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Category: particle physics – Page 69

High harmonic generation (HHG) is a highly non-linear phenomenon where a system (for example, an atom) absorbs many photons of a laser and emits photons of much higher energy, whose frequency is a harmonic (that is, a multiple) of the incoming laser’s frequency. Historically, the theoretical description of this process was addressed from a semi-classical perspective, which treated matter (the electrons of the atoms) quantum-mechanically, but the incoming light classically. According to this approach, the emitted photons should also behave classically.

Despite this evident theoretical mismatch, the description was sufficient to carry out most of the experiments, and there was no apparent need to change the framework. Only in the last few years has the scientific community begun to explore whether the emitted light could actually exhibit a quantum behavior, which the semi-classical theory might have overlooked. Several theoretical groups, including the Quantum Optics Theory group at ICFO, have already shown that, under a full quantum description, the HHG process emits light with quantum features.

However, experimental validation of such predictions remained elusive until, recently, a team led by the Laboratoire d’Optique Appliquée (CNRS), in collaboration with ICREA Professor at ICFO Jens Biegert and other multiple institutions (Institut für Quantenoptik—Leibniz Universität Hannover, Fraunhofer Institute for Applied Optics and Precision Engineering IOF, Friedrich-Schiller-University Jena), demonstrated the quantum optical properties of high-harmonic generation in semiconductors. The results, appearing in PRX Quantum, align with the previous theoretical predictions about HHG.

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Physicists at Loughborough University have made an exciting breakthrough in understanding how to fine-tune the behavior of electrons in quantum materials poised to drive the next generation of advanced technologies.

Quantum materials, like and strontium ruthenates, exhibit remarkable properties such as superconductivity and magnetism, which could revolutionize areas like computing and energy storage.

However, these materials are not yet widely used in real-world applications due to the challenges in understanding the complex behavior of their electrons—the particles that carry electrical charge.

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An optical lattice clock is a type of atomic clock that can be 100 times more accurate than cesium atomic clocks, the current standard for defining “seconds.” Its precision is equivalent to an error of approximately one second over 10 billion years. Owing to this exceptional accuracy, the optical lattice clock is considered a leading candidate for the next-generation “definition of the second.”

Professor Hidetoshi Katori from the Graduate School of Engineering at The University of Tokyo has achieved a milestone by developing the world’s first compact, robust, ultrahigh-precision optical clock with a device capacity of 250L.

As part of this development, the physics package for spectroscopic measurement of atomic clock transitions, along with the laser and control system used for trapping and spectroscopy of atoms, was miniaturized. This innovation reduced the device volume from the traditional 920 to 250 L, approximately one-quarter of the previous size.

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Particles called neutrons are typically very content inside atoms. They stick around for billions of years and longer inside some of the atoms that make up matter in our universe. But when neutrons are free and floating alone outside of an atom, they start to decay into protons and other particles. Their lifetime is short, lasting only about 15 minutes.

Physicists have spent decades trying to measure the precise lifetime of a neutron using two techniques, one involving bottles and the other beams. But the results from the two methods have not matched: they differ by about 9 seconds, which is significant for a particle that only lives about 15 minutes.

Now, in a new study published in the journal Physical Review Letters, a team of scientists has made the most precise measurement yet of a neutron’s lifetime using the bottle technique. The experiment, known as UCNtau (for Ultra Cold Neutrons tau, where tau refers to the neutron lifetime), has revealed that the neutron lives 14.629 minutes with an uncertainty of 0.005 minutes. This is a factor of two more precise than previous measurements made using either of the methods. While the results do not solve the mystery of why the bottle and beam methods disagree, they bring scientists closer to an answer.

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Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory and collaborators have a new way to use data from high-energy particle smashups to peer inside protons. Their approach uses quantum information science to map out how particle tracks streaming from electron-proton collisions are influenced by quantum entanglement inside the proton.

The results reveal that and gluons, the fundamental building blocks that make up a proton’s structure, are subject to so-called . This quirky phenomenon, famously described by Albert Einstein as “spooky action at a distance,” holds that particles can know one another’s state—for example, their spin direction—even when they are separated by a great distance.

In this case, entanglement occurs over incredibly short distances—less than one quadrillionth of a meter inside individual —and the sharing of information extends over the entire group of quarks and gluons in that proton.

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Unveiling Quantum Scars: A Window into Chaos in Graphene Quantum Dots.

In the realm of quantum physics, certain phenomena challenge our understanding of chaos and order.

Patterns in chaos have been proven, in the incredibly tiny quantum realm, by an international team co-led by UC Santa Cruz physicist Jairo Velasco, Jr. In a new paper published on November 27 in Nature, the researchers detail an experiment that confirms a theory first put forth 40 years ago stating that electrons confined in quantum space would move along common paths rather than producing a chaotic jumble of trajectories.

Electrons exhibit both particle and wave-like properties—they don’t simply roll like a ball. Electrons behave in ways that are often counterintuitive, and under certain conditions, their waves can interfere with each other in a way that concentrates their movement into certain patterns. The physicists call these common paths “unique closed orbits.”

Achieving this in Velasco’s lab required an intricate combination of advanced imaging techniques and over electron behavior within graphene, a material widely used in research because its unique properties and two-dimensional structure make it ideal for observing .

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We’ve all experienced the moment of panic when a glass slips from our hands, shattering into pieces upon hitting the ground. What if this common mishap could become a thing of the past?

Now, a new discovery by researchers at Tohoku University has offered insights into how resists breakage, potentially paving the way for highly durable, break-resistant materials. The breakthrough has wide ranging implications for glass-related industries.

Details of their findings are published in the journal Acta Materialia.

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Clay minerals are a major constituent of the Earth’s surface and are mainly found in the sediments of lakes, rivers and oceans. The properties of clay and claystone depend on how the tiny sediment particles are orientated. Using the European Synchrotron particle accelerator in Grenoble (France), a research team from the Martin Luther University Halle-Wittenberg (MLU) has succeeded for the first time in observing in detail how some of the processes work.

The study was published in the journal Communications Earth & Environment and provides researchers with insights into the structure and properties of sediments.

The formation of clay-rich sediments is difficult to study. “Sedimentation occurs, for example, on the hard-to-reach seafloor over a very long period of time. In addition, clay particles are only a few micrometers or less in size. As a result, conventional microscopy methods are not suitable for the observation of clay particles during sedimentation,” explains Dr. Rebecca Kühn, a geoscientist at MLU, lead researcher of the study.

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When NASA’s Voyager 2 spacecraft flew by Uranus in 1986, it provided scientists’ first—and, so far, only—close glimpse of this strange, sideways-rotating outer planet. Alongside the discovery of new moons and rings, baffling new mysteries confronted scientists. The energized particles around the planet defied their understanding of how magnetic fields work to trap particle radiation, and Uranus earned a reputation as an outlier in our solar system.

Now, new research analyzing the data collected during that flyby 38 years ago has found that the source of that particular mystery is a cosmic coincidence. It turns out that in the days just before Voyager 2’s flyby, the planet had been affected by an unusual kind of space weather that squashed the planet’s magnetic field, dramatically compressing Uranus’s magnetosphere.

“If Voyager 2 had arrived just a few days earlier, it would have observed a completely different magnetosphere at Uranus,” said Jamie Jasinski of NASA’s Jet Propulsion Laboratory in Southern California and lead author of the new work published in Nature Astronomy. “The spacecraft saw Uranus in conditions that only occur about 4% of the time.”

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