Complex sentence: A pseudogap can be seen with several different experimental methods, but probably the most popular is ARPES (Angle Resolved Photoemission Spectroscopy), which can measure the density of states of the electrons in a material.
Split into simpler sentences: A pseudogap can be seen with several different experimental methods. Probably the most popular is ARPES (Angle Resolved Photoemission Spectroscopy), which can measure the density of states of the electrons in a material.