PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

The quantum spin Hall effect is a fundamental property of light

2015-06-25
(Press-News.org) In a paper that crystalizes knowledge from a variety of experiments and theoretical developments, scientists from the RIKEN Center for Emergent Matter Science in Japan have demonstrated that the quantum spin Hall effect--an effect known to take place in solid state physics--is also an intrinsic property of light. Photons have neither mass nor charge, and so behave very differently from their massive counterparts, but they do share a property, called spin, which results in remarkable geometric and topological phenomena. The spin--a measure of the intrinsic angular momentum--can be thought of as an equivalent of the spin of a top. In the research published in Science, the team found that photons share with electrons a property related to spin--the quantum spin Hall effect. "We had previously done work looking at evanescent electromagnetic waves," says Konstantin Bliokh, who led the research, "and we realized the remarkable properties we found, an unusual transverse spin--was a manifestation of the fact that free-space light exhibits an intrinsic quantum spin Hall effect, meaning that evanescent waves with opposite spins will travel in opposite directions along an interface between two media." Evanescent waves propagate along the surface of materials, such as metals, at the interface with a vacuum, in the same way that ocean waves emerge at the interface between the air and the water, and they decay exponentially as they move away from the interface. The quantum spin Hall effect for electrons allows for the existence of an unusual type of material--called a topological insulator--which conducts electricity on the surface but not through the bulk of the material. The team was intrigued to learn that an analogy for these can be found for photons. Though light does not propagate through metals, it is known that it can propagate along interfaces between a metal and vacuum, in the form of so-called surface plasmons involving evanescent light waves. The group was able to show that the unusual transverse spin they found in evanescent waves was actually caused by the intrinsic quantum Hall effect of photons, and their findings also explain recent experiments that have shown spin-controlled unidirectional propagation of surface optical modes. Bliokh continues, "On a purely scientific level, this research deepens our understanding of the classical theory of light waves developed by James Clark Maxwell 150 years ago, and it could also lead to applications using optical devices that are based on the direction of spin." Franco Nori, who organized the project, says, "This work was made possible by the interdisciplinary nature of RIKEN, as we were able to bring together discoveries made in several different areas, to show that transverse spin, locked to the direction of propagation of waves, seems to be a universal feature of surface waves, even when they are of different nature."

INFORMATION:



ELSE PRESS RELEASES FROM THIS DATE:

Pre-empting pressure ulcers in individuals with spinal cord injury

2015-06-25
Pressure ulcers affect more than 2.5 million Americans annually and patients who have spinal cord injuries that impair movement are more vulnerable to ulcer development. Researchers at the University of Pittsburgh School of Medicine have devised a computational model that could enhance understanding, diagnosis and treatment of pressure ulcers related to spinal cord injury. The research publishing this week in PLOS Computational Biology, shows the results of virtual clinical trials that demonstrated that in order to effectively treat the lesions, anti-inflammatory measures ...

Revisiting the restriction of antibiotics

2015-06-25
Antibiotic resistance, and multi-drug resistance, is a major public health threat. A new study publishing in PLOS Computational Biology finds conditions where restricting certain antibiotics may increase the frequency of multiple drug resistance. Uri Obolski and Prof. Lilach Hadany and colleagues used a mathematical model and electronic medical records data to show that drug restriction may also lead to results opposite of those desired. Restriction might facilitate the spread of resistant pathogens, due to ineffective treatment with antibiotics that have high resistance ...

Poppies provide missing piece of morphine biosynthesis puzzle

2015-06-25
This news release is available in Japanese. Researchers studying poppy plants -- the natural source of pain-relieving alkaloids, such as morphine and codeine -- have identified a fusion gene that facilitates important, back-to-back steps in the plant's morphine-producing pathway. These findings, which build upon recent efforts to engineer the morphine biosynthesis pathway in yeast, complete the metabolic pathway for morphine and pave the way for cheaper, safer routes to producing the economically important drug without the need for cultivating poppy fields. For about ...

Smoother signals sent through optical fibers

2015-06-25
This news release is available in Japanese. Researchers have figured out a way to pump more light farther along an optical fiber, offering engineers a potential solution to the so-called "capacity crunch" that threatens to limit bandwidth on the Web. These findings, which represent a step toward a faster and vaster Internet, show that silica fibers -- the hair-like wires that form the basis of fiber-optic communication -- can handle a lot more data than researchers had originally estimated. Normally, information traveling through an optical fiber is subject to nonlinear ...

Backward-moving glacier helps scientists explain glacial earthquakes

2015-06-25
The relentless flow of a glacier may seem unstoppable, but a team of UK and US researchers have shown that during some calving events - when an iceberg breaks off into the ocean - the glacier moves rapidly backward and downward, causing the characteristic glacial earthquakes which until now have been poorly understood. This new insight into glacier behaviour should enable scientists to measure glacier calving remotely and will improve the reliability of models that predict future sea-level rise in a warming climate. The research is published today in Science Express. ...

Genetic discovery uncovers key tool for morphine production in poppies

2015-06-25
Scientists at the University of York and GlaxoSmithKline (GSK) Australia have made a key genetic discovery in poppies, paving the way for more effective painkillers. The discovery, published in the latest issue of Science, reveals the long sought after gene that is seen as a critical gateway step in the synthesis of the morphinan class of alkaloids, which include the painkiller drugs morphine and codeine. The gene, called STORR, is only found in poppy species that produce morphinans. The STORR gene evolved when two other genes encoding oxidase and reductase enzymes ...

Electrical engineers break power and distance barriers for fiber optic communication

Electrical engineers break power and distance barriers for fiber optic communication
2015-06-25
Electrical engineers have broken key barriers that limit the distance information can travel in fiber optic cables and still be accurately deciphered by a receiver. Photonics researchers at the University of California, San Diego have increased the maximum power -- and therefore distance -- at which optical signals can be sent through optical fibers. This advance has the potential to increase the data transmission rates for the fiber optic cables that serve as the backbone of the internet, cable, wireless and landline networks. The research is published in the June 26 issue ...

Top scientists call for improved incentives to ensure research integrity

2015-06-25
PITTSBURGH--Scientific controversies, from problems replicating results - such as with the now debunked association between autism and MMR vaccines - to researcher misconduct and sensationalism, have led to speculation of "trouble at the lab," as the Economist put it. The National Academy of Sciences (NAS) and the Annenberg Retreat at Sunnylands recently convened top scientists from Carnegie Mellon University, the University of California, Massachusetts Institute of Technology, Georgia Institute of Technology and other leading institutions to examine ways to return to ...

Computer simulation predicts development, progress of pressure sores

2015-06-25
PITTSBURGH, June 18, 2015 - Researchers at the University of Pittsburgh School of Medicine have devised a computational model that could enhance understanding, diagnosis and treatment of pressure ulcers related to spinal cord injury. In a report published online in PLOS Computational Biology, the team also described results of virtual clinical trials that showed that for effective treatment of the lesions, anti-inflammatory measures had to be applied well before the earliest clinical signs of ulcer formation. Pressure ulcers affect more than 2.5 million Americans annually ...

Chloroplast tubes play a key role in plants' immune defense

2015-06-25
Chloroplasts, better known for taking care of photosynthesis in plant cells, play an unexpected role in responding to infections in plants, researchers at UC Davis and the University of Delaware have found. When plant cells are infected with pathogens, networks of tiny tubes called stromules extend from the chloroplasts and make contact with the cell's nucleus, the team discovered. The tubes likely deliver signals from the chloroplast to the nucleus that induce programmed cell death of infected cells and prepare other cells to resist infection. The work is published online ...

LAST 30 PRESS RELEASES:

Menopause drug reduces hot flashes by more than 70%, international clinical trial finds

FGF21 muscle hormone associated with slow ALS progression and extended survival

Hitting the right note: The healing power of music therapy in the cardiac ICU

Cardiovascular disease risk rises in Mexico, despite improved cholesterol control

Flexible optical touch sensor simultaneously pinpoints pressure strength and location

Achalasia diagnosis simplified to AI plus X-ray

PolyU scholars pioneer smart and sustainable personal cooling technologies to address global extreme heat

NIH grant aims for childhood vaccine against HIV

Menstrual cycle and long COVID: A relation confirmed

WMO report on global water resources: 2024 was characterized by both extreme drought and intense rainfall

New findings explain how a mutation in a cancer-related gen causes pulmonary fibrosis

Thermal trigger

SNU materials science and engineering team identifies reconstruction mechanism of copper alloy catalysts for CO₂ conversion

New book challenges misconceptions about evolution and our place in the tree of life

Decoding a decade of grouper grunts unlocks spawning secrets, shifts

Smart robots revolutionize structural health monitoring

Serum-derived hsa_circ_101555 as a diagnostic biomarker in non-hepatocellular carcinoma chronic liver disease

Korea University study identifies age 70 as cutoff for chemotherapy benefit in colorectal cancer

Study explores brain cell communication called ‘crosstalk’

4 beer and wine discoveries

Massage Therapy Foundation awards $299,465 research grant to Children’s Hospital of Philadelphia

Chung-Ang University develops chloride-resistant Ru nanocatalysts for sustainable hydrogen production from seawater

Afghanistan’s August 2025 earthquake reveals the cost of international isolation, UN scientists warn

Shortlist announced for Panmure House Prize

Small nuclear RNA base editing a safer alternative to CRISPR, UC San Diego researchers find

Can Hayabusa2 touchdown? New study reveals space mission’s target asteroid is tinier and faster than thought

Millisecond windows of time may be key to how we hear, study finds

Graz University of Technology opens up new avenues in lung cancer research with digital cell twin

Exoplanets are not water worlds

Study shows increasing ‘healthy competition’ between menu options nudges patients towards greener, lower-fat hospital food choices

[Press-News.org] The quantum spin Hall effect is a fundamental property of light