Measuring Planck’s Constant With Compton Scattering

Measured values of the electron mass and Compton wavelength yield a value of Planck’s constant with a relative standard

uncertainty of 3 × 10−10. This is only slightly larger than the 1.3 × 10−10 relative standard uncertainty in measurements

performed using the Kibble balance. Compton scattering presents an alternative pathway for improving the value of

Planck’s constant.

Natural units of length, mass, and time offer viable solutions for improving the values of physical constants. While

extensive values of the Planck units lie beyond the reach of present-day instrumentation, certain product and quotient

pairs of Planck units such as the speed of light can be measured with relatively high precision. Better measurements of

certain unit pairs will improve the value of the gravitational constant.