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Category: quantum physics

Method for measuring energy amounts less than a trillionth of a billionth of a joule could boost quantum computing

The fundamentals of quantum mechanics are minuscule. Scientists constantly home in on finer resolutions to measure, quantify, and control these fundamentals, like photons that carry light and have no mass unless they are moving. The more precise the measurement, the more possibilities for better quantum technology or the ability to detect elusive dark-matter axions in deep space.

Now, researchers in Finland have successfully used a calorimeter, a type of ultra-sensitive heat-based energy sensor, to detect energy levels below one zeptojoule, or a trillionth of a billionth of a joule. For context, a zeptojoule is approximately the amount of work it takes for a red blood cell to move a nanometer, or a billionth of a meter, upwards in Earth’s gravity.

The team, led by Academy Professor Mikko Möttönen at Aalto University, together with industry collaborator IQM and the Technical Research Centre of Finland (VTT), used a novel technique to achieve the milestone measurement. The study is published in the journal Nature Electronics.

Resilient quantum sensor monitors Earth’s magnetic field from space for 10 months

From navigation to solar weather forecasting, many different areas of research require space-based sensors to measure Earth’s magnetic field as accurately as possible at any given moment. So far, however, existing sensors have consistently struggled with effects including drift, interference from the spacecraft itself, and the harsh conditions of orbit.

Through new research published in Physical Review Applied, Yarne Beerden and colleagues at Hasselt University in Belgium have developed a diamond-based quantum sensor which could offer a promising solution to these problems.

Quantum dot emitter delivers near-identical telecom photons at 40 million per second

Quantum technologies, devices that perform specific functions leveraging quantum mechanical effects, could soon outperform their classical counterparts on some tasks. Quantum emitters, devices that release individual particles of light (i.e., photons), are central components of many of these technologies, including quantum communication systems and quantum computers.

To enable the reliable operation of quantum technologies, emitters should emit photons with high consistency and coherence. In other words, they should ensure that the quantum properties of emitted photons remain stable and predictable.

Researchers at University of Copenhagen’s Niels Bohr Institute, Ruhr-University Bochum, University of Basel and Sparrow Quantum ApS recently developed a new photon emitter based on quantum dots, tiny structures that can trap electrons in confined regions and enable the controlled emission of individual photons.

Hybrid AI architecture could turn neuromorphic systems into reliable discovery machines

The artificial intelligence (AI) machines that guide the world can be grouped into three main categories: inference machines, learning machines and discovery machines. Researchers at Washington University in St. Louis are tackling the rarest of these machines. A new study points to a better way to build discovery machines, thanks to recent research led by Shantanu Chakrabartty, the Clifford W. Murphy Professor and vice dean for research in the McKelvey School of Engineering at Washington University in St. Louis.

The work, now published in Nature Communications, builds off previous research on establishing a hybrid systems architecture, one that employs “neuromorphic” architecture modeled on human neurobiology functions combined with systems that leverage quantum mechanics to find optimal solutions to complex problems.

The research shows that these machines can consistently produce state-of-the-art solutions with high reliability and with competitive time-to-solution metrics, Chakrabartty said.

‘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.

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