  Quantum algorithms such as dynamical decoupling can be used to improve the
sensitivity of a quantum sensor to a signal while suppressing sensitivity to
noise. Atomic clocks are among the most sensitive quantum sensors, with recent
improvements in clock technology allowing for unprecedented precision and
accuracy. These clocks are highly sensitive to variations in fundamental
constants, making them ideal probes for local ultralight scalar dark matter.
Further improvements to the sensitivity is expected in proposed nuclear clocks
based on the thorium 229m isomer. We investigate the use of various quantum
metrology algorithms in the search for dark matter using quantum clocks. We
propose a new broadband dynamical decoupling algorithm and compare it with
quantum metrology protocols that have been previously proposed and
demonstrated, namely differential spectroscopy and narrowband dynamical
decoupling. We conduct numerical simulations of scalar dark matter searches
with realistic noise sources and accounting for dark matter decoherence.
Finally, we discuss an alternative thorium nuclear transition excitation method
that bypasses the technical challenges associated with vacuum ultraviolet
lasers.
