<P> In 1924, Albert Einstein and Satyendra Nath Bose predicted the "Bose--Einstein condensate" (BEC), sometimes referred to as the fifth state of matter . In a BEC, matter stops behaving as independent particles, and collapses into a single quantum state that can be described with a single, uniform wavefunction . </P> <P> In the gas phase, the Bose--Einstein condensate remained an unverified theoretical prediction for many years . In 1995, the research groups of Eric Cornell and Carl Wieman, of JILA at the University of Colorado at Boulder, produced the first such condensate experimentally . A Bose--Einstein condensate is "colder" than a solid . It may occur when atoms have very similar (or the same) quantum levels, at temperatures very close to absolute zero (− 273.15 ° C). </P> <P> A fermionic condensate is similar to the Bose--Einstein condensate but composed of fermions . The Pauli exclusion principle prevents fermions from entering the same quantum state, but a pair of fermions can behave as a boson, and multiple such pairs can then enter the same quantum state without restriction . </P> <P> One of the metastable states of strongly non-ideal plasma is Rydberg matter, which forms upon condensation of excited atoms . These atoms can also turn into ions and electrons if they reach a certain temperature . In April 2009, Nature reported the creation of Rydberg molecules from a Rydberg atom and a ground state atom, confirming that such a state of matter could exist . The experiment was performed using ultracold rubidium atoms . </P>

Who taught that the basic element of matter is water