Quantum phase transitions in the triangular coupled-top model

We study the coupled-top model with three large spins located on a triangle. Depending coupling strength, there exist phases: disordered paramagnetic phase, ferromagnetic and frustrated antiferromagnetic which can be distinguished by mean-field approach. The paramagnetic-ferromagnetic phase transition is accompanied breaking of global $Z_2$ symmetry, whereas paramagnetic-antiferromagnetic both symmetry translational symmetry. Exact analytical results higher-order quantum effects beyond contribution, such as excitation energy, fluctuation, von Neumann entropy, achieved Holstein-Primakoff transformation symplectic in thermodynamic limit. Near critical point, energy gap closes, along divergence fluctuation certain quadrature entropy. Particular attention should paid to where geometric frustration takes effect. behaviors are quite different from those phases, highlight importance frustration. triangular provides simple feasible platform novel induced