Einstein-Pauli-Yukawa Paradox --- What is the Physical Reality?
  What is the momentum spectrum of a particle moving in an infinite deep square well? Einstein, Pauli and Yukawa had adopted different point of view than that in usual text books. The theoretical and experimental implication of this problem is discussed. 
Guang-jiong Ni (Depratment of Physics, Fudan University, Shanghai,   P.R. China)