BOSE-EINSTEIN CONDENSATION: TWENTY YEARS AFTER

arXiv (Cornell University), 2022

The piling up of a macroscopic fraction of noninteracting bosons in the lowest energy state of a system at very low temperatures is known as Bose-Einstein condensation. It took nearly 70 years to observe the condensate after their theoretical prediction. A brief history of the relevant developments, essentials of the basic theory, physics of the steps involved in producing the condensate in a gas of alkali atoms together with the pertinent theory, and some important features of the research work carried out in the last about 25 years have been dealt with. An effort has been made to present the material in a manner that it can be easily followed by undergraduate students as well as non-specialists and may even be used for classroom teaching.

The history of the Bose-Einstein condensate (BEC) is considered from Einstein's original conception, to London's revival with respect to superfluid 4He and to an explanation of today's concept of the BEC as a result of broken gauge symmetry and phase coherence. A discussion of the BEC's role in superfluidity shows that BEC is neither a necessary nor sufficient condition for superfluidity. The protocol to make BEC in dilute gases is outlined from the 1995 experiment by Cornell and Wieman.

Naturwissenschaften, 2002

Bose-Einstein condensation is one of the most curious and fascinating phenomena in physics. It lies at the heart of such intriguing processes as superfluidity and superconductivity. However, in most cases, only a small part of the sample is Bose-condensed and strong interactions are present. A weakly interacting, pure Bose-Einstein condensate (BEC) has therefore been called the "holy grail of atomic physics". In 1995 this grail was found by producing almost pure BECs in dilute atomic gases. We review the experimental development that led to the realization of BEC in these systems and explain how BECs are now routinely produced in about 25 laboratories worldwide. The tremendous experimental progress of the past few years is outlined and a number of recent experiments show the current status of the field. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.

The study of Bose–Einstein condensation in dilute gases draws on many different sub fields of physics. Atomic physics provides the basic methods for creating and manipulating these systems, and the physical data required to characterize them. Because interactions between atoms play a key role in the behaviour of ultracold atomic clouds, concepts and methods from condensed matter physics are used extensively. Investigations of spatial and temporal correlations of particles provide links to quantum optics, where related studies have been made for photons. Trapped atomic clouds have some similarities to atomic nuclei, and insights from nuclear physics have been helpful in understanding their properties.

Ultra Cold Atomic Systems: The Investigation and Application of Bose-Einstein Condensates, 2021

The emergence of highly effective cooling and trapping techniques for neutral atoms in the late 1990s was undeniably one of the largest scientific breakthroughs in atomic physics. The concept of Bose-Einstein condensates, first theorized by Albert Einstein and Satyendra Bose in the 1920s and later carried out experimentally in 1995, is a concept that enables us to study multitudinous phenomena, investigate the behaviour of atoms at a quantum scale, make precise measurements as well as proceed with many other research opportunities that were otherwise impossible to carry out. In constant pursuit of an even colder temperature, physicists in a laboratory at JILA, a joint institute of the University of Colorado, Boulder and NIST, created the first Bose-Einstein Condensate at barely 5 nanokelvin. This paper will revolve around the 5th state of matter and will begin with a concise explanation of what it is, followed by a succinct description of how it can be attained. Subsequently, it will highlight the properties exhibited by BEC’s and ultimately elaborate on a few of their potential applications.

Physics Today, 1999

BoseEinstein condensates are an ideal testing ground for quantum field theory in real time and at finite temperatures basic topics of great importance for diverse physical systems.

Physics of Particles and Nuclei, 2011

The review is devoted to the elucidation of the basic problems arising in the theoretical investigation of systems with Bose-Einstein condensate. Understanding these challenging problems is necessary for the correct description of Bose-condensed systems. The principal problems considered in the review are as follows: (i) What is the relation between Bose-Einstein condensation and global gauge symmetry breaking? (ii) How to resolve the Hohenberg-Martin dilemma of conserving versus gapless theories? (iii) How to describe Bose-condensed systems in strong spatially random potentials? (iv) Whether thermodynamically anomalous fluctuations in Bose systems are admissible? (v) How to create nonground-state condensates? Detailed answers to these questions are given in the review. As examples of nonequilibrium condensates, three cases are described: coherent modes, turbulent superfluids, and heterophase fluids.

Reviews of Modern Physics, 1999

The phenomenon of Bose-Einstein condensation of dilute gases in traps is reviewed from a theoretical perspective. Mean-field theory provides a framework to understand the main features of the condensation and the role of interactions between particles. Various properties of these systems are discussed, including the density profiles and the energy of the ground state configurations, the collective oscillations and the dynamics of the expansion, the condensate fraction and the thermodynamic functions. The thermodynamic limit exhibits a scaling behavior in the relevant length and energy scales. Despite the dilute nature of the gases, interactions profoundly modify the static as well as the dynamic properties of the system; the predictions of mean-field theory are in excellent agreement with available experimental results. Effects of superfluidity including the existence of quantized vortices and the reduction of the moment of inertia are discussed, as well as the consequences of coherence such as the Josephson effect and interference phenomena. The review also assesses the accuracy and limitations of the mean-field approach.

Physical Review A, 1997