Dec 18, 2015 07:39 AM
(This post was last modified: Dec 18, 2015 07:40 AM by C C.)
The world of physics in 2016
http://physicsworld.com/cws/article/news...cs-in-2016
EXCERPT: As another year draws to a close, it's time for me to peer into my crystal ball and predict the key events in physics that could take place in 2016. I always find it simpler and easier to say what's coming up in "big science" – dominated as it is by massive projects in particle physics, astronomy and cosmology that are planned years in advance. And next year is no exception....
The puzzle of the origin of elements in the universe
http://phys.org/news/2015-12-puzzle-elem...verse.html
EXCERPT: [...] "This result is an important piece in the puzzle of the origin of the elements in the universe, which the experiment has been studying for the last 25 years", remarked Paolo Prati, spokesperson for the LUNA experiment. "Stars generate energy and at the same time assemble atoms through a complex system of nuclear reactions. A very small number of these reactions have been studied in the conditions under which they occur inside stars, and a large proportion of those few cases have been observed with this accelerator"....
The ‘Benefits’ of Black Physics Students
http://www.nytimes.com/2015/12/17/opinio...dents.html
EXCERPT: [...] I had come from a tiny Christian high school where I didn’t get nearly as much scientific preparation as my dream to be a professional stargazer required. Yet there were people at Norfolk State University who believed in me and welcomed me. When I walked through the doors, my professors asked me if I wanted to understand physics, not what “unique perspective” I might bring. I did want to learn physics, so they told me that I was in the right place. [...] Obviously, black students march into classrooms all over this country and blow physical concepts out of the water with their individual intellects. The truly damaging part of Chief Justice Roberts’s question is the tacit implication that black students must justify their presence at all....
A step towards quantum electronics
http://www.sciencedaily.com/releases/201...151643.htm
RELEASE: Work of physicists at the University of Geneva (UNIGE), Switzerland, and the Swiss Federal Institute of Technology in Zurich (ETH Zurich), in which they connected two materials with unusual quantum-mechanical properties through a quantum constriction, could open up a novel path towards both a deeper understanding of physics and future electronic devices. Their results have just been published in the journal Science.
The researchers work with atoms that are trapped in laser beams and thus isolated from any external disturbance. Lasers are also used to cool the atoms to temperatures lower than those found anywhere else in the entire Universe. These 'ultracold' temperatures then enable creating clean materials that possess intriguing quantum-mechanical properties, such as unusual superconductivity. Thierry Giamarchi, professor at the UNIGE and responsible for the theoretical part of the study, explains: "In a cold-atom superconductor, the particles interact very strongly, whereas the interaction is usually very weak. This brings out strong-interaction effects through cooling could be compared to freezing water: the basic system is the same, but the result after cooling is very different."
The experimental team in Zurich, led by Tilman Esslinger and Jean-Philippe Brantut, has now overcome the challenges to efficiently transport ultracold atoms between two quantum superconductors with strong interactions through a single quantum point, a so-called quantum point contact. "With this new quantum connection, we can now reveal new effects in these superconducting quantum systems. It is a fundamental breakthrough in the way we can use quantum physics with cold atoms," says Giamarchi, from UNIGE's Faculty of Science.
A collaboration serving innovation
In general, it is difficult to produce a clean junction between quantum materials. Thanks to the collaboration between the teams in Geneva and Zurich, an important step has now been taken towards developing efficient junctions. For their ultracold atoms, the researchers produced junctions with a transparency close to 100 %. This advance is a crucial step towards understanding quantum transport in ultracold atoms and will enable fundamental studies of superconductors and other quantum materials. But interconnecting quantum materials such as superconductors might bring also new possibilities for more efficient information processing, beyond what is possible with techniques currently available for connecting, in computers and electronic devices, active elements such as transistors to form electronic circuits.
Now that junctions between quantum materials with strong interactions can be produced, scientists might eventually create novel materials that can be used in everyday applications. The unconventional approach developed in Geneva and Zurich therefore establishes the first basis for new technologies and opens up a new research direction that might lead to creating ultrafast and robust electronic networks -- a dream that many physicists share.
General relativity caught in action around black hole
https://www.sciencenews.org/article/gene...black-hole
EXCERPT: An effect of general relativity that is barely measurable on Earth has been spotted in full force around a black hole. Physicists detected the signature of a black hole twisting the fabric of spacetime around it. The discovery offers the best evidence yet of this relativity-driven twisting effect, known as frame dragging, around a black hole where it is most powerful. The research was reported December 16 at the Texas Symposium on Relativistic Astrophysics. Researchers captured the extreme frame dragging by analyzing X-rays emanating from a disk of star debris swirling around a black hole about 28,000 light-years away in the Milky Way. The data suggest that the disk’s matter is on a wild ride as the spacetime it occupies gets yanked and warped by the spinning black hole....
NuSTAR finds cosmic clumpy doughnut around black hole
http://www.sciencedaily.com/releases/201...154313.htm
RELEASE: The most massive black holes in the universe are often encircled by thick, doughnut-shaped disks of gas and dust. This deep-space doughnut material ultimately feeds and nourishes the growing black holes tucked inside.
Until recently, telescopes weren't able to penetrate some of these doughnuts, also known as tori.
"Originally, we thought that some black holes were hidden behind walls or screens of material that could not be seen through," said Andrea Marinucci of the Roma Tre University in Italy, lead author of a new Monthly Notices of the Royal Astronomical Society study describing results from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, and the European Space Agency's XMM-Newton space observatory.
With its X-ray vision, NuSTAR recently peered inside one of the densest of these doughnuts known to surround a supermassive black hole. This black hole lies at the center of a well-studied spiral galaxy called NGC 1068, located 47 million light-years away in the Cetus constellation.
The observations revealed a clumpy, cosmic doughnut.
"The rotating material is not a simple, rounded doughnut as originally thought, but clumpy," said Marinucci.
Doughnut-shaped disks of gas and dust around supermassive black holes were first proposed in the mid-1980s to explain why some black holes are hidden behind gas and dust, while others are not. The idea is that the orientation of the doughnut relative to Earth affects the way we perceive a black hole and its intense radiation. If the doughnut is viewed edge-on, the black hole is blocked. If the doughnut is viewed face-on, the black hole and its surrounding, blazing materials can be detected. This idea is referred to as the unified model because it neatly joins together the different black hole types, based solely upon orientation.
In the past decade, astronomers have been finding hints that these doughnuts aren't as smoothly shaped as once thought. They are more like defective, lumpy doughnuts that a doughnut shop might throw away.
The new discovery is the first time this clumpiness has been observed in an ultra-thick doughnut, and supports the idea that this phenomenon may be common. The research is important for understanding the growth and evolution of massive black holes and their host galaxies.
"We don't fully understand why some supermassive black holes are so heavily obscured, or why the surrounding material is clumpy," said co-author Poshak Gandhi of the University of Southampton in the United Kingdom. "This is a subject of hot research."
Both NuSTAR and XMM-Newton observed the supermassive black hole in NGC 1068 simultaneously on two occasions between 2014 to 2015. On one of those occasions, in August 2014, NuSTAR observed a spike in brightness. NuSTAR observes X-rays in a higher-energy range than XMM-Newton, and those high-energy X-rays can uniquely pierce thick clouds around the black hole. The scientists say the spike in high-energy X-rays was due to a clearing in the thickness of the material entombing the supermassive black hole.
"It's like a cloudy day, when the clouds partially move away from the sun to let more light shine through," said Marinucci.
NGC 1068 is well known to astronomers as the first black hole to give birth to the unification idea. "But it is only with NuSTAR that we now have a direct glimpse of its black hole through such clouds, albeit fleeting, allowing a better test of the unification concept," said Marinucci.
The team says that future research will address the question of what causes the unevenness in doughnuts. The answer could come in many flavors. It's possible that a black hole generates turbulence as it chomps on nearby material. Or, the energy given off by young stars could stir up turbulence, which would then percolate outward through the doughnut. Another possibility is that the clumps may come from material falling onto the doughnut. As galaxies form, material migrates toward the center, where the density and gravity is greatest. The material tends to fall in clumps, almost like a falling stream of water condensing into droplets as it hits the ground.
"We'd like to figure out if the unevenness of the material is being generated from outside the doughnut, or within it," said Gandhi.
"These coordinated observations with NuSTAR and XMM-Newton show yet again the exciting science possible when these satellites work together," said Daniel Stern, NuSTAR project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.
For more information on NuSTAR, visit:
http://www.nasa.gov/nustar
http://www.nustar.caltech.edu/
http://physicsworld.com/cws/article/news...cs-in-2016
EXCERPT: As another year draws to a close, it's time for me to peer into my crystal ball and predict the key events in physics that could take place in 2016. I always find it simpler and easier to say what's coming up in "big science" – dominated as it is by massive projects in particle physics, astronomy and cosmology that are planned years in advance. And next year is no exception....
The puzzle of the origin of elements in the universe
http://phys.org/news/2015-12-puzzle-elem...verse.html
EXCERPT: [...] "This result is an important piece in the puzzle of the origin of the elements in the universe, which the experiment has been studying for the last 25 years", remarked Paolo Prati, spokesperson for the LUNA experiment. "Stars generate energy and at the same time assemble atoms through a complex system of nuclear reactions. A very small number of these reactions have been studied in the conditions under which they occur inside stars, and a large proportion of those few cases have been observed with this accelerator"....
The ‘Benefits’ of Black Physics Students
http://www.nytimes.com/2015/12/17/opinio...dents.html
EXCERPT: [...] I had come from a tiny Christian high school where I didn’t get nearly as much scientific preparation as my dream to be a professional stargazer required. Yet there were people at Norfolk State University who believed in me and welcomed me. When I walked through the doors, my professors asked me if I wanted to understand physics, not what “unique perspective” I might bring. I did want to learn physics, so they told me that I was in the right place. [...] Obviously, black students march into classrooms all over this country and blow physical concepts out of the water with their individual intellects. The truly damaging part of Chief Justice Roberts’s question is the tacit implication that black students must justify their presence at all....
A step towards quantum electronics
http://www.sciencedaily.com/releases/201...151643.htm
RELEASE: Work of physicists at the University of Geneva (UNIGE), Switzerland, and the Swiss Federal Institute of Technology in Zurich (ETH Zurich), in which they connected two materials with unusual quantum-mechanical properties through a quantum constriction, could open up a novel path towards both a deeper understanding of physics and future electronic devices. Their results have just been published in the journal Science.
The researchers work with atoms that are trapped in laser beams and thus isolated from any external disturbance. Lasers are also used to cool the atoms to temperatures lower than those found anywhere else in the entire Universe. These 'ultracold' temperatures then enable creating clean materials that possess intriguing quantum-mechanical properties, such as unusual superconductivity. Thierry Giamarchi, professor at the UNIGE and responsible for the theoretical part of the study, explains: "In a cold-atom superconductor, the particles interact very strongly, whereas the interaction is usually very weak. This brings out strong-interaction effects through cooling could be compared to freezing water: the basic system is the same, but the result after cooling is very different."
The experimental team in Zurich, led by Tilman Esslinger and Jean-Philippe Brantut, has now overcome the challenges to efficiently transport ultracold atoms between two quantum superconductors with strong interactions through a single quantum point, a so-called quantum point contact. "With this new quantum connection, we can now reveal new effects in these superconducting quantum systems. It is a fundamental breakthrough in the way we can use quantum physics with cold atoms," says Giamarchi, from UNIGE's Faculty of Science.
A collaboration serving innovation
In general, it is difficult to produce a clean junction between quantum materials. Thanks to the collaboration between the teams in Geneva and Zurich, an important step has now been taken towards developing efficient junctions. For their ultracold atoms, the researchers produced junctions with a transparency close to 100 %. This advance is a crucial step towards understanding quantum transport in ultracold atoms and will enable fundamental studies of superconductors and other quantum materials. But interconnecting quantum materials such as superconductors might bring also new possibilities for more efficient information processing, beyond what is possible with techniques currently available for connecting, in computers and electronic devices, active elements such as transistors to form electronic circuits.
Now that junctions between quantum materials with strong interactions can be produced, scientists might eventually create novel materials that can be used in everyday applications. The unconventional approach developed in Geneva and Zurich therefore establishes the first basis for new technologies and opens up a new research direction that might lead to creating ultrafast and robust electronic networks -- a dream that many physicists share.
General relativity caught in action around black hole
https://www.sciencenews.org/article/gene...black-hole
EXCERPT: An effect of general relativity that is barely measurable on Earth has been spotted in full force around a black hole. Physicists detected the signature of a black hole twisting the fabric of spacetime around it. The discovery offers the best evidence yet of this relativity-driven twisting effect, known as frame dragging, around a black hole where it is most powerful. The research was reported December 16 at the Texas Symposium on Relativistic Astrophysics. Researchers captured the extreme frame dragging by analyzing X-rays emanating from a disk of star debris swirling around a black hole about 28,000 light-years away in the Milky Way. The data suggest that the disk’s matter is on a wild ride as the spacetime it occupies gets yanked and warped by the spinning black hole....
NuSTAR finds cosmic clumpy doughnut around black hole
http://www.sciencedaily.com/releases/201...154313.htm
RELEASE: The most massive black holes in the universe are often encircled by thick, doughnut-shaped disks of gas and dust. This deep-space doughnut material ultimately feeds and nourishes the growing black holes tucked inside.
Until recently, telescopes weren't able to penetrate some of these doughnuts, also known as tori.
"Originally, we thought that some black holes were hidden behind walls or screens of material that could not be seen through," said Andrea Marinucci of the Roma Tre University in Italy, lead author of a new Monthly Notices of the Royal Astronomical Society study describing results from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, and the European Space Agency's XMM-Newton space observatory.
With its X-ray vision, NuSTAR recently peered inside one of the densest of these doughnuts known to surround a supermassive black hole. This black hole lies at the center of a well-studied spiral galaxy called NGC 1068, located 47 million light-years away in the Cetus constellation.
The observations revealed a clumpy, cosmic doughnut.
"The rotating material is not a simple, rounded doughnut as originally thought, but clumpy," said Marinucci.
Doughnut-shaped disks of gas and dust around supermassive black holes were first proposed in the mid-1980s to explain why some black holes are hidden behind gas and dust, while others are not. The idea is that the orientation of the doughnut relative to Earth affects the way we perceive a black hole and its intense radiation. If the doughnut is viewed edge-on, the black hole is blocked. If the doughnut is viewed face-on, the black hole and its surrounding, blazing materials can be detected. This idea is referred to as the unified model because it neatly joins together the different black hole types, based solely upon orientation.
In the past decade, astronomers have been finding hints that these doughnuts aren't as smoothly shaped as once thought. They are more like defective, lumpy doughnuts that a doughnut shop might throw away.
The new discovery is the first time this clumpiness has been observed in an ultra-thick doughnut, and supports the idea that this phenomenon may be common. The research is important for understanding the growth and evolution of massive black holes and their host galaxies.
"We don't fully understand why some supermassive black holes are so heavily obscured, or why the surrounding material is clumpy," said co-author Poshak Gandhi of the University of Southampton in the United Kingdom. "This is a subject of hot research."
Both NuSTAR and XMM-Newton observed the supermassive black hole in NGC 1068 simultaneously on two occasions between 2014 to 2015. On one of those occasions, in August 2014, NuSTAR observed a spike in brightness. NuSTAR observes X-rays in a higher-energy range than XMM-Newton, and those high-energy X-rays can uniquely pierce thick clouds around the black hole. The scientists say the spike in high-energy X-rays was due to a clearing in the thickness of the material entombing the supermassive black hole.
"It's like a cloudy day, when the clouds partially move away from the sun to let more light shine through," said Marinucci.
NGC 1068 is well known to astronomers as the first black hole to give birth to the unification idea. "But it is only with NuSTAR that we now have a direct glimpse of its black hole through such clouds, albeit fleeting, allowing a better test of the unification concept," said Marinucci.
The team says that future research will address the question of what causes the unevenness in doughnuts. The answer could come in many flavors. It's possible that a black hole generates turbulence as it chomps on nearby material. Or, the energy given off by young stars could stir up turbulence, which would then percolate outward through the doughnut. Another possibility is that the clumps may come from material falling onto the doughnut. As galaxies form, material migrates toward the center, where the density and gravity is greatest. The material tends to fall in clumps, almost like a falling stream of water condensing into droplets as it hits the ground.
"We'd like to figure out if the unevenness of the material is being generated from outside the doughnut, or within it," said Gandhi.
"These coordinated observations with NuSTAR and XMM-Newton show yet again the exciting science possible when these satellites work together," said Daniel Stern, NuSTAR project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.
For more information on NuSTAR, visit:
http://www.nasa.gov/nustar
http://www.nustar.caltech.edu/