Searching for primordial black hole dark matter with pulsar timing arrays

We discuss the possibility of detecting the presence of primordial black holes (PBHs), such as those that might account for galactic dark matter, using modification of pulsar timing residuals when PBHs pass within similar to 1000 AU and impart impulse accelerations to the Earth. With this technique, PBHs with masses around M-PBH similar to 10(25) g (similar to 0.1 lunar masses) can be detected. Currently, the constraints on the abundance of such dark matter candidates are weak. A 30 yr-long monitoring campaign with the proposed Square Kilometer Array can rule out a PBH fraction more than similar to 1/10 in the solar neighborhood in the form of dark matter with mass M-PBH similar to 10(25) g.