A universal quantum processor with ancilla-based readout for tweezer clocks

We realize programmable quantum circuits for optical clock qubits using strontium-88 atoms trapped in optical tweezers. We demonstrate high-fidelity entangling gates mediated by Rydberg interactions and combine these with local addressing, dynamical connectivity, and mid-circuit ancilla-based detection to realize algorithms designed to improve quantum metrology. First, we utilize such universal programmability to demonstrate the simultaneous generation of a cascade of clock Greenberger-Horne-Zeilinger (GHZ) states of different sizes, which collectively form an optimal entangled probe state. Second, we design repetitive ancilla-based quantum logic spectroscopy (QLS) of clock qubits. We show that this enables fast phase detection with non-destructive conditional reset of clock qubits and minimal dead time between repetitions. We discuss prospects for hybrid devices composed of processing and sensing modules and show first steps toward such a design. Our demonstration extends the set of operations accessible for hybrid quantum processor-clock devices and highlights how these can be harnessed to improve the performance of quantum sensors.