Tuesday, October 23, 2012

Cracking the Quantum Safe


This summer, physicists celebrated a triumph that many consider fundamental to our understanding of the physical world: the discovery, after a multibillion-dollar effort, of the Higgs boson.

Given its importance, many of us in the physics community expected the event to earn this year’s Nobel Prize in Physics. Instead, the award went to achievements in a field far less well known and vastly less expensive: quantum information.

It may not catch as many headlines as the hunt for elusive particles, but the field of quantum information may soon answer questions even more fundamental — and upsetting — than the ones that drove the search for the Higgs. It could well usher in a radical new era of technology, one that makes today’s fastest computers look like hand-cranked adding machines.

The basis for both the work behind the Higgs search and quantum information theory is quantum physics, the most accurate and powerful theory in all of science. With it we created remarkable technologies like the transistor and the laser, which, in time, were transformed into devices — computers and iPhones — that reshaped human culture.

But the very usefulness of quantum physics masked a disturbing dissonance at its core. There are mysteries — summed up neatly in Werner Heisenberg’s famous adage “atoms are not things” — lurking at the heart of quantum physics suggesting that our everyday assumptions about reality are no more than illusions.

Take the “principle of superposition,” which holds that things at the subatomic level can be literally two places at once. Worse, it means they can be two things at once. This superposition animates the famous parable of Schrödinger’s cat, whereby a wee kitty is left both living and dead at the same time because its fate depends on a superposed quantum particle.

For decades such mysteries were debated but never pushed toward resolution, in part because no resolution seemed possible and, in part, because useful work could go on without resolving them (an attitude sometimes called “shut up and calculate”). Scientists could attract money and press with ever larger supercolliders while ignoring such pesky questions.

But as this year’s Nobel recognizes, that’s starting to change. Increasingly clever experiments are exploiting advances in cheap, high-precision lasers and atomic-scale transistors. Quantum information studies often require nothing more than some equipment on a table and a few graduate students. In this way, quantum information’s progress has come not by bludgeoning nature into submission but by subtly tricking it to step into the light.

by Adam Frank, NY Times |  Read more:
Illustration: Jesse Tise