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Category: computing – Page 671

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Control of spin waves in magnonic crystals is essential for magnon-based computing. Crystals made of ferromagnetic metals offer versatility in band structure design, but strong magnetic damping restricts their transmission efficiency. Yttrium iron garnet (YIG) with ultralow damping is the palpable alternative, yet its small saturation magnetization limits dipolar coupling between discrete units. Here, we experimentally demonstrate low-loss spin-wave manipulation in magnonic crystals of physically separated nanometer-thick YIG stripes. We enhance the transmission of spin waves in allowed minibands by filling the gaps between YIG stripes with CoFeB. Thus-formed magnonic crystals exhibit tunable bandgaps of 50–200 MHz with nearly complete suppression of the spin-wave signal. We also show that Bragg scattering on only two units produces clear frequency gaps in spin-wave transmission spectra. The integration of strong ferromagnets in nanometer-thick YIG-based magnonic crystals provides effective spin-wave manipulation and low-loss propagation, a vital parameter combination for magnonic technologies.

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Theorists attribute the unexpectedly slow thermalization of cold atoms seen in recent experiments to an effect called quantum many-body scarring.

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Researchers still have some way to go before they can assemble enough quantum bits (qubits) to make a practical, large-scale quantum computer. But already the best prototypes, made up of several tens of qubits, are opening our eyes to new behavior in the quantum realm. Last year, a team from Harvard University and the Massachusetts Institute of Technology (MIT) unveiled a quantum “simulator” made up of a row of 51 interacting atoms [1]. Exciting the individual atoms in various patterns (Fig. 1), they discovered something unexpected: atoms in certain patterns took at least 10 times longer to relax towards thermal equilibrium than atoms in other patterns. Four groups of theorists have tried to make sense of this observation [2–6], in all cases attributing the slow thermalization to a never-before-seen effect called quantum many-body scarring.

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Researchers at Purdue University have announced a breakthrough that could have a significant impact on batteries of the future. The team says that the runtime for the battery in a phone or computer depends on how many lithium-ions can be stored in the negative electrode material inside the battery. When those ions are depleted, the battery is unable to deliver an electrical current.

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How long the battery of your phone or computer lasts depends on how many lithium ions can be stored in the battery’s negative electrode material. If the battery runs out of these ions, it can’t generate an electrical current to run a device and ultimately fails.

Materials with a higher storage capacity are either too heavy or the wrong shape to replace graphite, the currently used in today’s batteries.

Purdue University scientists and engineers have introduced a potential way that these materials could be restructured into a new electrode design that would allow them to increase a battery’s lifespan, make it more stable and shorten its charging time.

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In regenerative medicine, scientists aim to significantly advance techniques that can control stem cell lineage commitment. For example, mechanical stimulation of mesenchymal stem cells (MSCs) at the nanoscale can activate mechanotransduction pathways to stimulate osteogenesis (bone development) in 2-D and 3D culture. Such work can revolutionize bone graft procedures by creating graft material from autologous or allogenic sources of MSCs without chemically inducing the phenomenon. Due to increasing biomedical interest in such mechanical stimulation of cells for clinical use, both researchers and clinicians require a scalable bioreactor system to provide consistently reproducible results. In a new study now published on Scientific Reports, Paul Campsie and a team of multidisciplinary researchers at the departments of biomedical engineering, computing, physics, and molecular, cell and systems biology engineered a new bioreactor system to meet the existing requirements.

The new instrument contained a vibration plate for bioreactions, calibrated and optimized for nanometer vibrations at 1 kHz, a power supply unit to generate a 30 nm vibration amplitude and custom six-well cultureware for cell growth. The cultureware contained magnetic inserts to attach to the bioreactor’s magnetic vibration plate. They assessed osteogenic protein expression to confirm the differentiation of MSCs after initial biological experiments within the system. Campsie et al. conducted atomic force microscopy (AFM) of the 3D gel constructs to verify that strain hardening of the gel did not occur during vibrational stimulation. The results confirmed to be the result of nano-vibrational stimulations provided by the bioreactor alone.

The increasing incidence of skeletal injuries due to age-related conditions such as osteoporosis and osteoarthritis is a metric of the depleting quality of human life. The development of treatments for increased bone density or fracture healing are prime targets for the regenerative potential of mesenchymal stem (MSCs). Researchers have demonstrated controlled osteogenesis (development of bones) of MSCs via mechanical stimulation using several methods, including passive and active strategies. Passive methods typically alter the substrate topography to influence the cell adhesion profile, while active methods include exposure to varied forces from external sources.

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The previously “impossible to solve” problems for some of the biggest financial, technological and academic institutions will soon be solved in Poughkeepsie.

That’s according to IBM, which announced the opening of its first Quantum Computing Center on Wednesday, based on its Poughkeepsie campus.

Quantum computing is “nothing short of a revolution for how we are going to process information,” Director of IBM Research Dario Gil said. While computers have traditionally processed binary code — a collection of ones and zeroes — quantum computers, he said, process information in qubits, or quantum bits.

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IBM continues to push its quantum computing efforts forward and today announced that it will soon make a 53-qubit quantum computer available to clients of its IBM Q Network. The new system, which is scheduled to go online in the middle of next month, will be the largest universal quantum computer available for external use yet.

The new machine will be part of IBM’s new Quantum Computation Center in New York State, which the company also announced today. The new center, which is essentially a data center for IBM’s quantum machines, will also feature five 20-qubit machines, but that number will grow to 14 within the next month. IBM promises a 95 percent service availability for its quantum machines.

IBM notes that the new 53-qubit system introduces a number of new techniques that enable the company to launch larger, more reliable systems for cloud deployments. It features more compact custom electronics for improves scaling and lower error rates, as well as a new processor design.

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A team from Dartmouth College and MIT has designed and conducted the first lab test to successfully detect and characterize a class of complex, “non-Gaussian” noise processes that are routinely encountered in superconducting quantum computing systems.

The characterization of non-Gaussian noise in superconducting quantum bits is a critical step toward making these systems more precise.

The joint study, published in Nature Communications, could help accelerate the realization of systems. The experiment was based on earlier conducted at Dartmouth and published in Physical Review Letters in 2016.

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