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A measurement of the charge radius of an aluminum nucleus probes the assumption that there are only three families of quarks.

In the standard model of particle physics, matter is made of elementary particles called quarks and leptons. Quarks are the heavy constituents that form, for example, protons and neutrons, whereas leptons are the light constituents, such as the electron. The six known quarks—up, down, charm, strange, top, and bottom—are split into three families. But could there be a fourth family? Answering that question would require hundreds of different measurements in particle and nuclear physics. However, not all these measurements are yet available or precise enough, and many parameter values are only inferred or extrapolated. Now Peter Plattner at CERN in Switzerland and his colleagues show how a single one of these measurements can shift our understanding of this fundamental question [1].

In the quantum-mechanical framework of the standard model, quarks can oscillate among their different flavors. The best-known example occurs in the beta decay of radioactive nuclei: a proton is transformed into a neutron (or vice versa) when one of its quarks oscillates from up to down (or down to up). The rate of beta decay depends on many factors involving both nuclear and atomic physics, but the rate at which the quarks oscillate is described by a single quantity: V_ud, the so-called matrix element of the transformation of an up quark into a down quark.

Insider Brief.

Scientists report on a new approach that can significantly improve the study and understanding of entanglement in quantum materials.

The researchers were led by Peter Zoller at the University of Innsbruck and the Institute of Quantum Optics and Quantum Information of the Austrian Academy of Sciences.

Will artificial intelligence serve humanity — or will it spawn a new species of conscious digital beings with their own agenda?

It’s a question that has sparked scores of science-fiction plots, from “Colossus: The Forbin Project” in 1970, to “The Matrix” in 1999, to this year’s big-budget tale about AI vs. humans, “The Creator.”

The same question has also been lurking behind the OpenAI leadership struggle — in which CEO Sam Altman won out over the nonprofit board members who fired him a week earlier.

In the basement of Kirchhoff-Institut für Physik in Germany, researchers have been simulating the Universe as it might have existed shortly after the Big Bang. They have created a tabletop quantum field simulation that involves using magnets and lasers to control a sample of potassium-39 atoms that is held close to absolute zero. They then use equations to translate the results at this small scale to explore possible features of the early Universe.

The work done so far shows that it’s possible to simulate a Universe with a different curvature. In a positively curved universe, if you travel in any direction in a straight line, you will come back to where you started. In a negatively curved universe, space is bent in a saddle shape. The Universe is currently flat or nearly flat, according to Marius Sparn, a PhD student at Kirchhoff-Institut für Physik. But at the beginning of its existence, it might have been more positively or negatively curved.

Researchers are claiming a breakthrough in quantum communications, thanks to a new diamond-stretching technique they say greatly increases the temperatures at which qubits remain entangled, while also making them microwave-controllable.

Quantum networking is an emerging field that uses weird quantum phenomena to send and receive information. These networks will be impossible to hack, and will use quantum entanglement to cover large distances, creating pairs of qubits which mirror each other’s quantum state without any physical connection.

Diamond-based qubits are capable of maintaining their state of entanglement for a decent length of time – but only provided they’re kept incredibly cold – just a hair above absolute zero. That limits their usefulness, because it’d mean you’d need a giant, energy-intensive cooling apparatus at every node of your quantum network.

The authors present a series of correlated insulating states of twisted bilayer graphene that is detected using an atomic force microscope tip. An additional experiment demonstrates the coupling of a mechanical oscillator to a quantum device.

A future quantum network may become less of a stretch thanks to researchers at the University of Chicago, Argonne National Laboratory and Cambridge University.

A team of researchers announced a breakthrough in quantum network engineering. By “stretching” thin films of diamond, they created quantum bits that can operate with significantly reduced equipment and expense. The change also makes the bits easier to control.

The researchers hope the findings, published Nov. 29 in Physical Review X, can make future quantum networks more feasible.

More stable clocks could measure quantum phenomena, including the presence of dark matter.

The practice of keeping time relies on stable oscillations. In grandfather clocks, the length of a second is marked by a single swing of the pendulum. In digital watches, the vibrations of a quartz crystal mark much smaller fractions of time. And in atomic clocks, the world’s state-of-the-art timekeepers, the oscillations of a laser beam stimulate atoms to vibrate at 9.2 billion times per second. These smallest, most stable divisions of time set the timing for today’s satellite communications, GPS systems, and financial markets.

A clock’s stability depends on the noise in its environment. A slight wind can throw a pendulum’s swing out of sync. And heat can disrupt the oscillations of atoms in an atomic clock. Eliminating such environmental effects can improve a clock’s precision. But only by so much.

Chinese researchers report the successful quantum storage of entangled photons at telecom wavelengths within a crystal, in a breakthrough achievement that reportedly lasted 387 times longer than past similar experiments.

The research team, based at Nanjing University, says their findings could potentially “pave the way for realizing quantum networks based on solid-state devices.”

The Coming Quantum Internet