In mathematical or physics notation, "+ h.c." indicates that additional terms exist which are the Hermitian conjugates of all the preceding terms.
Notes on verification
Standard notational convention in physics, confirmed by multiple independent expert sources including forum discussions, researcher explanations, and arXiv literature usage.
Sources
- + h.c. (en.wikipedia.org)
- https://www.researchgate.net/post/What_is_the_hc_term_that_comes_along_with_hopping_term_t_in_the_single_band_Hubbard_model_of_RVB (researchgate.net)
- https://www.physicsforums.com/threads/meaning-of-h-c-in-lagrangians-elsewhere.454071/ (physicsforums.com)
- https://arxiv.org/pdf/0801.0940 (arxiv.org)