A few questions about BEC: A) When these bosons condensate, many particles fill the ground state. I read from textbooks that this would imply that they occupy the same position. -1- experiments are done with Rb atoms, which consist of protons, neutrons and electrons. Wouldn't the electrons and protons in the atoms repel each other respectively? Can the particles really occupy the same position? -2- what happens to the electromagnetic and strong interaction? Wouldn't the particles form molecules or different nucleus if the particles are so close to each other? B) How did they detect the position of the condensate? Can the wavefunction^2 be measured?