  We consider a pair of quantum dot-based spin qubits that interact via
microwave photons in a superconducting cavity, and that are also parametrically
driven by separate external electric fields. For this system, we formulate a
model for spin qubit entanglement in the presence of mutually off-resonant
qubit and cavity frequencies. We show that the sidebands generated via the
driving fields enable highly tunable qubit-qubit entanglement using only ac
control and without requiring the qubit and cavity frequencies to be tuned into
simultaneous resonance. The model we derive can be mapped to a variety of qubit
types, including detuning-driven one-electron spin qubits in double quantum
dots and three-electron resonant exchange qubits in triple quantum dots. The
high degree of nonlinearity inherent in spin qubits renders these systems
particularly favorable for parametric drive-activated entanglement. We
determine multiple common resonance conditions for the two driven qubits and
the cavity and identify experimentally relevant parameter regimes that enable
the implementation of entangling gates with suppressed sensitivity to cavity
photon occupation and decay. The parametrically driven sideband resonance
approach we describe provides a promising route toward scalability and
modularity in spin-based quantum information processing through drive-enabled
tunability that can also be implemented in micromagnet-free electron and hole
systems for spin-photon coupling.
