PauliChainCombine
PauliChainCombine[exp]
is (nearly) the inverse operation to PauliChainExpand
.
See also
Overview, PauliChain, PCHN, PauliIndex, PauliIndexDelta, DIDelta, PauliChainJoin, PauliChainExpand, PauliChainFactor.
Examples
(PCHN[CSISD[q], Dir3, Dir4] FAD[{k, me}])/(2 CSPD[q, q]) + 1/(2 CSPD[q, q])*
FAD[k, {k - q, me}] (-2 DCHN[CSISD[q], Dir3, Dir4] CSPD[q, q] + 2 DCHN[1, Dir3, Dir4]*
me CSPD[q, q] + DCHN[CSISD[q], Dir3, Dir4] (-me^2 + CSPD[q, q]))
PauliChainCombine[%]
2q2k2.((k−q)2−me2)(q2−me2)((1)Dir3Dir4σ⋅q)+2meq2(1)Dir3Dir4−2q2((1)Dir3Dir4σ⋅q)+2q2(k2−me2)(σ⋅q)Dir3Dir4
2q2k2.((k−q)2−me2)(1)Dir3Dir4(q2−me2)σ⋅q+2meq2(1)Dir3Dir4−2q2(1)Dir3Dir4σ⋅q+2q2(k2−me2)(σ⋅q)Dir3Dir4