Quantum RAM

If yer gonna build a quantum computer, yer gonna need some quantum memory to store qubits.

Enter quantum random access memory–which like most quantum things is just like plain old vanilla RAM except all a-ghostly and a-spooky. Brrrrr.

Here’s how RAM works. Each memory cell is connected to a circuit tree in which the branches can be switched on or off. Addressing a single memory cell means arranging the switches so that the only path through the circuit tree goes to the cell in question.

One important problem is how many switches yer have to pull to address a specific memory cell. In conventional RAM it’s in the 2^n ballpark (where n is the number of cells).

Now Seth “Lurver” Lloyd at MIT and a few buddies in Italy have worked out a quantum memory architecture that requires on n switches to be thrown (or thereabouts).

That’s a significant reduction. What’s more, the team says the idea can be used to improve the performance of classical RAM. Reducing the switching from 2^n to n could dramatically reduce power consumption in conventional RAM.

And ain’t we all lookin for greener RAM?

Ref: arxiv.org/abs/0708.1879: Quantum Random Access Memory