Violin technique once. "Double stopping" is also used to mean playing on three or all four strings at once, although such practices are more properly called "triple" or "quadruple stopping". Collectively, double, triple and quadruple stopping is called "multiple stopping". However, triple or quadruple stopping is more commonly just called a chord. Sounding an open string alongside a fingered note is another way to get a harmony. While sometimes also called a double stop, it is more properly called a drone, as the drone note (the open string) may be sustained for a passage of different notes played on the adjacent string.
Double beta decay or double beta decay are predicted to be very long; hence, quadruple beta decay is unlikely to be realized. The eight candidate nuclei for quadruple beta decay include Zr, Xe, and Nd capable of quadruple beta-minus decay, and Xe, Ba, Gd, and Dy capable of quadruple beta-plus decay or electron capture. In theory, quadruple beta decay may be experimentally observable in three of these nuclei, with the most promising candidate being Nd. Double beta decay In nuclear physics, double beta decay is a type of radioactive decay in which two neutrons are simultaneously transformed into two protons, or vice versa,