  We propose an efficient yet simple protocol to generate arbitrary symmetric
entangled states with only global single-qubit rotations in a teared Hilbert
space. The system is based on spin-1/2 qubits in a resonator such as atoms in
an optical cavity or superconducting qubits coupled to a metal microwave
resonator. By sending light or microwave into the resonator, it induces AC
Stark shifts on particular angular-momentum eigenstates (Dicke states) of
qubits. Then we are able to generate barriers that hinder transitions between
adjacent Dicke states and tear the original Hilbert space into pieces.
Therefore, a simple global single-qubit rotation becomes highly non-trivial,
and thus generates entanglement among the many-body system. By optimal control
of energy shifts on Dicke states, we are able to generate arbitrary symmetric
entangled states. We also exemplify that we can create varieties of useful
states with near-unity fidelities in only one or very few steps, including W
states, spin-squeezed states (SSS), and Greenberger-Horne-Zeilinger (GHZ)
states. Particularly, the SSS can be created by only one step with a squeezing
parameter $\xi_R^2\sim1/N^{0.843}$ approaching the Heisenberg limit (HL). Our
finding establishes a way for universal entanglement generations with only
single-qubit drivings where all the multiple-qubit controls are integrated into
simply switching on/off microwave. It has direct applications in the
variational quantum optimizer which is available with existing technology.
