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Quantum computing and quantum communication require a different way of thinking about handling information. Not only are quantum states extremely delicate, but you can’t copy a quantum state.

To put it in perspective.
If I want to send a qubit from a lab in Europe to somewhere in New York, that qubit has to make it all the way by itself—you can’t read and replace it along the way.

To get around this limitation, you have to make use of quantum mechanics: teleporting quantum states from one place to another.
To do that in a flexible way that allows computation, you need to store quantum states as they arrive.

That means you need some sort of register that stacks qubits on top of each other.

This is quite challenging.

But, it seems that ions embedded in a crystal might be able to do the job.

Before we journey into the heart of ions, crystals, and qubits, let’s see why we can’t just take ideas from classical computing and bolt them onto quantum computing.
Qubits are not bits
A very simple example that comes up in normal computing is sending one bit to two gates at the same time.

All I need to do is to have a branch in a wire so that the branches terminates at two different gates.

The bit is then sent to both gates.

This can be done because the bit consists of many charges, so the junction simply sends half the charge to one gate and half to the other. Of course there are limits to that approach but, even if I needed to branch many more times, I could simply increase the amount of charge in each copy of the bit through some kind of amplifier.
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