Dark Matter Search Results from 1.54 Tonne$\cdot$Year Exposure of PandaX-4T

In this letter, we report the dark matter search results from the commissioning run and the first science run of the PandaX-4T experiment. A blind analysis is carried out on the entire data set. The data processing is improved compared to previous work, unifying the low-level signal reconstruction in a wide energy range up to 120 keV. With a total exposure of 1.54 tonne$\cdot$year, no significant excess of nuclear recoil events is found. The lowest 90% confidence level exclusion on the spin-independent cross section is $1.6\times {10}^{-47}{\mathrm{c}\mathrm{m}}^2$ at a dark matter mass of 40 GeV$\mathrm{/}{c}^2$. Our results represent the most stringent constraint for a dark matter mass above 100 GeV$\mathrm{/}{c}^2$.