Limits on neutron Lorentz violation from pulsar timing

Pulsars are the most accurate naturally occurring clocks, and data about them can be used to set bounds on neutron-sector Lorentz violations. If $SO(3)$ rotation symmetry is completely broken for neutrons, then pulsars’ rotation speeds will vary periodically. Pulsar timing data limits the relevant Lorentz-violating coefficients to be smaller than $1.7\times {10}^{-8}$ at at least 90% confidence.