A Brief History of Our Understanding of BEC: From Bose to Beliaev

TL;DR

This paper reviews the historical development of Bose-Einstein Condensation (BEC) understanding from 1925 to 1965, highlighting key contributions and the evolution of the macroscopic wavefunction concept, culminating in foundational work for modern atomic gases.

Contribution

It provides a comprehensive historical overview emphasizing the conceptual evolution of BEC theory and its foundational role in current atomic gas research.

Findings

Key historical contributions identified and contextualized.

The emergence of the macroscopic wavefunction concept.

Foundational theoretical work for modern atomic gases.

Abstract

We review how our current ideas about BEC developed in the early period 1925-1965, which had the specific goal of understanding superfluid $^4$He. This history is presented by commenting on the key contributions made by Einstein, Fritz London, Tisza, Landau, Bogoliubov, Oliver Penrose and Feynman. We emphasize the emergence of the concept of a macroscopic wavefunction describing the condensate. Starting with the fundamental work of Beliaev in 1957, the period 1957-1965 was a golden era for theoretical studies of interacting Bose-condensed gases. This work provided a sound conceptual basis for understanding the properties of trapped atomic gases which were discovered thirty years later.