New tests of local Lorentz invariance and local position invariance of   gravity with pulsars
  New tests are proposed to constrain possible deviations from local Lorentz invariance and local position invariance in the gravity sector. By using precise timing results of two binary pulsars, i.e., PSRs J1012+5307 and J1738+0333, we are able to constrain (strong-field) parametrized post-Newtonian parameters $\hat{\alpha}_1$, $\hat{\alpha}_2$, $\hat{\xi}$ to high precision, among which, $|\hat{\xi}| < 3.1\times10^{-4}$ (95% C.L.) is reported here for the first time. 
Lijing Shao, Norbert Wex, Michael Kramer
gr-qc astro-ph.GA