# How short is the time for the manifestation of small amounts of energy to justify the existence of quantum fluctuations?

Uncertainty Principle allows the appearance of small amounts of energy from nothing, always on the condition that they disappear in a very short time.

Speaking in seconds, how brief should these phenomena be? Among other things, it serves to explain that, even for a very short time, it is possible to violate the energy conservation law.

I would like to know how long it actually takes (in seconds)

• – PM 2Ring Aug 13 at 11:02
• @PM2Ring Maybe is related to here, but seems that "time" here can't be translate in seconds as unit measure of time? – Aron Aug 13 at 13:05
• Well, strictly speaking, the uncertainty principle does not allow you to violate the energy conservation law. In QM, energy is always conserved. But anyway, the time-energy uncertainty equation is $\Delta E \Delta t \ge \hbar / 2$. If we treat that as an equality and let $\Delta E$ = 1.022 MeV, the rest energy of an electron + positron pair, we get $\Delta t=3.22\times 10^{-22}$ seconds. But please don't take that calculation too seriously. – PM 2Ring Aug 13 at 17:02