. Scientific Frontline: Physics
Showing posts with label Physics. Show all posts
Showing posts with label Physics. Show all posts

Monday, April 8, 2024

Kerr-Enhanced Optical Spring for Next-Generation Gravitational Wave Detectors

A novel technique for enhancing optical spring that utilizes the Kerr effect to improve the sensitivity of gravitational wave detectors (GWDs) has recently been developed by scientists at Tokyo Tech. This innovative design uses optical non-linear effects from the Kerr effect in the Fabry-Perot cavity to achieve high signal amplification ratios and optical spring constant, with potential applications in not only GWDs but also in a range of optomechanical systems.

The detection of gravitational waves stands as one of the most significant achievements in modern physics. In 2017, gravitational waves from the merger of a binary neutron star were detected for the first time which uncovered crucial information about our universe, from the origin of short gamma-ray bursts to the formation of heavy elements. However, detecting gravitational waves emerging from post-merger remnants has remained elusive due to their frequency range lying outside the range of modern gravitational wave detectors (GWDs). These elusive waves hold important insights into the internal structure of neutron stars, and since these waves can be observed once every few decades by modern GWDs, there is an urgent need for next-generation GWDs.

One way to enhance the sensitivity of GWDs is signal amplification using an optical spring. Optical springs, unlike their mechanical counterparts, leverage radiation pressure force from light to mimic spring-like behavior. The stiffness of optical springs, such as in GWDs, is determined by the light power within the optical cavity. Thus, enhancing the resonant frequency of optical springs requires increasing the intracavity light power which, however, can result in thermally harmful effects and prevent the detector from working properly.

Friday, April 5, 2024

Chemical reactions can scramble quantum information as well as black holes

Rice University theorist Peter Wolynes and collaborators at the University of Illinois Urbana-Champaign have shown that molecules can be as formidable at scrambling quantum information as black holes.
Image Credit: Courtesy of Martin Gruebele; DeepAI was used in image production

If you were to throw a message in a bottle into a black hole, all of the information in it, down to the quantum level, would become completely scrambled. Because in black holes this scrambling happens as quickly and thoroughly as quantum mechanics allows, they are generally considered nature’s ultimate information scramblers.

New research from Rice University theorist Peter Wolynes and collaborators at the University of Illinois Urbana-Champaign, however, shows that molecules can be as formidable at scrambling quantum information as black holes. Combining mathematical tools from black hole physics and chemical physics, they have shown that quantum information scrambling takes place in chemical reactions and can nearly reach the same quantum mechanical limit as it does in black holes. The work is published online in the Proceedings of the National Academy of Sciences.

“This study addresses a long-standing problem in chemical physics, which has to do with the question of how fast quantum information gets scrambled in molecules,” Wolynes said. “When people think about a reaction where two molecules come together, they think the atoms only perform a single motion where a bond is made or a bond is broken.

Thursday, April 4, 2024

“It’s ultimately about predicting everything” – theory could be a map to hunted quantum materials

Photo Credit: Vendi Jukic Buca

A breakthrough in theoretical physics is an important step towards predicting the behavior of the fundamental matter of which our world is built. It can be used to calculate systems of enormous quantities of quantum particles, a feat thought impossible before. The University of Copenhagen research may prove of great importance for the design of quantum computers and could even be a map to superconductors that function at room-temperature.

On the fringes of theoretical physics, Berislav Buca investigates the nearly impossible by way of "exotic" mathematics. His latest theory is no exception. By making it possible to calculate the dynamics, i.e., movements and interactions, of systems with enormous quantities of quantum particles, it has delivered something that had been written off in physics. An impossibility made possible.

The unexpected presence of a white cat adorns the illustrations of Buca's research. Pulci the cat is his eye-catching muse. Arrows through the cat's body illustrate the quantum mechanical origin of the playful cat's movements – and this is precisely the relationship that Buca is trying to understand by making it possible to calculate the dynamics of the very smallest particles.

The breakthrough has reinvigorated an old and fundamental scientific question: Theoretically, if all behavior in the universe can be calculated by way of the laws of physics, can we then predict everything by calculating its smallest particles? 

Heat flows the secret to order in prebiotic molecular kitchen

Schematic visualization of heat flows in rock cracks.
Illustration Credit: Christof Mast

Life is complicated. What is true for our everyday existence also holds for the many complex processes that take place inside cells. Proteins constantly have to be synthesized, cell walls built, and DNA replicated. This can only work when reaction partners converge at the right time in sufficiently high concentrations while suffering little disruption from other substances. Over the course of billions of years, evolution has perfected these mechanisms and ensured that such vital processes occur with high efficiency at the correct place.

Circumstances were probably a lot more chaotic four billion years ago, when prebiotic reactions created the conditions for the emergence of the first lifeforms. For these reactions, too, it was necessary for the ‘right’ substances to be brought together at the ‘right’ time in one place, so that more complex biomolecules like RNA and amino acid chains could form. While such reactions are possible to recreate in the laboratory thanks to manual intermediate steps, it is highly challenging for them to come about in a simple ‘primordial soup’ – that is to say, a very dilute mixture of prebiotic building blocks. So how could nature create suitable conditions for the origin of life?

Physics of Complex Fluids: Ring Polymers Show Unexpected Motion Patterns Under Shear

Schematic of poly[2]catenane slip tumbling and bonded ring gradient tumbling.
Illustration Credit: Reyhaneh A. Farimani

An international research team is attracting the attention of experts in the field with computational results on the behavior of ring polymers under shear forces: Reyhaneh Farimani, University of Vienna, and her colleagues showed that for the simplest case of connected ring pairs, the type of linkage – chemically bonded vs. mechanically linked – has profound effects on the dynamic properties under continuous shear. In these cases, novel rheological patterns emerge. In addition to being recently published in the prestigious journal Physical Review Letters, the study received an "Editors' Suggestion" for its particular novelty.

The shearing of fluids – meaning the sliding of fluid layers over each other under shear forces – is an important concept in nature and in rheology, the science that studies the flow behavior of matter, including liquids and soft solids. Shear forces are lateral forces applied parallel to a material, inducing deformation or slippage between its layers. Fluid shear experiments allow the characterization of important rheological properties such as viscosity (resistance to deformation or flow) and thixotropy (decrease in viscosity under the influence of shear) which are important in applications ranging from industrial processes to medicine. Studies on the shear behavior of viscoelastic fluids, created by introducing polymers into Newtonian fluids, have already been conducted in recent years. However, a novel approach in the current research involves the consideration of polymer topology – the spatial arrangement and structure of molecules – by using ring polymers. Ring polymers are macromolecules composed of repeating units, forming closed loops without free ends. 

Wednesday, April 3, 2024

Self-assembly of complex systems: hexagonal building blocks are better

Professor Erwin Frey
Photo Credit: © Benjamin Asher / Ludwig-Maximilians-Universität München

Complex systems in nature, like their synthetic counterparts in technology, comprise a large number of small components that assemble of their own accord through molecular interactions. Gaining a better understanding of the principles and mechanisms of this self-assembly is important for the development of new applications in domains such as nanotechnology and medicine.

Professor Erwin Frey, Chair of Statistical and Biological Physics at LMU and member of the ORIGINS Excellence Cluster, and his research fellow Dr. Florian Gartner has now investigated an aspect of self-assembly that has received little attention before now: What role do the shape and the number of possible bonds between particles play? As the researchers report in the journal Physical Review X, their results show that hexagonal morphologies – in other words, six-sided structures – such as molecules with six binding sites are ideal for self-assembly.

Kapitza-Dirac effect used to show temporal evolution of electron waves

Time dependent interference fringes from the ultrafast Kapitza Dirac Effect. An electron wave packet is exposed to two counterpropagating ultrashort laser pulses. The time span from back to front is 10 pico seconds.
Illustration Credit: © Goethe University Frankfurt

One of the most fundamental interactions in physics is that of electrons and light. In an experiment at Goethe University Frankfurt, scientists have now managed to observe what is known as the Kapitza-Dirac effect for the first time in full temporal resolution. This effect was first postulated over 90 years ago, but only now are its finest details coming to light. 

It was one of the biggest surprises in the history of science: In the early days of quantum physics around 100 years ago, scholars discovered that the particles which make up our matter always behave like waves. Just as light can scatter at a double slit and produce scattering patterns, electrons can also display interference effects. In 1933, the two theorists Piotr Kapitza and Paul Dirac proved that an electron beam is even diffracted from a standing light wave (due to the particles' properties) and that interference effects as a result of the wave properties are to be expected. 

A German-Chinese team led by Professor Reinhard Dörner from Goethe University Frankfurt has succeeded in using this Kapitza-Dirac effect to visualize even the temporal evolution of the electron waves, known as the electrons' quantum mechanical phase. The researchers have now presented their results in the journal Science

Monday, April 1, 2024

‘Frankenstein design’ enables 3D printed neutron collimator

Images of the 3D printed “Frankenstein design” collimator show the “scars” where the individual parts are joined, which are clearly visible at right.
Photo Credit: Genevieve Martin/ORNL, U.S. Dept. of Energy

The time-tested strategy of divide and conquer took on a new, high-tech meaning during neutron experiments by scientists at the Department of Energy’s Oak Ridge National Laboratory. They discovered that the problems they faced while attempting to 3D print a one-piece collimator could be solved by instead developing a “Frankenstein design” involving multiple body parts – and some rather obvious scars.

Collimators are important components used in neutron scattering. Similar to X-rays, neutrons are used to study energy and matter at the atomic scale. Neutron collimators can be thought of as funnels that help guide neutrons toward a detector after they interact with experimental sample materials. These funnels primarily serve to reduce the number of stray neutrons that interfere with data collection, for example, neutrons that scatter off sample holders, or from other apparatuses used in the experiment such as high-pressure cells. 

During this process, most of the unwanted neutrons, those scattering from features other than the sample, enter channels inside the collimators at odd angles and are absorbed by channel walls, also referred to as blades. The blades act like the gutters on a bowling lane, which capture bowling balls that are not headed toward the pins.

Friday, March 29, 2024

Magnetic Avalanche Triggered by Quantum Effects

Christopher Simon holds a crystal of lithium holmium yttrium fluoride.
Photo Credit: Lance Hayashida/Caltech

Iron screws and other so-called ferromagnetic materials are made up of atoms with electrons that act like little magnets. Normally, the orientations of the magnets are aligned within one region of the material but are not aligned from one region to the next. Think of groups of tourists in Times Square pointing to different billboards all around them. But when a magnetic field is applied, the orientations of the magnets, or spins, in the different regions line up and the material becomes fully magnetized. This would be like the packs of tourists all turning to point at the same sign.

The process of spins lining up, however, does not happen all at once. Rather, when the magnetic field is applied, different regions, or so-called domains, influence others nearby, and the changes spread across the material in a clumpy fashion. Scientists often compare this effect to an avalanche of snow, where one small lump of snow starts falling, pushing on other nearby lumps, until the entire mountainside of snow is tumbling down in the same direction.

Thursday, March 28, 2024

New Nanoceramics Could Help Improve Smartphone and TV Displays

Nanoceramics are strong because they are made under high pressure.
Photo Credit: Anna Marinovich

Scientists from the Ural Federal University, together with colleagues from India and the Ural Branch of the Russian Academy of Sciences, have developed a nanoceramic that glows in three main colors - red, green, and blue. The new material is extremely strong because it is created under high pressure. Scientists believe that the characteristics of the new nanoceramics - luminescence, strength, and transparency - will be useful for creating screens with improved brightness and detail for smartphones, televisions, and other devices. The scientists published detailed information about the new nanoceramics and their properties in the journal Applied Materials Today

"We obtained optically transparent nanoceramics capable of luminescing in red, green, and blue colors. This was made possible by adding carbon particles that act as carbon nanodots. During the synthesis process, the carbon components are encapsulated between the ceramic particles, creating defects on their surface. We believe that these defects create several energy levels in the carbon nanodots, allowing the material to glow in different colors in the visible spectrum", explains Arseny Kiryakov, the co-author of the work, Associate Professor of the UrFU Department of Physical Techniques and Devices for Quality Control.

A Tiny Spot Leads to a Large Advancement in Nano-processing, Researchers Reveal

A conceptual illustration of single-shot laser processing by an annular-shaped radially polarized beam, focused on the back surface of a glass plate.
Illustration Credit: ©Y. Kozawa et al.

Focusing a tailored laser beam through transparent glass can create a tiny spot inside the material. Researchers at Tohoku University have reported on a way to use this small spot to improve laser material processing, boosting processing resolution.

Laser machining, like drilling and cutting, is vital in industries such as automotive, semiconductors, and medicine. Ultra-short pulse laser sources, with pulse widths from picoseconds to femtoseconds, enable precise processing at scales ranging from microns to tens of microns. But recent advancements demand even smaller scales, below 100 nanometers, which existing methods struggle to achieve.

The researchers focused on a laser beam with radial polarization, known as a vector beam. This beam generates a longitudinal electric field at the focus, producing a smaller spot than conventional beams.

Scientists have identified this process as promising for laser processing. However, one drawback is that this field weakens inside the material due to light refraction at the air-material interface, limiting its use.

A new type of cooling for quantum simulators

Tiantian Zhang and Maximilian Prüfer discussing measurements in the quantum lab
Photo Credit: Courtesy of Technische Universität Wien

Quantum experiments always have to deal with the same problem, regardless of whether they involve quantum computers, quantum teleportation or new types of quantum sensors: quantum effects break down very easily. They are extremely sensitive to external disturbances - for example, to fluctuations caused simply by the surrounding temperature. It is therefore important to be able to cool down quantum experiments as effectively as possible.

At TU Wien (Vienna), it has now been shown that this type of cooling can be achieved in an interesting new way: A Bose-Einstein condensate is split into two parts, neither abruptly nor particularly slowly, but with a very specific temporal dynamic that ensures that random fluctuations are prevented as perfectly as possible. In this way, the relevant temperature in the already extremely cold Bose-Einstein condensate can be significantly reduced. This is important for quantum simulators, which are used at TU Wien to gain insights into quantum effects that could not be investigated using previous methods.

Scientists propose a new way to search for dark matter

(Left) The new dark matter detection proposal looks for frequent interactions between nuclei in a detector and low-energy dark matter that may be present in and around Earth. (Right) A conventional direct detection experiment looks for occasional recoils from dark matter scattering.
Image Credit: Anirban Das, Noah Kurinsky and Rebecca Leane

Ever since its discovery, dark matter has remained invisible to scientists, despite the launch of multiple ultra-sensitive particle detector experiments around the world over several decades. 

Now, physicists at the Department of Energy’s (DOE) SLAC National Accelerator Laboratory are proposing a new way to look for dark matter using quantum devices, which might be naturally tuned to detect what researchers call thermalized dark matter.

Most dark matter experiments hunt for galactic dark matter, which rockets into Earth directly from space, but another kind might have been hanging around Earth for years, said SLAC physicist Rebecca Leane, who was an author on the new study. 

“Dark matter goes into the Earth, bounces around a lot, and eventually just gets trapped by the gravitational field of the Earth,” Leane said, bringing it into an equilibrium scientists refer to as thermalized. Over time, this thermalized dark matter builds up to a higher density than the few loose, galactic particles, meaning that it could be more likely to hit a detector. Unfortunately, thermalized dark matter moves much more slowly than galactic dark matter, meaning it would impart far less energy than galactic dark matter – likely too little for traditional detectors to see.

New machine to enhance understanding of nuclear weapons’ behavior

Bob Webster, deputy Laboratory director for Weapons (far right); Mike Furlanetto, Scorpius Advanced Sources and Detection project director (center); and Geoffrey Zehnder, project engineer (far left); discuss the prototype module Lab employees constructed for Scorpius' first accelerator cells and modules.
Photo Credit: Courtesy of Los Alamos National Laboratory

On March 7, assembly began at Los Alamos National Laboratory on a groundbreaking machine that will allow scientists to use real plutonium in experiments while studying the conditions immediately before the nuclear phase of a weapon's functioning. The machine will prove instrumental in the Laboratory's stockpile stewardship mission, which ensures the safety, security and reliability of the nation's nuclear weapons through computational tools and engineering test facilities, rather than underground testing.

Although the plutonium used will never reach criticality — the condition that forms a self-sustaining nuclear reaction — the tests performed as part of the Scorpius Advanced Sources and Detection (ASD) project will provide essential knowledge about how the key element in nuclear weapons behaves.

The components being built will be the first two accelerator cell modules for Scorpius.

"This means we have officially started building, and I am so looking forward to seeing this experiment in my lifetime," said Bob Webster, deputy Laboratory director for Weapons.

Wednesday, March 13, 2024

Explaining a supernova’s ‘string of pearls’

The simulation shows the shape of the gas cloud on the left and the vortices, or regions of rapidly rotating flow, on the right. Each ring represents a later time in the evolution of the cloud. It shows how a gas cloud that starts as an even ring with no rotation becomes a lumpy ring as the vortices develop. Eventually the gas breaks up into distinct clumps.
Illustration Credit: Michael Wadas, Scientific Computing and Flow Laboratory

Physicists often turn to the Rayleigh-Taylor instability to explain why fluid structures form in plasmas, but that may not be the full story when it comes to the ring of hydrogen clumps around supernova 1987A, research from the University of Michigan suggests.

In a study published in Physical Review Letters, the team argues that the Crow instability does a better job of explaining the “string of pearls” encircling the remnant of the star, shedding light on a longstanding astrophysical mystery.

“The fascinating part about this is that the same mechanism that breaks up airplane wakes could be in play here,” said Michael Wadas, corresponding author of the study and a graduate student in mechanical engineering at the time of the work.

In jet contrails, the Crow instability creates breaks in the smooth line of clouds because of the spiraling airflow coming off the end of each wing, known as wingtip vortices. These vortices flow into one another, creating gaps—something we can see because of the water vapor in the exhaust. And the Crow instability can do something that Rayleigh-Taylor could not: predict the number of clumps seen around the remnant.

“The Rayleigh-Taylor instability could tell you that there might be clumps, but it would be very difficult to pull a number out of it,” said Wadas, who is now a postdoctoral scholar at the California Institute of Technology.

New research on tungsten unlocks potential for improving fusion materials

Through a combination of modeling and state-of-the-art experimental techniques, researchers shed light on the complex behavior of phonons in tungsten. This advancement could lead to the development of more efficient and resilient fusion reactor materials.
Image Credit: Courtesy of SLAC National Accelerator Laboratory

In the pursuit of clean and endless energy, nuclear fusion is a promising frontier. But in fusion reactors, where scientists attempt to make energy by fusing atoms together, mimicking the sun's power generation process, things can get extremely hot. To overcome this, researchers have been diving deep into the science of heat management, focusing on a special metal called tungsten.

New research, led by scientists at the Department of Energy’s SLAC National Accelerator Laboratory, highlights tungsten's potential to significantly improve fusion reactor technology based on new findings about its ability to conduct heat. This advancement could accelerate the development of more efficient and resilient fusion reactor materials. Their results were published today in Science Advances.

"What excites us is the potential of our findings to influence the design of artificial materials for fusion and other energy applications," said collaborator Siegfried Glenzer, director of the High Energy Density Division at SLAC. “Our work demonstrates the capability to probe materials at the atomic scale, providing valuable data for further research and development."

Scientists reveal the first unconventional superconductor that can be found in mineral form in nature

A miassite crystal grown by Paul Canfield.
Photo Credit: Paul Canfield

Scientists from Ames National Laboratory have identified the first unconventional superconductor with a chemical composition also found in nature. Miassite is one of only four minerals found in nature that act as a superconductor when grown in the lab. The team’s investigation of miassite revealed that it is an unconventional superconductor with properties similar to high-temperature superconductors. Their findings further scientists’ understanding of this type of superconductivity, which could lead to more sustainable and economical superconductor-based technology in the future.

Superconductivity is when a material can conduct electricity without energy loss. Superconductors have applications including medical MRI machines, power cables, and quantum computers. Conventional superconductors are well understood but have low critical temperatures. The critical temperature is the highest temperature at which a material acts as a superconductor.

In the 1980s, scientists discovered unconventional superconductors, many of which have much higher critical temperatures. According to Ruslan Prozorov, a scientist at Ames Lab, all these materials are grown in the lab. This fact has led to the general belief that unconventional superconductivity is not a natural phenomenon.

Prozorov explained that it is difficult to find superconductors in nature because most superconducting elements and compounds are metals and tend to react with other elements, like oxygen. He said that miassite (Rh17S15) is an interesting mineral for several reasons, one of which is its complex chemical formula. “Intuitively, you think that this is something which is produced deliberately during a focused search, and it cannot possibly exist in nature,” said Prozorov, “But it turns out it does.”

Satellites for quantum communications

Tobias Vogl investigates single photon sources in 2D materials in an experimental setup
Photo Credit: Jens Meyer / University of Jena

Through steady advances in the development of quantum computers and their ever-improving performance, it will be possible in the future to crack our current encryption processes. To address this challenge, researchers at the Technical University of Munich (TUM) are participating in an international research consortium to develop encryption methods that will apply physical laws to prevent the interception of messages. To safeguard communications over long distances, the QUICK³ space mission will deploy satellites.

How can it be ensured that data transmitted through the internet can be read only by the intended recipient? At present our data are encrypted with mathematical methods that rely on the idea that the factorization of large numbers is a difficult task. With the increasing power of quantum computers, however, these mathematical codes will probably no longer be secure in the future.

Ultra-short light pulses enable high-precision "artificial nose"

Hongtao Hu and Vinzenz Stummer
Photo Credit: Courtesy of Technische Universität Wien

A new spectroscopy method has been developed at TU Wien: Using a series of laser pulses, chemical analyses can be carried out much faster and more precisely than before.

Whether you want to analyze environmental samples in nature or monitor a chemical experiment, you often need highly sensitive sensors that can "sniff out" even tiny traces of a certain gas with extreme accuracy. Variants of Raman spectroscopy are often used for this purpose: Different molecules react in very characteristic ways to light of different wavelengths. If you irradiate a sample with the appropriate light and measure exactly how the light is modified by the sample, you can find out whether the sample contains a certain gas or not.

However, scientists at TU Wien (Vienna) have now taken a significant step forward in this area: a new method has been developed to generate and precisely control suitable light for such experiments. This not only enables much greater accuracy than before; the method also works without moving parts and is therefore much faster than the best technologies to date. The method has now been published in the journal Light: Science and Applications.

Is life based on a seeming violation of Newton’s law in molecular interactions?

Interactions between molecules that are not equal and opposite, a seeming violation of Newton’s third law of motion, can occur naturally according to new research. A kinase enzyme adds a chemical modification to other molecules, resulting in a phosphorylated protein. Phosphatase enzymes remove the modifications, such that the kinases create products that are acted upon by phosphatases and vice versa. Researchers demonstrated that the kinase is attracted to the phosphatase, but the phosphatase is repelled by the kinase, in what is called a non-reciprocal interaction.
Illustration Credit: Niladri Sekhar Mandal / Pennsylvania State University

It turns out that every action may not have an equal and opposite reaction, despite what Newton’s third law of motion says, according to new research conducted by a team from Penn State and the University of Maine. The finding could offer insight into how certain molecular interactions could have evolved in a pre-life world.

The work was published in the journal Chem, and the researchers said this is the first demonstration of the mechanism by which these interactions occur at the molecular level. Last year’s discovery by researchers at Kyoto University that sperm movement does not cause an opposite reaction in its environment as it moves provided an example of a seeming violation of Newton’s third law of motion, but it did not address the mechanism.

“We all have heard the phrase ‘every action has an equal and opposite reaction,’ to describe Newton’s third law of motion, but we see examples that seemingly violate this every day, especially in the behavior of complex living systems small and large where there is constant input of energy,” said Ayusman Sen, Verne M. Willaman Professor of Chemistry in the Eberly College of Science at Penn State and one of the research team leaders. “An example at the larger scale is that a predator is attracted to its prey, but the prey is repelled by the predator. This type of interaction is called non-reciprocal, and we were interested to see if it also occurred in the much simpler interactions among molecules with constant energy input.”

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