Reduced Planck constant
J·s
The reduced Planck constant is Planck's constant divided by 2π. It is the quantum of angular momentum and the natural unit of action in quantum mechanics — it sets the scale at which quantum effects dominate.
Used in
- Heisenberg uncertainty principle Δx·Δp ≥ ħ/2
- Schrödinger equation and photon energy E = ħω
Source: SI defining constants / CODATA 2018