1. The problem statement, all variables and given/known data Assume that we have a system where the two lowest one-particle states are with eigen energy E1 and with eigen energy E2. What is the lowest eigen energy E and the wave function for a two-particle system if a) they are bosons b) they are fermions 2. The attempt at a solution a) The symmetric (boson) wave function becomes The energy is of course 2E1 because bosons can be in the same quantum state. According to my book, the answer is only, so before proceeding with b) I want to know what I have done wrong.