Meanwhile, at Yale, in January, a team of physicists found a way to observe qubits without ruining their superposition. Instead of interacting with the qubits directly, the team took partial measurements of the particle's quantum state. They still disturbed the qubit, but it was in a known way, so they could correct for it.
This research goes some way to building quantum computers. But alone, these machines wouldn't make an Internet; they need to be connected and exchange information. That's where sending qubits over long distances comes into play.
At the University of Innsbruck, Andreas Stute and his colleagues did this with ionized atoms. The researchers put a single calcium ion between two highly reflective mirrors. They hit the ion with a laser, which changed its quantum state, writing a single qubit of information onto it. They then hit the ion with a second laser. The ion emitted a photon, which carried the qubit they wrote down a fiber optic cable.
Last year, a similar experiment, with un-ionized atoms of rubidium, was conducted at the Max Planck Institute of Quantum Optics in Germany. Stephan Ritter, a physicist there, led a group that transmitted the rubidium atom's quantum state from one "node" of a network to another.
Both sets of experiments are important to building a quantum Internet, as they demonstrate that qubits can travel long distances.
Making a quantum computer and full-on Internet is still hard -- and still some years away. But even with the challenges, it's clear that quantum computers that outperform the familiar electronic ones are coming. It's just a question of when.
"Many, though not all, of the fundamental questions about whether such computer are possible in principle have been answered," Munro said. "Now we can get to real R&D."