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Category: quantum physics

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.

Physicists just found a tiny flaw in time itself

Physicists are rethinking one of quantum mechanics’ biggest puzzles: how fuzzy possibilities become definite reality. New research suggests that spontaneous “collapse” processes—possibly linked to gravity—could subtly blur time itself. This wouldn’t affect clocks we use today, but it reveals a hidden limit to how precise time can ever be. The findings open a new path toward uniting quantum physics with gravity.

Mobile qubits on a chip move us a step closer to everyday quantum computers

For years, quantum computers have lived under a huge bubble of hype, promising to revolutionize numerous fields, from medicine and battery design to materials science and cybersecurity. But realizing their potential on any serious practical level will only be possible if large numbers of qubits (the basic units of information) can interact with each other with high precision and flexibility.

One of the main things holding that back is that traditional qubits are fixed in place, meaning they can only talk to their immediate neighbors. But in a new paper published in Nature, scientists describe how they overcame this limitation by using mobile qubits that can be moved around a chip. Lars R. Schreiber at the JARA-FIT Institute for Quantum Information in Germany has also published a News & Views piece in the same journal.

Testing quantum collapse theory with the XENONnT dark matter detector

Theories of quantum mechanics predict that some particles can exist in superpositions, which essentially means that they can be in more than one state at once. When a particle’s state is measured, however, this superposition appears to “collapse” into a single outcome; a phenomenon often referred to as the “measurement problem.”

In recent years, various theoretical physicists have tried to explain why and how this collapse happens. This led to the introduction of various models, such as the Continuous Spontaneous Localization (CSL) and Diósi–Penrose models.

Both these models predict that spontaneous quantum collapse would also lead to the emission of faint X-ray radiation. The experimental detection of this radiation would thus provide evidence of these theories’ validity.

Quantum metallurgy: Electron crystals deform and melt

In a process analogous to how solids melt into liquids, the electrons in many different metals form crystal-like patterns that can deform and melt, opening new pathways for neuromorphic computing and superconductors, University of Michigan Engineering researchers have found.

“Our work shows that these quantum structures, which are often thought to have a highly ordered structure, actually span a continuum of disorder that could be leveraged to engineer and control these materials,” said Robert Hovden, associate professor of materials science and engineering and corresponding author of the study published in Matter.

“Metallurgists often control defects, or disorder, in metals to produce specific properties,” Hovden said. “A similar approach might help us harness the potential of quantum materials in future devices. Quantum metallurgy could be the future.”

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