What Does h.c. Signify in Quantum Mechanics Formulas?

[phonon44145]

A textbook gives the following interaction Hamiltonian describing the interaction of an atom (having transition dipole moment [itex]\mu[/itex]) with a photon whose polarization can be [itex]\epsilon_{1}[/itex] or [itex]\epsilon_{2}[/itex]):

H = g [itex]\Sigma[/itex][itex]^{2}_{s=1}[/itex][itex]\mu[/itex][itex]\bullet[/itex][itex]\epsilon[/itex]_s[itex]\sigma^{-}[/itex]a[itex]^{+}_{s}[/itex] + h.c.

where [itex]\sigma^{-}[/itex] is Pauli spin-flip operator and a[itex]^{+}_{s}[/itex] is the creation/annihilation operator.

What does "h.c." stand for in this formula?

 

[Polyrhythmic]

Hermitean conjugate.

 

[phonon44145]

Thanks for the quick reply. But I still cannot quite see how to write the second term explicitly. Am I correct in assuming that μ and ϵ1, ϵ2 should not change, σ− will become σ+, and creation operator will change to annihilation operator?

 

[phonon44145]

Also, what does g stand for - gyromagnetic ratio?