Learn how engineers at the CERN LHC use TensorFlow to reconstruct thousands of particles in one go in this guest article by Jan Kieseler.
Levitation has long been a staple of magic tricks and movies. But in the lab, it’s no trick. Scientists can levitate droplets of liquid, though mixing them and observing the reactions has been challenging. The pay-off, however, could be big as it would allow researchers to conduct contact-free experiments without containers or handling that might affect the outcome. Now, a team reporting in ACS’ Analytical Chemistry has developed a method to do just that.
Scientists have made devices to levitate small objects, but most methods require the object to have certain physical properties, such as electric charge or magnetism. In contrast, acoustic levitation, which uses sound waves to suspend an object in a gas, doesn’t rely on such properties. Yet existing devices for acoustic levitation and mixing of single particles or droplets are complex, and it is difficult to obtain measurements from them as a chemical reaction is happening. Stephen Brotton and Ralf Kaiser wanted to develop a versatile technique for the contactless control of two chemically distinct droplets, with a set of probes to follow the reaction as the droplets merge.
Phosphorus, the element critical for life´s origin and life on Earth, may be even Venus.
Scientists studying the origin of life in the universe often focus on a few critical elements, particularly carbon, hydrogen, and oxygen. But two new papers highlight the importance of phosphorus for biology: an assessment of where things stand with a recent claim about possible life in the clouds of Venus, and a look at how reduced phosphorus compounds produced by lightning might have been critical for life early in our own planet’s history.
First a little biochemistry: Phosphine is a reduced phosphorus compound with one phosphorus atom and three hydrogen atoms. Phosphorus is also found in its reduced form in the phosphide mineral schreibersite, in which the phosphorus atom binds to three metal atoms (either iron or nickel). In its reduced form, phosphorus is much more reactive and useful for life than is phosphate, where the phosphorus atom binds to four oxygen atoms. Phosphorus is also the element that is most enriched in biological molecules as compared to non-biological molecules, so it’s not a bad place to start when you’re hunting for life.
Behind the scenes of the Electron-Ion Collider, green accelerators that waste no energy, and chiral magnetic effect results debuting this summer.
When the Electron Ion Collider received the go-ahead in January 2020, it became the only new major accelerator in the works anywhere in the world.
“All the stars aligned,” said Elke-Caroline Aschenauer, Brookhaven National Laboratory Staff Scientist and a leader in developing the EIC plans. “We have the technology to build this unique particle accelerator and detector to do the measurements that, together with the underlying theory, can for the first time provide answers to longstanding fundamental questions in nuclear physics.”
Conducting atom-optical experiments in space is interesting for fundamental physics and challenging due to different environment compared to ground. Here the authors report matter-wave interferometry in space using atomic BECs in a sounding rocket.
Thermoelectrics directly convert heat into electricity and power a wide array of items—from NASA’s Perseverance rover currently exploring Mars to travel coolers that chill beverages.
A Clemson University physicist has joined forces with collaborators from China and Denmark to create a new and potentially paradigm-shifting high-performance thermoelectric compound.
A material’s atomic structure, which is how atoms arrange themselves in space and time, determines its properties. Typically, solids are crystalline or amorphous. In crystals, atoms are in an orderly and symmetrical pattern. Amorphous materials have randomly distributed atoms.
KAIST researchers have developed a novel nanofiber production technique called ‘centrifugal multispinning’ that will open the door for the safe and cost-effective mass production of high-performance polymer nanofibers. This new technique, which has shown up to a 300 times higher nanofiber production rate per hour than that of the conventional electrospinning method, has many potential applications including the development of face mask filters for coronavirus protection.
Nanofibers make good face mask filters because their mechanical interactions with aerosol particles give them a greater ability to capture more than 90% of harmful particles such as fine dust and virus-containing droplets.
The impact of the COVID-19 pandemic has further accelerated the growing demand in recent years for a better kind of face mask. A polymer nanofiber-based mask filter that can more effectively block harmful particles has also been in higher demand as the pandemic continues.
Spin waves could unlock the next generation of computer technology, a new component allows physicists to control them.
Researchers at Aalto University have developed a new device for spintronics. The results have been published in the journal Nature Communications, and mark a step towards the goal of using spintronics to make computer chips and devices for data processing and communication technology that are small and powerful.
Traditional electronics uses electrical charge to carry out computations that power most of our day-to-day technology. However, engineers are unable to make electronics do calculations faster, as moving charge creates heat, and we’re at the limits of how small and fast chips can get before overheating. Because electronics can’t be made smaller, there are concerns that computers won’t be able to get more powerful and cheaper at the same rate they have been for the past 7 decades. This is where spintronics comes in.
Nobel laureate in physics Richard Feynman once described turbulence as “the most important unsolved problem of classical physics.”
Understanding turbulence in classical fluids like water and air is difficult partly because of the challenge in identifying the vortices swirling within those fluids. Locating vortex tubes and tracking their motion could greatly simplify the modeling of turbulence.
But that challenge is easier in quantum fluids, which exist at low enough temperatures that quantum mechanics — which deals with physics on the scale of atoms or subatomic particles — govern their behavior.
Majorana modes are, however, notoriously elusive. In part, this is because it is hard to create the conditions required to generate them in an experimental setting. Many theoretical proposals have predicted MZMs should be present in quasi-2D materials, which consist of a small number of 2D layers stacked on top of each other. However, all previous proposals required heterostructures – that is, structures where the stacked layers have differing material composition and structure. Practically, these heterostructures are difficult if not downright impossible to grow.
To make matters worse, Majorana modes can only be observed indirectly. Like detectives trying to catch a culprit with only circumstantial evidence, physicists have a hard time ruling out alternative explanations for the phenomena they observe. This has led to high-profile premature claims of Majorana discovery, including Microsoft Quantum Lab’s recent retraction of a Nature paper in which they purported to observe MZMs in nanowires.
In their new work, Zhang and his coauthor show that Majorana modes should be present in a much simpler setting: thin films of an iron-based superconducting material. Like previous proposals, the system they study is quasi-2D, but crucially all layers are of the same kind. The iron-based thin films naturally accommodate Majorana fermions that are helical – left or right-handed – and move along the edges of the system in their preferred direction. This is due to a special “time-reversal” symmetry, wherein interchanging the left-moving and right-moving quasiparticles makes it look like time is propagating backwards in the system.
