  We report new experimental results on the search for dark photons based on a
near-quantum-limited haloscope equipped with a superconducting cavity. The
loaded quality factor of the superconducting cavity is $6\times10^{5}$, so that
the expected signal from dark photon dark matter can be enhanced by more than
one order compared to a copper cavity. A Josephson parametric amplifier with a
near-quantum-limited noise temperature has been utilized to minimize the noise
during the search. Furthermore, a digital acquisition card based on field
programmable gate arrays has been utilized to maximize data collection
efficiency with a duty cycle being 100$\%$. This work has established the most
stringent constraints on dark photons at around 26.965 $\mu$eV. In the future,
our apparatus can be extended to search for other dark matter candidates, such
as axions and axion-like particles, and scrutinize new physics beyond the
Standard Model.
