quantum of circulation

physics Half the ratio of the Planck constant to the mass of the electron, = 3.636 947 550(24) × 10^-4 m²·s^-1 with relative standard uncertainty 6.7 × 10^-9.
[Mohr P. J., Taylor B. N. CODATA Recommended Values of the Fundamental Physical Constants: 2002 (to be published)]
[Mohr P. J., Taylor B. N. Rev. Mod. Phys. Vol. 72:351-495 (2000)]
[Mohr P. Phys. Today Vol. 53:7, 11-16 (2000)]
[For latest recommended values, see http://physics.nist.gov/cuu/Constants/index.html]