Researchers at the University of Basel in Switzerland have succeeded in observing the "forbidden" infrared spectrum of a charged molecule for the first time. These extremely weak spectra offer perspectives for extremely precise measurements of molecular properties and may also contribute to the development of molecular clocks and quantum technology. The results were published in the scientific journal Nature Physics.
Spectroscopy, the study of the interaction between matter and light, is probably the most important method for investigating the properties of molecules. Molecules can only absorb light at well-defined wavelengths which correspond to the difference between two quantum-mechanical energy states. This is referred to as a spectroscopic transition. An analysis of the wavelengths and the intensity of the transitions provides information about the chemical structure and molecular motions, such as vibration or rotation.
In certain cases, however, the transition between two energy levels is not permitted. The transition is then called "forbidden". Nevertheless, this restriction is not categorical, meaning that forbidden transitions can still be observed with an extremely sensitive method of measurement. Although the corresponding spectra are extremely weak, they can be measured to an exceptionally accurate degree. They provide information on molecular properties with a level of precision not possible within allowed spectra.
In the present study, individual charged nitrogen molecules (ions) were generated in a well-defined molecular energy state. The ions were then implanted into a structure of ultra-cold, laser-cooled calcium ions – a Coulomb crystal – in an ultra-high vacuum chamber. The molecular ions were thus cooled to a few thousandths of a degree above absolute zero to localize in space. In this isolated, cold environment, the molecules could be investigated without perturbations over long periods of time. This enabled the researchers to excite and observe forbidden transitions in the infrared spectral domain using an intensive laser.
Physicists at the University of Geneva have succeeded in teleporting the quantum state of a photon to a crystal over 25 kilometers of optical fiber. The experiment, carried out in the laboratory of Professor Nicolas Gisin, constitutes a first, and simply pulverises the previous record of 6 kilometres achieved ten years ago by the same UNIGE team. Passing from light into matter, using teleportation of a photon to a crystal, shows that, in quantum physics, it is not the composition of a particle which is important, but rather its state, since this can exist and persist outside such extreme differences as those which distinguish light from matter. The results obtained by Félix Bussières and his colleagues are reported in the latest edition of Nature Photonics.
Quantum physics, and with it the UNIGE, is again being talked about around the world with the Marcel Benoist Prize for 2014 being awarded to Professor Nicolas Gisin, and the publication of experiments in Nature Photonics. The latest experiments have enabled verifying that the quantum state of a photon can be maintained whilst transporting it into a crystal without the two coming directly into contact. One needs to imagine the crystal as a memory bank for storing the photon's information; the latter is transferred over these distances using the teleportation effect.
The experiment not only represents a significant technological achievement but also a spectacular advance in the continually surprising possibilities afforded by the quantum dimension. By taking the distance to 25 kilometres of optical fibre, the UNIGE physicists have significantly surpassed their own record of 6 kilometres, the distance achieved during the first long-distance teleportation achieved by Professor Gisin and his team in 2003.
Archaeologists have discovered a massive burial mound in northern Greece after two years of digging project at an ancient site. The recent excavation on a hillock near ancient Amphipolis revealed third chamber of an ancient tomb as well as...
Mystery is always something that people enjoy. Everyone and anyone feels like they could come up with their own assumptions or theories of how, what or when something happened, and it could not be proven whether it is wrong or right.
Researchers at Princeton University have begun crystallizing light as part of an effort to answer fundamental questions about the physics of matter.
The researchers are not shining light through crystal – they are transforming light into crystal. As part of an effort to develop exotic materials such as room-temperature superconductors, the researchers have locked together photons, the basic element of light, so that they become fixed in place.
"It's something that we have never seen before," said Andrew Houck, an associate professor of electrical engineering and one of the researchers. "This is a new behavior for light."
The results raise intriguing possibilities for a variety of future materials. But the researchers also intend to use the method to address questions about the fundamental study of matter, a field called condensed matter physics.
"We are interested in exploring – and ultimately controlling and directing – the flow of energy at the atomic level," said Hakan Türeci, an assistant professor of electrical engineering and a member of the research team. "The goal is to better understand current materials and processes and to evaluate materials that we cannot yet create."
The team's findings, reported online on Sept. 8 in the journal Physical Review X, are part of an effort to answer fundamental questions about atomic behavior by creating a device that can simulate the behavior of subatomic particles. Such a tool could be an invaluable method for answering questions about atoms and molecules that are not answerable even with today's most advanced computers.
In part, that is because current computers operate under the rules of classical mechanics, which is a system that describes the everyday world containing things like bowling balls and planets. But the world of atoms and photons obeys the rules of quantum mechanics, which include a number of strange and very counterintuitive features. One of these odd properties is called "entanglement" in which multiple particles become linked and can affect each other over long distances.
Photographer: Meire Ruiz; Meire's Web site Summary Author: Meire Ruiz; Jim Foster The photo above shows a hole punch and fallstreak as observed from almost directly below. It was taken from Itanhaem, Sao Paulo, Brazil, on September 5, 2014. A...
Back in the 1960′s Cleve Backster concluded, can plants actually have feelings and hear sound? He is the former CIA interrogation specialist that connected polygraph sensors to plants and discovered that they reacted to harm (i.e.
Emissions of greenhouse gases are rising so fast that within one generation the world will have used up its margin of safety for limiting global warming to 2°C (3.6°F), an international team of scientists warned.
A report by the Global Carbon Project (GCP), published two days ahead of the UN climate summit on Tuesday, found that carbon dioxide (CO2) emissions from fossil-fuel combustion and cement production grew by 2.3 percent in 2013, reaching a record 36 billion tonnes of CO2. It predicted a further 2.5-percent increase in 2014.
It means that the world's "carbon quota" is fast being used up, according to the GCP research. Like an allowance, the quota is the maximum of heat-trapping gas that can be emitted before warming breaches 2°C as compared to the start of the Industrial Revolution in 1750.
"With current emission rates. the remaining 'quota' to surpass 2°C of global warming will be used up in around 30 years—or one generation," its authors said. "Total future CO2 emissions cannot exceed 1,200 billion tonnes for a likely—66 percent—chance of keeping average global warming under 2°C since pre-industrial times."
Member states have agreed to limit global warming to 2°C above pre-industrial levels, although they have not set a date by which this should be achieved.
The negotiations are supposed to climax in Paris at the end of 2015, providing a global pact that should come into force in 2020. But the talks are complex and bitterly-fought, with divisions over who should shoulder the burden of curbing the emissions.
"If this were a bank statement it would say our credit is running out," Dave Reay, a professor at the University of Edinburgh in Scotland, said in a commentary. "We've already burned through two-thirds of our global carbon allowance and avoiding dangerous climate change now requires some very difficult choices."
The great desert was born some 7 million years ago, as remnants of a vast sea called Tethys closed up. The movement of tectonic plates that created the Mediterranean Sea and the Alps also sparked the drying of the Sahara some 7 million years ago, according to the latest computer simulations of Earth’s ancient climate.
Though North Africa is currently covered by the world’s largest non-polar desert, climate conditions in the region have not been constant there for the last several million years. Subtle changes in Earth’s tilt toward the sun periodically increase the amount of solar energy received by the Northern Hemisphere in summer, altering atmospheric currents and driving monsoon rains. North Africa also sees more precipitation when less of the planet’s water is locked up in ice. Such increases in moisture limit how far the Sahara can spread and can even spark times of a “green Sahara”, when the sparse desert is replaced by abundant lakes, plants and animals.
Before the great desert was born, North Africa had a moister, semiarid climate. A few lines of evidence, including ancient dune deposits found in Chad, had hinted that the arid Sahara may have existed at least 7 million years ago. But without a mechanism to explain how it emerged, few scientists thought that the desert we see today could really be that old. Instead, most scientists argue that the Sahara took shape just 2 to 3 million years ago. Terrestrial and marine evidence suggest that North Africa underwent a period of drying at that time, when the Northern Hemisphere started its most recent cycle of glaciation.
Now Zhongshi Zhang of the Bjerknes Centre for Climate Research in Bergen, Norway, and colleagues have run simulations of climate change in North Africa over the last 30 million years. Their simulations take into account changes in Earth’s orbital position, atmospheric chemistry and the ratio of land to ocean as driven by tectonic forces. The models shows that precipitation in North Africa declined by more than half about 7 million years ago, causing the region to dry out. But this effect could not be explained by changes in vegetation, Earth’s tilt or greenhouse gas concentrations—leaving tectonic action.
About 250 million years ago, a huge body of water called the Tethys Sea separated the supercontinents of Laurasia to the north and Gondwana to the south. As those supercontinents broke apart and shuffled around, the African plate collided with the Eurasian plate, birthing the Alps and the Himalayas but closing off the bulk of the Tethys Sea. As the plates kept moving, the sea continued to shrink, eventually diminishing into the Mediterranean.
What set off the aridification in Africa was the replacement of the western arm of the Tethys Sea with the Arabian Peninsula around 7 to 11 million years ago. Replacing water with land, which reflects less sunlight, altered the region’s precipitation patterns. This created the desert and heightened its sensitivity to changes in Earth’s tilt, the researchers conclude in a study published today in Nature.
A single dose of a popular class of psychiatric drug used to treat depression can alter the brain’s architecture within hours, even though most patients usually don’t report improvement for weeks, a new study suggests.
Life can be so intricate and novel that even a single cell can pack a few surprises, according to a study led by Princeton University researchers. The pond-dwelling, single-celled organism Oxytricha trifallax has the remarkable ability to break its own DNA into nearly a quarter-million pieces and rapidly reassemble those pieces when it's time to mate, the researchers report in the journal Cell.
The organism internally stores its genome as thousands of scrambled, encrypted gene pieces. Upon mating with another of its kind, the organism rummages through these jumbled genes and DNA segments to piece together more than 225,000 tiny strands of DNA. This all happens in about 60 hours.
The organism's ability to take apart and quickly reassemble its own genes is unusually elaborate for any form of life, explained senior author Laura Landweber, a Princeton professor of ecology and evolutionary biology. That such intricacy exists in a seemingly simple organism accentuates the "true diversity of life on our planet," she said.
"It's one of nature's early attempts to become more complex despite staying small in the sense of being unicellular," Landweber said. "There are other examples of genomic jigsaw puzzles, but this one is a leader in terms of complexity. People might think that pond-dwelling organisms would be simple, but this shows how complex life can be, that it can reassemble all the building blocks of chromosomes."
From a practical standpoint, Oxytricha is a model organism that could provide a template for understanding how chromosomes in more complex animals such as humans break apart and reassemble, as can happen during the onset of cancer, Landweber said. While chromosome dynamics in cancer cells can be unpredictable and chaotic, Oxytricha presents an orderly step-by-step model of chromosome reconstruction, she said.
"It's basically bad when human chromosomes break apart and reassemble in a different order," Landweber said. "The process in Oxytricha recruits some of the same biological mechanisms that normally protect chromosomes from falling apart and uses them to do something creative and constructive instead."
Gertraud Burger, a professor of biochemistry at the University of Montreal, said that the "rampant and diligently orchestrated genome rearrangements that take place in this organism" demonstrate a unique layer of complexity for scientists to consider when it comes to studying an organism's genetics.
"This work illustrates in an impressive way that the genetic information of an organism can undergo substantial change before it is actually used for building the components of a living cell," said Burger, who is familiar with the work but had no role in it.
"Therefore, inferring an organism's make-up from the genome sequence alone can be a daunting task and maybe even impossible in certain instances," Burger said. "A few cases of minor rearrangements have been described in earlier work, but these are dilettantes compared to [this] system."
Damselflies - in pictures The Guardian A green-eyed damselfly peeks out from behind pink flower petals The eyes have it - a green-eyed damselfly peeks out from behind petals. A green-eyed damselfly clutches a stalk.