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ICFO researchers present a non-destructive technique for measuring at the atomic scale

2013-05-06

(Press-News.org) Improving our understanding of the human brain, gathering insights into the origin of our universe through the detection of gravitational waves, or optimizing the precision of GPS systems- all are difficult challenges to master because they require the ability to visualize highly fragile elements, which can be terminally damaged by any attempt to observe them. Now, quantum physics has provided a solution. In an article published in Nature Photonics, researchers at the Institute of Photonic Sciences (ICFO) report the observation of a highly fragile and volatile body through a new quantum-mechanical measurement technique. Researchers from the group led by Morgan Mitchell applied the so-called "quantum non-demolition measurement" to a tiny cloud of atoms. They were able to observe the spinning of the electrons in the atoms, and more importantly, the atom cloud was not disturbed in the process. It is the first time quantum non-demolition measurement has been demonstrated with any material object. The same method could be extended to permit the observation of individual atoms. In the experiment, scientists prepared light pulses with photons in complementary states, and then sent them through the cloud of atoms, measuring their polarization on the way out. "A first measurement gives us information reflecting the action of the first light pulse. A second measurement, taken with photons in a complementary state from the first, cancels the influence of the preliminary pulse, allowing us to observe the original characteristics of the object," explains Dr. Robert Sewell, researcher at ICFO. This process has enabled the team to gather precise information on the magnetic field of the atom's surroundings. The information obtained exceeds the so-called "standard quantum limit", which quantifies the maximum amount of information obtainable with any traditional probing. Two achievements made this possible. On one hand, researchers were able to structure the observation so that the noise resulting from the visualization was shifted away from the object being measured and into a different variable. In addition, they introduced quantum statistical correlations among the atoms so that they were able to gather in one measurement what previously they needed a collection of measurements to observe. "This experiment provides rigorous proof of the effectiveness of quantum physics for measuring delicate objects" concludes Sewell.

### About ICFO: ICFO-The Institute of Photonic Sciences conducts research targeting the forefront of the science and technology of light, with programs directed at applications in Health, Renewable Energies, Information Technologies, Security and Industrial processes, among others. The center hosts 250 researchers working in 60 different laboratories. All research groups and facilities are located in a dedicated 14.000 m2 building situated in the Mediterranean Technology Park in the metropolitan area of Barcelona. END

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Organic vapors affect clouds leading to previously unidentified climate cooling

2013-05-06

University of Manchester scientists, writing in the journal Nature Geoscience, have shown that natural emissions and manmade pollutants can both have an unexpected cooling effect on the world's climate by making clouds brighter. Clouds are made of water droplets, condensed on to tiny particles suspended in the air. When the air is humid enough, the particles swell into cloud droplets. It has been known for some decades that the number of these particles and their size control how bright the clouds appear from the top, controlling the efficiency with which clouds scatter ...

Improving materials that convert heat to electricity and vice-versa

2013-05-06

ANN ARBOR---Thermoelectric materials can be used to turn waste heat into electricity or to provide refrigeration without any liquid coolants, and a research team from the University of Michigan has found a way to nearly double the efficiency of a particular class of them that's made with organic semiconductors. Organic semiconductors are carbon-rich compounds that are relatively cheap, abundant, lightweight and tough. But they haven't traditionally been considered candidate thermoelectric materials because they have been inefficient in carrying out the essential heat-to-electricity ...

Protein complex may play role in preventing many forms of cancer, Stanford study shows

2013-05-06

STANFORD, Calif. - Researchers at the Stanford University School of Medicine have identified a group of proteins that are mutated in about one-fifth of all human cancers. The finding suggests that the proteins, which are members of a protein complex that affects how DNA is packaged in cells, work to suppress the development of tumors in many types of tissues. The broad reach of the effect of mutations in the complex, called BAF, rivals that of another well-known tumor suppressor called p53. It also furthers a growing notion that these so-called chromatin-regulatory complexes ...

Portable device provides rapid, accurate diagnosis of tuberculosis, other bacterial infections

2013-05-06

A handheld diagnostic device that Massachusetts General Hospital (MGH) investigators first developed to diagnose cancer has been adapted to rapidly diagnose tuberculosis (TB) and other important infectious bacteria. Two papers appearing in the journals Nature Communications and Nature Nanotechnology describe portable devices that combine microfluidic technology with nuclear magnetic resonance (NMR) to not only diagnose these important infections but also determine the presence of antibiotic-resistant bacterial strains. "Rapidly identifying the pathogen responsible for ...

Study evaluates effect of different supplements on reducing risk of progression to advanced AMD

2013-05-06

In a large, multicenter, randomized clinical trial that included persons at high risk for progression to advanced age-related macular degeneration (AMD), adding the carotenoids lutein and zeaxanthin, the omega-3 fatty acids DHA and EPA, or both to a formulation of antioxidant vitamins and minerals that has shown effectiveness in reducing risk did not further reduce risk of progression to advanced AMD, according to a study published by JAMA. The study is being released early online to coincide with its presentation at the Association for Research in Vision and Ophthalmology ...

Discovery helps show how breast cancer spreads

2013-05-06

Researchers at Washington University School of Medicine in St. Louis have discovered why breast cancer patients with dense breasts are more likely than others to develop aggressive tumors that spread. The finding opens the door to drug treatments that prevent metastasis. It has long been known that women with denser breasts are at higher risk for breast cancer. This greater density is caused by an excess of a structural protein called collagen. "We have shown how increased collagen in the breasts could increase the chances of breast tumors spreading and becoming more ...

Discovery may help prevent chemotherapy-induced anemia

2013-05-06

May 5, 2013 — (Bronx, NY) — Cancer chemotherapy can cause peripheral neuropathy—nerve damage often resulting in pain and muscle weakness in the arms and legs. Now, researchers at Albert Einstein College of Medicine of Yeshiva University have discovered that chemo also induces an insidious type of nerve damage inside bone marrow that can cause delays in recovery after bone marrow transplantation. The findings, made in mice and published online today in Nature Medicine, suggest that combining chemotherapy with nerve-protecting agents may prevent long-term bone marrow injury ...

Epilepsy cured in mice using brain cells

2013-05-06

UCSF scientists controlled seizures in epileptic mice with a one-time transplantation of medial ganglionic eminence (MGE) cells, which inhibit signaling in overactive nerve circuits, into the hippocampus, a brain region associated with seizures, as well as with learning and memory. Other researchers had previously used different cell types in rodent cell transplantation experiments and failed to stop seizures. Cell therapy has become an active focus of epilepsy research, in part because current medications, even when effective, only control symptoms and not underlying ...

Microwave oven cooks up solar cell material

2013-05-06

SALT LAKE CITY, May 6, 2013 – University of Utah metallurgists used an old microwave oven to produce a nanocrystal semiconductor rapidly using cheap, abundant and less toxic metals than other semiconductors. They hope it will be used for more efficient photovoltaic solar cells and LED lights, biological sensors and systems to convert waste heat to electricity. Using microwaves "is a fast way to make these particles that have a broad range of applications," says Michael Free, a professor of metallurgical engineering. "We hope in the next five years there will be some commercial ...

Flame retardants may be toxic to children

2013-05-06

WASHINGTON, DC – Chemicals called polybrominated diphenyl ethers (PBDEs) have been used for decades to reduce fires in everyday products such as baby strollers, carpeting and electronics. A new study to be presented on Monday, May 6, at the Pediatric Academic Societies (PAS) annual meeting shows that prenatal exposure to the flame retardants is associated with lower intelligence and hyperactivity in early childhood. "In animal studies, PBDEs can disrupt thyroid hormone and cause hyperactivity and learning problems," said lead author Aimin Chen, MD, PhD, assistant professor ...

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