Question: Do you think there is a Quantum Realm?

Joshua McAteer answered on 13 Nov 2020: last edited 13 Nov 2020 5:07 pm

Like in the Antman film? No there isn’t. There are different size scales where different effects are dominant. For us slow heavy humans, air resistance (drag) isn’t something we think about a lot, but for insects, it is like swimming through a thick sticky liquid. This is because the drag effects are proportionally higher on smaller things than they are on larger things.

There are systems that are mostly affected by quantum mechanics, to the point where you can ignore forces like gravity as its effect is very small. You can call this a ‘quantum realm’, but what this really means is that there is a gradual process when as the sizes of objects change, some areas of physics become more important and other areas become less important in determining what happens.

Computer chips are made up of transistors, which use layers of silicon to control the flow of electricity. Older computer chips can be understood with a knowledge of electronics, and you can write down simple equations describing the system behaviour. Modern computer chips use transistors that are so small – only a few dozen atoms across – that quantum effects start to be significant. They are always present, but when there are many atoms the quantum effects cancel out. These quantum effects can be characterised, but they are also slightly random. The switching effect of the transistor can be compromised when these random effects become too common.

Transistors have on and off states, where they either conduct or don’t conduct electricity. When the transistors become very small, you get rare events where electrons are allowed to ‘tunnel’ through the transistor even when it is switched off.

The result of this is that engineers need to include error-checking devices into computer chips, and design new ways of laying out transistors so that they work more reliably. This requires a knowledge of quantum mechanics to work out where the electrons go.

I don’t know if that is exactly the answer you were looking for. You couldn’t shrink yourself down to a ‘new world’. But there are different size scales where different maths is used to describe what’s going on.