  The existence of quantum tricriticality and exotic phases are found in a
Dicke triangle (TDT) where three cavities, each one containing an ensemble of
three-level atoms, are connected to each other through the action of an
artificial magnetic field. The conventional superradiant phase (SR) is
connected to the normal phase through first- and second-order boundaries, with
tricritical points located at the intersection of such boundaries. Apart from
the SR phase, a chiral superradiant (CSR) phase is found by tuning the
artificial magnetic field. This phase is characterized by a nonzero photon
current and its boundary presents chiral tricritical points (CTCPs). Through
the study of different critical exponents, we are able to differentiate the
universality class of the CTCP and TCP from that of second-order critical
points, as well as find distinctive critical behavior among the two different
superradiant phases. The TDT can be implemented in various systems, including
atoms in optical cavities as well as the circuit QED system, allowing the
exploration of a great variety of critical manifolds.
