What is Bose-Einstein condensation?

Bose-Einstein condensation is a phenomenon that occurs at extremely low temperatures, close to absolute zero. In this state, a group of bosons—particles that follow Bose-Einstein statistics—occupies the same quantum state, effectively behaving as a single quantum entity. This collective behavior leads to unique physical properties that cannot be observed in higher temperature regimes.

At these low temperatures, the individual atoms lose their distinct identities due to their wave-like nature, allowing them to overlap and occupy the lowest energy state available. As a result, they coalesce into a single macroscopic quantum state. This process can be observed in certain types of gases, such as rubidium at temperatures only a few billionths above absolute zero, resulting in a "superfluid" state with unusual characteristics.

The other options represent different concepts not related to the unique characteristics of Bose-Einstein condensation.