The role of discrete orbital symmetry in mesoscopic physics is manifested in
a system consisting of three identical quantum dots forming an equilateral
triangle. Under a perpendicular magnetic field, this system demonstrates a
unique combination of Kondo and Aharonov-Bohm features due to an interplay
between continuous [spin-rotation SU(2)] and discrete (permutation C3v)
symmetries, as well as U(1) gauge invariance. The conductance as a function of
magnetic flux displays sharp enhancement or complete suppression depending on
contact setups.Comment: 4 pages, 3 .eps figure