ScienceDaily: Quantum Physics News

Optics: Statistics light the way

Wed, 22 May 2013 13:10:10 EDT

A revelation of how photoreceptive cells in the eye distinguish between different light sources could pave the way for a novel class of optical devices.

New method for tailoring optical processors

Tue, 21 May 2013 12:16:16 EDT

Physicists and engineers have unveiled a robust new method for arranging metal nanoparticles in geometric patterns that can act as optical processors that transform incoming light signals into output of a different color.

Magnetic fingerprints of superfluid helium-3

Tue, 21 May 2013 10:54:54 EDT

Superconducting sensors have allowed for highly sensitive measurements of the nuclear magnetic resonance of thin helium-3 layers.

Coming into existence: Lab sets a new record for creating heralded photons

Mon, 20 May 2013 15:42:42 EDT

A new experiment establishes a heralding efficiency that might allow loopholes to be eliminated in the validation of spooky action-at-a-distance in quantum reality.

Competition in the quantum world

Sun, 19 May 2013 19:48:48 EDT

Physicists have gained a deep insight into the nature of quantum mechanical phase transitions. Scientists have simulated the competition between two rival dynamical processes at a novel type of transition between two quantum mechanical orders.

World's smallest liquid droplets ever made in the lab, experiment suggests

Thu, 16 May 2013 20:06:06 EDT

Physicists may have created the smallest drops of liquid ever made in the lab. That possibility has been raised by the results of a recent experiment at the Large Hadron Collider, the world's largest and most powerful particle collider located at the European Laboratory for Nuclear and Particle Physics (CERN) in Switzerland. Evidence of the minuscule droplets was extracted from the results of colliding protons with lead ions at velocities approaching the speed of light.

New method proposed for detecting gravitational waves from ends of universe

Thu, 16 May 2013 16:17:17 EDT

A new window into the nature of the universe may be possible with a device proposed by scientists that would detect elusive gravity waves from the other end of the cosmos.

Carbon in a twirl: The science behind a self-assembled nano-carbon helix

Thu, 16 May 2013 10:55:55 EDT

Nanotechnology draws on the fabrication of nanostructures. Scientists have now succeeded in growing a unique carbon structure at the nanoscale that resembles a tiny twirled mustache. Their method might lead the way to the formation of more complex nano-networks.

First direct proof of Hofstadter butterfly fractal observed in moiré superlattices

Wed, 15 May 2013 13:15:15 EDT

Scientists have directly observed a rare quantum effect that produces a repeating butterfly-shaped energy spectrum, confirming the longstanding prediction of this quantum fractal energy structure called Hofstadter's butterfly.

Catching graphene butterflies: Dramatically changing electronic properties of world's thinnest material

Wed, 15 May 2013 13:15:15 EDT

A large international team of researchers has shown that when graphene placed on top of insulating boron nitride, or 'white graphene', the electronic properties of graphene change dramatically revealing a pattern resembling a butterfly. The pattern is referred to as the elusive Hofstadter butterfly that has been known in theory for many decades but never before observed in experiments.

Observation of second sound in a quantum gas

Wed, 15 May 2013 13:15:15 EDT

Second sound is a quantum mechanical phenomenon, which has been observed only in superfluid helium. Physicists have now proven the propagation of such a temperature wave in a quantum gas.

Squishy hydrogels may be the ticket for studying biological effects of nanoparticles

Wed, 15 May 2013 12:51:51 EDT

A class of water-loving, jelly-like materials with uses ranges ranging from the mundane, such as superabsorbent diaper liners, to the sophisticated, such as soft contact lenses, could be tapped for a new line of serious work: testing the biological effects of nanoparticles, according to scientists.

Obtaining polymers with à la carte optical and electrical properties

Wed, 15 May 2013 08:53:53 EDT

Scientists have created nanostructured composite materials with specific optical and electrical properties that vary according to size. These properties allow researchers to synthesize particles of the size corresponding to the desired properties, and by adding these particles to polymers, to give the final product one specific property or another.

New principle may help explain why nature is quantum

Tue, 14 May 2013 11:27:27 EDT

Like small children, scientists are always asking the question 'Why?'. One question they've yet to answer is why nature picked quantum physics, in all its weird glory, as a sensible way to behave. Researchers tackle this perennial question in a new paper.

Photonic quantum computers: A brighter future than ever

Mon, 13 May 2013 10:38:38 EDT

Harnessing the unique features of the quantum world promises a dramatic speed-up in information processing as compared to the fastest classical machines. Scientists have succeeded in prototyping a new and highly resource efficient model of a quantum computer -- the boson sampling computer.

Graphene joins the race to redefine the ampere

Sun, 12 May 2013 14:12:12 EDT

New research could pave the way for redefining the ampere in terms of fundamental constants of physics. The world's first graphene single-electron pump provides the speed of electron flow needed to create a new standard for electrical current based on electron charge.

Perfectly doped quantum dots yield 'colors to dye for'

Fri, 10 May 2013 12:45:45 EDT

This focuses on an ultra-precise method for doping the tiny semiconductors produces vivid hues.

Flawed diamonds promise sensory perfection: Electron spin extended for incredibly tiny magnetic detectors

Fri, 10 May 2013 10:21:21 EDT

By extending the coherence time of electron states to over half a second, scientists have improved the performance of one of the most potent sensors of magnetic fields on the nanoscale -- a diamond defect no bigger than a pair of atoms called a nitrogen vacancy center. The achievement is important news for nanoscale sensors and quantum computing.

Scientists demonstrate pear shaped atomic nuclei

Thu, 09 May 2013 10:43:43 EDT

Scientists have shown that some atomic nuclei can assume the shape of a pear which contributes to our understanding of nuclear structure and the underlying fundamental interactions.

Device for portable, ultra-precise clocks and quantum sensors developed

Thu, 09 May 2013 09:08:08 EDT

Researchers have developed a portable way to produce ultracold atoms for quantum technology and quantum information processing.

Exotic atoms hold clues to unsolved physics puzzle at the dawn of the universe

Wed, 08 May 2013 17:21:21 EDT

An international team of physicists has found the first direct evidence of pear shaped nuclei in exotic atoms. The findings could advance the search for a new fundamental force in nature that could explain why the Big Bang created more matter than antimatter -- a pivotal imbalance in the history of everything.

Graphene quantum dots may someday tell if it will rain on Mars

Wed, 08 May 2013 13:18:18 EDT

Chemical engineers may be able to improve humidity and pressure sensors, particularly those used in outer space.

Speed test of quantum versus conventional computing: Quantum computer wins

Wed, 08 May 2013 12:28:28 EDT

A quantum computer system is “thousands of times faster” than conventional computing in solving an important problem type, a computer science professor finds.

Quantum optics with microwaves: Hong-Ou-Mandel effect demonstrated

Wed, 08 May 2013 09:30:30 EDT

Physicists have demonstrated one of the quintessential effects of quantum optics -- known as the Hong-Ou-Mandel effect -- with microwaves, whose frequency is 100,000 times lower than that of visible light. The experiment takes quantum optics into a new frequency regime and could eventually lead to new technological applications.

Elucidating energy shifts in optical tweezers

Wed, 08 May 2013 09:29:29 EDT

Physicists are providing an all-in-one guide to help calculate the effect the use of optical tweezers has on the energy levels of atoms under study. A small piece of paper sticks to an electrically charged plastic ruler. The principle of this simple classroom physics experiment is applied at the microscopic scale by so-called optical tweezers to get the likes of polystyrene micro-beads and even living cells to "stick" to a laser beam, or to trap atoms at ultra-low temperatures.

New delivery for cancer drugs

Tue, 07 May 2013 15:49:49 EDT

Nanopharmaceuticals are beginning to demonstrate their capacity to place the drugs directly in the tumor, where they will do the most good, rather than let them roam freely in the body.

Scaling up gyroscopes: From navigation to measuring Earth's rotation

Mon, 06 May 2013 16:12:12 EDT

Researchers discuss “large ring laser gyroscopes” that are six orders of magnitude more sensitive than gyroscopes commercially available.

Highly fragile, volatile body observed with new quantum-mechanical measurement technique

Sun, 05 May 2013 14:59:59 EDT

Scientists have observed a highly fragile and volatile body through a new quantum-mechanical measurement technique.

How to frustrate a quantum magnet: 16 atomic ions simulate a quantum antiferromagnet

Fri, 03 May 2013 10:50:50 EDT

Frustration crops up throughout nature when conflicting constraints on a physical system compete with one another. The way nature resolves these conflicts often leads to exotic phases of matter that are poorly understood. In a new article, researchers describe how to frustrate a quantum magnet composed of sixteen atomic ions -- to date the largest ensemble of qubits to perform a simulation of quantum matter.

Use of laser light yields versatile manipulation of a quantum bit

Wed, 01 May 2013 14:51:51 EDT

By using light, researchers have manipulated the quantum state of a single atomic-sized defect in diamond -- the nitrogen-vacancy center -- in a method that not only allows for more unified control than conventional processes, but is more versatile, and opens up the possibility of exploring new solid-state quantum systems.

Best of both worlds: Towards a quantum Internet with combined optical and electrical technique

Wed, 01 May 2013 13:18:18 EDT

Scientists have achieved a breakthrough in quantum science that brings the prospect of a network of ultra-powerful quantum computers -- connected via a quantum internet -- closer to reality. The team is the first to have detected the spin, or quantum state, of a single atom using a combined optical and electrical approach.

Graphene's high-speed seesaw

Tue, 30 Apr 2013 13:13:13 EDT

A new transistor capable of revolutionizing technologies for medical imaging and security screening has been developed by graphene researchers. The researchers report the first graphene-based transistor with bistable characteristics, which means that the device can spontaneously switch between two electronic states. Such devices are in great demand as emitters of electromagnetic waves in the high-frequency range between radar and infra-red, relevant for applications such as security systems and medical imaging.

Does antimatter fall up or down? First direct evidence of how atoms of antimatter interact with gravity

Tue, 30 Apr 2013 11:34:34 EDT

The atoms that make up ordinary matter fall down, so do antimatter atoms fall up? Do they experience gravity the same way as ordinary atoms, or is there such a thing as antigravity? Recent results, which measured the ratio of antihydrogen's unknown gravitational mass to its known inertial mass, did not settle the matter. Far from it. If an antihydrogen atom falls downward, its gravitational mass is no more than 110 times greater than its inertial mass. If it falls upward, its gravitational mass is at most 65 times greater. What the results do show is that measuring antimatter gravity is possible, using an experimental method that points toward much greater precision in future.

One step closer to a quantum computer

Tue, 30 Apr 2013 09:24:24 EDT

Scientists have succeeded in both initializing and reading nuclear spins, relevant to qubits for quantum computers, at room temperature.

Movement of pyrrole molecules defy 'classical' physics

Fri, 26 Apr 2013 11:54:54 EDT

Quantum laws loom ever larger in physical world as new research finds quantum phenomena in effect on a molecular level.

Einstein's gravity theory passes toughest test yet

Thu, 25 Apr 2013 14:22:22 EDT

A strange stellar pair nearly 7,000 light-years from Earth has provided physicists with a unique cosmic laboratory for studying the nature of gravity. The extremely strong gravity of a massive neutron star in orbit with a companion white dwarf star puts competing theories of gravity to a test more stringent than any available before.

New matter-antimatter difference observed in LHCb experiment at CERN

Wed, 24 Apr 2013 09:45:45 EDT

Researchers at CERN are reporting the first observation of matter-antimatter asymmetry in the decays of the particle known as the B0s. It is only the fourth subatomic particle known to exhibit such behavior.

The crystal's corners: New nanowire structure has potential to increase semiconductor applications

Tue, 23 Apr 2013 13:57:57 EDT

New research describes the discovery of a new structure that is a fundamental game changer in the physics of semiconductor nanowires.

Light bursts out of a flying mirror

Tue, 23 Apr 2013 13:41:41 EDT

Researchers have succeeded in generating flashes of extreme ultraviolet radiation via the reflection from a mirror that moves close to the speed of light.

Scientists provide 'new spin' on emerging quantum technologies

Tue, 23 Apr 2013 09:10:10 EDT

Scientists have shed new light on a fundamental area of physics which could have important implications for future electronic devices and the transfer of information at the quantum level.

Technique unlocks design principles of quantum biology

Fri, 19 Apr 2013 12:09:09 EDT

Researchers have created a synthetic compound that mimics the complex quantum dynamics observed in photosynthesis and may enable fundamentally new routes to creating solar-energy technologies.

A new twist for quantum systems

Wed, 17 Apr 2013 13:18:18 EDT

Physicists have developed a method for precisely controlling quantum systems by exploiting a trick that helps cats to land on their feet and motorists to fit their cars into parking spots. In the longer run, the method could lead to the development of more reliable quantum computers.

Quantum computing taps nucleus of single atom

Wed, 17 Apr 2013 13:18:18 EDT

Australian engineers have demonstrated that quantum information can be "written" onto the nucleus of a single atom and "read" out with incredible accuracy. The result was achieved using a silicon chip that can be wired up and operated electronically.

Molecular rings mystery solved after 20 years

Tue, 16 Apr 2013 08:51:51 EDT

Although the double benzene molecule tried to reveal its structure in experiments in 1993, chemists at the time were unable to find an explanation for the spectral peaks they saw. Now, 20 years later, theoretical chemists have come up with a theory.

Photons run out of loopholes: Quantum world really is in conflict with our everyday experience

Mon, 15 Apr 2013 12:49:49 EDT

Physicists have carried out an experiment with photons in which they have closed an important loophole. The researchers have thus provided the most complete experimental proof that the quantum world is in conflict with our everyday experience.

'Spooky action at a distance' in the quantum world shortly before final proof

Mon, 15 Apr 2013 09:48:48 EDT

Physicists have succeeded in closing the last local realistic loophole for systems of entangled photons.

Bose-Einstein condensates evaluated for quantum computers

Thu, 11 Apr 2013 10:58:58 EDT

Physicists have examined how Bose-Einstein condensates (BEC) might be used to provide communication among the nodes of a distributed quantum computer. The researchers determined the amount of time needed for quantum information to propagate across their BEC.

Advancing secure communications: A better single-photon emitter for quantum cryptography

Tue, 09 Apr 2013 14:50:50 EDT

In a development that could make the advanced form of secure communications known as quantum cryptography more practical, researchers have demonstrated a simpler, more efficient single-photon emitter that can be made using traditional semiconductor processing techniques.

A step toward optical transistors?

Tue, 09 Apr 2013 12:47:47 EDT

Researchers have demonstrated a new way to control light in semiconductor nanocrystals.

Material turns 'schizophrenic' on way to superconductivity

Fri, 05 Apr 2013 10:48:48 EDT

Physicists on the hunt for the origins of high-temperature superconductivity have published new findings this week about a material that becomes "schizophrenic" -- simultaneously exhibiting the characteristics of both a metallic conductor and an insulator. In a theoretical analysis, researchers offer an explanation for a strange series of observations described earlier this year by researchers at the Stanford Linear Accelerator Center in Menlo Park, Calif.

Don't call it vaporware: Scientists use cloud of atoms as optical memory device

Thu, 04 Apr 2013 09:28:28 EDT

Talk about storing data in the cloud. Scientists have taken this to a whole new level by demonstrating that they can store visual images within quite an ethereal memory device -- a thin vapor of rubidium atoms. The effort may prove helpful in creating memory for quantum computers.

Quantum tricks drive magnetic switching into the fast lane

Wed, 03 Apr 2013 20:03:03 EDT

Researchers in the U.S. and Greece have found a new way to switch magnetism that is at least 1000 times faster than currently used in magnetic memory technologies. Magnetic switching is used to encode information in hard drives, RAM and other computing devices.

Search for dark matter: Experiment measures antimatter excess in cosmic ray flux

Wed, 03 Apr 2013 11:53:53 EDT

The international team running the Alpha Magnetic Spectrometer (AMS) today announced the first results in its search for dark matter. They report the observation of an excess of positrons in the cosmic ray flux. The results are consistent with the positrons originating from the annihilation of dark matter particles in space, but not yet sufficiently conclusive to rule out other explanations.

Building quantum states with individual silicon atoms

Wed, 03 Apr 2013 11:27:27 EDT

By introducing individual silicon atom 'defects' using a scanning tunneling microscope, scientists have coupled single atoms to form quantum states.

Quantum cryptography: On wings of light

Wed, 03 Apr 2013 07:19:19 EDT

Physicists have, for the first time, successfully transmitted a secure quantum code through the atmosphere from an aircraft to a ground station.

Quantum dot commands light: A solid state ultrafast logic gate on a photon

Mon, 01 Apr 2013 09:26:26 EDT

If you could peek at the inner workings of a computer processor you would see billions of transistors switching back and forth between two states. In optical communications, information from the switches can be encoded onto light, which then travels long distances through glass fiber. Researchers are working to harness the quantum nature of light and semiconductors to expand the capabilities of computers in remarkable ways.

Quantum computing? Physicists' new technique for cooling molecules may be a stepping stone to quantum computing

Wed, 27 Mar 2013 14:41:41 EDT

At the heart of next-generation computers may be a collection of ultracold molecules held at temperatures a mere fraction of a degree above absolute zero. By combining two traditional atomic cooling technologies, physicists have pioneered a new technique for bringing normally springy molecules to a frozen standstill. Their results may be an important stepping stone towards future quantum computing.

Speed of light may not be fixed, scientists suggest; Ephemeral vacuum particles induce speed-of-light fluctuations

Mon, 25 Mar 2013 11:11:11 EDT

Two new articles challenge established wisdom about the nature of vacuum. In one article scientists have identified a quantum level mechanism for interpreting vacuum as being filled with pairs of virtual particles with fluctuating energy values. As a result, the inherent characteristics of vacuum, like the speed of light, may not be a constant after all, but fluctuate.

Measuring the magnetism of antimatter: Antiprotons measured more accurately than ever before

Mon, 25 Mar 2013 09:40:40 EDT

In a breakthrough that could one day yield important clues about the nature of matter itself, scientists have succeeded in measuring the magnetic charge of single particles of matter and antimatter more accurately than ever before.

Laser empties atoms from the inside out

Mon, 25 Mar 2013 09:35:35 EDT

Plasma physicists have used one of the world's most powerful lasers to create highly unusual plasma composed of hollow atoms. The experimental work demonstrated that it is possible to remove the two most deeply bound electrons from atoms, emptying the inner most quantum shell and leading to a distinctive plasma state.