**Introduction**

**Chapter 1**

**Provisional chapter**

**Introductory Chapter**

**Introductory Chapter**

Additional information is available at the end of the chapter

**1. Generalities on superfluidity and superconductivity**

**2. Topological properties of superfluids and superconductors**

Recently, there has been a growing interest in both fields for the important implications of the two phenomena in terms of their topological properties. In particular, if stirred, superfluids form cellular vortices that rotate indefinitely. On the other hand, also multiply-connected superconductors form vortices giving rise to flux quantization that can be just like the quantization of

Roberto ZivieriAdditional information is available at the end of the chapter

DOI: 10.5772/intechopen.77318

This book deals with the recent advancements in two topical subjects of condensed matter physics, superfluidity, and superconductivity. In principle, the two phenomena are very similar because they occur as a function of temperature and in the presence of the vanishing of a physical quantity marking a phase transition below a critical temperature. A superfluid is a fluid having zero viscosity while a superconductor is a conductor with zero resistance. Superfluidity occurs in liquid helium and in ultracold atomic gases while superconductivity is typical of elements like niobium and lead, of some niobium alloys, or compounds like yttrium barium and copper oxide and compounds containing iron. Regarding the latter, since the first discoveries, the interplay between superconductivity and magnetism has also been investigated finding that the magnetic state of superconductors can be described as ideal diamagnetism. The behaviour toward the external magnetic field allows to distinguish between first- and second-type superconductors. Instead, the critical temperature in correspondence of which superconductivity arises allows to distinguish between low- and high-critical temperature superconductors. After their initial discovery, superfluidity was explained as a quantum mechanical phenomenon, while superconductivity was described first according to a phenomenological and classical theory and only in a second moment in terms of a microscopic quantum mechanical theory.

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

http://dx.doi.org/10.5772/intechopen.77318

Roberto Zivieri

#### **Chapter 1 Provisional chapter**

#### **Introductory Chapter Introductory Chapter**

Roberto Zivieri

Additional information is available at the end of the chapter Roberto ZivieriAdditional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.77318
