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A laser for vibrational energy, rather than for light, operating in the quantum regime could teach researchers about the interplay between spin, vibration, and dissipation in quantum mechanics.

Phonon lasers replace the light excitations (photons) that are used in a standard laser with vibrational excitations of matter (phonons). Researchers have now coaxed two ions into forming a phonon laser containing fewer than 10 phonons, placing it firmly in the quantum regime [1], whereas previous phonon lasers had at least 10,000 phonons. The researchers plan to use this quantum phonon laser as a tool to investigate the role of dissipation in the behavior of quantum systems.

Dissipation—energy leaking into or out of a system in the form of heat—is often seen as a nuisance in physics, for example, when it takes the form of air resistance and reduces the fuel efficiency of a car or an airplane. But quantum systems also exhibit dissipation, and its effects in the quantum realm are not fully understood. Jonathan Home of the Swiss Federal Institute of Technology (ETH) in Zurich and his colleagues wanted to investigate how two separate sources of dissipation can interact to affect the behavior of a quantum system. “A laser is the simplest quantum system we could think of” that allows such experiments, Home says.

CERN’s Large Hadron Collider has detected the signals of two new four-quark states that are unusual because of their charges and their quark compositions.

Using the full capabilities of the Quantinuum H1-1 quantum computer, researchers from the Department of Energy’s Oak Ridge National Laboratory not only demonstrated best practices for scientific computing on current quantum systems but also produced an intriguing scientific result.

By modeling singlet fission —in which absorption of a single photon of light by a molecule produces two excited states —the team confirmed that the linear H₄ molecule’s energetic levels match the fission process’s requirements. The linear H₄ molecule is, simply, a molecule made of four hydrogen atoms arranged in a linear fashion.

A molecule’s energetic levels are the energies of each quantum state involved in a phenomenon, such as singlet fission, and how they relate and compare with one another. The fact that the linear molecule’s energetic levels are conducive to singlet fission could prove to be useful knowledge in the overall effort to develop more efficient solar panels.

The technology can also be used in fog and smoke, aiding firefighters.

This is according to a report by PopSci published on Wednesday.

Researchers at Purdue University and Los Alamos National Laboratory have joined forces to engineer something they call “heat-assisted detection and ranging,” or HADAR, which consists of a completely new camera imaging system based on AI interpretations of heat signatures. The technology could soon allow vehicles and robots to see at night time.

Continue reading “Scientists invent accurate AI-powered heat vision for driving at night” »

Researchers at Leipzig University have developed a highly efficient method to investigate systems with long-range interactions that were previously puzzling to experts. These systems can be gases or even solid materials such as magnets whose atoms interact not only with their neighbors but also far beyond.

Professor Wolfhard Janke and his team of researchers use Monte Carlo computer simulations for this purpose. This stochastic process, named after the Monte Carlo casino, generates random system states from which the desired properties of the system can be determined. In this way, Monte Carlo simulations provide deep insights into the physics of phase transitions.

The researchers have developed a new algorithm that can perform these simulations in a matter of days, which would have taken centuries using conventional methods. They have published their new findings in the journal Physical Review X.

Carbon nanotubes, large cylindrical molecules composed of hybridized carbon atoms arranged in a hexagonal structure, recently attracted significant attention among electronics engineers. Due to their geometric configuration and advantageous electronic properties, these unique molecules could be used to create smaller field-effect transistors (FETs) that exhibit high energy efficiencies.

FETs based on carbon nanotubes have the potential to outperform smaller transistors based on silicon, yet their advantage in real-world implementations has yet to be conclusively demonstrated. A recent paper by researchers at Peking University and other institutes in China, published in Nature Electronics, outlines the realization of FETs based on carbon nanotubes that can be scaled to the same size of a 10 nm silicon technology node.

“Recent progress in achieving wafer-scale high density semiconducting carbon nanotube arrays brough us one step closer to the practical use of carbon nanotubes in CMOS circuits,” Zhiyong Zhang, one of the researchers who carried out the study, told Phys.org. “However, previous research efforts have mainly focused on the scaling of channel or gate length of carbon nanotube transistors while keeping large contact dimensions, which cannot be accepted for high density CMOS circuits in practical applications.

Powders of samples were weighed into precleaned Savillex beakers and dissolved with mixtures of 22 M HF and 14 M HNO₃ acids in a 2:1 volume ratio. The modern OIBs and four reference materials (that is, BHVO-2, BCR-2, AGV-2 and BIR-1) were digested on a hot plate at 120 °C for four days. Note that all chondrite and Archaean ultramafic/mafic rock samples were digested in Parr bomb vessels at 220 °C for three days to ensure full dissolution of refractory phases. Dissolution of the dried samples in 5–10 ml 6 M HCl at 120 °C and evaporation was carried out several times to decompose the fluorides formed from HF digestion until clear solutions were obtained. An aliquot of each sample was taken and spiked with a prepared ⁴⁷ Ti–⁴⁹ Ti double spike to determine in advance the Ti concentration using an iCAP RQ inductively coupled plasma mass spectrometer at the Centre for Star and Planet Formation (StarPlan) at the University of Copenhagen. Afterwards, aliquots containing 6 µg Ti were taken and mixed with a ⁴⁷ Ti–⁴⁹ Ti double spike as described previously in ref. ³⁴. The dried mixtures were dissolved with 6 M HCl at 120 °C overnight to ensure sample–spike equilibration.

Titanium was separated from matrix elements following a three-step purification protocol using AG1x8 (200–400 meshes) and DGA resins^34,68, that is, first to separate Fe with 6 M HCl elution on AG1x8 columns, second to remove most of the major and trace elements through 12 M HNO₃ elution and to collect Ti with Milli-Q H₂O on DGA columns and third to purify Ti from the remaining matrix elements with 4 M HF cleaning on AG1x8 columns. An extra DGA pass can be carried out to remove trace amounts of Ca and Cr in the final Ti cuts. To destroy the resin particles and organics from column chemistry, the Ti cuts were treated with 14 M HNO₃ at 120 °C before storage in 0.5 M HNO₃ + 0.01 M HF acids.

Titanium isotopic compositions of the purified samples were measured using the ThermoFisher Scientific Neoma Multicollector ICP-MS. Sample solutions with 500–800 ppb Ti dissolved in 0.5 M HNO₃ + 0.01 M HF were introduced into the multicollector inductively coupled plasma source mass spectrometer by means of an APEX HF desolvating nebulizer from Elemental Scientific and a sapphire injector was used instead of the quartz-made injector to reduce the production of silicon fluorides from the use of HF solvent. An actively cooled membrane desolvation component was attached after the APEX to suppress oxide formation and to stabilize the signals, and N₂ gas at a flow rate of a few ml min⁻¹ was added to improve the sensitivity. Such a setting typically provides an intensity of around 15 V on ⁴⁸ Ti⁺ at an uptake rate of about 50 μl min⁻¹ for a 600-ppb Ti solution under a medium mass-resolution mode.

Until the early 20th century, the question of whether light is a particle or a wave had divided scientists for centuries. Isaac Newton held the former stance and advocated for his “corpuscular” theory. But by the early 19th century, the wave theory was making a comeback, thanks in part to the work of a French civil engineer named Augustin-Jean Fresnel.

Born in 1,788 to an architect, the young Fresnel had a strict religious upbringing, since his parents were Jansenists — a radical sect of the Catholic Church that embraced predestination. Initially he was home-schooled, and did not show early academic promise; he could barely read by the time he was eight. Part of this may have been due to all the political upheaval in France at the time. Fresnel was just one year old when revolutionaries stormed the Bastille in 1,789, and five when the Reign of Terror began.

Eventually the family settled in a small village north of Caen, and when Fresnel was 12, he was enrolled in a formal school. That is where he discovered science and mathematics. He excelled at both, so much so that he decided to study engineering, first at the École Polytechnique in Paris, and then at the École Nacionale des Ponts et Chaussées.

With 147 fused benzene rings and 920 conjugated atoms, the nanoribbon shows optoelectronic properties that could compete with quantum dots.