In physics, the Planck charge, denoted by , is one of the base units in the system of natural units called Planck units. It is a quantity of electric charge defined in terms of fundamental physical constants.
- is the speed of light in the vacuum
- is the reduced Planck constant
- is the permittivity of free space
- is the elementary charge
- is the fine structure constant.
The Gaussian cgs units are defined so that , in which case has the following simple form,
It is customary in theoretical physics to adopt the Lorentz–Heaviside units (also known as rationalized cgs). When made natural (, ), they are like the SI system with . Therefore, it is more appropriate to instead define the Planck charge as
When charges are measured in units of , which is commonly used in quantum field theory, we have
Notes and references
- Stock, Michael; Witt, Thomas J (2006). "CPEM 2006 round table discussion 'Proposed changes to the SI'". Metrologia. 43 (6): 583. Bibcode:2006Metro..43..583S. doi:10.1088/0026-1394/43/6/014.
- Pavšič, Matej (2001). The Landscape of Theoretical Physics: A Global View. Dordrecht: Kluwer Academic. pp. 347–352. ISBN 0-7923-7006-6.
- The Feynman Lectures on Physics, Volume II, ch. 8: Electrostatic Energy