Two-dimensional electronic spectroscopy for the quantum-optics enthusiast

Recent interest in the role of quantum mechanics in the primary events of photosynthetic energy transfer has led to a convergence of nonlinear optical spectroscopy and quantum optics on the topic of energy-transfer dynamics in pigment-protein complexes. The convergence of these two communities has unveiled a mismatch between the background and terminology of the respective fields. To make connections, we provide a pedagogical guide to understanding the basics of two-dimensional electronic spectra aimed at researchers with a background in quantum optics.