What's Wrong With Quantum Computing

Decoherence!

What's Wrong With Quantum Computing

welcomia/Shutterstock

What's Wrong With Quantum Computing JAMIE CONDLIFFE | Gizmodo-Australia

It’s vast ability to assume many states at once — in theory — means that quantum computers can provide untold power, many times faster than any classical computer. In practice, it’s rather more difficult.

First off, building a quantum computer is no mean feat. While the technology required to create computers full of traditional bits is well established, manufacturing qubits is far from straightforward.

For starters, no one is quite sure what the best way to make one is. Some techniques involve trapping ions, electrons or other tiny little particles; some propose using superconductors to create microscopic quantum circuits; others suggest it might be possible to use photons and complex optical apparatus to achieve a similar goal. What these techniques all have in common, however, is the fact that they’re currently plausible on the small scale but incredibly difficult to realize on the large. Essentially, that limits quantum computers to research machines, at least for now.

The scaling problem itself is a result of quantum decoherence — or, rather, wanting to eliminate it. The problem is that, as good ol’ Schroedinger was only too keen to point out, quantum systems need to be isolated from the rest of world in order to work. Interactions with the external world cause the system to decohere, collapsing down and taking a binary state, just like a normal computer.

But the very guts of a quantum computer — quantum gates, lattice vibrations, background nuclear spin of the qubits — can all introduce decoherence effects, too. The solution? Decide on...

Read the entire article

{ more articles }