Physicists have been able to describe our entire universe using just two mathematical models:

General Relativity, for gravity, and the Standard Model, for everything else. While the

Standard Model has been tested to exquisite precision and is generally successful, it has some

serious inconsistencies: it fails, for example, to explain why matter dominates over antimatter in

our universe. New models aiming to eliminate these inconsistencies often introduce additional

symmetry violation, which in turn results in symmetry-violating properties in fundamental particles

like electrons. In particular, many new physics theories predict that the electron will have a

non-zero electric dipole moment (EDM) aligned with the spin axis, which violates time-reversal

symmetry. Placing limits on the magnitude of the electron EDM directly constrains new physics

theories at energies beyond the reach of the Large Hadron Collider. Here we present a new

experimental limit on the electron’s electric dipole moment using trapped HfF^{+} in rotating bias

fields: |de| < 4.4 × 10^{−30} e·cm. Our measurement is a factor of 2.5 better than the previous best

limit.