# Margolus–Levitin theorem

The Margolus–Levitin theorem, named for Norman Margolus and Lev B. Levitin, gives a fundamental limit on quantum computation (strictly speaking on all forms on computation). The processing rate cannot be higher than 6 × 1033 operations per second per joule of energy. Or stating the bound for one bit:

A quantum system of energy E needs at least a time of ${\displaystyle {\frac {h}{4E}}}$ to go from one state to an orthogonal state, where h is Planck's constant (6.626 × 10−34 J·s) and E is average energy.

• Sinitsyn, Nikolai A. (2017). "Is there a quantum limit on speed of computation?" (PDF). arXiv:1701.05550. Bibcode:2018PhLA..382..477S. doi:10.1016/j.physleta.2017.12.042. Cite journal requires |journal= (help)