Three spin-1/2 particles are fixed in position on the vertices of an equilateral triangle. the interaction amongst themselves and with a uniform external magnetic field, b, is described by the hamiltonian where s, i 1,3, are spin operators, and a is a constant (in units of energy/12). (a) obtain the eigenvalues and eigenvectors of h (b) discuss the degeneracies of the spectrum when b-0. (c) discuss the nature of the ground state when a 0 and when a < 0, still for b 0. (d) discuss the effect the magnetic field causes to the degeneracies when it is switched on.