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MIT Physicists Achieve Breakthrough in Measuring Quantum Geometry of Electrons

Tuesday, January 14, 2025 / No Comments

quantum geometry illustrationMIT physicists, in collaboration with international researchers, have made a groundbreaking discovery by directly measuring the quantum geometry of electrons in solids, a feat previously thought impossible. Their findings, published in the November 25, 2024, issue of Nature Physics, open new avenues for understanding and controlling the quantum properties of materials.

Using a method called angle-resolved photoemission spectroscopy (ARPES), the team adapted the technique to measure the quantum geometry of a kagome metal, a material known for its exotic quantum properties. This approach provided direct insights into the wave function, a fundamental aspect of quantum physics that describes an electron’s wave-like behavior. The discovery paves the way for studying quantum geometry in a wide range of materials, with potential applications in quantum computing, advanced electronics, and magnetic devices.

Riccardo Comin, the Class of 1947 Career Development Associate Professor of Physics at MIT, who led the research, described the work as a "blueprint for obtaining previously inaccessible information about quantum materials." Mingu Kang PhD ’23, the study's first author and now a Kavli Postdoctoral Fellow at Cornell University, emphasized that this achievement resulted from close collaboration between experimentalists and theorists.

The research was carried out under unique circumstances during the Covid-19 pandemic. Kang, based in South Korea at the time, collaborated with theorists in the region, while Comin conducted critical experiments at the Italian Light Source Elettra. Despite the challenges, the team’s efforts culminated in a significant milestone in quantum material science.

The study also highlights the importance of global partnerships, with contributions from Seoul National University, Stanford University, Cornell University, and the University of Trieste, among others. The work was supported by various organizations, including the U.S. Air Force Office of Scientific Research, the National Science Foundation, and the Samsung Science and Technology Foundation.

This groundbreaking research not only advances the fundamental understanding of quantum materials but also opens doors to new technological possibilities, marking a significant step forward in the field of condensed matter physics.

Revolutionary Nanofiltration Process Reduces Aluminum Waste and Boosts Sustainability

Wednesday, January 8, 2025 / No Comments

 

nanofiltration process for aluminum
MIT engineers have introduced a groundbreaking nanofiltration process that promises to revolutionize the aluminum manufacturing industry by tackling its significant environmental challenges. Aluminum, the second-most-produced metal globally, is expected to see a 40% surge in demand by the end of the decade, further exacerbating the environmental burden of its production. 

Traditional methods produce significant waste, particularly cryolite sludge, a byproduct of the electrolysis process used to extract aluminum from alumina. This sludge, which contains residual aluminum ions along with impurities like sodium and potassium, is typically discarded, contributing to hazardous waste streams and resource inefficiency. The innovative membrane developed by MIT researchers selectively captures more than 99% of aluminum ions from cryolite waste, enabling their recovery and reuse in the production process.

 This approach not only reduces waste but also enhances production efficiency by recycling aluminum that would otherwise be lost. The membrane’s positively charged coating uniquely repels highly charged aluminum ions while allowing other ions to pass through, maintaining performance even in highly acidic conditions. 

Scaled-up implementations of this technology could dramatically decrease the need for fresh aluminum mining, fostering a circular economy and reducing environmental harm. The research, published in ACS Sustainable Chemistry and Engineering, underscores the potential of advanced filtration technologies to meet rising industrial demands sustainably while mitigating their ecological footprint. This innovation is a significant step toward cleaner aluminum production and highlights the broader possibilities of nanotechnology in addressing global sustainability challenges.

Revolutionary All-Optical Nanoscale Force Sensors Unveiled

Thursday, January 2, 2025 / No Comments

All-Optical Nanoscale Sensors of Force illustration
A team of researchers led by Columbia University School of Engineering and Applied Science has made a transformative breakthrough in force-sensing technology. By creating luminescent nanoscale sensors capable of detecting mechanical forces, the innovation opens new frontiers in fields such as robotics, cellular biophysics, medicine, and even space exploration.

These sensors, described in a study published in Nature, are designed as luminescent nanocrystals that respond to mechanical pressure by changing their intensity or color. What sets them apart is their ability to operate using light alone, allowing fully remote read-outs with no need for physical connections or wires. This "all-optical" capability means the sensors can function in environments that were previously inaccessible to conventional force sensors.

Unparalleled Sensitivity and Dynamic Range

The sensors demonstrate remarkable sensitivity and a dynamic range far exceeding existing technologies. They provide a 100-fold improvement in force sensitivity over current nanoparticles that rely on rare-earth ions for optical response. Furthermore, their dynamic range spans over four orders of magnitude in force, making them uniquely equipped to measure forces from piconewtons to micronewtons.

Jim Schuck, associate professor of mechanical engineering at Columbia, remarked, "We expect our discovery will revolutionize the sensitivities and dynamic range achievable with optical force sensors, and will immediately disrupt technologies in areas from robotics to cellular biophysics and medicine to space travel."

Versatility Across Scales and Systems

These new nanosensors can function across scales, enabling their use from subcellular systems to macroscopic engineered environments. For example, they could be deployed in developing embryos, migrating cells, nanoelectromechanical systems (NEMS), or advanced batteries. This versatility eliminates the need for multiple sensor types, as a single nanosensor can continuously monitor forces across these varied scales.

"What makes these force sensors unique—apart from their unparalleled multiscale sensing capabilities—is that they operate with benign, biocompatible, and deeply penetrating infrared light," explained Natalie Fardian-Melamed, a postdoctoral scholar and co-lead author of the study. "This allows one to peer deep into various technological and physiological systems and monitor their health from afar."

Leveraging the Photon-Avalanching Effect

The researchers built these nanosensors by exploiting the photon-avalanching effect. In this phenomenon, the absorption of a single photon triggers a cascade of emitted photons, amplifying the sensor's response to external stimuli. The core technology relies on nanocrystals doped with rare-earth ions, such as thulium. By adjusting the spacing between these ions, the team achieved unprecedented sensitivity to mechanical forces.

This discovery was initially unexpected. While tapping on the nanoparticles with an atomic force microscopy (AFM) tip, the researchers observed a dramatic response in the photon avalanching behavior. "We discovered this almost by accident," Schuck noted. "We suspected these nanoparticles were sensitive to force, but their response far exceeded our expectations."

Customized Sensor Designs for Specific Applications

Following their initial findings, the team developed specialized nanosensors tailored to respond to forces in different ways. Some sensors change the color of their luminescence under applied force, while others begin photon avalanching only when force is applied. These advancements provide unprecedented flexibility for sensing applications.

Real-World Impact and Future Directions

The researchers are now focusing on applying these sensors to practical systems. For instance, they aim to study force dynamics in developing embryos, an area with significant implications for developmental biology and medicine. Additionally, they plan to integrate self-calibrating capabilities into the sensors, allowing them to function autonomously.

Schuck highlighted the broader significance of the discovery, citing the work of Nobel Laureate Ardem Patapoutian, who emphasized the challenges of probing environmentally sensitive processes. "These sensors allow one to sensitively and dynamically map critical changes in forces and pressures in real-world environments that are currently unreachable with today's technologies," he said.

With their combination of high sensitivity, wide dynamic range, and adaptability, these nanosensors represent a transformative advancement in force-sensing technology, with the potential to redefine the limits of engineering, biology, and physics.

Journal Reference:

Natalie Fardian-Melamed, et al. Infrared nanosensors of piconewton to micronewton forces. Nature, 2025; DOI: 10.1038/s41586-024-08221-2

For more information, visit Columbia University’s official release

Wireless Micro Antennas Harness Light to Monitor Cellular Signals

Friday, December 20, 2024 / No Comments


wireless antennas

MIT researchers have unveiled a groundbreaking biosensing technology using organic electro-scattering antennas (OCEANs), which eliminate the need for wires and amplifiers in monitoring cellular electrical activity. These tiny antennas, constructed from the polymer PEDOT:PSS, detect changes in electrical signals by altering their optical properties, enabling them to scatter light in proportion to the surrounding electrical environment.

 Arrays of these antennas, each only a micrometer wide, allow for high-resolution, wireless measurement of electrical signals with extreme sensitivity, capable of detecting voltages as low as 2.5 millivolts. The antennas are fabricated through a scalable process that uses focused ion beams to create nanoscale holes in a glass substrate, followed by a polymer growth phase driven by electric currents. Designed for in vitro studies, OCEANs can continuously record signals for over 10 hours, providing biologists with a powerful tool to study cellular communication and responses to environmental changes. By facilitating wireless and high-throughput data collection, this innovation holds promise for advancing the understanding of biological processes, improving diagnostics, and enabling precise evaluation of therapeutics.

 Future developments include testing with live cell cultures, reshaping antennas to penetrate cell membranes, and exploring integration into nanophotonic devices for next-generation sensing applications. Funded by the National Institutes of Health and the Swiss National Science Foundation, this research opens new avenues for bioengineering and biotechnology, pushing the boundaries of how electrical signals in biological systems can be studied and harnessed.

MIT Develops Ultrafast Photonic Processor to Transform AI Computing

Thursday, December 5, 2024 / No Comments

 

Photonic processorMIT researchers have unveiled a groundbreaking photonic processor that leverages light to perform computations, offering unparalleled speed and efficiency for artificial intelligence (AI) systems. Unlike traditional electronic processors, which rely on electrical signals, this novel technology uses photons, enabling ultrafast processing while drastically reducing energy consumption. This advancement is particularly significant as the computational demands of AI models, such as those used in deep learning, continue to grow exponentially.

The photonic processor employs innovative methods to transmit and manipulate data using optical signals, allowing it to execute operations at speeds previously unattainable by conventional hardware. Its ability to handle parallel computations with greater efficiency makes it a game-changer for applications requiring immense processing power, such as real-time language translation, large-scale data analysis, and advanced robotics.

One of the processor's key advantages is its potential to overcome the heat limitations associated with electronic chips. By reducing reliance on electrical signals, the photonic approach minimizes heat generation, enabling more sustainable and scalable AI development. This technology could pave the way for next-generation computing systems that are not only faster but also more environmentally friendly.

MIT's innovation represents a significant leap in AI hardware, promising to bridge the gap between the increasing computational needs of modern AI and the limitations of current electronic processing systems.

New Study Challenges Traditional Theories on How Migratory Birds Navigate

Saturday, November 16, 2024 / No Comments

A study led by Dr. Richard Holland from Bangor University has redefined how migratory birds, like the Eurasian reed warbler, navigate long distances.

While scientists have long believed that birds rely heavily on Earth's magnetic field for navigation, emerging evidence suggests that their methods may be far more complex and multifaceted.

New findings indicate that migratory birds likely combine magnetic sensing with visual cues, star patterns, and even olfactory signals to guide their journeys. This integrated approach may help explain their remarkable precision in reaching specific locations thousands of miles away.


The research also raises intriguing questions about how environmental changes, such as magnetic field disruptions and light pollution, might impact these navigation systems. As scientists continue to unravel the mysteries of bird migration, this new understanding could have important implications for conservation efforts aimed at protecting these incredible traveler.

CT Scans Reveal Secrets of 3,000-Year-Old ‘Locked Mummy’ of Egyptian Aristocrat

Wednesday, November 13, 2024 / No Comments


 A recent CT scan study has unlocked details about a 3,000-year-old Egyptian mummy known as Lady Chenet-aa, a high-status woman from ancient Egypt, whose unique burial method had puzzled experts for years. This mummy, stored at Chicago’s Field Museum, had been wrapped in an unusual paper-mâché-like coffin called cartonnage, seemingly sealed without any visible entry points. 

The recent scans revealed that after preparing her body, Egyptian embalmers softened the cartonnage with humidity, slit it along the back, and carefully lowered her mummified remains inside before sealing the slit with a seam and securing it with a wooden peg at the feet. This method explains the “locked” appearance that had mystified archaeologists.

The scans also highlighted fascinating details about Chenet-aa’s life and afterlife preparations. She was in her 30s or 40s at her death and had lost several teeth, likely due to the abrasive nature of ancient Egyptian food containing gritty sand. To ensure her vision in the afterlife, her eyes were supplemented with artificial replacements, a practice in line with ancient Egyptian beliefs in a physical afterlife.

 This discovery is a remarkable example of how modern technology, like CT scans, can reveal intricate details about ancient burial practices and beliefs, shedding light on the Egyptian approach to death and the afterlife preparation rituals for the elite

Groundbreaking Achievement: High-Performance Computing Analyzes Quantum Photonics on a Large Scale for the First Time

Monday, October 28, 2024 / No Comments

Scientists at Paderborn University have successfully utilized high-performance computing, represented by their supercomputer Noctua, to conduct a large-scale analysis of a quantum photonics experiment for the first time.

Researchers at Paderborn University in Germany have developed high-performance computing (HPC) software capable of analyzing and describing the quantum states of a photonic quantum detector.

HPC utilizes advanced classical computers to handle large datasets, conduct complex calculations, and swiftly tackle challenging problems. However, many classical computational methods cannot be directly applied to quantum applications. This new study indicates that HPC may offer valuable tools for quantum tomography, the technique employed to ascertain the quantum state of a quantum system.

In their study, the researchers state, “By developing customized open-source algorithms using high-performance computing, we have performed quantum tomography on a photonic quantum detector at a mega-scale.”

HPC enables mega-scale quantum tomography

A quantum photonic detector is a sophisticated instrument designed to detect and measure individual light particles (photons). Highly sensitive, it can collect detailed information about various properties of photons, including their energy levels and polarization. This data is invaluable for quantum research, experiments, and technologies.

Accurately determining the quantum state of the photonic detector is crucial for achieving precise measurements. However, the process of performing quantum tomography on such an advanced tool requires handling large volumes of data.

This is where the newly developed HPC software comes into play. To showcase its capabilities, the researchers stated, “We performed quantum tomography on a megascale quantum photonic detector covering a Hilbert space of 10610^6.”

Hilbert space is a mathematical concept that describes a multi-dimensional space where each point represents a possible state of a quantum system. It includes an inner product for calculating distances and angles between states, which is essential for understanding concepts such as probability and superposition. These spaces can possess infinite dimensions, representing a wide array of potential states.

With the HPC software, the researchers successfully “completed calculations that described the quantum photonic detector within a few minutes—faster than anyone else before,” they added.

Classical Computing Breakthroughs Spark New Advances in Quantum Technology

HPC is not just limited to determining the state of the quantum photonic detector. By leveraging the inherent structure of quantum tomography, the researchers were able to enhance the efficiency of the process.

This optimization enables them to manage and reconstruct quantum systems with up to 101210^{12} elements. “This demonstrates the unprecedented extent to which this tool can be applied to quantum photonic systems,” said Timon Schapeler, the first author of the study and a research scientist at Paderborn University.

“As far as we know, our work is the first contribution in the field of classical high-performance computing that facilitates experimental quantum photonics on a large scale,” Schapeler added.

The HPC-driven quantum tomography approach holds promise for advancing more efficient data processing, quantum measurement, and communication technologies in the future.

The study is published in the journal Quantum Science and Technology.


Is there life after death?

Sunday, October 19, 2014 / No Comments

there is life after death This is the finding of a study by the University of Southampton for four years in 2060 patients with cardiac arrest.

Even when the brain has stopped working and the body is clinically dead, something survives. Consciousness, the soul? according to the study conducted by scientists at the University of Southampton (UK), published Tuesday, October 7, 40% of those who survived their cardiac arrest evoke a strange sense of conscience, while they were state of clinical death.

According to Dr. Sam Parnia, who led the study for four years in 2060 patients, "the evidence suggests that here, in the first minutes after death, consciousness is not annihilated," he explains in an interview with the Daily Mail (English). "We do not know if it fades after, but directly after death, we are still conscious.'s Brain does not stop when the heart stops beating."

Nearly 40% remember something

Nearly 39% of patients surveyed for the study recalled having realized what was happening, without thereby keep an accurate memory. 46% reported a feeling of fear or persecution, 9% had a near death experience, and 2% said they were fully aware of and able, somehow, "get out" of their own bodies. They remember accurately seeing and hearing things after their heart has stopped. Until now, it was estimated that those who reported experiences of life after death victims were "hallucinations".

Cornell’s researchers Probe Beyond the Big Bang

Tuesday, September 16, 2014 / No Comments

Cornell’s experimental cosmology research group recently announced the first results from a Cosmic Microwave Background study using a polarization-sensitive camera (ACTPol).

A long tradition of research in cosmology at Cornell College of Arts and Sciences gave birth to a vigorous effort by a new generation of cosmologists to understand the cosmic microwave background (CMB), the thermal radiation left over from the Big Bang.

"A big part of all knowledge about the history of the universe as a whole is revealed when you fully understand the WBC," said Michael Niemack, assistant professor of physics, which focuses on labor shares CMB.

Cosmology, the study of the nature and evolution of the universe, has made ​​great strides in the past 30 years, said Jeevak Parpia, professor and chair of physics. "We are in an era of cosmology" precision "."

"This is a time of rapid progress in the field," says Liam McAllister, associate professor of physics and an expert on string theory teacher. "I'm not sure about this new discovery published any day see arXiv tonight."

Henry Tye, Horace White Professor of Physics Emeritus, was one of the first to realize inflation in string theory, and left a legacy of unusual cooperation with Cornell among cosmologists of all kinds. McAllister said it is rare to find a school like Cornell where meaningful collaborations among string theorists, experimentalists and astronomers, as their research and Niemack by associate professor of Astronomy Rachel Bean.

"Cosmology at Cornell University is a wonderful example of the culture of collaboration within the arts and sciences disciplines, instrumentalists and highly qualified to reflect on the theoretical implications of physical laws" the researchers said Gretchen Ritter, Harold Tanner Dean of the College of Arts and Sciences.

"The search for the CMB is a rich, constantly evolving field with a mixture of science that excites both astronomy and physics communities," said Terry Herter, president of astronomy. "Trying to understand the origin and evolution of the universe and fundamental physics at the same time -. There is nothing better than this"

McAllister, Receives National Science Foundation Award for his work on early theoretical models of the early universe career, seeks to understand how theories of inflation that occurred in the early universe can be based on a certain theoretical basis and outside a mathematically consistent structure.

"We want to understand the physics behind inflation," he said. "One of our responsibilities as theorists is to try to predict future results and interpret experimental results from existing experiences."

McAllister, what is needed is a theory in which the laws of gravity are inherently quantum mechanical, but behave according to classical physics in systems that are quite large and slow. So far, he said, string theory is the only approach that provides a consistent theory of quantum gravity.

Experimentally, measurements of the CMB at higher resolution than Niemack continues directly related to tests of general relativity Bean interested.

The completion of the Cornell Caltech Atacama Telescope (CCAT), which will be the largest submillimeter telescope in the global project will be a boon for cosmologists, Niemack said. Bean and he intends to use CCAT to investigate clusters of galaxies with much higher speeds than is now possible accuracy.

Experiments probing the CMB have the potential to reveal the laws of nature in a much more fundamental than that level has proved otherwise manner. "For example, the results of the observations of the CMB polarization could have a transformative effect on the types of problems related to the early universe theorists continue," McAllister said.


"That's what makes it so attractive," said Niemack. "Any of these experiences or observations basically could change the way we view the universe."

Experimental cosmology

Experimental research group at Cornell cosmology - including assistant professor of physics Michael Niemack, Francesco De Bernardis postdocs and Shawn Henderson, and graduate students Brian Koopman and Patricio Gallardo - recently announced the first results of a micro waves of cosmic microwave background using a polarization-sensitive camera (ACTPol) Niemack who led the design of the Atacama Cosmology for 6 yards.

"ACTPol has a unique place in science that can chase better than anyone else because of the capabilities we have built in our instrument," Niemack said. "We are looking for small, tiny signs, roughly a part in 107 over the bottom of a range of scales that have not been examined before."


An update will be completed this year will add three times more detectors and channel ACTPol additional frequency, allowing the group to investigate the physics at the energy scale of grand unification, the energy of a billion times higher than they were tested in the large Hadron Collider.

Photograph an object with a light that does not illuminate

Thursday, September 4, 2014 / No Comments
Form the image of an object with light waves that do not originate seems impossible. At least in classical physics. Using pairs of entangled photons, Austrian physicists were able to do so. The advantage of this new quantum imaging technique to provide images of objects in an otherwise inaccessible spectral band.
The study of the properties of light and open applications seems endless as shown recently in a group of researchers from Vienna, in an article published in Nature magazine (available free from arXiv). In Euclid Feynman by Leonardo da Vinci, Descartes and Huygens, the theory of light and images has never ceased to amaze us as we were of geometrical optics theory wave Fresnel and Maxwell finally to the theory of photons Einstein. In recent decades, is quantum optics, which is at the front of the stage just behind the multiple applications of the theory of image processing.


If the quantum entanglement of photons already had applications in quantum cryptography and in the context of research on quantum information and foundations of physics, now here enters the field of images, allowing the new magic tricks .. . quantum. In this case, the image of an object is obtained from photons that have not interacted with it, and even a different wavelength from those they are entangled and which are introduced in the interaction with the object. This new technique makes it possible to form images of objects in the same band of wavelengths given if there are no tools to actually take a picture of these objects.

A new imaging technique for quantum biology

But how physicists have taken the Institute for Quantum Optics and Quantum Information (IQOQI) Vienna Center for Quantum Science and Technology (VCQ) and the University of Vienna to accomplish such a feat? As often with quantum entanglement, they did it with a laser and nonlinear optical phenomena that can be generated with some crystals. 

In fact, there are linear crystal means providing two beams at the output of entangled photon pairs with an input of a photon beam produced by a laser. As part of the experiment conducted by the researchers, a laser beam (green color on the picture above) to consider as first red drops in a splitter to give two beams so that each then is directed to a nonlinear crystal. At the output of each crystal, so it is not a photon beam red (yellow in the picture) and a beam of photons of longer wavelength, for example in the infrared. Red photons are entangled photon pairs with infrared. 

The infrared beam from the first crystal is then directed onto the object to be examined characteristics within a band infrared hard, in any case, a measurable pickup device image. The infrared photons scattered by the object and then enters the second crystal where they combine with infrared photons generated by the arrival of the second laser beam in the experiment originally produced in the separator outlet. Quantum entanglement then allows the information carried by infrared photons from the object to be mirrored end up as a correlation with red photons emerging from the second glass. Then, the outgoing beams of red photons in the first and second glass is recombined. Magically, then an image of the object can be formed in the red band of the spectrum, but that is the image we wanted to achieve in the infrared spectral range. Finally we got around the obstacle of the lack of effective detector in the spectral band where we wanted to carry out observations and have an image of an object with the light that is never made ​​direct interaction with the object. 


Physicists believe that this imaging technique with quantum entanglement of photons must be versatile enough so that one day could have applications in biology and medicine.

a Neutron Halo Around Neutron-Rich Magnesium Nuclei

Tuesday, September 2, 2014 / No Comments
Using the RIKEN radioactive isotope beam factory, physicists have shown that the extra neutrons in a nucleus rich in magnesium produce neutron halo neutron.
The most stable nuclei are composed of roughly an equal number of protons and neutrons. With the right equipment, however, physicists can create many additional nuclei with neutrons. These neutron-rich nuclei are short-lived, but represent an important tool for developing a better understanding of how the elements were created in the universe tool.

A joint study conducted by Nobuyuki Kobayashi and Takashi Nakamura of Tokyo Institute of Technology involving researchers RIKEN Nishina Center for Accelerator-Based Science has now revealed that the extra neutrons in a nucleus neutron-rich magnesium halo1 produce neutrons.

The researchers used RIKEN beam Radioactive Isotope factory to produce magnesium-cores 37, which consists of 25 neutrons and 12 protons. To test its properties, the researchers observed what happened when these nuclei were bombarded against a white lead. "We found that the magnesium-37 nuclei easily broken in a core of magnesium-36 and a single neutron" says Kobayashi. "Therefore, we conclude that magnesium-37 has a neutron halo."

Halos of neutrons are neutrons dilute cloud surrounding the neutrons and protons are more compacted than in the center of a core. They have been identified in the past, but predominantly in the nuclei with less than 20 neutrons. Magnesium-37 is so far from the heavier nuclei have been found to have a nuclear halo. Evidence of a halo-shaped structure also means that the magnesium-37 cores are deformed and do not conform to the conventional spherical shape.

The researchers then conducted a similar experiment using a carbon target. While lead target experiments revealed reaction cores electrostatic forces, using a carbon target was used to study the response to 37-magnesium nuclear forces, which are sensitive to rotational movement of the neutrons. Neutrons present in the previously studied halogen light nuclei, in which the core is surrounded by a neutron, lack of rotation and are known as halos waves S. However, Kobayashi and colleagues found that the magnesium-neutron halo 37 had a measurable rotation or angular momentum, called a halo waves P.

The results provide crucial information on the reasons why some nuclei are stable, while others rot. "Our results indicate that the formation of halos may be a universal feature in the neutron-rich nuclei," says Ken-Ichiro Yoneda, one of the researchers who contributed to the RIKEN project. "The reason is that there are, however, is still unclear. Hopefully accumulate more detailed information on other neutron-rich nuclei so that we can better understand the information mechanism of halo formation."

3D Grid "tornadoes" Mysterious Quantum Revealed in liquid helium

Wednesday, August 27, 2014 / No Comments

 new experience at SLAC National Accelerator Laboratory revealed a 3D "quantum tornadoes" inside microscopic droplets of supercooled liquid helium, allowing scientists to see a demonstration of the first macroscopic quantum world wide grid.
Menlo Park, California - The experience of the Department of Energy SLAC National Accelerator Laboratory revealed a "tornado" 3D quantum well organized into microscopic droplets of supercooled liquid helium grid - the first time this training has been seen on a small scale.

The findings of an international team of researchers offer a new perspective on the characteristics of the stranger Nanoscale called "superfluid" state liquid helium. When cooled to the point, liquid helium behaves according to the rules of quantum mechanics as applied to the subject in the smallest scales and defy the laws of classical physics. The superfluid state is one of the few examples of large-scale quantum behavior makes the behavior easier to see and study.

The results, which are detailed in the August 22 edition of Science, could help shed light on similar quantum states, such as superconducting materials that conduct electricity with an efficiency of 100 percent or collective foreign particles, Bose -Einstein bent, acting as a single unit.

"What we found in this experiment was really surprising., Not expecting the beauty and clarity of the results," said Christoph Bostedt, co-leader of the experience and senior researcher at the Linac coherent light source SLAC (of LCLS) the DOE Office of Science Ease of use where the experiment was conducted.

"We saw a demonstration of the quantum world to the macroscopic scale," said Ken Ferguson, a doctoral student at Stanford University working at LCLS.

Although small tornadoes had seen before in the cooled helium, not seen in these droplets, which were packed 100,000 times denser than at any previous experience superfluids, Ferguson said.

Studying the Quantum Traits of a Superfluid

Helium can be cooled to the point where it becomes a friction material which remains liquid and below the freezing point of most of the fluids. Atoms attract slight oscillation are endless - a quantum state of perpetual motion that prevents them from freezing. The unique properties of superfluid helium, which have been the subject of several Nobel Prize, let you upload and cover the sides of a container, and filtered through the holes of the molecule on the scale that would have occurred in the same liquid at temperatures higher.

In experiment LCLS, researchers jets fine droplets stream helium chain nanometric grains in vacuum. Each drop became a tower while flying in an airplane, turning up to 2 million times per second, and cooled at a cooler temperature than outer space. The X-ray laser took pictures of individual droplets, indicating dozens of small tornadoes, called "quantum swirls" with vortex cores that are the width of an atom.


The rapid rotation of chilled helium nanodroplets caused a dense pattern evenly spaced 3-D to form vortices. This exotic formation that resembles the ordered crystalline structure of a solid and demonstrates the quantum state of the droplets is very different from the solitary vortex formed in an ordinary liquid such as coffee cup vigorously stirred.

More Surprises in Store

The researchers also discovered some surprising ways superfluid droplets. In a normal liquid, droplets can form shapes peanut during rapid rotation, but the superfluid droplets took a very different way. About 1 percent of these forms unexpectedly wheel shaped and reaches a rotation speed never observed in conventional counterparts.

Oliver Gessner, a senior scientist at the Lawrence Berkeley and co-leader in the experiment, Laboratory said: "Now we've shown that we can detect and characterize qualitative shift in helium nanodroplets, it is important to understand its origin and, ultimately, trying to control. "

Andrey Vilesov University of Southern California, the third co-leader of the experiment, added: "The experience exceeded our expectations achieving best evidence of vortices, their configurations in the droplets and form droplets rotation LCLS has been possible with images.".

He said LCL data analysis should provide more detailed information on the shape and arrangement of vortices information: "Sure there will be more surprises to come."


Other contributors to the research were the Stanford PULSE Institute; University of California, Berkeley; Max Planck Society; Center for Free Electron Laser Science at DESY; PNSensor GmbH; Chinese University of Hong Kong; and Kansas State University. This work was funded by the National Science Foundation, the Department of Energy Office of Science of the United States and the Max Planck Society.

Researchers Observe What Happens During a Quantum Phase Transition

Monday, August 25, 2014 / No Comments




When ice is heated, the water molecules that form the structure vibrate harder until they finally forces are no longer strong enough to keep them together - the ice melts and becomes liquid water. Quantum physics predicts that similar phenomena may occur if the quantum fluctuations of the particles in a material can be changed. These state changes caused by the purely quantum effects - known as quantum phase transitions - play an important role in many surprising phenomena in semiconductor systems, including high temperature superconductivity. Researchers from Switzerland, Britain, France and China specifically amended the magnetic structure of TlCuCl3 material by exposing it to a variable external pressure at different temperatures. How to neutron scattering measurements, we were able to observe what happens at quantum phase transition, and compare the "quantum melting" of the magnetic structure with the "thermal fuse" conventional phase transition.

If water is liquid or solid form of ice, which depends on two energy takes over. One is the binding energy of the water molecules, the kinetic energy of other molecular motion, which is getting stronger, the higher the temperature. If ice is heated above zero degrees centigrade, the movement of the molecules becomes so intense that the hydrogen bonds are no longer able to hold together and melting ice. The general physical condition is changed or, in the terminology of physics, a phase transition occurs. A similar phenomenon was observed in the magnets - if a magnet is heated, it becomes non-magnetic - and for a similar reason. We can imagine that the magnet is composed of many tiny bar magnets, physicists refer to as magnetic moments. If all these moments are aligned in parallel, all the magnetic material is controlled and behaves like a magnet. If the material is heated, the direction of the moments fluctuates more strongly until the forces alignment and magnetic order disappears exceed: fade effect.

Quantum-physical state
This "classical" fusion is triggered by changes in temperature, but a comparable and equally fundamental phenomenon is determined by the laws of quantum physics. Quantum mechanics tells us that certain properties of the particles of a material can not be known exactly. This uncertainty is often called quantum fluctuations: similar to conventional fluctuations described above, the position or alignment of the magnetic moments of particles fluctuates over time. Although the origin of two types of fluctuations is completely different, in some situations, they may have similar effects. A "merger" of the state of the network ordered system triggered by quantum fluctuations - quantum phase transition - is quantum physics equivalent of the transition from classical phase heat. Phase transitions in quantum mechanics are the key to many of the most exotic phenomena in solid state physics, including high-temperature superconductivity.

The challenge of quantum fluctuations
Researchers at the Paul Scherrer Institute (Villigen, Switzerland) have teamed up with colleagues from University College London, the Institut Laue-Langevin (Grenoble, France) and Renmin University (Beijing, China) to study the precise impact of quantum fluctuations and their interaction with classical fluctuations. The main experimental challenge was to find a system for direct control of quantum fluctuations, and it uses TlCuCl3 materials, which was produced at the University of Bern. Changing conventional fluctuations is simple - the material can be heated and cooled. However, to control the quantum fluctuations in a magnetic material forces alignment between the moments to be modified. Investigators have exploited the fact that TlCuCl3 is relatively soft, so that the inter-atomic distances, and therefore the interactive forces in the material can be modified by applying an external pressure. In the experiment, varying the pressure and temperature in a wide range and the material studied using neutron sources ILL and PSI. This allowed them to determine exactly how the state of matter has changed over the quantum and classical phase transitions.

Disorder is not necessarily disorder
The researchers studied the arrangement of the magnetic moments. In TlCuCl3 moments come in pairs, and the magnetic forces of low pressure between the pairs are weaker, giving a state without magnetic order. "However, this disorder is completely different from a conventional disordered magnet, where the directions of the magnetic moments are just random," says Christian Rüegg, a head of laboratory at the Paul Scherrer Institute and supervisor of the research project. "Here the other two adjacent magnetic moments form a pair, with the two moments pointing in diametrically opposite directions. Interaction between neighboring pairs, however, is not strong enough, so no order is made long range. "In this case the laws of quantum physics do not specify that one of those moments of pairs of points in any direction and it was the most complete uncertainty about the orientation of the individual moments corresponds to strong quantum fluctuations. If now the pressure is increased, the magnetic moments move together so that the moments of adjacent pairs feel each other with increasing force until the coupled state is replaced by a long-range magnetic order: a quantum phase transition occurs due to pressure.

Quantum dynamics of the magnetic moments
In their experiment, the researchers focused mainly on "magnetic excitations" into matter, which provide very accurate information about the quantum states of information now information. These excitations can be imagined as a time of coordinated common magnetic oscillation, like a wave of water, or the vibration of a guitar string. excitations are related to "disorder" in the magnetic material that other excitations, the stronger the magnetic moments fluctuate physics. quantum requires most of the magnetic excitation in TlCuCl3 minimum energy required to excite, and the ease with which they can be activated dependent on the interaction between the magnetic moments - in this experiment and the temperature controlled by the pressure in the sample . researchers have shown that some excitations both low and high pressures require relatively high levels of energy and rarely addressed. However, if the pressure is adjusted to the value where quantum phase transition occurs, the energy decreases and a minimum number of different excitations can be observed. These include the origin and mathematical description is exactly analogous to the Higgs boson in particle physics, so some researchers refer to the Higgs particle in solid materials. Rüegg explains: "We were very surprised to find that these excitations have played a key role, regardless of whether the order was destroyed by quantum mechanics or classical fluctuations - a fascinating feature of quantum phase transitions." 

Neutrons reveal excitations 

Researchers conducted experiments neutron spectroscopy neutron source at the Institute Paul Scherrer Institut Laue-and Langevin. In the measurement, a current passing through neutron sample TlCuCl3 and watch the path and the rate of change of neutron. This allowed the team to study both the order and magnetic excitations if the neutron emerges move slower than its entry, must have lost its energy by activating emotion. "These fluctuations can not be observed with neutrons and it is vital that you have the opportunity to study the sample at different levels of pressure and temperature," says Martin Boehm, who oversaw the measures at ILL. "In doing so, we benefit from the neutron essential characteristics: they can fly through the walls of the pressure cell where the sample is virtually unrestricted. "

Miracle Material 


"This type of spectroscopy experiment can be done for the first time TlCuCl3 because the magnetic interactions are so sensitive to the applied pressure," says Rüegg. "In all other documents we know that a much larger pressure is needed, which means that you can only use very small samples -. Too small for spectroscopic experiments with neutrons Otherwise, you can try to produce many different samples vary slightly in structure, but it would take a long time and still would not give a complete picture of the behavior. "