Using a one-of-a-kind instrument designed and built at the National Institute of Standards and Technology, an international team of researchers have "unveiled" a quartet of graphene's electron states and discovered that electrons in graphene can split up into an unexpected and tantalizing set of energy levels when exposed to extremely low temperatures and extremely high magnetic fields.
Tractor beams, energy rays that can move objects, are a science fiction mainstay. But now they are becoming a reality -- at least for moving very tiny objects.
Galileo Galilei`s experiments on the motions of falling and rolling objects, described in his 1638 book, `Two New Sciences,` are considered by many to be the beginning of modern science. Now researchers at MIT have conducted a variation on his experiments that has produced unexpected results.
(PhysOrg.com) -- "Brownian motion is a very old concept," Klaus Kroy tells PhysOrg.com. "The laws explaining it were formulated more than a century ago by Albert Einstein. However, we are finding some interesting divergences from what has been known for all these years." Brownian motion is the random movement of small particles dissolved in a liquid or gas. It is the result of the particles` collisions with the solvent molecules.
(PhysOrg.com) -- Seven years ago Northwestern University physicist Adilson E. Motter conjectured that the expansion of the universe at the time of the big bang was highly chaotic. Now he and a colleague have proven it using rigorous mathematical arguments.
A researcher at the Hebrew University of Jerusalem, together with Israeli and foreign collaborators, has revealed how physical qualities -- and not only chemical ones - may have an influence in determining how adult stem cells from the bone marrow develop into differentiated ones. This represents an important step in understanding the mechanisms that direct and regulate the specialization of stem cells from their undefined state.
(PhysOrg.com) -- While the optical laser celebrated its 50th anniversary earlier this year, some scientists have been working on a new type of coherent beam amplifier for sound rather than light. Scientists theorize that phonons, which are the smallest discrete unit of vibrational energy, can be amplified by a phonon laser to generate a highly coherent beam of sound (particularly, high-frequency ultrasound), similar to how an optical laser generates a highly coherent beam of light. However, phonon laser research is still a relatively new area. In a new study, scientists have for the first time demonstrated the possibility that phonons can be collectively excited in an ultra-cold atomic gas in a way that is similar to how an optical laser excites photons, prompting the scientists to call the proposed device a "phaser."
The recently opened Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory (SNAL) provides scientists around the world with a brilliant new tool to understand fundamental properties of atoms and materials at previously unreachable dimensions.
When water freezes or boils, its atomic structure undergoes a phase transition in response to temperature change. Phase transitions are common in nature, and have been exploited to make devices such as digital memories. Complex oxides, which involve multiple cationic elements that enable fine tuning of properties, exhibit a particularly rich set of phase transitions because electrons in these materials are correlated with each other, leading to collective behavior and complex self-organized patterns.
(PhysOrg.com) -- One of the most controversial questions in cosmology is why the fundamental constants of nature seem fine-tuned for life. One of these fundamental constants is the fine-structure constant, or alpha, which is the coupling constant for the electromagnetic force and equal to about 1/137.0359. If alpha were just 4% bigger or smaller than it is, stars wouldn't be able to make carbon and oxygen, which would have made it impossible for life as we know it to exist. Now, results from a new study show that alpha seems to have varied a tiny bit in different directions of the universe billions of years ago, being slightly smaller in the northern hemisphere and slightly larger in the southern hemisphere. One intriguing possible implication is that the fine-structure constant is continuously varying in space, and seems fine-tuned for life in our neighborhood of the universe.
A tiny optical device built into a silicon chip has achieved the slowest light propagation on a chip to date, reducing the speed of light by a factor of 1,200 in a study reported in Nature Photonics (published online September 5 and in the November print issue).
(PhysOrg.com) -- The modern world -- with its ubiquitous electronic devices and electrical power -- can trace its lineage directly to the discovery, less than two centuries ago, of the link between electricity and magnetism. But while engineers have harnessed electromagnetic forces on a global scale, physicists still struggle to describe the dance between electrons that creates magnetic fields.
Blacksmiths make horseshoes by heating, beating and bending iron, but what's happening to the metal's individual atoms during such a process? Cornell researchers, using computational modeling, are providing new insight into how atoms in crystals rearrange as the material is bent and shaped.
(PhysOrg.com) -- The many ways in which water differs from other molecules is both a scientific curiosity and an important factor in shaping the Earth. Among water's unique properties are that it expands when it freezes, it boils and freezes at higher temperatures than expected for a compound with its molecular structure, and it has the ability to absorb large amounts of heat without getting hot. In a recent study, scientists have investigated another unique phenomenon of water called regelation, which occurs when frozen water - or ice - melts under high pressures, even if the temperature is below freezing. Once the pressure is lifted, the water refreezes.
(PhysOrg.com) -- In Swinburne University's 'cold molecules lab', where temperatures one millionth of a degree above absolute zero are routinely achieved, researchers are making significant advances in understanding the weird and wonderful world of quantum mechanics.
Roberto Carlos' free kick goal against France in 1997's Tournoi de France is thought by many to have been the most skilful free kick goal - from 35m with a powerful curling banana trajectory - ever scored; but by others to have been an incredible fluke.
A new experiment proposed* by physicists at the National Institute of Standards and Technology may allow researchers to test the effects of gravity with unprecedented precision at very short distances -- a scale at which exotic new details of gravity's behavior may be detectable.
For the casual observer it is fascinating to watch the orderly and seemingly choreographed motion of hundreds or even thousands of fish, birds or insects. However, the formation and the manifold motion patterns of such flocks raise numerous questions fundamental to the understanding of complex systems.
Measurements taken* at the National Institute of Standards and Technology may help physicists develop a clearer understanding of high-temperature superconductors, whose behavior remains in many ways mysterious decades after their discovery. A new copper-based compound exhibits properties never before seen in a superconductor and could be a step toward solving part of the mystery.
Researchers at the National Institute of Standards and Technology 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.
