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Category: particle physics – Page 178

A Breakthrough on the Edge: One Step Closer to Topological Quantum Computing

Researchers at the University of Cologne have achieved a significant breakthrough in quantum materials, potentially setting the stage for advancements in topological superconductivity and robust quantum computing / publication in Nature Physics.

A team of experimental physicists led by the University of Cologne have shown that it is possible to create superconducting effects in special materials known for their unique edge-only electrical properties. This discovery provides a new way to explore advanced quantum states that could be crucial for developing stable and efficient quantum computers. Their study, titled ‘Induced superconducting correlations in a quantum anomalous Hall insulator’, has been published in Nature Physics.

Superconductivity is a phenomenon where electricity flows without resistance in certain materials. The quantum anomalous Hall effect is another phenomenon that also causes zero resistance, but with a twist: it is confined to the edges rather than spreading throughout. Theory predicts that a combination of superconductivity and the quantum anomalous Hall effect will give rise to topologically-protected particles called Majorana fermions that will potentially revolutionize future technologies such as quantum computers. Such a combination can be achieved by inducing superconductivity in the edge of a quantum anomalous Hall insulator that is already resistance-free. The resultant chiral Majorana edge state, which is a special type of Majorana fermions, is a key to realizing ‘flying qubits’ (or quantum bits) that are topologically protected.

Cosmic Correlations Show How Visible Matter Shapes the Universe

On cosmological scales, dark matter so dominates the gravitational behavior of the Universe that, to first approximation, researchers can ignore the gravitational pull of visible matter when simulating the large-scale distribution of galaxies. Still, determining subtle yet important properties of the Universe, such as variations in the amount of dark energy, requires knowing the exact locations of the subatomic particles (baryons) that make up the Universe’s visible matter, as well as what these particles are doing and how they are interacting with dark matter. Now Tassia Ferreira of the University of Oxford, UK, and her collaborators have identified a statistical correlation between two observable features of the Universe that has the potential to reveal the extent of astronomers’ understanding of how baryons shape the large-scale structure of the cosmos [1].

The uncovered correlation is between variations across the sky of the amount of “cosmic shear” and the intensity of the diffuse background of cosmic x rays. Cosmic shear is the apparent warping of the shapes and positions of distant galaxies by the gravitational pulls of intervening clusters of galaxies and other large concentrations of matter. The x-ray background emanates mostly from hot, thin plasma held in the gravitational potentials of those same intervening structures.

Ferreira and her collaborators found that the cosmic shear and the x-ray background are strongly correlated. This correlation is unsurprising given that both features are manifestations of the same dark-matter structures. But the researchers also found that the baryons’ locations influenced how well various physical models reproduced the correlation. One important factor is the amount of plasma (which is made of baryons) that supermassive black holes expel into intergalactic space.

Researchers trap atoms, force them to serve as photonic transistors

This could be the road to quantum computation.

“In contrast, solid-state emitters embedded in a photonic circuit are hardly ‘the same’ due to slightly different surroundings influencing each emitter. It is much harder for many solid-state emitters to build up phase coherence and collectively interact with photons like cold atoms. We could use cold atoms trapped on the circuit to study new collective effects,” Hung continues.

The platform demonstrated in this research could provide a photonic link for future distributed quantum computing based on neutral atoms. It could also serve as a new experimental platform for studying collective light-matter interactions and for synthesizing quantum degenerate trapped gases or ultracold molecules.

“Unlike electronic transistors used in daily life, our atom-coupled integrated photonic circuit obeys the principles of quantum superposition,” explains Hung. “This allows us to manipulate and store quantum information in trapped atoms, which are quantum bits known as qubits. Our circuit may also efficiently transfer stored quantum information into photons that could ‘fly’ through the photonic wire and a fiber network to communicate with other atom-coupled integrated circuits or atom-photon interfaces. Our research demonstrates a potential to build a based on cold-atom integrated nanophotonic circuits.”

Cosmic microwave background experiments could probe connection between cosmic inflation, particle physics

Various large-scale astrophysical research projects are set to take place over the next decade, several of which are so-called cosmic microwave background (CMB) experiments. These are large-scale scientific efforts aimed at detecting and studying CMB radiation, which is essentially thermal radiation originating from the early universe.

Scientists pin down the origins of the moon’s tenuous atmosphere

While the moon lacks any breathable air, it does host a barely-there atmosphere. Since the 1980s, astronomers have observed a very thin layer of atoms bouncing over the moon’s surface. This delicate atmosphere—technically known as an “exosphere”—is likely a product of some kind of space weathering. But exactly what those processes might be has been difficult to pin down with any certainty.

New Microscope Unlocks Hidden Atomic Architecture in Advanced Materials

Researchers at the University of Sydney have developed a new microscopy method that uses atom probe tomography to observe atomic-scale changes in materials. This advancement enhances understanding of materials properties and could lead to stronger alloys for aerospace, more efficient semiconductors, and better magnets for motors.

Researchers at the University of Sydney have developed a new microscopy method using atom probe tomography to explore atomic-level changes in materials, promising significant advances in materials science and engineering.

A new microscopy technique enables researchers to observe minute changes in the atomic structure of crystalline materials, such as advanced steels used in shipbuilding and custom silicon for electronics. This method has the potential to enhance our understanding of the fundamental origins of material properties and behavior.

Physicists report new insights into exotic particles key to magnetism

MIT physicists and colleagues report new insights into exotic particles key to a form of magnetism that has attracted growing interest because it originates from ultrathin materials only a few atomic layers thick. The work, which could impact future electronics and more, also establishes a new way to study these particles through a powerful instrument at the National Synchrotron Light Source II at Brookhaven National Laboratory.

Experiment uses quantum techniques to stimulate photons, enhancing search for dark matter

Scientists cannot observe dark matter directly, so to “see” it, they look for signals that it has interacted with other matter by creating a visible photon. However, signals from dark matter are incredibly weak. If scientists can make a particle detector more receptive to these signals, they can increase the likelihood of discovery and decrease the time to get there. One way to do this is to stimulate the emission of photons.

Quantum Computers Need a Quantum Internet: Here’s Why

Research on quantum internet technology highlights the challenge of producing stable photons at telecom wavelengths, with recent studies focusing on material improvements and advanced emission techniques to enhance quantum network efficiency.

Computers benefit greatly from being connected to the internet, so we might ask: What good is a quantum computer without a quantum internet?

The secret to our modern internet is the ability for data to remain intact while traveling over long distances, and the best way to achieve that is by using photons. Photons are single units (“quanta”) of light. Unlike other quantum particles, photons interact very weakly with their environment. That stability also makes them extremely appealing for carrying quantum information over long distances, a process that requires maintaining a delicate state of entanglement for an extended period of time. Such photons can be generated in a variety of ways. One possible method involves using atomic-scale imperfections (quantum defects) in crystals to generate single photons in a well-defined quantum state.

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