Question: whats the difference between normal computers and quantum ones?

Gautam Kambhampati answered on 13 Mar 2019:

In any computer, we store stuff as a binary number. So for example, the letter ‘a’ is stored as ‘01100001’ inside your computer.

In a normal computer, we use tiny circuits called transistors that are about 7nm big to store these 0s and 1s. This is around the same size as the DNA in your cells. We can’t make them any smaller because there will be lots of interference between all the different wires in the circuit since they’re so close together.

But instead, we can use individual atoms or molecules to store the information. A 7nm transistor has about 60 atoms in it, so if we can use each atom individually to store information we’d be able to store a lot more! This is how a quantum computer works.