ABSTRACT
F ig u r e 1 0 .2 . G rap hs with f ix e d e x te rn a l f ie ld cpr . (a) B a s i c g ra p h e lem ent showing the coupling
1/2 σ2 r . (b) A g r a p h fo r the fre e en ergy . (c) A g ra p h fo r the su scep t ib i l i ty . (d) A g rap h fo r ( (x) σ^(χ ' ) ) c . D ashed l in e s r e p r e s e n t the in te ract io n u and dotted l in e s φ .
