The quantum phase problem: a critical review

Gilad Gour

This book is the third volume of review papers on advanced problems of phase transitions and critical phenomena, following the success of the first two volumes in 2004 and in 2007. Broadly, the book aims to demonstrate that the phase transition theory, which experienced its 'golden age' during the 70s and 80s, is far from over and there is still a good deal of work to be done, both at the fundamental level and in respect of applications. This volume presents a broad spectrum of problems connected with criticality. It covers its theoretical backgrounds, analytical approaches and numerical simulations to describe criticality in specific systems (ionic fluids, diluted magnets, polymers), as well as phase transitions on complex networks and in the minority game model. As the first two volumes, this book is based on the review lectures that were given in Lviv (Ukraine) at the "Ising lectures" - a traditional annual workshop on phase transitions and critical phenomena which brings together scientists working in the field with university students and those who are interested in the subject.

L. Mandeļ

Michael Martin Nieto

After reviewing the role of phase in quantum mechanics, I discuss, with the aid of a number of unpublished documents, the development of quantum phase operators in the 1960's. Interwoven in the discussion are the critical physics questions of the field: are there (unique) quantum phase operators and are there quantum systems which can determine their nature? I conclude with a critique of recent proposals which have shed new light on the problem.

Jan Sładkowski

CLIVE F. BAILLIE

We review Monte Carlo computer simulations of spin models — both discrete and continuous. We explain the phenomenon of critical slowing which seriously degrades the efficiency of standard local Monte Carlo algorithms such as the Metropolis algorithm near phase transitions. We then go onto describe in detail the new algorithms which ameliorate the problem of critical slowing down, and give their dynamical critical exponent values.