A state of matter formed at temperatures near absolute zero in which atoms occupy the same quantum state.
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A Bose-Einstein condensate is a state of matter formed from a gas of bosonic atoms cooled to temperatures near absolute zero, typically around 100 nK. At such low temperatures the atomic wavelengths overlap, and many atoms drop into the lowest quantum state, sharing a single wavefunction. The atoms then behave as one coherent matter wave rather than as separate particles. The first condensate was made in 1995 using rubidium vapour, and it has since been used to study quantum behaviour on a large scale. Condensates also serve as sources for highly precise atom interferometers.
Key ideas: Condensation occurs when the thermal de Broglie wavelength, h / sqrt(2 pi m kT), becomes comparable to the interatomic spacing. Only bosons, particles with integer spin, can pile into one ground state. Atoms are trapped magnetically and cooled by lasers and then evaporative cooling to nanokelvin temperatures at extremely low densities, far below air density.
Common mistakes and connections: Students think a condensate is a solid or a liquid; it is a dilute gas in a single quantum state. Fermions cannot form one directly because of the Pauli exclusion principle, though paired fermions can behave similarly. Links to wave-particle duality, quantum numbers and superfluid helium.
Bosons cooled near 0 K (about 170 nK for Rb-87) pile into the single lowest energy level, forming one macroscopic quantum state. The interactive lesson shows this as a live animation or chart.
In one experiment, light was slowed to about 17 m/s, roughly bicycle speed, while passing through a sodium condensate.
A state of matter formed at temperatures near absolute zero in which atoms occupy the same quantum state.
Bose-Einstein Condensate is a advanced topic in States of Matter & Solutions. It builds on beginner and intermediate topics, so review those first if needed.
Study these earlier topics in States of Matter & Solutions first: States of Matter, Kinetic Molecular Theory, Plasma.
The next topics in States of Matter & Solutions are Pressure and Barometer.
Yes. The interactive lesson includes a self-check question on Bose-Einstein Condensate, and the States of Matter & Solutions quiz draws on every topic in this area.
Bose-Einstein Condensate is topic 4 of 109 in States of Matter & Solutions.