Parity-symmetry-breaking quantum phase transition via parametric drive in a cavity magnonic system

We study the parity-symmetry-breaking quantum phase transition (QPT) in a cavity magnonic system driven by a parametric field, where the magnons in a ferrimagnetic yttrium-iron-garnet sphere strongly couple to a microwave cavity. With appropriate parameters, this cavity magnonic system can exhibit a rich phase diagram, including the parity-symmetric phase, parity-symmetry-broken phase, and bistable phase. When increasing the drive strength beyond a critical threshold, the cavity magnonic system undergoes either a first- or second-order nonequilibrium QPT from the parity-symmetric phase with microscopic excitations to the parity-symmetrybroken phase with macroscopic excitations, depending on the parameters of the system. Our work provides an alternate way to engineer the QPT in a hybrid quantum system containing the spin ensemble in a ferri- or ferromagnetic material with strong exchange interactions.

Automated summary

We studied the parity-symmetry-breaking quantum phase transition in a cavity magnonic system driven by a parametric field, which can exhibit a rich phase diagram including parity-symmetric, parity-symmetry-broken, and bistable phases with appropriate parameters. Beyond a critical threshold of drive strength, the system undergoes a first- or second-order nonequilibrium QPT from the parity-symmetric phase with microscopic excitations to the parity-symmetrybroken phase with macroscopic excitations, depending on the system parameters. Our work offers an alternative way to engineer the QPT in a hybrid quantum system containing a spin ensemble in ferri- or ferromagnetic materials with strong exchange interactions.