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# [Solved]: Qubits Related to RAM?

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Problem Detail:

I read in this article that the amount of bits that can be emulated by a certain number of qubits is 2^(number of qubits). This is because each qubit can be in one of 2 states after it collapses, and so before all the quantum... whatevers collapse, that is the function that gets that result. At least, that was generally what it was saying, but I probably mangled the explanation myself; sorry.

Anyway, this relation (2^n) happens to be the same as the relation between memory registers and RAM in classical computers (i.e. if the computer has n bits in the register, it can have up to 2^n bytes in RAM). Is this important? Does it mean qubits will become like the memory registers and their states like the RAM when we switch to quantum computers? Or is it just something that seems important but is actually meaningless in practice?

By the way, there don't seem to be any tags for some things I referenced, like RAM & memory registers. Is that because the site is so new, or am I just not looking hard enough?

#### Answered By : Yuval Filmus

This coincidence just shows that the function \$n \mapsto 2^n\$ shows up in many places. For example, an \$n\$ bit register can store up to \$2^n\$ different values. If wireless frequency is parametrized using \$n\$ bits, then there are up to \$2^n\$ possible frequencies (in fact, there are probably a bit less). If an IP address is \$n\$ bits, then there are at most \$2^n\$ possible IP addresses (in fact, there are fewer). If a cryptographic key is \$n\$ bits long, then there are \$2^n\$ possible keys. And so on.