Where are the electrons?

Rutgers University, New Brunswick, NJ, USA.

Foundations of physics

According to the Copenhagen interpretation of quantum mechanics, a quantum particle such as an electron does not have a position until one looks - until one performs an appropriate "measurement." This raises several questions:

.- Why should "looking" be so important?

.- What does it even mean to find the position of an object that doesn't have a position until one looks?

.- Is it necessary to be so extreme?

The answer to the latter question is: Not at all! There is a version of quantum mechanics, Bohmian mechanics, in which quantum particles always have positions; when we look we find the particles where they are: measurement then reveals the positions (just as the word measurement suggests) rather than creating them.

What is the price that must be paid to replace Copenhagen quantum mechanics with Bohmian mechanics? None whatsoever. More precisely, the precise is negative. With Bohmian mechanics one replaces the complicated, bordering on incoherent, measurement postulates of Copenhagen quantum mechanics with a single simple obvious evolution equation for the positions of the particles. Moreover, the measurement postulates themselves, including quantum probabilities and the collapse of the wave packet, are no longer incoherent and become theorems of Bohmian mechanics. Who could ask for anything more?

But there is more. And much of that more can be found in the work of scientists such as Xavier Oriols on applied Bohmian mechanics.

January, 2022