We know that light has mass and that beaming enough light at something can push it away - solar sails that will move a craft through the cosmos are based on this idea and NASA tested that concept earlier today when it launched NanoSail-D, a nanosatellite (cubesat) which will unfold to a 100 square foot polymer sail and travel in low earth orbit for a few months.Sails? We don't need no stinking sails. Credit: NASA
Physicists from the University of Bonn have developed a completely new source of light, a Bose-Einstein condensate consisting of photons, something not known to be possible, which may potentially be suitable for designing light sources resembling lasers that work in the x-ray range.
By cooling Rubidium atoms deeply and concentrating a sufficient number of them in a compact space, they suddenly become indistinguishable. They behave like a single huge "super particle." Physicists call this a Bose-Einstein condensate.
It's been the decade of metamaterials
, with breakthroughs toward an invisibility cloak
occurring every few months. With conventional materials, light typically travels along a straight line, but with metamaterials, scientists can exploit additional flexibility to create blind spots by deflecting certain parts of the electromagnetic spectrum. Basically, an image can be altered or made to look like it has disappeared.
Quantum cryptography is the technology of the future for military and financial organizations because it sends information as entangled particles of light - anyone who tries to tap into the information changes it in a way that reveals their presence.
The data is encoded with an encrypted key but one important limitation is range. The longest distance over which an encrypted key can be sent is approximately 100 kilometers but new technology developed by researchers increases 30-fold the amount of time the memory can hold information, which means that a series of quantum repeaters, arrayed like Christmas lights on a string, could reach distances in excess of 1,000 kilometers.
Sure, high energy physics costs billions these days (and watch out for birds
- and lightning
) but table-top experiments with tuned lasers and sensitive detectors can also continue to achieve the precision necessary for exploring the basic laws of physics at the heart of relativity and quantum mechanics.
Unable to exercise? Some new research may be hope in keeping muscles from atrophy. Researchers from Stanford University have shown how to use light to induce muscle contraction.
But don't cancel your gym membership just yet. The study used bioengineered mice whose nerve-cell surfaces were coated with special light-sensitive proteins.
They used a technology known as optogenetics, which involves the insertion of a specialized gene derived from algae into the genomes of experimental animals. This gene encodes a light-sensitive protein that situates itself on nerve-cell surfaces. Particular wavelengths of light can trigger nerve activity in animals endowed with these proteins, modifying nerve cells' firing patterns at the experimenters' will.
A "cat state" is a curiosity of the quantum world, where particles can exist in "superpositions" of two opposite properties simultaneously. Cat state is a reference to German physicist Erwin Schrödinger's famed 1935 theoretical notion of a cat that is both alive and dead simultaneously.
Researchers at the National Institute of Standards and Technology (NIST) have created "quantum cats" made of photons, particles of light, boosting prospects for manipulating light in new ways to enhance precision measurements as well as computing and communications based on quantum physics.
Optics normally treats the behaviour of packages of light waves (photons). However, when passing through appropriately shaped fields, particles may behave similar as photons. A beam of electrons that is not too dense will under such conditions behave similar to light beams that pass comparable lenses. In a dense beam the electrons will influence each others path via their own Coulomb field.
Future technology such as quantum cryptography and computation, or perhaps even larger scale teleportation, requires a deeper understanding of the phenomenon known as "entanglement", the quantum non-local connection, an aspect of quantum theory at the heart of the EPR paradox developed by Einstein, Podolsky and Rosen in 1935 which was experimentally verified in 1980 by Alain Aspect.
Two photons are entangled if the properties of one depend on those of the other, whatever the distance separating them. A new source of entangled photons twenty times brighter than all existing systems has been developed by a team from the Laboratoire de Photonique et de Nano-structures (LPN) of CNRS and they say the device is capable of considerably boosting the rate of quantum communications.
When light is used to transmit information, modulated light pulses travel along optical fibers, which can become weaker due to optical attenuation in the fiber and so are refreshed in signal regeneration stations along the way, where the signals are amplified and filtered.
But when light itself, or more precisely its optical frequency, is the information, and when this information is to be transmitted with extreme precision, conventional amplification techniques reach their limits.