500 phases of matter have been defined in a new classification system based on symmetry protected phases

Tweet Condensed matter physics – the branch of physics responsible for discovering and describing most of these phases – has traditionally classified phases by the way their fundamental building blocks – usually atoms – are arranged. The key is something called symmetry.

Using modern mathematics – specifically group cohomology theory and group super-cohomology theory – the researchers have constructed and classified the symmetry-protected phases in any number of dimensions and for any symmetries. Their new classification system will provide insight about these quantum phases of matter, which may in turn increase our ability to design states of matter for use in superconductors or quantum computers. Examples of symmetry-protected phases include some topological superconductors and topological insulators, which are of widespread immediate interest because they show promise for use in the coming first generation of quantum electronics.

To understand symmetry, imagine flying through liquid water in an impossibly tiny ship: the atoms would swirl randomly around you and every direction – whether up, down, or sideways – would be the same. The technical term for this is "symmetry" – and liquids are highly symmetric. Crystal ice, another phase of water, is less symmetric. If you flew through ice in the same way, you would see the straight rows of crystalline structures passing as regularly as the girders of an unfinished skyscraper. Certain angles would give you different views. Certain paths would be blocked, others wide open. Ice has many symmetries – every "floor" and every "room" would look the same, for instance – but physicists would say that the high symmetry of liquid water is broken.

Classifying the phases of matter by describing their symmetries and where and how those symmetries break is known as the Landau paradigm. More than simply a way of arranging the phases of matter into a chart, Landau’s theory is a powerful tool which both guides scientists in discovering new phases of matter and helps them grapple with the behaviours of the known phases. Physicists were so pleased with Landau’s theory that for a long time they believed that all phases of matter could be described by symmetries. That’s why it was an eye-opening experience when they discovered a handful of phases that Landau couldn’t describe.

New states contain a new kind of order: topological order. Topological order is a quantum mechanical phenomenon: it is not related to the symmetry of the ground state, but instead to the global properties of the ground state’s wave function. Therefore, it transcends the Landau paradigm, which is based on classical physics concepts.

String net theory of light and electrons

Science - etry-Protected Topological Orders in Interacting Bosonic Systems

Order Parameters, Broken Symmetry, and Topology - Online introduction to the theoretical framework used to study the bewildering variety of phases in condensed-matter physics. They emphasize the importance of the breaking of symmetries, and develop the idea of an order parameter through several examples. They discuss elementary excitations and the topological theory of defects.

Zspace interactive holographic 3D display

Tweet Infinite Z has a virtual holographic 3D display and pen input device that goes by the name zSpace. This technology combines stereoscopic images with infrared cameras that actually track head and hand movements to construct a more realistic holographic effect.

For the zSpace illusion to work, you need to wear a pair of special glasses. Not only do the glasses perform the required image separation for stereoscopy, but they also have embedded infrared reflectors to help the system track your head. This allows you to move your head so that you can view a hovering object from different perspectives. The screen actually changes what is being displayed based on where you’re looking at it. This innovation allows the illusion of three dimensions to work much more effectively. The system has real-world uses now in architecture and medicine.

The zSpace is designed for professionals working in fields like 3D modeling, so it is priced accordingly. It’s available for $3,995 and people enrolled in Infinite Z’s developer program can buy a device for only $1,500.

“Virtual Holographic 3-D,” also lets you manipulate virtual objects as if they really were floating just inches in front of you. The special stylus connected to the display also contains sensors that allow its movement to be tracked in three dimensions. You can use the stylus to “grab” parts of the virtual image in front of you and move them around in 3-D space.

Graphene sheets coated with nanowires made into flexible solar cells

Tweet MIT researchers have produced a new kind of photovoltaic cell based on sheets of flexible graphene coated with a layer of nanowires. The approach could lead to low-cost, transparent and flexible solar cells that could be deployed on windows, roofs or other surfaces.

Illustration shows the layered structure of the new device, starting with a flexible layer of graphene, a one-atom-thick carbon material. A layer of polymer is bonded to that, and then a layer of zinc-oxide nano wires (shown in magenta), and finally a layer of a material that can extract energy from sunlight, such as quantum dots or a polymer-based material. Illustration courtesy of the research team

Nanoletters - Graphene Cathode-Based ZnO Nanowire Hybrid Solar Cells

DARPA challenge to find innovative approaches to adaptive, software-based radio communications

Tweet ARPA seeks innovative approaches that ensure robust communications in such congested and contested environments.

The DARPA Spectrum Challenge is a competition for teams to create software-defined radio protocols that best use communication channels in the presence of other users and interfering signals.

Using a standardized radio hardware platform, the team that finds the best strategies for guaranteeing successful communication in the presence of other competing radios will win. In addition to bragging rights for the winning teams, one team could win as much as $150,000.

High priority radios in the military and civilian sectors must be able to operate regardless of the ambient electromagnetic environment, to avoid disruption of communications and potential loss of life. Rapid response operations, such as disaster relief, further motivate the desire for multiple radio networks to effectively share the spectrum without requiring direct coordination or spectrum preplanning. Consequently, the need to provide robust communications in the presence of interfering signals is of great importance.

Progress on the Vortex Rocket Engine

Tweet Orbitec has flown a radical new engine technology that promises to cut the size, weight and therefore the cost of putting a rocket – and payload – into space.

Regular rocket engines get incredibly hot, reaching temperatures upwards of 3,000C (5,400F) or more, hot enough to melt the metal chamber in which the rocket fuel mixes with oxygen and burns. At these extremes, even rockets with sidewalls made of heat-resistant superalloys would fail catastrophically.

Orbitec’s alternative approach keeps the hot burning gases away from the chamber surfaces altogether. The company’s patented designs create a cyclonic swirl, or vortex, of fuel and oxygen that holds the searing gases and fumes in the very centre of the cylindrical combustion chamber, away from the vulnerable sidewalls.

“Our vortex generator eliminates the high temperatures at the inner surfaces of the engine,” says Martin Chiaverini, principal propulsion engineer at the firm. “You can touch the exterior during lab-test firings and not get burned.”

The vortex, or swirl, is produced by placing the oxidiser nozzles at the base of the combustion chamber and aiming them tangentially to the inner surface of its curving walls. This produces an outer vortex of cool gases that spiral up the walls forming a protective, cooling barrier. When this meets the top of the chamber it is mixed with rocket fuel and forced inward and down, forming a second, inner, descending vortex in the centre of the chamber that is concentrated like a tornado

Parabolic Arc covered the October launch.

India has nuclear plant delays and higher costs and Japan shifting to pro-nuclear policies

Tweet 1. Commercial operation of the Kudankulam Nuclear Power Project has been delayed to January, 2013 It is India's first 1,000MW first unit.

2. Russia has told India that Kudankulam nuclear power plants 3 and 4 would cost “double”, after New Delhi decided that the next two reactors would come under the new civil nuclear liability law, and not be covered by the agreement on Kudankulam 1 and 2.

Russia extending credit lines worth $3.2 billion for Kudankulam 3 and 4 early this year, initial costs had been estimated to be between $ 6 billion and $ 7 billion. This figure could now double.

Moscow had urged New Delhi to recognise Kudankulam 3 and 4 as being grandfathered under the agreement for Kudankulam 1 and 2, and argued that the inter-governmental agreement of 2008, which firms up plans for setting up four additional reactors, was done before the liability law.

Liquid Metal Made into Wires That Stretch Eight Times Their Original Length

Tweet Researchers from North Carolina State University have created conductive wires that can be stretched up to eight times their original length while still functioning. The wires can be used for everything from headphones to phone chargers, and hold potential for use in electronic textiles.

To make the wires, researchers start with a thin tube made of an extremely elastic polymer and then fill the tube with a liquid metal alloy of gallium and indium, which is an efficient conductor of electricity.

The tube, filled with liquid metal, can be stretched many times its original length.