2011 Science News of the Year: Matter & Energy

Baile Zhang and G. Barbastathis/SMART Centre

Quantum theory gets physical

Reality can be understood not only in terms of the flow of energy, but also in terms of the flow of information. So says a team of physicists with a new take on quantum theory (SN: 8/13/11, p. 12). This theory, which explains how matter behaves at the atomic scale, is built on abstract mathematical formulations that seem to defy common sense. But the new take begins with intuitive principles connected to the physical world.

At the idea’s core is a postulate called “purification.” In simplest terms, purification means that you can know everything there is to know about something even if you don’t know everything about its parts. Using this postulate and five axioms drawn from information theory, the researchers have derived the basic mathematical framework of quantum mechanics. The framework also predicts phenomena routinely observed in the lab — including entanglement, Einstein’s “spooky action at a distance.”

This recent approach to quantum theory is part of a larger movement, inspired by the late physicist John Wheeler, to try to recast the explanation of the universe in terms of information. Proponents speculate that their ideas could ultimately solve one of the grandest problems in physics itself: how to unite quantum mechanics and gravity. Devin Powell

Cosmic mimics  Simulations suggest that time travel is impossible in a metamaterial universe (SN: 5/7/11, p. 12), but riding a spacetime bubble could allow travel at up to one-quarter light speed (SN Online: 8/21/11).

Big-time cloaking  Teams use carpet cloaks to hide 3-D objects big enough to see, moving invisibility beyond the microscopic (SN: 2/26/11, p. 12). Physicists also find ways to hide events in time (SN: 8/13/11, p. 12) and to shield objects from detection by visible light (SN: 8/27/11, p. 16) and sound waves (SN Online: 6/30/11).

The next graphene Scientists grow atom-thin sheets of silicon, with a structure similar to that of graphene (SN: 4/23/11, p. 14).

Sexual fireworks  A mouse egg explosively releases zinc atoms just after fertilization, outbursts that appear to jump-start embryonic development (SN: 6/4/11, p. 12).

Wave of reality  The fuzzy quantum shape that describes the speed or location of a single particle, its “wave function,” is directly measured in the lab (SN: 7/16/11, p. 14).

Atomtronics Physicists choreo­graph atoms in an ultracold gas to flow as a controllable current, a step toward building the world’s first “atomtronic” device (SN: 3/12/11, p. 5).

Hydrogen head shot  The lightest atom on Earth is directly imaged for the first time (SN: 3/12/11, p. 13).

Magnetricity  A current of “magnetricity” is created, as north and south magnetic poles split and move independently (SN: 3/12/11, p. 13).

Screwy symmetry  A new form of symmetry called “rotational-reversal” symmetry is discovered (SN: 5/7/11, p. 9).