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Category: particle physics – Page 222

Year 1997 Basically this detailed the use of magnetism to levitate frogs.

When pigs fly? That could be sooner than you think. A group of researchers in the Netherlands and in England has made a frog levitate in a magnetic field. Although the feat might seem no more than a curiosity, researchers say that the floating amphibians may lead the way to a cheap alternative to space-based science experiments.

Many materials are diamagnetic—that is, when placed near a magnet, their atoms fight the magnetic field, and the object tries to scoot away. If such a material is placed in a strong enough magnetic field, it levitates. Superconductors, for example, are perfect diamagnets and can levitate over even weak magnets, which is why levitating trains like those in Japan can fly over the tracks. Organic material like living cells is very weakly diamagnetic, says J. C. Maan, a physicist at the University of Nijmegen in the Netherlands. So he and colleagues employed a very strong magnet (chiefly used for crystallography experiments) to float the frog. It took 16 teslas—a very powerful field indeed—to lift the confused amphibian off the ground.

“It’s a little surprising how easy it is to do this,” says James Brooks, a physicist at the National High Magnetic Field Laboratory in Tallahassee, Florida. “It’s not incredibly exotic equipment. Any scientist who is awake will ask ‘What can I do with this?’” Brooks notes that the magnetic fields might provide a way to study materials in milligravity—without sending them into space—because the levitating object is in a net zero field. Researchers could study the effects of microgravity on crystal growth and also on the growth and development of living cells, without costly space missions.

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Glass nanoparticles trapped by lasers in extreme vacuum are considered a promising platform for exploring the limits of the quantum world. Since the advent of quantum theory, the question at which sizes an object starts being described by the laws of quantum physics rather than the rules of classical physics has remained unanswered.

A team formed by Lukas Novotny (ETH Zurich), Markus Aspelmeyer (University of Vienna), Oriol Romero-Isart (University of Innsbruck), and Romain Quidant (Zurich) is attempting to answer precisely this question within the ERC-Synergy project Q-Xtreme. A crucial step on the way to this goal is to reduce the energy stored in the motion of the nanoparticle as much as possible, i.e. to cool the particle down to the so-called quantum ground-state.

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Since the advent of quantum mechanics, the field of physics has been divided into two distinct areas: classical physics and quantum physics. Classical physics deals with the movements of everyday objects in the macroscopic world, while quantum physics explains the strange behaviors of tiny elementary particles in the microscopic world.

Many solids and liquids are made up of particles that interact with each other at close distances, leading to the creation of “quasiparticles.” Quasiparticles are stable excitations that act as weakly interacting particles. The concept of quasiparticles was introduced in 1941 by Soviet physicist Lev Landau and has since become a crucial tool in the study of quantum matter. Some well-known examples of quasiparticles include Bogoliubov quasiparticles in superconductivity, excitons in semiconductors.

Semiconductors are a type of material that has electrical conductivity between that of a conductor (such as copper) and an insulator (such as rubber). Semiconductors are used in a wide range of electronic devices, including transistors, diodes, solar cells, and integrated circuits. The electrical conductivity of a semiconductor can be controlled by adding impurities to the material through a process called doping. Silicon is the most widely used material for semiconductor devices, but other materials such as gallium arsenide and indium phosphide are also used in certain applications.

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Researchers are coming to understand that the best performing materials in sustainable energy applications, such as converting sunlight or waste heat to electricity, often use collective fluctuations of clusters of atoms within a much larger structure. This process is often referred to as “dynamic disorder.”

Understanding dynamic disorder in materials could lead to more energy-efficient thermoelectric devices, such as solid-state refrigerators and , and also to better recovery of useful energy from , such as car exhausts and power station exhausts, by converting it directly to electricity. A was able to take heat from radioactive plutonium and convert it to electricity to power the Mars Rover when there was not enough sunlight.

When materials function inside an operating device, they can behave as if they are alive and dancing—parts of the material respond and change in amazing and unexpected ways. This dynamic disorder is difficult to study because the clusters are not only so small and disordered, but they also fluctuate in time. In addition, there is “boring” non-fluctuating disorder in materials that researchers aren’t interested in because the disorder doesn’t improve properties. Until now, it has been impossible to see the relevant dynamic disorder from the background of less relevant static disorder.

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After 85 years of searching, researchers have confirmed the existence of a massless particle called the Weyl fermion for the first time ever. With the unique ability to behave as both matter and anti-matter inside a crystal, this strange particle can create electrons that have no mass.

The discovery is huge, not just because we finally have proof that these elusive particles exist, but because it paves the way for far more efficient electronics, and new types of quantum computing. “Weyl fermions could be used to solve the traffic jams that you get with electrons in electronics — they can move in a much more efficient, ordered way than electrons,” lead researcher and physicist M. Zahid Hasan from Princeton University in the US told Anthony Cuthbertson over at IBTimes. “They could lead to a new type of electronics we call ‘Weyltronics’.”

So what exactly is a Weyl fermion? Although we’re often taught in high school science that the Universe is made up of atoms, from a particle physics point of view, everything is actually made up of fermions and bosons. Put very simply, fermions are the building blocks that make up all matter, such as electrons, and bosons are the things that carry force, such as photons.

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Protons may have more “charm” than we thought, new research suggests.

A proton is one of the subatomic particles that make up the nucleus of an atom. As small as protons are, they are composed of even tinier elementary particles known as quarks, which come in a variety of “flavors,” or types: up, down, strange, charm, bottom, and top.

Typically, a proton is thought to be made of two up quarks and one down quark. But a new study finds it’s more complicated than that.

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For the first time, an experiment was able to demonstrate that it isn’t just identical quantum particles that can become entangled, but particles with opposite electric charges, too. (The π+ and the π–, for what it’s worth, are one another’s antiparticle.) The technique of passing two heavy nuclei very close to one another at nearly the speed of light allows for photons, arising from the electromagnetic field of each nucleus, to interact with the other nucleus, occasionally forming a rho particle that decays into two pions. When both nuclei do this at once, the entanglement can be seen, and the radius of the atomic nucleus can be measured.

It’s also remarkable that measuring the size of the nucleus through this method, which uses the strong force rather than the electromagnetic force, gives a different, larger result than one would get by using the nuclear charge radius. As lead author on the study, James Brandenburg, put it, “Now we can take a picture where we can really distinguish the density of gluons at a given angle and radius. The images are so precise that we can even start to see the difference between where the protons are and where the neutrons are laid out inside these big nuclei.” We now have a promising method to probe the internal structure of these complex, heavy nuclei, with more applications, no doubt, soon to come.

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