ELI5: How do quantum bits work?

**Quantum bits, or qubits, are like special coins that can be heads, tails, or both at the same time, unlike regular coins which can only be one or the other.

Imagine you have a regular coin. It can be either heads or tails. That's like a regular bit** in a computer. A bit is either a 0 or a 1. Simple!

Now, imagine a magical spinning coin. While it's spinning, it's kind of both heads and tails at the same time. It's not decided yet! That's like a qubit. It can be a 0, a 1, or a combination of both.

Here's how it works in a bit more detail:

• Superposition: The spinning coin is in superposition. This means it's in a mix of both heads and tails until you look at it. Think of it like a light switch that's not fully on or fully off, but somewhere in between. The qubit is simultaneously a 0 and a 1, in a proportion.
• Measurement: When you stop the spinning coin and look at it, it has to be either heads or tails. This is called measurement. When we measure a qubit, it "collapses" out of its superposition and becomes either a 0 or a 1.
• Entanglement: Now imagine you have two of these magical coins. If they are entangled, flipping one instantly tells you what the other one will be, even if they are far apart! It's like having two spinning coins that are magically linked – if one lands on heads, the other instantly lands on tails, no matter how far apart they are.