical modeling as a powerful lens to represent and analyze complex phenomena, this book bridges disciplines through quantitative abstraction and predictive insight.This book highlights the role of computational models in capturing the behavior of physical systems, particularly within solid mechanics and fluid dynamics, where accurate simulations support efficient design and analysis. Contributions on dynamical systems theory explore intricate aspects of system stability, nonlinear dynamics, and bifurcation analysis, deepening our understanding of evolving systems. By showcasing the integration of AI and ML with traditional modeling frameworks, this book illustrates how intelligent tools enhance predictive capabilities, facilitate data-driven decision making, and offer scalable solutions to real-world complexity.

This conference celebrates the 40th anniversary of the first Rochester Conference and honours Prof. Susumu Okubo on his 60th birthday. The original Rochester Conference brought a small group of leading physicists to discuss current results and trends in both theory and experiment. The present conference has also adhered to this format — covering the developments in particle physics over the last forty years and presenting the latest theoretical and experimental results in the field.

New Edition: Field Theory (3rd Edition)Traditionally, field theory is taught through canonical quantization with a heavy emphasis on high energy physics. However, the techniques of field theory are applicable as well and are extensively used in various other areas of physics such as condensed matter, nuclear physics and statistical mechanics. The path integral approach brings out this feature most clearly. In this book, the path integral approach is developed in detail completely within the context of quantum mechanics. Subsequently, it is applied to various areas of physics.

New Edition: Field Theory (3rd Edition)Traditionally, field theory is taught through canonical quantization with a heavy emphasis on high energy physics. However, the techniques of field theory are applicable as well and are extensively used in various other areas of physics such as condensed matter, nuclear physics and statistical mechanics. The path integral approach brings out this feature most clearly. In this book, the path integral approach is developed in detail completely within the context of quantum mechanics. Subsequently, it is applied to various areas of physics.

This text contains the texts of papers given at a symposium in honour of J.B. French in 1993. Topics discussed include: fluctuation properties of nuclear states; symmetry in nuclear physics; and solitons and nucleons.

Of late, the fields of astroparticle physics, particle physics and nuclear physics have been developing at a dramatic speed. This book constitutes the proceedings of a symposium intended to highlight some of the main directions being pursued in these related areas, and to seek a commonality among them. The symposium was held to honor the many achievements of Professor Adrian Melissinos, who has contributed to most of the developments addressed at the meeting.

This set of lecture notes on quantum mechanics aims to teach, in a simple and straightforward manner, the basic theory behind the subject, drawing on examples from all fields of physics to provide both background as well as context. The self-contained book includes a review of classical mechanics and some of the necessary mathematics. Both the standard fare of quantum mechanics texts - the harmonic oscillator, the hydrogen atom, angular momentum as well as topics such as symmetry with a discussion on periodic potentials, the relativistic electron, spin and scattering theory are covered. Approximation methods are discussed with a view to applications; these include stationary perturbation theory, the WKB approximation, time dependent perturbations and the variational principle. Together, the seventeen chapters provide a very comprehensive introduction to quantum mechanics. Selected problems are collected at the end of each chapter in addition to the numerous exercises sprinkled throughout the text. The book is written in a simple and elegant style, and is characterized by clarity, depth and excellent pedagogical organization.