Macroscopic Quantum Effects in Magnetic Systems: An Overview

G. S. Agarwal

Macroscopic magnetic systems like YIG spheres provide a new platform to study quantum features like entanglement, squeezing and other quantum states besides effects like bistability and spin currents. I give an overview of recent developments.

Christian Ngô, Marcel H. Van de Voorde

This chapter is a brief overview of the physics governing processes at the nanoscale. We are used to the macroscopic world and have developed an understanding, based on what is usually called “classical physics” of the behavior of the objects that we see with our eyes. However, classical physics is not able to explain certain phenomena occurring at the atomic or molecular level or below. Compared to macroscopic systems, quantum effects can become important and certain classical physical effects, which are negligible for macroscopic objects, can become prominent. We present here some new aspects showing how nano-objects behave compared to what is expected by extrapolating our knowledge on macroscopic systems. Further items will be introduced in the subsequent chapters when needed. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Hermann Haken, Hans Christoph Wolf

Indrani Bose

Quantum magnetism is one of the most active areas of research in condensed matter physics. There is significant research interest specially in low-dimensional quantum spin systems. Such systems have a large number of experimental realizations and exhibit a variety of phenomena the origin of which can be attributed to quantum effects and low dimensions. In this review, an overview of some aspects of quantum magnetism in low dimensions is given. The emphasis is on key concepts, theorems and rigorous results as well as models of spin chains, ladders and frustated magnetic systems.

Hermann Haken, Hans Christoph Wolf