2010/11/01 by G. Jona-Lasinio, G. Jona‐Lasinio · 1 citation
Chemistry · Physics and Astronomy · #Molecular spectroscopy and chirality #Origins and Evolution of Life #Quantum Mechanics and Applications
paper · pdf · doi:10.1143/ptp.124.731
crossref issued 2010/11/01 · crossref published 2010/11/01 · crossref published-print 2010/11/01 · openalex publication_date 2010/11/01 · crossref created 2010/11/22 · crossref deposited 2017/08/24 · openalex created_date 2025/10/10 · crossref indexed 2026/07/31 · openalex updated_date 2026/07/31
Spontaneous symmetry breaking (SSB) is a widespread phenomenon in several areas of physics. In this paper I wish to illustrate some situations where spontaneous symmetry breaking presents non obvious aspects. The first example is taken from molecular physics and is related to the paradox of existence of chiral molecules. The second case refers to a Dirac field in presence of a magnetic field. Gusynin, Miransky and Shovkovy have shown that Nambu-Jona-Lasinio (NJL) models, where SSB of chiral symmetry takes place for the nonlinear coupling over a certain threshold, in presence of a magnetic field exhibit SSB for any value of the coupling. They called this phenomenon magnetic catalysis. I will discuss this problem in 2 + 1 dimensions from an operatorial point of view and show that the basic phenomenon is a double pairing induced by the magnetic field in the vacuum for any value of the mass. This pairing provides the environment responsible for chiral symmetry breaking in NJL models with very weak nonlinearities. The third case illustrates briefly SSB in stationary nonequilibrium states and its possible relevance in natural phenomena.