Ionic Liquids' Good Vibrations Change Laser Colors with Ease

Shooting a green laser through a tube filled with a particular ionic liquid (right side of photo) can easily convert the green laser light to orange (upper left)—a long-sought color for medical applications. The method can be tailored for different color shifts by choosing different ionic liquids.
Photo Credit: Brookhaven National Laboratory

Lasers are intense beams of colored light. Depending on their color and other properties, they can scan your groceries, cut through metal, eradicate tumors, and even trigger nuclear fusion. But not every laser color is available with the right properties for a specific job. To fix that, scientists have found a variety of ways to convert one color of laser light into another. In a study just published in the journal Physical Review Applied, scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory demonstrate a new color-shifting strategy that’s simple, efficient, and highly customizable.

The new method relies on interactions between the laser and vibrational energy in the chemical bonds of materials called “ionic liquids.” These liquids are made only of positively and negatively charged ions, like ordinary table salt, but they flow like viscous fluids at room temperature. Simply shining a laser through a tube filled with a particular ionic liquid can downshift the laser’s energy and change its color while retaining other important properties of the laser beam.

Coating bubbles with protein results in a highly stable contrast agent for medical use

Bacteria produce gas vesicles
Image Credit: Aalto University

Inspired by the bubbles bacteria create inside their cells, researchers developed a similar system by coating tiny gas vesicles with protein. The resulting bubbles are safe, highly stable, and function as contrast agent in medical applications. They could be used to diagnose, for example, cardiological issues, blood flow, and liver lesions.

Bacteria produce gas vesicles, tiny thin-walled sacs filled with air or fluid, to help them float. This phenomenon has captured the attention of scientists who see potential for similar bubble-based designs in fields like medicine. A team of researchers at Aalto University’s Department of Applied Physics, led by Professor Robin Ras, have now used the same idea to create a new kind of contrast agent for use in medical applications such as ultrasound imaging. The research was recently published in the Proceedings of the National Academy of Sciences.

Data Reveal a Surprising Preference in Particle Spin Alignment

New data show that local fluctuations in the nuclear strong force may influence the spin orientation of particles called phi mesons (made of two quarks held together by the exchange of gluons).
Illustration Credit: Brookhaven National Laboratory

Given the choice of three different “spin” orientations, certain particles emerging from collisions at the Relativistic Heavy Ion Collider (RHIC), an atom smasher at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, appear to have a preference. As described in a paper just published in Nature by RHIC’s STAR collaboration, the results reveal a preference in global spin alignment of particles called phi mesons. Conventional mechanisms—such as the magnetic field strength or the swirliness of the matter generated in the particle collisions—cannot explain the data. But a new model that includes local fluctuations in the nuclear strong force can.

“It could be that the strong force fluctuations are the missing factor. Previously we hadn’t realized the strong force can influence particle spin in this way,” said Aihong Tang, a STAR physicist at Brookhaven who was involved in the analysis.

This explanation is still subject to debate and further verification is needed, the STAR physicists say. But if it proves to be true, “these measurements give us a way to gauge how large the local fluctuations in the strong force are. They provide a new avenue to study the strong force from a different perspective,” Tang said.

Artifacts, Begone! NIST Improves Its Flagship Device for Measuring Mass

For the first time, scientists have integrated a quantum resistance standard directly into mass measurements made with the one-of-a-kind NIST-4 Kibble balance. Using the quantum standard in this way increases the accuracy of the measurements. This animation shows how the new quantum resistance standard, called QHARS, works. The QHARS device uses a sheet of graphene (a single layer of carbon atoms) attached to superconducting electrical contacts. When cooled to low temperature and placed in a strong magnetic field, electrons in the graphene begin moving in closed loops, a phenomenon known as the quantum Hall effect. This behavior results in the graphene having a specific resistance, providing an absolute reference for measuring current in the NIST-4 Kibble balance. 
Video Credit: Sean Kelley/NIST

In a brightly lit subterranean lab at the National Institute of Standards and Technology (NIST) sits a room-sized electromechanical machine called the NIST-4 Kibble balance.

The instrument can already measure the mass of objects of roughly 1 kilogram, about as heavy as a quart of milk, as accurately as any device in the world. But now, NIST researchers have further improved their Kibble balance’s performance by adding to it a custom-built device that provides an exact definition of electrical resistance. The device is called the quantum Hall array resistance standard (QHARS), and it consists of a set of several smaller devices that use a quirk of quantum physics to generate extremely precise amounts of electrical resistance. The researchers describe their work in a Nature Communications paper.

Excavation of massive underground caverns for DUNE halfway complete

When complete later this year, this cavern will be around 500 feet long, 65 feet wide and 90 feet high. It will be one of three caverns that will provide space to house particle detector modules and other equipment for the Deep Underground Neutrino Experiment.
Photo Credit: David Smith, Fermilab

Deep below the surface in South Dakota, construction crews have been working tirelessly to carve out a network of caverns and tunnels that one day will house a huge neutrino experiment. Their efforts are paying off: With almost 400,000 tons of rock extracted from the earth, the excavation is now half complete.

Once finished, the Long-Baseline Neutrino Facility will be the site of the international Deep Underground Neutrino Experiment. DUNE will focus on studying neutrinos, elusive particles that may hold the answers to many of the universe’s mysteries, such as why our universe is made of matter and how black holes and neutron stars are born. More than 1,000 scientists and engineers from over 30 countries are a part of LBNF/DUNE.

LBNF will provide the space, infrastructure and particle beam for DUNE, hosted by the U.S. Department of Energy’s Fermi National Accelerator Laboratory. It includes underground caverns for a near detector at Fermilab, about 40 miles west of Chicago, and a far detector located 800 miles away at the Sanford Underground Research Facility in South Dakota.

Deflecting lightning with a laser lightning rod

During tests carried out on the summit of the Säntis by Jean-Pierre Wolf and Aurélien Houard's team, the scientists noted that the discharge could follow the laser beam of the "LLR" for several dozen meters before reaching the tower of the operator Swisscom (in red and white).
Photo Credit: Xavier Ravinet - UNIGE

A European consortium led by UNIGE, École Polytechnique (Paris), EPFL, hes-so and TRUMPF has managed to guide lightning using a high-power laser installed at the top of Mount Säntis in Switzerland.

Forest fires, power cuts and damaged infrastructure…lightning fascinates and destroys in equal measure, causing as many as 24,000 deaths a year worldwide not to mention widespread destruction. Even today, the lightning rod invented by Benjamin Franklin is the best form of protection. And yet, these rods do not always provide optimal protection for sensitive sites. A European consortium consisting of the University of Geneva (UNIGE), École Polytechnique (Paris), EPFL, hes-so and TRUMPF scientific lasers (Munich) has developed a promising alternative: the Laser Lightning Rod or LLR. After testing the LLR on the summit of Säntis (in Switzerland), the researchers now have proof of its feasibility. The rod can deflect lightning over several dozen meters even in poor weather. The results of this research are published in the journal Nature Photonics.

Sandia work at the heart of next generation nuclear reactor

A team of Sandia National Laboratories researchers is testing materials to make the next generation of fusion reactors. This container is used to expose the samples to nuclear fusion. It holds seven samples of innovative tungsten alloys, post exposure.
Photo Credit: Jonathan Coburn

A team of Sandia National Laboratories researchers working on the reactor at the DIII-D National Fusion Facility is testing materials to make the next generation of fusion reactors, in the quest to develop more carbon-free energy sources.

These magnetic confinement fusion reactors, called tokamaks, use magnetic fields to shape plasma into a donut shape that generates power from nuclear fusion. DIII-D is the largest such facility currently operating in the Department of Energy complex. Tokamaks create high heat and particle fluxes that can cause significant erosion of the reactor wall materials. If these materials contaminate the core plasma, it could make it impossible to bring the reactor to a temperature high enough to start stable, safe fusion.

Jonathan Coburn is one such researcher, part of a team of Sandians that collaborates with DIII-D to test and develop much needed specialized fusion materials for the hot fusion plasma environment.

By detecting tiny flashes of heat, scientist pave way for more stable quantum computers

Measuring the heat of a phase slip in a Josephson junction is a significant step forward for quantum thermodynamics toward better quantum technologies.
Photo Credit: Kuan Yen Tan/Aalto University

An international collaboration between quantum scientists resulted in a new way to measure heat dissipation in superconducting quantum circuits – crucial building blocks for quantum technologies such as computers. The discovery represents a step forward for experimental quantum thermodynamics, the field investigating the interaction of the quantum world and heat, and paves the way for improved quantum devices.

As heat sets limits for traditional computing, so it does for quantum computers. Detecting and controlling the heat dissipation of quantum computers is central for developing better and more stable machines. Researchers at Aalto, the Universitét Grenoble Alpes and University of Konstanz worked together to test a theory about heat dissipation in a so-called phase slip in a quantum device. The result was a reliable and efficient way to measure dissipation that could be scaled to cover a range of quantum applications. The discovery was recently published in Nature Physics.

Controlling quantum states in individual molecules with two-dimensional ferroelectrics

Researchers used electricity to control the internal states of molecules.
Illustration Credit: Jose Lado/Aalto University

Researchers demonstrated how to control the quantum states of individual molecules with an electrically controllable substrate.

Controlling the internal states of quantum systems is one of the biggest challenges in quantum materials. At the deepest level, single molecules can display different quantum states, even while possessing the same number of electrons. These states are associated with different electron configurations, which can lead to dramatically different properties.

The capability of controlling the electronic configuration of single molecules could lead to major developments in both fundamental science and technology. On the one hand, controlling the internal states of molecules may allow for the development of new artificial materials with exotic properties. On the other hand, it might also make possible the ultimate miniaturization of classical computer memories, with the two configurations could make it possible to encode a 0 and a 1 in a classical memory unit at the molecular level. However, controlling the internal states of molecules still remains a challenge, and realistic, scalable strategies for overcoming it have not been proposed.

Organelles grow in random bursts

Shankar Mukherji, assistant professor of physics in Arts & Sciences
Photo Credit: Washington University in St. Louis

Eukaryotic cells — the ones that make up most of life as we know it, including all animals, plants and fungi — are highly structured objects.

These cells assemble and maintain their own smaller, internal bits: the membrane-bound organelles like nuclei, which store genetic information, or mitochondria, which produce chemical energy. But much remains to be learned about how they organize themselves into these spatial compartments.

Physicists at Washington University in St. Louis conducted new experiments that show that eukaryotic cells can robustly control average fluctuations in organelle size. By demonstrating that organelle sizes obey a universal scaling relationship that the scientists predict theoretically, their new framework suggests that organelles grow in random bursts from a limiting pool of building blocks.

The study was published Jan. 6 in Physical Review Letters.

“In our work, we suggest that the steps by which organelles are grown — far from being an orderly ‘brick-by-brick’ assembly — occur in stochastic bursts,” said Shankar Mukherji, assistant professor of physics in Arts & Sciences.

New quantum computing architecture could be used to connect large-scale devices

This image shows a module composed of superconducting qubits that can be used to directionally emit microwave photons.
Illustration Credit: Massachusetts Institute of Technology / Courtesy of the researchers

Quantum computers hold the promise of performing certain tasks that are intractable even on the world’s most powerful supercomputers. In the future, scientists anticipate using quantum computing to emulate materials systems, simulate quantum chemistry, and optimize hard tasks, with impacts potentially spanning finance to pharmaceuticals.

However, realizing this promise requires resilient and extensible hardware. One challenge in building a large-scale quantum computer is that researchers must find an effective way to interconnect quantum information nodes — smaller-scale processing nodes separated across a computer chip. Because quantum computers are fundamentally different from classical computers, conventional techniques used to communicate electronic information do not directly translate to quantum devices. However, one requirement is certain: Whether via a classical or a quantum interconnect, the carried information must be transmitted and received.

To this end, MIT researchers have developed a quantum computing architecture that will enable extensible, high-fidelity communication between superconducting quantum processors. In work published today in Nature Physics, MIT researchers demonstrate step one, the deterministic emission of single photons — information carriers — in a user-specified direction. Their method ensures quantum information flows in the correct direction more than 96 percent of the time.

First-ever observation of quantum interference between dissimilar particles

Daniel Brandenburg and Zhangbu Xu at the STAR detector of the Relativistic Heavy Ion Collider (RHIC).
Photo Credit: Courtesy of Brookhaven National Laboratory

Nuclear physicists have found a new way to use the Relativistic Heavy Ion Collider (RHIC)—a particle collider at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory—to see the shape and details inside atomic nuclei. The method relies on particles of light that surround gold ions as they speed around the collider and a new type of quantum entanglement that’s never been seen before.

Through a series of quantum fluctuations, the particles of light (a.k.a. photons) interact with gluons—gluelike particles that hold quarks together within the protons and neutrons of nuclei. Those interactions produce an intermediate particle that quickly decays into two differently charged “pions” (π). By measuring the velocity and angles at which these π+ and π- particles strike RHIC’s STAR detector, the scientists can backtrack to get crucial information about the photon—and use that to map out the arrangement of gluons within the nucleus with higher precision than ever before.

“This technique is similar to the way doctors use positron emission tomography (PET scans) to see what’s happening inside the brain and other body parts,” said former Brookhaven Lab physicist James Daniel Brandenburg, a member of the STAR collaboration who joined The Ohio State University as an assistant professor in January 2023. “But in this case, we’re talking about mapping out features on the scale of femtometers—quadrillionths of a meter—the size of an individual proton.”

Was That Explosion Chemical or Nuclear?

From left to right: Tim Johnson, Hunter Knox, and Harry Miley bring together different perspectives to better detect underground nuclear explosions. 
Composite Image Credit: by Shannon Colson | Pacific Northwest National Laboratory

If an underground explosion occurs anywhere in the world, there is a good chance that a seismologist can pinpoint it. However, they won’t necessarily be able to tell you what kind of explosion had occurred—whether it is chemical or nuclear in nature. New research from Pacific Northwest National Laboratory (PNNL) scientists makes detecting nuclear explosions easier.

“To a seismologist, chemical and nuclear explosions look identical,” said Harry Miley, Laboratory Fellow and physicist in the National Security Directorate at PNNL. “Radionuclide detection technologies, like the PNNL-developed Xenon International and Radionuclide Aerosol Sampler/Analyzer, known as RASA, can discriminate between the two by detecting radioactive atoms that are created in nuclear explosions. However, we have very little scientific understanding of the geologic containment of these atoms following an explosion.”

When an underground explosion occurs, gases travel through fractures in the ground and escape into the atmosphere. Instruments such as Xenon International and RASA can then detect radionuclide gases, but their chemical signatures may be greatly affected by rock damage that the gases must pass through.

The Donnan Potential, Revealed at Last

Staff scientist Ethan Crumlin at Berkeley Lab's Advanced Light Source.
Photo Credit: Marilyn Sargent/Berkeley Lab

The Donnan electric potential arises from an imbalance of charges at the interface of a charged membrane and a liquid, and for more than a century it has stubbornly eluded direct measurement. Many researchers have even written off such a measurement as impossible.

But that era, at last, has ended. With a tool that’s conventionally used to probe the chemical composition of materials, scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) recently led the first direct measurement of the Donnan potential.

“We were naïve enough to believe we could do the impossible.”

Ethan Crumlin, Berkeley Lab staff scientist, Advanced Light Source (ALS)

Crumlin and his collaborators recently reported the measurement in Nature Communications.

Such a measurement could yield new insights in many areas that focus on membranes. The Donnan potential plays a critical role in transporting ions through a cellular membrane, for example, which ties it to biological functions ranging from muscle contractions to neural signaling. Ion exchange membranes are also important in energy storage strategies and water purification technologies.

Researchers aim to explore how matter gets its mass by confining quarks

STAR chamber
The research on quark confinement was inspired in part by nuclear research carried out at the Brookhaven National Laboratory in the U.S. Pictured here is a giant particle detector that can image subatomic interactions. This apparatus is investigating rapidly rotating quark matter.
Full Resolution Image
Image Credit: Brookhaven National Laboratory CC BY-NC-ND 2.0

A new way to study quarks, one of the building blocks of the protons and neutrons that make up atomic nuclei, is proposed. This has never been done before and doing so would help answer many fundamental questions in physics. In particular, researchers could use the new approach to determine how matter gets its mass.

The study of matter can seem a bit like opening a stack of Russian matryoshka dolls, each level down revealing another familiar, yet different, arrangement of components smaller and harder to explore than the one before. On our everyday scale, we have objects we can see and touch. Whether water in a glass or the glass itself, these are mostly arrangements of molecules too small to see. The tools of physics (microscopes, particle accelerators, and so forth) let us peer deeper to reveal molecules are made from atoms. But it doesn’t stop there — atoms are made from a nucleus surrounded by electrons.

Scientists Have Figured Out How to Use Silicone to Protect against Radiation

Scientists plan to investigate a broader set of materials that can attenuate radiation.
Photo Credit: Anastasia Farafontova

An international team of scientists has developed a material that can be used in the future as radiation protection against gamma radiation, in particular, it can be used to create radiation protection for Nuclear Power Station workers. The new material is based on silicone using zinc oxide nano powder additions. The results of research on the new material and its properties have been published in the journal Optical Materials. Physicists from Russia (Ural Federal University), Jordan, and Turkey took part in the work.

"Gamma radiation is widespread in the health care, food and aerospace industries. Excessive exposure can be harmful to human health. Gamma radiation is now attenuated or absorbed using lead, concrete, lead-oxide, tungsten, or tin-based materials. These protective materials are not always convenient to use as protection against gamma rays. In addition, they are expensive, too heavy and highly toxic to humans and the environment. This is why it is important to find new materials and optimize their composition for radiation protection, which will ensure human and environmental safety," says Oleg Tashlykov, Associate Professor at the Department of Nuclear Power Plants and Renewable Energy Sources at UrFU.

Particles of Light May Create Fluid Flow, Data-Theory Comparison Suggests

Brookhaven Lab theorist Bjoern Schenke's hydrodynamic calculations match up with data from collisions of photons with atomic nuclei at the Large Hadron Collider's ATLAS detector, suggesting those collisions create a fluid of "strongly interacting" particles.
Photo Credit: Brookhaven National Laboratory

A new computational analysis by theorists at the U.S. Department of Energy’s Brookhaven National Laboratory and Wayne State University supports the idea that photons (a.k.a. particles of light) colliding with heavy ions can create a fluid of “strongly interacting” particles. In a paper just published in Physical Review Letters, they show that calculations describing such a system match up with data collected by the ATLAS detector at Europe’s Large Hadron Collider (LHC).

As the paper explains, the calculations are based on the hydrodynamic particle flow seen in head-on collisions of various types of ions at both the LHC and the Relativistic Heavy Ion Collider (RHIC), a DOE Office of Science user facility for nuclear physics research at Brookhaven Lab. With only modest changes, these calculations also describe flow patterns seen in near-miss collisions, where photons that form a cloud around the speeding ions collide with the ions in the opposite beam.

“The upshot is that, using the same framework we use to describe lead-lead and proton-lead collisions, we can describe the data of these ultra-peripheral collisions where we have a photon colliding with a lead nucleus,” said Brookhaven Lab theorist Bjoern Schenke, a coauthor of the paper. “That tells you there’s a possibility that, in these photon-ion collisions, we create a small dense strongly interacting medium that is well described by hydrodynamics—just like in the larger systems.”

National Ignition Facility achieves fusion ignition

The target chamber of LLNL’s National Ignition Facility, where 192 laser beams delivered more than 2 million joules of ultraviolet energy to a tiny fuel pellet to create fusion ignition on Dec. 5, 2022.
Photo Credit: Lawrence Livermore National Laboratory

The U.S. Department of Energy (DOE) and DOE’s National Nuclear Security Administration (NNSA) today announced the achievement of fusion ignition at Lawrence Livermore National Laboratory (LLNL) — a major scientific breakthrough decades in the making that will pave the way for advancements in national defense and the future of clean power. On Dec. 5, a team at LLNL’s National Ignition Facility (NIF) conducted the first controlled fusion experiment in history to reach this milestone, also known as scientific energy breakeven, meaning it produced more energy from fusion than the laser energy used to drive it. This first-of-its-kind feat will provide unprecedented capability to support NNSA’s Stockpile Stewardship Program and will provide invaluable insights into the prospects of clean fusion energy, which would be a game-changer for efforts to achieve President Biden’s goal of a net-zero carbon economy.

“This is a landmark achievement for the researchers and staff at the National Ignition Facility who have dedicated their careers to seeing fusion ignition become a reality, and this milestone will undoubtedly spark even more discovery,” said U.S. Secretary of Energy Jennifer M. Granholm. “The Biden-Harris Administration is committed to supporting our world-class scientists — like the team at NIF — whose work will help us solve humanity’s most complex and pressing problems, like providing clean power to combat climate change and maintaining a nuclear deterrent without nuclear testing.”

Cities on asteroids? It could work—in theory

In what they deem a “wildly theoretical” paper, Rochester researchers imagine covering an asteroid in a flexible, mesh bag made of ultralight and high-strength carbon nanofibers as the key to creating human cities in space.
Illustration Credit: University of Rochester | Michael Osadciw

Rochester scientists use physics and engineering principles to show how asteroids could be future viable space habitats.

This past year, Jeff Bezos launched himself into space, while Elon Musk funded a space flight for a non-astronaut crew. Space collaborations between government and private entities, including Musk’s SpaceX and Bezos’s Blue Origin have become increasingly common. But with the recent emergence of the so-called “New Space” movement, aerospace companies are working to develop low-cost access to space for everyone, not only billionaires.

For a future beyond Earth, however, humans need places to accommodate homes, buildings, and other structures for millions of people to live and work.

Right now, space cities exist only in science fiction. But are space cities feasible in reality? And, if so, how?

According to new research from University of Rochester scientists, our future may lie in asteroids.

In what they deem a “wildly theoretical” paper published in the journal Frontiers in Astronomy and Space Sciences, the researchers, including Adam Frank, the Helen F. and Fred H. Gowen Professor of Physics and Astronomy, and Peter Miklavčič, a PhD candidate in mechanical engineering and the paper’s first author, outline a plan for creating large cities on asteroids.

Brookhaven Lab to Lead New 'Saturated Glue' Theory Collaboration

Gluons at the Speed of Light
Gluons are always popping in and out of existence like blinking fireflies. But when nuclei or protons are accelerated to high energies, the gluons inside appear to multiply. That's because time operates in weird ways near the speed of light. The "blinking" appears to slow down, which makes the gluons linger longer. Energetic particle collisions can help physicists study this gluon-dominated state and, guided by new approaches to nuclear theory, search for signs of gluon saturation.
Illustration Credit: Brookhaven National Laboratory

The U.S. Department of Energy (DOE) has announced funding for a new Topical Theory Collaboration to be led by DOE’s Brookhaven National Laboratory that will aid in the discovery and exploration of a saturated state of gluons. These aptly named particles carry the nuclear strong force, acting as the ‘glue’ that holds together quarks, the building blocks of all visible matter. By understanding gluons’ ability to split and recombine and potentially reach a state of saturation, scientists hope to gain deeper insight into the strong force and the role gluons play in generating the mass, spin, and other properties of hadrons—composite particles made of quarks, such as the protons and neutrons of atomic nuclei.

The SatURated GluE (SURGE) Topical Theory Collaboration aims to develop calculations and a theoretical framework for discovering this unique saturated form of gluonic matter. Such a saturated state is predicted by the theory of quantum chromodynamics (QCD) to be observable in particles accelerated to high energies in particle colliders such as the Relativistic Heavy Ion Collider (RHIC) at Brookhaven Lab, the Large Hadron Collider (LHC) at Europe’s CERN laboratory, and the future Electron-Ion Collider (EIC) at Brookhaven.