Geometry and topology have been a fascination in physics since the start of the 20th century. A leading example is Einstein's geometrical theory of gravity. At the beginning of the 1970s, topological ideas entered areas of condensed matter physics. These advances were driven by new seminal ideas resolving a serious contradiction between experiment and the standard interpretation of a rigorous mathematical theorem which led to the study of new exotic topological phases of matter. Topological defect driven phase transitions in thin, two dimensional films of superfluids, superconductors and crystals have provided great insight into the mechanism governing these topological phases present in those physical systems. Moreover, many of these topological properties remain 'protected' against disorder and topological distortion perturbations. An example of possible applications of such robustness to perturbations is in the search for encoding information in quantum computers, potentially providing the platform for fault-tolerant quantum computations.In the past four decades, the discovery of topological phases engendered great interest in condensed matter physics. It also attracted the attention of researchers working on quantum information, quantum materials and simulations, high energy physics and string theory. This unique volume contains articles written by some of the most prominent names in the field, including Nobel Laureate John Michael Kosterlitz and Professor Jorge V José. They originate from talks and discussions by leading experts at a recent workshop. They review previous works as well as addressing contemporary developments in the most pressing and important issues on various aspects of topological phases and topological phase transitions.

On the 40th anniversary of the Berezinskii–Kosterlitz–Thouless Theory (BKT), this informative volume looks back at some of the developments and achievements and varied physics applications which ensued from the beautiful BKT vortex-unbinding seminal idea.During the last four decades, BKT theory, which is undeniably one of the most important developments in condensed matter and theoretical physics of the second half of the twentieth century, has expanded widely. It has been used and extended from many different theoretical and experimental perspectives. New and unexpected features have been uncovered from the BKT theory. Since its inception, apart from applications in condensed matter physics, the theory has been actively applied in other branches of physics, such as high energy physics, atomic physics, nuclear physics, statistical physics, nonlinear systems, etc. This makes the theory an indispensable topic for all who are involved in physics.An international team of experts, each of whom has left his mark on the developments of this remarkable theory and experimental applications, contribute both historical essays and more detailed current technical and experimental accounts to this volume. These articles highlight the new discoveries from the respective authors' perspectives.This unique volume celebrates the impact over four decades of the BKT theory on modern physics. In addition to the historical perspective provided by Kosterlitz and Thouless's overview, the volume provides a comprehensive description of experimental and theoretical applications and extensions of the BKT theory.

Geometry and topology have been a fascination in physics since the start of the 20th century. A leading example is Einstein's geometrical theory of gravity. At the beginning of the 1970s, topological ideas entered areas of condensed matter physics. These advances were driven by new seminal ideas resolving a serious contradiction between experiment and the standard interpretation of a rigorous mathematical theorem which led to the study of new exotic topological phases of matter. Topological defect driven phase transitions in thin, two dimensional films of superfluids, superconductors and crystals have provided great insight into the mechanism governing these topological phases present in those physical systems. Moreover, many of these topological properties remain 'protected' against disorder and topological distortion perturbations. An example of possible applications of such robustness to perturbations is in the search for encoding information in quantum computers, potentially providing the platform for fault-tolerant quantum computations.In the past four decades, the discovery of topological phases engendered great interest in condensed matter physics. It also attracted the attention of researchers working on quantum information, quantum materials and simulations, high energy physics and string theory. This unique volume contains articles written by some of the most prominent names in the field, including Nobel Laureate John Michael Kosterlitz and Professor Jorge V José. They originate from talks and discussions by leading experts at a recent workshop. They review previous works as well as addressing contemporary developments in the most pressing and important issues on various aspects of topological phases and topological phase transitions.

On the 40th anniversary of the Berezinskii–Kosterlitz–Thouless Theory (BKT), this informative volume looks back at some of the developments and achievements and varied physics applications which ensued from the beautiful BKT vortex-unbinding seminal idea.During the last four decades, BKT theory, which is undeniably one of the most important developments in condensed matter and theoretical physics of the second half of the twentieth century, has expanded widely. It has been used and extended from many different theoretical and experimental perspectives. New and unexpected features have been uncovered from the BKT theory. Since its inception, apart from applications in condensed matter physics, the theory has been actively applied in other branches of physics, such as high energy physics, atomic physics, nuclear physics, statistical physics, nonlinear systems, etc. This makes the theory an indispensable topic for all who are involved in physics.An international team of experts, each of whom has left his mark on the developments of this remarkable theory and experimental applications, contribute both historical essays and more detailed current technical and experimental accounts to this volume. These articles highlight the new discoveries from the respective authors' perspectives.This unique volume celebrates the impact over four decades of the BKT theory on modern physics. In addition to the historical perspective provided by Kosterlitz and Thouless's overview, the volume provides a comprehensive description of experimental and theoretical applications and extensions of the BKT theory.