Science magazine’s breakthrough of the year: The first quantum machine

Contact: Natasha Pinol, npinol@aaas.org
16-Dec-2010

(American Association for the Advancement of Science) Back in March, a group of researchers designed a gadget that moves in ways that can only be described by quantum mechanics -- the set of rules that governs the behavior of tiny things like molecules, atoms, and subatomic particles. In recognition of the conceptual ground their experiment breaks, the ingenuity behind it and its many potential applications, Science has called this discovery the most significant scientific advance of 2010.

Physicists Andrew Cleland and John Martinis from the University of California at Santa Barbara and their colleagues designed the machine—a tiny metal paddle of semiconductor, visible to the naked eye—and coaxed it into dancing with a quantum groove. First, they cooled the paddle until it reached its "ground state," or the lowest energy state permitted by the laws of quantum mechanics (a goal long-sought by physicists). Then they raised the widget's energy by a single quantum to produce a purely quantum-mechanical state of motion. They even managed to put the gadget in both states at once, so that it literally vibrated a little and a lot at the same time—a bizarre phenomenon allowed by the weird rules of quantum mechanics.

Science and its publisher, AAAS, the nonprofit science society, have recognized this first quantum machine as the 2010 Breakthrough of the Year. They have also compiled nine other important scientific accomplishments from this past year into a top ten list, appearing in a special news feature in the journal's 17 December 2010 issue. Additionally, Science news writers and editors have chosen to spotlight 10 "Insights of the Decade" that have transformed the landscape of science in the 21st Century.

"This year's Breakthrough of the Year represents the first time that scientists have demonstrated quantum effects in the motion of a human-made object," said Adrian Cho, a news writer for Science. "On a conceptual level that's cool because it extends quantum mechanics into a whole new realm. On a practical level, it opens up a variety of possibilities ranging from new experiments that meld quantum control over light, electrical currents and motion to, perhaps someday, tests of the bounds of quantum mechanics and our sense of reality."

The quantum machine proves that the principles of quantum mechanics can apply to the motion of macroscopic objects, as well as atomic and subatomic particles. It provides the key first step toward gaining complete control over an object's vibrations at the quantum level. Such control over the motion of an engineered device should allow scientists to manipulate those minuscule movements, much as they now control electrical currents and particles of light. In turn, that capability may lead to new devices to control the quantum states of light, ultra-sensitive force detectors and, ultimately, investigations into the bounds of quantum mechanics and our sense of reality. (This last grand goal might be achieved by trying to put a macroscopic object in a state in which it's literally in two slightly different places at the same time—an experiment that might reveal precisely why something as big as a human can't be in two places at the same time.)

"Mind you, physicists still haven't achieved a two-places-at-once state with a tiny object like this one," said Cho. "But now that they have reached the simplest state of quantum motion, it seems a whole lot more obtainable—more like a matter of 'when' than 'if.'"

Science's list of the nine other groundbreaking achievements from 2010 follows. …

Science's breakthrough of the year: The first quantum machine

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Exotic antimatter detected at Relativistic Heavy Ion Collider (RHIC)

Scientists report discovery of heaviest known antinucleus and first antinucleus containing an anti-strange quark, laying the first stake in a new frontier of physics

UPTON, NY — An international team of scientists studying high-energy collisions of gold ions at the Relativistic Heavy Ion Collider (RHIC), a 2.4-mile-circumference particle accelerator located at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, has published evidence of the most massive antinucleus discovered to date. The new antinucleus, discovered at RHIC’s STAR detector, is a negatively charged state of antimatter containing an antiproton, an antineutron, and an anti-Lambda particle. It is also the first antinucleus containing an anti-strange quark. The results will be published online by Science Express on March 4, 2010.

“This experimental discovery may have unprecedented consequences for our view of the world,” commented theoretical physicist Horst Stoecker, Vice President of the Helmholtz Association of German National Laboratories. “This antimatter pushes open the door to new dimensions in the nuclear chart — an idea that just a few years ago, would have been viewed as impossible.”

The discovery may help elucidate models of neutron stars and opens up exploration of fundamental asymmetries in the early universe.

All terrestrial nuclei are made of protons and neutrons (which in turn contain only up and down quarks). The standard Periodic Table of Elements is arranged according to the number of protons, which determine each element’s chemical properties. Physicists use a more complex, three-dimensional chart to also convey information on the number of neutrons, which may change in different isotopes of the same element, and a quantum number known as “strangeness,” which depends on the presence of strange quarks (see diagram). Nuclei containing one or more strange quarks are called hypernuclei.

For all ordinary matter, with no strange quarks, the strangeness value is zero and the chart is flat. Hypernuclei appear above the plane of the chart. The new discovery of strange antimatter with an antistrange quark (an antihypernucleus) marks the first entry below the plane. …

Exotic Antimatter Detected at Relativistic Heavy Ion Collider (RHIC)

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Quantum with fewer dead cats: first macro mechanical quantum device

Part of the reason the field of quantum mechanics seems so confusing is that it’s hard to really see the theories in action. A physicist can talk about qubits and atoms all he wants, but we laypeople still say “pics or it didn’t happen.” Well, we still don’t have pics (unless you count the delightful illustration of the Schrodinger’s cat thought experiment), but a researcher at UC Santa Barbara has made progress in bringing quantum systems into the sight of ordinary people. Andrew Cleland and his team created the first mechanical device that both operates as a quantum system and can be seen with the naked eye.

The device is little more than a simple piezoelectric resonator made of a teeny-tiny piece of quartz-like material attached to metal plates. The material expands and contracts – kind of like a balloon – with electrical voltage administered at a very precise high frequency. A qubit was then “wired” to the resonator. The device had to be cooled nearly to absolute zero to eliminate most of the atomic movements of the qubit and the resonator. And once the team excited the qubit with a pulse of energy, the resonator fluctuated. For the first time ever, quantum vibrations could be observed on a macro scale. If you’ve been completely lost by all of this talk about qubits and resonators, the short version is this: the device converts a quantum state to mechanical vibrations. And compared with other, similar experiments, it’s gigantic. …

Quantum With Fewer Dead Cats: First Macro Quantum Device

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Golden Ratio discovered in quantum world: hidden symmetry observed for the first time in solid state matter

ScienceDaily (Jan. 7, 2010) — Researchers from the Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), in cooperation with colleagues from Oxford and Bristol Universities, as well as the Rutherford Appleton Laboratory, UK, have for the first time observed a nanoscale symmetry hidden in solid state matter. They have measured the signatures of a symmetry showing the same attributes as the golden ratio famous from art and architecture.

The research team is publishing these findings in the Jan. 8, 2010 issue of the journal Science.

On the atomic scale particles do not behave as we know it in the macro-atomic world. New properties emerge which are the result of an effect known as the Heisenberg's Uncertainty Principle. In order to study these nanoscale quantum effects the researchers have focused on the magnetic material cobalt niobate. It consists of linked magnetic atoms, which form chains just like a very thin bar magnet, but only one atom wide and are a useful model for describing ferromagnetism on the nanoscale in solid state matter.

When applying a magnetic field at right angles to an aligned spin the magnetic chain will transform into a new state called quantum critical, which can be thought of as a quantum version of a fractal pattern. Prof. Alan Tennant, the leader of the Berlin group, explains "The system reaches a quantum uncertain -- or a Schrödinger cat state. This is what we did in our experiments with cobalt niobate. We have tuned the system exactly in order to turn it quantum critical."

By tuning the system and artificially introducing more quantum uncertainty the researchers observed that the chain of atoms acts like a nanoscale guitar string. Dr. Radu Coldea from Oxford University, who is the principal author of the paper and drove the international project from its inception a decade ago until the present, explains: "Here the tension comes from the interaction between spins causing them to magnetically resonate. For these interactions we found a series (scale) of resonant notes: The first two notes show a perfect relationship with each other. Their frequencies (pitch) are in the ratio of 1.618…, which is the golden ratio famous from art and architecture." Radu Coldea is convinced that this is no coincidence. "It reflects a beautiful property of the quantum system -- a hidden symmetry. Actually quite a special one called E8 by mathematicians, and this is its first observation in a material," he explains. …

Golden Ratio Discovered in Quantum World: Hidden Symmetry Observed for the First Time in Solid State Matter

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Scientists demonstrate laser with controlled polarization

Cambridge, Mass. – April 13, 2009 – Applied scientists at the Harvard School of Engineering and Applied Sciences (SEAS) in collaboration with researchers from Hamamatsu Photonics in Hamamatsu City, Japan, have demonstrated, for the first time, lasers in which the direction of oscillation of the emitted radiation, known as polarization, can be designed and controlled at will. The innovation opens the door to a wide range of applications in photonics and communications. Harvard University has filed a broad patent on the invention.

Spearheaded by graduate student Nanfang Yu and Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, both of SEAS, and by a team at Hamamatsu Photonics headed by Dr. Hirofumi Kan, General Manager of the Laser Group, the findings will be published as a cover feature of the April 13 issue of Applied Physics Letters.

"Polarization is one of the key features defining a laser beam. Controlling it represents an important new step towards beam engineering of lasers with unprecedented flexibility, tailored for specific applications," explains Capasso. "The novelty of our approach is that instead of being conducted externally, which requires bulky and expensive optical components, manipulation of the beam polarization is achieved by directly integrating the polarizer on the laser facet. This compact solution is applicable to semiconductor lasers and other solid-state lasers, all the way from communication wavelengths to the mid-infrared and Terahertz spectrum". …

Scientists demonstrate laser with controlled polarization

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Quantum teleportation between distant matter qubits: first between atoms 1 meter apart

 

For the first time, scientists have successfully teleported information between two separate atoms in unconnected enclosures a meter apart – a significant milestone in the global quest for practical quantum information processing. Teleportation may be nature's most mysterious form of transport: Quantum information, such as the spin of a particle or the polarization of a photon, is transferred from one place to another, without traveling through any physical medium.

Quantum Teleportation Between Distant Matter Qubits: First Between Atoms 1 Meter Apart
Fri, 23 Jan 2009 16:00:00 GMT

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