Science
Demon hunting: Physicists confirm 67-year-old prediction of massless, neutral composite particle
Researchers have discovered Pines’ demon, a collection of electrons in a metal that behaves like a massless wave.
Newswise — In 1956, theoretical physicist David Pines predicted that electrons in a solid can do something strange. While they normally have a mass and an electric charge, Pines asserted that they can combine to form a composite particle that is massless, neutral, and does not interact with light. He called this particle a “demon.” Since then, it has been speculated to play an important role in the behaviors of a wide variety of metals. Unfortunately, the same properties that make it interesting have allowed it to elude detection since its prediction.
Now, a team of researchers led by Peter Abbamonte, a professor of physics at the University of Illinois Urbana-Champaign, have finally found Pines’ demon 67 years after it was predicted. As the researchers report in the journal Nature, they used a nonstandard experimental technique that directly excites a material’s electronic modes, allowing them to see the demon’s signature in the metal strontium ruthenate.
“Demons have been theoretically conjectured for a long time, but experimentalists never studied them,” Abbamonte said. “In fact, we weren’t even looking for it. But it turned out we were doing exactly the right thing, and we found it.”
The elusive demon
One of the most important discoveries of condensed matter physics is that electrons lose their individuality in solids. Electric interactions make the electrons combine to form collective units. With enough energy, the electrons can even form composite particles called plasmons with a new charge and mass determined by the underlying electric interactions. However, the mass is usually so large that plasmons cannot form with the energies available at room temperature.
Pines found an exception. If a solid has electrons in more than one energy band, as many metals do, he argued that their respective plasmons can combine in an out-of-phase pattern to form a new plasmon that is massless and neutral: a demon. Since demons are massless, they can form with any energy, so they may exist at all temperatures. This has led to speculation that they have important effects on the behavior of multi-band metals.
Demons’ neutrality means that they do not leave a signature in standard condensed matter experiments. “The vast majority of experiments are done with light and measure optical properties, but being electrically neutral means that demons don’t interact with light,” Abbamonte said. “A completely different kind of experiment was needed.”
A serendipitous discovery
Abbamonte recalls that he and his collaborators were studying strontium ruthenate for an unrelated reason—the metal is similar to high-temperature superconductors without being one. Hoping to find clues to why the phenomenon occurs in other systems, they were conducting the first survey of the metal’s electronic properties.
The research group of Yoshi Maeno, a professor of physics at Kyoto University, synthesized high-quality samples of the metal which Abbamonte and former graduate student Ali Husain examined with momentum-resolved electron energy-loss spectroscopy. A nonstandard technique, it uses energy from electrons shot into the metal to directly observe the metal’s features, including plasmons that form. As the researchers were looking through the data, though, they found something unusual: an electronic mode with no mass.
Husain, now a research scientist at Quantinuum, recalled, “At first, we had no idea what it was. Demons are not in the mainstream. The possibility came up early on, and we basically laughed it off. But, as we started ruling things out, we started to suspect that we had really found the demon.”
Edwin Huang, a Moore Postdoctoral Scholar at UIUC and condensed matter theorist, was eventually asked to calculate the features of strontium ruthenate’s electronic structure. “Pines’ prediction of demons necessitates rather specific conditions, and it was not clear to anyone whether strontium ruthenate should have a demon at all,” he said. “We had to perform a microscopic calculation to clarify what was going on. When we did this, we found a particle consisting of two electron bands oscillating out-of-phase with nearly equal magnitude, just like Pines described.”
The importance of just measuring stuff
According to Abbamonte, it was no accident that his group discovered the demon “serendipitously.” He emphasized that he and his group were using a technique that is not widely employed on a substance that has not been well studied. That they found something unexpected and significant is a consequence of simply trying something different, he believes.
“It speaks to the importance of just measuring stuff,” he said. “Most big discoveries are not planned. You go look somewhere new and see what’s there.”
Support was provided by the U.S. Department of Energy, the Japan Society for the Promotion of Science, the National Science Foundation, and the Gordon and Betty Moore Foundation.
Source: University Of Illinois Grainger College Of Engineering
Blog
NASA’s Dragon Departs the Station with Exciting Science: What to Expect
Exciting news as SpaceX Dragon departs the International Space Station, carrying scientific research and hardware. Don’t miss NASA’s coverage!
Exciting news from the realm of space exploration! NASA and its incredible international partners are gearing up for an eventful departure as the SpaceX Dragon cargo spacecraft bids farewell to the International Space Station on Sunday, April 28 (weather permitting). This pivotal moment will mark the return of scientific research samples and hardware, acquired during the spacecraft’s stay at the orbiting laboratory. Enthusiastically, NASA is providing extensive coverage of the undocking and departure, ensuring that we don’t miss a moment of this extraordinary event.
Undocking and Departure:
NASA will commence its coverage of the undocking and departure at 12:45 p.m. EDT, accessible through various means such as NASA+, NASA Television, the NASA app, YouTube, and the agency’s website. If you’re curious about experiencing the event firsthand, worry not – NASA offers streaming options on multiple platforms, including social media.
Dragon will gracefully undock from the zenith port of the Harmony module, promptly at 1:05 p.m., after receiving ground control commands from SpaceX in Hawthorne, California. Following undocking, it will steadily propel itself away from the International Space Station, creating a safe distance between them.
Return to Earth:
Upon re-entering Earth’s atmosphere, the Dragon spacecraft will elegantly splash down off the coast of Florida, with the ultimate goal of delivering more than 4,100 pounds of supplies and scientific experiments back to home soil. While NASA will not be broadcasting the splashdown, you can stay tuned to the agency’s space station blog for continuous updates and fascinating insights.
Scientific Endeavors:
Among the plethora of captivating studies making their way back to Earth, one standout is the Flawless Space Fibers-1 experiment. This investigation has achieved remarkable milestones, producing over seven miles of optical fiber during its stay on the space station. By exploring new hardware and manufacturing processes for high-quality optical fibers in space, it shattered previous records, drawing more than half a mile of fiber in just one day.
Another striking study travelling aboard Dragon is GEARS (Genomic Enumeration of Antibiotic Resistance in Space), which surveys the space station for antibiotic-resistant organisms. By analyzing genetic data, scientists aim to understand how these bacteria adapt to space, providing insights to protect future astronauts on long-duration missions.
MISSE-18 (Materials International Space Station Experiment-18-NASA) is yet another exciting experiment coming back to Earth. It examines the performance and durability of materials and components when exposed to the harsh environment of space. Coatings, quantum dots, a lunar regolith simulant composite, and other materials are studied to enhance our understanding of their behavior in space conditions.
Additionally, the Immune Cell Activation experiment, sponsored by the European Space Agency (ESA), promises fascinating results. It investigates whether microgravity affects the incorporation of magnetic nanoparticles into immune and melanoma cells. The outcomes of this research could contribute to the development of novel therapeutics targeting central nervous system diseases and skin cancers such as melanoma.
Future Implications:
These returning experiments represent only a fraction of the hundreds of ongoing investigations aboard the International Space Station. Ranging across biology and biotechnology, physical sciences, and Earth and space science, these studies are crucial for astronaut health during long-duration space travel. They also serve as critical stepping stones towards NASA’s Artemis campaign, ensuring the advancement of human and robotic exploration beyond low Earth orbit – ultimately leading us to the Moon and Mars.
The impending departure of the SpaceX Dragon cargo spacecraft from the International Space Station promises an exhilarating journey back to Earth. With an array of scientific research samples and hardware aboard, the Dragon’s return holds tremendous scientific significance. Thanks to NASA’s dedicated coverage, you can witness this extraordinary milestone through various platforms. As we eagerly await the spacecraft’s splashdown off Florida’s coast, let’s celebrate the accomplishments and look forward to the groundbreaking discoveries that lie ahead.
Get breaking news, images and features from the space station on Instagram, Facebook, and X.
Learn more about the International Space Station at:
https://www.nasa.gov/international-space-station
https://stmdailynews.com/category/science
Space and Tech
Exciting News: NASA Live Coverage of Roscosmos Cosmonauts on a Spacewalk!
Don’t miss NASA’s live coverage of Roscosmos cosmonauts on a spacewalk outside the International Space Station! #SpaceExploration
Get ready to witness a truly incredible event – a spacewalk outside the International Space Station conducted by two Roscosmos cosmonauts! NASA will be providing live coverage of this historic moment on Thursday, April 25, starting at 10:30 a.m. EDT. You definitely don’t want to miss this!
The spacewalk, expected to begin at 10:55 a.m. EDT, could last up to an impressive seven hours. So make sure to clear your schedule and prepare yourself for some out-of-this-world action!
But don’t worry if you can’t be near a TV, because NASA has got you covered. They will be streaming the spacewalk on various platforms including NASA+, NASA Television, the NASA app, YouTube, and their very own website. How convenient is that?
If you’re wondering how to catch this incredible event, fret not! NASA has made it super easy for everyone to enjoy the live coverage. You can stream NASA TV through numerous platforms, including social media. Just follow the instructions provided and you’ll be all set to witness history!
During this captivating spacewalk, Expedition 71 crewmates Oleg Kononenko and Nikolai Chub will embark on their mission. Their primary objective is to complete the deployment of a panel on a synthetic radar system located on the Nauka module. They will also be installing equipment and experiments on the Poisk module, which will be used to analyze the level of corrosion on various surfaces and modules of the space station. Science at its finest!
This noteworthy spacewalk will mark the 270th in support of the International Space Station. For Kononenko, this will be his seventh spacewalk, and he will be wearing the distinguished Orlan spacesuit with the red stripes. Chub, on the other hand, will be going on his second spacewalk and will be wearing the awe-inspiring spacesuit with the blue stripes. Talk about a fashionable space adventure!
So grab your popcorn, gather your friends and family, and get ready for an exhilarating experience. This upcoming spacewalk promises to be an event that will leave you in awe of the immense accomplishments and ongoing science conducted aboard the International Space Station.
Remember, you can catch all the action on NASA+, NASA Television, the NASA app, YouTube, and their website. Don’t miss out on this thrilling live coverage. Be a part of history and witness the wonders of space exploration firsthand. See you there!
Get breaking news, images, and features from the space station on the station blog, Instagram, Facebook, and X.
Learn more about International Space Station research and operations at:
News
NASA Leadership Visits Mexico: Strengthening Cooperation for a Brighter Future
NASA leadership visiting Mexico to strengthen cooperation in space exploration, climate change, and STEM education. Exciting partnership ahead! 🚀🌎🔬 #NASA #MexicoCooperation
In a remarkable effort to deepen ties and enhance space collaboration with nations across the globe, NASA Administrator Bill Nelson and Deputy Administrator Pam Melroy will be visiting Mexico City on April 22 and 23. This visit aims to foster bilateral cooperation in various innovation and research areas, including Earth science and exploration. Recognizing the significance of such interaction, this blog post delves into the details of this auspicious visit, highlighting the potential benefits and areas of collaboration between NASA and Mexico.
Strengthening Bilateral Cooperation:
NASA’s engagement with senior Mexican government officials, such as President Andrés Manuel López Obrador and Mexican Space Agency (AEM) leaders, underscores the intent to strengthen the relationship between the two countries. With a collective focus on addressing climate change, both NASA and AEM are working collaboratively to achieve mutual goals. This cooperation extends not only to environmental challenges but also encompasses technology development, space exploration, and scientific research.
Nanosatellite Technology Demonstrators:
Mexico’s involvement as a signatory of the Artemis Accords reinforces the country’s commitment to participating in a practical and prosperous alliance for space exploration. NASA and AEM are investing effort and resources in nanosatellite technology demonstrators, which hold immense promise for the future of space exploration. Through joint endeavors, both organizations are pushing the boundaries of scientific knowledge while fostering innovation and pushing the frontiers of human capabilities.
Ecological Focus on Earth Day:
The timing of the visit is significant as it coincides with Earth Day on April 22. Mexico’s collaboration with NASA in Earth science initiatives will be at the forefront of discussions during the visit. By leveraging NASA’s expertise and missions, Mexico aims to further expand its understanding of our planet’s dynamics. Topics such as air quality analysis and improved water resource management hold immense potential, enabling both countries to address pressing ecological challenges and work towards sustainable solutions.
Inspiring the Next Generation:
Nelson and Melroy’s commitment to fostering scientific curiosity and excellence extends to engaging with students in Mexico. The NASA officials will participate in dialogue with students, emphasizing the importance of STEM education and their pivotal roles as members of the Artemis Generation. By inspiring young minds to pursue careers in science, technology, engineering, and mathematics, NASA aims to empower the future workforce, ensuring continued progress and innovation.
NASA’s visit to Mexico serves as a testament to the importance of international cooperation and scientific collaboration. The shared vision of addressing global challenges, such as climate change, necessitates partnerships that transcend borders. Through strengthened ties with Mexico and initiatives focusing on Earth science, nanosatellite technology, and STEM education, NASA and its Mexican counterparts are paving the way for a brighter and more prosperous future. Such cooperative endeavors hold the potential to unlock breakthrough discoveries, foster innovation, and inspire the next generation of explorers.
For more information about NASA’s international partnerships, visit:
Office of International and Interagency Relations Mission
The mission of the Office of International and Interagency Relations (OIIR) is to provide executive leadership and coordination for all NASA international and interagency activities and partnerships, and for policy interactions between NASA and other U.S. Executive Branch offices and agencies.
OIIR Organizationabout Office of International and Interagency Relations Mission
About OIIR
OIIR serves as the principal Agency liaison with the National Security Council, the Office of Science and Technology Policy, and U.S. departments and agencies.
OIIR is responsible for:
- Ensuring that NASA’s international engagements are in alignment with Administration direction and U.S. laws and regulations
- Negotiating cooperative and reimbursable agreements with foreign space and aeronautics partners
- Providing advice and guidance to Agency leadership on the implementation of NASA interagency and international partnerships
- Providing management oversight and staff support of NASA’s advisory committees, commissions and panels
- Managing the NASA Export Control Program
- Coordinating foreign travel by NASA employees
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