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Category: particle physics – Page 534

One of the enduring sci-fi moments of the big screen—R2-D2 beaming a 3D image of Princess Leia into thin air in “Star Wars”—is closer to reality thanks to the smallest of screens: dust-like particles.

Scientists have figured out how to manipulate nearly unseen specks in the air and use them to create 3D images that are more realistic and clearer than holograms, according to a study in Wednesday’s journal Nature. The study’s lead author, Daniel Smalley, said the new technology is “printing something in space, just erasing it very quickly.”

In this case, scientists created a small butterfly appearing to dance above a finger and an image of a graduate student imitating Leia in the Star Wars scene.

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In a sci-fi feeling first, engineers at the University of Bristol used the world’s most powerful acoustic tractor beam to demonstrate that it’s possible to stably contain objects larger than the wavelength of sound.

In other words, they were able to levitate objects notably larger than what’s ever been possible before; a feat that theoretically opens up the potential of one day levitating humans.

Acoustic tractor beams use sound, or more specifically soundwaves, to hold particles in mid-air. While magnetic levitation also exists, acoustic levitation tends to work better for handling liquids and solids.

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An idea for an experiment that could unite the stubborn fields of quantum mechanics and general relativity has been given new life by two groups of physicists from the UK.

The fact that quantum theory doesn’t play well with gravity is a massive stumbling block in physics, one that has long eluded some of the greatest minds in science.

Quantum mechanics is the modelling of discrete particles as probabilities that don’t truly exist until we’ve nailed down a measurement. Not that quantum physics is vague – a century of testing has made it one of the most robust theories in science.

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Physicists have created what they say is the first device that’s capable of generating particles that behave as if they have negative mass.

The device generates a strange particle that’s half-light/half-matter, and as if that isn’t cool enough, it could also be the foundation for a new kind of laser that could operate on far less energy than current technologies.

This builds on recent theoretical work on the behaviour of something called a polariton, which appears to behave as if it has negative mass – a mind-blowing property that sees objects move towards the force pushing it, instead of being pushed away.

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There’s an unidentified source of infrared throughout the universe. By looking at the specific wavelengths of the light, scientists think that come from carbon—but not just any carbon, a special kind where the atoms are arranged in multiple hexagonal rings. No one has been able to spot one of these multi-ring “polycyclic aromatic hydrocarbons,” or PAHs in space—even though the infrared emissions imply that these PAHs should make up 10 percent of the universe’s carbon. Now, scientists have found a new hint.

A team of researchers in the United States and Russia are now reporting spotting a special single-carbon-ring-containing molecule, called benzonitrile, with a radio telescope in a part of space called the Taurus Molecular Cloud-1. Benzonitrile only has one hexagonal ring of carbon, so it’s not a poly cyclic aromatic hydrocarbon itself. But it could be a potential precursor and could help explain the mysterious radiation.

Before you even ask, yes, this “aromatic” benzonitrile molecule has a smell. “I can tell you from personal experience it smells like almonds,” study first author Brett McGuire from the National Radio Astronomy Observatory told Gizmodo, who has encountered the molecule in the lab.

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A team from Griffith’s Centre for Quantum Dynamics in Australia have demonstrated how to rigorously test if pairs of photons — particles of light — display Einstein’s “spooky action at a distance”, even under adverse conditions that mimic those outside the lab.

They demonstrated that the effect, also known as , can still be verified even when many of the photons are lost by absorption or scattering as they travel from source to destination through an optical fiber channel. The experimental study and techniques are published in the journal Science Advances.

Quantum nonlocality is important in the development of new global information networks, which will have transmission security guaranteed by the laws of physics. These are the networks where powerful quantum computers can be linked.

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To the best of our knowledge, we humans can only experience this world in three spatial dimensions (plus one time dimension): up and down, left and right, and forward and backward. But in two physics labs, scientists have found a way to represent a fourth spatial dimension.

This isn’t a fourth dimension that you can disappear into or anything like that. Instead, two teams of physicists engineered special two-dimensional setups, one with ultra-cold atoms and another with light particles. Both cases demonstrated different but complementary outcomes that looked the same as something called the “quantum Hall effect” occurring in four dimensions. These experiments could have important implications to fundamental science, or even allow engineers to access higher-dimension physics in our lower-dimension world.

“Physically, we don’t have a 4D spatial system, but we can access 4D quantum Hall physics using this lower-dimensional system because the higher-dimensional system is coded in the complexity of the structure,” Mikael Rechtsman, professor at Penn State University behind one of the papers, told Gizmodo. “Maybe we can come up with new physics in the higher dimension and then design devices that take advantage the higher-dimensional physics in lower dimensions.”

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For the first time, physicists have built a two-dimensional experimental system that allows them to study the physical properties of materials that were theorized to exist only in four-dimensional space. An international team of researchers from Penn State, ETH Zurich in Switzerland, the University of Pittsburgh, and the Holon Institute of Technology in Israel have demonstrated that the behavior of particles of light can be made to match predictions about the four-dimensional version of the “quantum Hall effect”—a phenomenon that has been at the root of three Nobel Prizes in physics—in a two-dimensional array of “waveguides.”

A paper describing the research appears January 4, 2018 in the journal Nature along with a paper from a separate group from Germany that shows that a similar mechanism can be used to make a gas of exhibit four-dimensional quantum Hall as well.

“When it was theorized that the quantum Hall effect could be observed in four-dimensional space,” said Mikael Rechtsman, assistant professor of physics and an author of the paper, “it was considered to be of purely theoretical interest because the real world consists of only three spatial dimensions; it was more or less a curiosity. But, we have now shown that four-dimensional quantum Hall physics can be emulated using photons—particles of light—flowing through an intricately structured piece of glass—a array.”

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