  We study the quantum metric in a driven Tavis-Cummings model, comprised of
multiple qubits interacting with a quantized photonic field. The parametrical
driving of the photonic field breaks the system's U(1) symmetry down to a ${\rm
Z}_2$ symmetry, whose spontaneous breaking initiates a superradiant phase
transition. We analytically solved the eigenenergies and eigenstates, and
numerically simulated the system behaviors near the critical point. The
critical behaviors near the superradiant phase transition are characterized by
the quantum metric, defined in terms of the response of the quantum state to
variation of the control parameter. In addition, a quantum metrological
protocol based on the critical behaviors of the quantum metric near the
superradiant phase transition is proposed, which enables greatly the achievable
measurement precision.
