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First direct nanomagnet measurement finds switching attempts far slower than long-assumed

A compass always points north—or does it? Magnets normally maintain a stable direction of magnetization, pointing from south to north (S→N). However, this direction can change under strong magnetic fields or heat. For example, a compass placed near a strong magnet may no longer point in the right direction.

Magnets can also lose their magnetism when exposed to high levels of heat. This isn’t just relevant to wayfinding during your camping trips—if the magnets in hard drives and memory storage devices are affected, it could mean losing all of your precious data.

Researchers at Tohoku University sought to better understand the intricate ways in which this thermally-activated switching occurs in nanomagnets, and successfully measured it experimentally for the very first time. The results are published in Communications Materials.

Gene-screen strategy separates Parkinson’s promoters from protectors, revealing new drug targets

A novel strategy that combines computational and experimental approaches has allowed researchers at Baylor College of Medicine and the Duncan Neurological Research Institute (Duncan NRI) at Texas Children’s Hospital to distinguish alterations in gene function that contribute to Parkinson’s disease from those that protect from the condition. The study, published in Neurobiology of Disease, revealed novel risk factors and previously unrecognized therapeutic targets, offering hope for a future in which effective therapies will be available to prevent, slow down or stop this devastating disease.

“Parkinson’s disease is the most common neurodegenerative movement disorder—it affects more than 10 million people worldwide,” said corresponding author Dr. Juan Botas, professor of molecular and human genetics and molecular and cellular biology at Baylor. Botas also is a member of the Duncan NRI and director of the High Throughput Behavioral Screening Core at Texas Children’s.

“People with the condition have tremors, muscle stiffness and balance problems. They move slowly with a shuffling gait; their symptoms often start gradually and worsen over the years. Current therapies only relieve symptoms but do not prevent the gradual loss of brain cells called neurons that cause the disease,” said Dr. Botas.

Scientists invent artificial neurons that ‘talk’ to real brain cells, paving way to better brain implants

Engineers have printed tiny, artificial neurons that can “talk” to mouse brain cells, and the development could pave the way to innovations in computing and medicine.

The work, published April 15 in the journal Nature Nanotechnology, adds to a growing field that aims to build computers that mimic the inner workings of the brain.

On computing quantum waves exactly from classical action

The fundamental quantum postulates on the existence of a wave function, its propagation with the Schrödinger equation in theorem 3.2 and the wave collapse at a measurement in lemma 3.3 are derived from the classical theorem 2.4. Furthermore, analytic computations of the classical action are simpler than solving the Feynman path integral and potentially easier than solving the Schrödinger equation directly. In addition, theorem 3.2 is a multi-particle result.

The J classical multipaths in theorem 3.2 and lemma 3.3 are strictly determined by the initial and final conditions. In the double slit experiment, the probabilistic quantum observation results from the non-Lipschitz constraint force in the slit. For the harmonic oscillator, the Coulomb wave, the particle in the box, or the spinning particle, the initial probabilistic density distribution is classically propagated forward in time. In the EPR experiment [64,65], theorem 2.4 determines a constant angular momentum χo↑,χo↓ over time, and lemma 3.3 in turn allows a classical interpretation that the decision which spin correlation is sensed behind the filters is already taken when the particles separate.

Quantum chips could scale faster with new spin-qubit readout that reduces sensors and wiring

Quantum computers, devices that process information leveraging quantum mechanical effects, could tackle some tasks that are difficult or impossible to solve using classical computers. These systems represent data as qubits, units of information that can exist in multiple states at once, unlike the bits used by classical computers that represent data using binary values (“0” or “1”).

Some of the quantum computers developed in recent years store quantum information in the spin (i.e., intrinsic angular momentum) of electrons or nuclei that are trapped in small semiconductor-based structures, known as quantum dots. For these devices to operate reliably, however, engineers need to be able to precisely measure the quantum states of the spin qubits they rely on, a process that is known as qubit readout. It would also be advantageous for these states to be precisely measured in a way that is architecturally compact, or in other words, using space-efficient hardware as opposed to numerous bulkier components.

Researchers at Quantum Motion and University College London (UCL) recently introduced a new approach to clearly read out the states of spin qubits leveraging high-frequency electrical signals. This method, introduced in a paper published in Nature Electronics, was developed by Jacob F. Chittock-Wood and his colleagues while he was completing his Ph.D. at UCL.

New 3D device harnesses living brain cells for computing

Princeton researchers have combined brain cells and advanced electronics into a single 3D device that can be programmed to recognize patterns using computational techniques. Past attempts at using brain cells to do computation have relied on 2D cultures grown in a petri dish or 3D clusters that are probed and monitored from outside. The Princeton device takes a different approach, working from the inside out.

Using advanced fabrication techniques, the team created a 3D mesh made of microscopic metal wires and electrodes supported by a thin epoxy coating. Because the coating is so thin, it has just the right amount of flexibility to interface with the soft neurons that grow around it. The team used the mesh as a scaffold to culture tens of thousands of neurons into a vast 3D network that can be used to do computation.

The study was published in Nature Electronics on Apr. 23.

Excuse me, is that solar panel pointing in the right direction?

On a bright morning, graduate student Jeremy Klotz and professor Shree Nayar walked through upper Manhattan with a tall tripod and a camera that takes 360-degree images. Their route took them to bike docking stations, which use solar energy to power their kiosks, docking mechanisms, wireless communication, and even E-bike recharging in recent installations. At each docking station, the researchers raised the camera above the panel, snapped a spherical picture, and sent it to Klotz’s laptop.

Seconds later, the team’s computer vision program told them something remarkable: how much energy that panel would generate in a year—and how much it could generate if it were pointed at the optimal angle.

As it turns out, the solar panels powering the bike docking stations—and likely many solar panels across New York City and other urban destinations—may be leaving significant energy untapped simply because they are not at their best orientation.

Soundwaves settle debate about elusive quantum particle

It was a head-spinning discovery. In 2018, researchers in Japan claimed to find concrete evidence of an elusive particle, a Majorana fermion, in a quantum spin liquid called ruthenium trichloride. Majoranas are highly sought-after by quantum materials scientists because when a pair are localized, or trapped, they can securely encode information and form a stable qubit—the building block of quantum computing.

Some researchers heralded the finding and used it to launch their own studies, while others believed the breakthrough—which was made by measuring what’s called the thermal Hall effect—was actually a mirage caused by defects in the material sample.

Cornell researchers have now waded into the debate and their findings, published in Nature, show both camps were wrong. By measuring the movement of sound waves rather than the flow of heat, the team discovered the thermal Hall effect was caused by rotating lattice vibrations called chiral phonons.

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