ELI5, if bits are like a lightbulb being turned on and off, what are qubits?
In: 2
Lightbulbs that you can vary their intensity, not fully on/off. In my head I’m associating it more with analogue data rather than discrete binary data.
Lightbulbs being turned part way on and really close to their neighbors
Tweak one to push more power through it and it heats its neighbors and changes how much power they consume. They heat the original bulb and their other neighbors and change how much power everyone consumes just a bit.
Qbits don’t have discrete values and they impact their neighbors and they’re really not analogous to anything you can hold because quantum mechanics is probabilistic not deterministic like most large scale things
Quantum computers don’t solve the same kinds of problems as digital computers. You don’t want to feed a quantum computer 2+5+8-4 because you’ll get 10.97 one minute and 11.04 the next because it doesn’t work in discrete values. They’re better for things like traveling salesman problems where you tweak how much they interact with each other(the lengths of the paths) and they settle into a low energy state.
What I WANT to say is that qubits are akin to dimmer switch light bulbs, which can be anywhere on the spectrum between on and off, but it is more complicated than that.
Quibits can be “half way between” 0 and 1, but there’s more to it than that.
Two quibit can both be half 1 and half 0, but still completely different from one another.
You can think of binary bits as apple or orange. Clear, distinct and different.
You can think of quantum qubits as smoothies with different quantities of apple juice and orange juice.
This analogy isn’t perfect, but it’s the most accurate explanation I can give without diving into imaginary numbers and other abstract nonELI5 concepts.
EDIT:
You know what, here’s a really butchered explanation for you that might help.
Let’s stick with the smoothie idea.
Qubits are like a smoothie mixing oranges and apples, BUT the ingredients are spread across FOUR cups instead of ONE. Let’s call the cups north, east, south and west.
You CAN mix all of the orange and apple together into the east cup, but you could put some of the orange in the north cup or spread orange across North and East, while apple is in South and West.
In this way, you can have HALF apple and HALF orange, but there’s many different ways that you might get that. There is no one “halfway between apple and orange”.
In fact, you might have two quibits that are both halfway between apple and orange, but one has the apple and orange both in the east and another has apple in West and orange in East. These two (despite both being half and half) are considered “opposite” in the same way that all orange or all apple are considered “opposite”.
EDIT EDIT:
Another analogy is colour.
Binary is black and white.
Qubits are any colour.
There is no one colour that is “half way” between back and white. There is a grey colour between black and white, but there’s also a blue or a red and so on that could be considered half way. There are countless half way points, but they are all very much different from one another.
Qubits are… also like a lightbulb that can be on or off! Quantum bits are still bits in the sense that they are binary, and when you “measure” them, that is to say, look whether the light is on or off you’ll get one or the other.
However, when you and no one else is looking (more precisely, when they are not interacting with any measurements), they can be in a state which is a superposition of on and off.
The easiest analogy to understand superposition is sound. When more than one thing makes sound at the same time, the sounds just overlap each other. The possibilities in a quantum superposition overlap like that, and also like sound, can interfere with one another.
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