Simon Geyer

CMOS-compatible spin qubits in silicon are front runner candidates for scaling up quan-
tum computers. Hole spin qubits are particularly promising because they experience a strong
spin-orbit interaction, enabling fast single qubit gates even at elevated temperatures above
4 K. Here, we demonstrate for the first time an exchange-based two-qubit gate in hole silicon fin field effect transistors (FinFETs), current workhorses of the semiconductor industry.
We perform a spectroscopic measurement that fully determines the Hamiltonian of the two
qubits, including exchange interactions, and we find that these interactions are highly tunable, reaching up to 0.5 GHz. The strong spin-orbit interaction induces a strikingly large
anisotropy of the exchange splitting, with changes of almost 100% depending on the direction of the magnetic field. Such a large anisotropy is found to enhance the speed and
fidelity of controlled rotations, a prototypical two-qubit entangling gate, offering a strong
advantage over competing architectures such as electron spin qubits. We demonstrate the
first two-qubit gate for holes in silicon by performing a controlled rotation gate with a conditional spin-flip in <30 ns. Our work brings hole spin qubits in silicon one step closer to the
implementation of a large-scale semiconducting quantum computer.