Friday, May 17, 2013

Quantum Foam Computers?

It's my understanding that individual universes within a superposed and entangled quantum computer cannot communicate. Were they permitted to, that would amount to Schrodinger's cats (plural) talking to one other in order to decide whether or not to be alive. Alas, we cannot decide which universe we land in; we are guaranteed only that entangled states shall be consistent when the wave function collapses. Is this not the central point of the EPR paradox?

In practice, the user manual for the DWave quantum computer refers to the probability of obtaining a particular result to a given combinatorial problem. The probability appears to be monotonically related to the reciprocal of the potential energy associated with the result. It's not as though universes can chat with one another while in superposition, then force the system to collapse to the global minimum. Such state may only be reached with luck after several iterations of the same experiment.

But is this really a limitation of quantum physics, or just our understanding thereof? In particular, if the plankscale wormholes of quantum foam actually exist, then it should be possible to create a superposed, entangled, and interuniversally connected quantum computer. This would amount to a network of universes, as opposed to merely a group of universes. Such networked "foambits" would seem to be the next logical evolutionary step of the quantum computer.

Alternatively, if as some physicists hypothesize, gravity can leak from one universe into another, then the equivalent of a quantum foam computer might be constructed on a macroscopic scale, allowing gravity waves to propagate information among universes while in superposition. To this end, masses in superposition are known science (granted, not of the black hole magnitude which popularized gravity waves in the first place).

And if the rumors are true that quantum computers can at best square root the complexity of a classical problem, then what additional reduction might be had by virtue of foambits rather than qubits?

I haven't the vaguest proposal as to how to engineer a quantum foam computer, but the concept seems compelling, if the physics pan out.