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Category: quantum physics – Page 16

‘Elegant triangle’ experiment suggests quantum internet may be closer than we think

For more than 60 years, Bell’s theorem has been the gold standard for demonstrating that quantum mechanics defies the rules of classical physics. Now, an international team of researchers, including Constructor University Professor Dr. Nicolas Gisin, has extended this principle to new limits, using an “elegant triangle” to reveal new forms of quantum nonlocality that specifically emerge in multi-node quantum networks.

The study, published in Physical Review Letters, opens a new frontier in our understanding of how quantum correlations behave in realistic network settings, one that could help usher in the age of a quantum internet.

“This is not simply a more elaborate version of Bell’s theorem applied to networks, it’s something genuinely new that only emerges when multiple independent quantum sources interact through entangled measurements,” explained Dr. Gisin, who collaborated on the experiment with researchers from China, France and Austria.

Researchers find coherent ferrons—polarization waves with potential across quantum and telecom applications

In new research published in Nature Materials, a team of researchers led by Columbia University chemist Xiaoyang Zhu, in collaboration with fellow Columbians Xavier Roy, Milan Delor, Dmitri Basov, and James McIver, has observed coherent ferrons for the first time.

Ferrons are electronic quasiparticles, predicted since the 1960s, that carry polarization. The oscillating polarization wave that the team, led by Columbia postdocs Jeongheon Choe and Taketo Handa, observed represents a new type of information carrier that could prove much faster than conventional electronics.

In ferroelectric materials, the dipole moments of unit cells line up, becoming polarized. Collective excitation of these dipoles creates the ferron quasiparticle, which has an inherent dipole moment. This means one side of each tiny particle is slightly more negatively charged than the other. Ferrons are similar to another quasiparticle that’s been of interest to Zhu and colleagues in recent years: magnons.

New ‘trick’ fixes major flaw in neutral-atom quantum computers — inching us closer to a superpowerful system

A new “geometry‑based” quantum swap gate makes neutral‑atom computers far less sensitive to laser noise — bringing large‑scale, stable quantum processors a step closer to reality.

Good vibrations for quantum communications: Engineers couple single phonon to single atomic spin

Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have demonstrated, for the first time, a single quantum of vibrational energy interacting with a single atomic spin, seeding a pathway to quantum technologies that use sound as an information carrier, instead of light or electricity. The results are published in Nature.

Led by Marko Lončar, the Tiantsai Lin Professor of Electrical Engineering, the researchers engineered a nanometer-scale mechanical resonator around a single color-center spin qubit in diamond. These color centers, atomic defects in the diamond’s crystal structure, act as quantum memory capable of storing quantum information. The researchers’ new system can host sufficiently strong spin-phonon interactions for quantum information storage—a key challenge thus far in the field.

“At the heart of the experiment is a phonon—the smallest possible unit of sound,” Lončar said. “When we listen to music, it takes countless phonons working together to move our eardrums and maybe even get us spinning on the dance floor. But qubits are far more sensitive: a single phonon can be enough to change their quantum state—to excite them, or, as in our experiment, to help them relax.”

Versions of You in Other Universes May Be Subtly Affecting Your Destiny, Oxford Physicist Says

You may think you’re the protagonist of your own story. According to Oxford physicist Vlatko Vedral, however, you’re more like a puppet — whose strings are being pulled into a million parallel universes at any given time.

As Vedral argues in a recent issue of Popular Mechanics, the pop-sci version of the “observer effect” — where the act of observation or measurement affects a system — gets the cause-and-effect backward. The typical story goes something like this: quantum objects hang out in multiple states at once, until some observer glances over. At this point, the multiple states collapse and only one is left, an assumption that can lead various woo-woo interpretations, like that we create reality simply by observing it.

Physics, Verdal says, does not support that idea. That collapse effect isn’t a special power of human consciousness, but rather a fact of physics that says interactions — any interaction — forces a quantum system to commit to a definite state.

Quantum battery charges in a quadrillionth of a second with a laser — larger prototypes could last for years after charging for just a minute

This allows all molecules within the battery to charge at a constant speed, no matter its size. The more molecules involved, the more efficiently energy is absorbed throughout the system, meaning charging times actually decrease in real terms as the battery size increases.

“Similar to conventional batteries, quantum batteries charge, store and discharge energy,”, explained Hutchinson in the statement. “But while everyday batteries rely on chemical reactions, quantum batteries leverage properties of quantum mechanics. The advantage of quantum is that the system absorbs light in a single, giant ‘super absorption’ event and this charges the battery faster.”

Quantum Breakthrough Turns Simple Forces Into Powerful New Interactions

Scientists have created a new way to generate powerful quantum interactions, achieving the first-ever demonstration of quadsqueezing.

This breakthrough makes previously hidden quantum effects visible and usable for advanced technologies.

Oxford scientists demonstrate first-ever quadsqueezing quantum interaction.

Quantum Metallurgy Might Be A New Frontier For Superconducting Materials And Artificial Neurons

“The key emphasis here is that disorder is a really important parameter. It’s this tunable thing when we’re playing with quantum phases.”

Modifying the structure of electron crystals is extremely exciting. In superconductors, materials that transport electricity without resistance, the superconducting state can coincide with changes to charge-density waves.

“When we’re doing basic science in these really exotic materials and exotic phases, dramatically new innovations happen,” Hovden told IFLScience. “Technological revolutions like the semiconductor, transistor, and computer happened because we did basic science on atomic structures, on atoms, on matter.”

Team steers electron spin ballistically in graphene

Researchers at The University of Manchester’s National Graphene Institute have shown that electrons in ultra-clean graphene can be steered with high precision while keeping their spin information intact, a key requirement for future low-power electronics and quantum devices.

In a new study published in Physical Review X, the team demonstrates how electrons can travel ballistically, i.e. without experiencing any scattering or resistance, over micrometer distances in graphene at low temperature and maintain spin coherence all the way up to room temperature.

By using a technique known as transverse magnetic focusing (TMF), they were able to bend electron trajectories like light rays traversing a lens and show that these curved paths carry a clear spin signature.

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