OK! In fact, what trouble me a lot is that for second quantization, we always consider operators like:
\sum_{i=1}^N f(x_i) (Sinlge-body operator)
\sum_{i<j}^N V(x_i,x_j) (Two-body operator)
But we seldom consider operators, liked x1, x2 or (x2-x1)^2, (x3-x2)^2. So what I actually want to...
Dear All:
I have a quite mysterious and cumbersome question concerning with the expectation values for a system of identical particles. For example, suppose I have a system of N identical bosons given by the wavefunction ψ(x1,x2,...xN), which is of course symmetrized. My concern is:
1...