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Category: computing – Page 76

Nonlinear optics explores how powerful light (e.g. lasers) interacts with materials, resulting in the output light changing colour (i.e. frequency) or behaving differently based on the intensity of the incoming light. This field is crucial for developing advanced technologies such as high-speed communication systems and laser-based applications. Nonlinear optical phenomena enable the manipulation of light in novel ways, leading to breakthroughs in fields like telecommunications, medical imaging, and quantum computing. Two-dimensional (2D) materials, such as graphene—a single layer of carbon atoms in a hexagonal lattice—exhibit unique properties due to their thinness and high surface area. Graphene’s exceptional electronic properties, related to relativistic-like Dirac electrons and strong light-matter interactions, make it promising for nonlinear optical applications, including ultrafast photonics, optical modulators, saturable absorbers in ultrafast lasers, and quantum optics.

Dr. Habib Rostami, from the Department of Physics at the University of Bath, has co-authored pioneering research published in Advanced Science. This study involved an international collaboration between an experimental team at Friedrich Schiller University Jena in Germany and theoretical teams at the University of Pisa in Italy and the University of Bath in the UK. The research aimed to investigate the ultrafast opto-electronic and thermal tuning of nonlinear optics in graphene.

This study discovers a new way to control high-harmonic generation in a graphene-based field-effect transistor. The team investigated the impact of lattice temperature, electron doping, and all-optical ultrafast tuning of third-harmonic generation in a hexagonal boron nitride-encapsulated graphene opto-electronic device. They demonstrated up to 85% modulation depth along with gate-tuneable ultrafast dynamics, a significant improvement over previous static tuning. Furthermore, by changing the lattice temperature of graphene, the team could enhance the modulation of its optical response, achieving a modulation factor of up to 300%. The experimental fabrication and measurement took place at Friedrich Schiller University Jena. Dr. Rostami played a crucial role in the study by crafting theoretical models. These models were developed in collaboration with another theory team at the University of Pisa to elucidate new effects observed in graphene.

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Researchers at the UChicago Pritzker School of Molecular Engineering (UChicago PME) have realized a new design for a superconducting quantum processor, aiming at a potential architecture for the large-scale, durable devices the quantum revolution demands.

Unlike the typical quantum chip design that lays the information-processing qubits onto a 2D grid, the team from the Cleland Lab has designed a modular quantum processor comprising a reconfigurable router as a central hub. This enables any two qubits to connect and entangle, where in the older system, qubits can only talk to the qubits physically nearest to them.

“A quantum computer won’t necessarily compete with a classical computer in things like memory size or CPU size,” said UChicago PME Prof. Andrew Cleland.

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Current laser technologies for the extended short-wave infrared (SWIR) spectral range rely on expensive and complex materials, limiting their scalability and affordability. To address these challenges, ICFO researchers have presented a novel approach based on colloidal quantum dots in an Advanced Materials article. The team managed to emit coherent light (a necessary condition to create lasers) in the extended SWIR range with large colloidal quantum dots made of lead sulfide (PbS).

This new CQD-based technology offers a solution to the aforementioned challenges while maintaining compatibility with silicon CMOS platforms (the technology used for constructing integrated circuit chips) for on-chip integration.

Their PbS colloidal quantum dots are the first semiconductor lasing material to cover such a broad wavelength range. Remarkably, the researchers accomplished this without altering the dots’ chemical composition. These results pave the way towards the realization of more practical and compact lasers.

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Researchers have set a new record for quantum entanglement — bringing reliable quantum computers a step closer to reality. The scientists successfully entangled 24 “logical qubits” — low-error quantum bits of information created by combining multiple physical qubits. This is the highest number ever achieved to date.

They also demonstrated that logical qubits can maintain error correction as the number of qubits increases, a crucial step toward larger, more fault-tolerant quantum systems. The researchers detailed their work in a study published Nov. 18 on the preprint database arXiv.

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Researchers have developed a new computational method to explore the neutron matter inside neutron stars at densities higher than previously studied.

This method provides insights into the behavior of neutrinos during supernova explosions, enhancing the accuracy of simulations and potentially improving our understanding of such cosmic events.

Advances in Neutron Matter Simulation.

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Researchers from City University of Hong Kong (CityUHK) and local collaborators have made a groundbreaking discovery of a new vortex electric field, poised to revolutionize future electronic, magnetic, and optical devices. This research holds immense promise for significantly enhancing the performance of various devices, particularly by improving memory stability and accelerating computing speeds.

Read Full Story.

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SACRAMENTO — A magnitude 5.5 earthquake that struck in a remote area of Nevada on Monday afternoon sent shaking throughout Central California, including the Sacramento area.

In Sacramento, one person saw ornaments on a Christmas tree sway, as did some blinds for less than a minute. Water sloshed in a swimming pool, another person said. In Davis, a computer swayed for just a few seconds and a desk chair was jolted, while a young man reported feeling his bed sway and an unnerved poodle sought comfort.

In Reno, about 50 miles northwest of the quake’s epicenter, someone at KTVN-TV captured a video of the star on the newsroom’s Christmas tree still quivering — barely — as staffers scrambled to cover the earthquake. One person could be heard saying they hadn’t felt anything.

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We tie our shoes, we put on neckties, we wrestle with power cords. Yet despite deep familiarity with knots, most people cannot tell a weak knot from a strong one by looking at them, new Johns Hopkins University research finds.

Researchers showed people pictures of two and asked them to point to the strongest one. They couldn’t.

They showed people videos of each knot, where the knots spin slowly so they could get a good long look. They still failed.

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