Scientists solve half-century-old magnesium dimer mystery

2 days 1 hour ago
Magnesium dimer (Mg2) is a fragile molecule consisting of two weakly interacting atoms held together by the laws of quantum mechanics. It has recently emerged as a potential probe for understanding fundamental phenomena at the intersection of chemistry and ultracold physics, but its use has been thwarted by a half-century-old enigma—five high-lying vibrational states that hold the key to understanding how the magnesium atoms interact but have eluded detection for 50 years.

Oriented hexagonal boron nitride foster new type of information carrier

2 days 6 hours ago
Today's computers use the presence or absence of charge (0s and 1s) to encode information, where the physical motion of charges consume energy and cause heat. A novel alternative is to utilize the wave quantum number of electrons by which information encoding is possible without physically moving the carriers. This study shows that manipulation of the wave quantum number is possible by controlling the stacking configuration and the orientation of different two-dimensional materials.

Research team reports an important step to making optical simulators real-world devices

2 days 8 hours ago
A group of Skoltech scientists, in collaboration with colleagues from the University of Southampton (UK), developed a fully optical approach to control the couplings between polariton condensates in optical lattices. This study is an important step toward the practical application of optical polariton condensate lattices as a platform for simulating condensed matter phases. The research results were published in the journal Physical Review Letters, where the paper was featured on the front cover.

Discovery about the edge of fusion plasma could help realize fusion power

2 days 8 hours ago
A major roadblock to producing safe, clean and abundant fusion energy on Earth is the lack of detailed understanding of how the hot, charged plasma gas that fuels fusion reactions behaves at the edge of fusion facilities called "tokamaks." Recent breakthroughs by researchers at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) have advanced understanding of the behavior of the highly complex plasma edge in doughnut-shaped tokamaks on the road to capturing the fusion energy that powers the sun and stars. Understanding this edge region will be particularly important for operating ITER, the international fusion experiment under construction in France to demonstrate the practicality of fusion energy.

Capturing the coordinated dance between electrons and nuclei in a light-excited molecule

3 days 2 hours ago
Using a high-speed "electron camera" at the Department of Energy's SLAC National Accelerator Laboratory, scientists have simultaneously captured the movements of electrons and nuclei in a molecule after it was excited with light. This marks the first time this has been done with ultrafast electron diffraction, which scatters a powerful beam of electrons off materials to pick up tiny molecular motions.

Scientists boost microwave signal stability a hundredfold

3 days 4 hours ago
Researchers at the National Institute of Standards and Technology (NIST) have used state-of-the-art atomic clocks, advanced light detectors, and a measurement tool called a frequency comb to boost the stability of microwave signals 100-fold. This marks a giant step toward better electronics to enable more accurate time dissemination, improved navigation, more reliable communications and higher-resolution imaging for radar and astronomy. Improving the microwave signal's consistency over a specific time period helps ensure reliable operation of a device or system.

New mobile health tool measures hemoglobin without drawing blood

3 days 8 hours ago
Researchers have developed a way to use smartphone images of a person's eyelids to assess blood hemoglobin levels. The ability to perform one of the most common clinical lab tests without a blood draw could help reduce the need for in-person clinic visits, make it easier to monitor patients who are in critical condition, and improve care in low- and middle-income countries where access to testing laboratories is limited.

Searching for scalar dark matter using compact mechanical resonators

3 days 8 hours ago
Researchers at University of Delaware, University of Arizona and Haverford College have recently introduced the idea of searching for scalar dark matter using compact acoustic resonators. Their paper, published in Physical Review Letters, theoretically demonstrates the potential of mechanical systems in searching for dark matter.

4-D electric circuit network with topology

4 days 5 hours ago
In recent years, topology has emerged as an important tool to classify and characterize properties of materials. It has been found that many materials exhibit a number of unusual topological properties, which are unaffected by deformations, e.g., stretching, compressing, or twisting. These topological properties include quantized Hall currents, large magnetoresistance, and surface excitations that are immune to disorder. It is hoped that these properties could be utilized for future technologies, such as, low-power electronics, ultrafast detectors, high-efficiency energy converters, or for quantum computing.

Molecule-plasmon coupling strength tunes surface-enhanced infrared absorption spectral lineshapes

4 days 6 hours ago
Plasmon-enhanced molecular spectroscopies have attracted tremendous attention as powerful detection tools with ultrahigh sensitivity down to the single-molecule level. The optical response of molecules in the vicinity of nanostructures with plasmon resonance would be dramatically enhanced through interactions with plasmons. However, beyond the signal amplification, the molecule-plasmon interaction also inevitably induce strong modifications in the spectral lineshapes and distort the implied chemical information of molecules. A typical example is surface-enhanced infrared absorption (SEIRA) spectra. Due to the dominated molecule-plasmon coupling, the lineshapes of molecular absorption spectra exhibit complicated asymmetric Fano lineshapes, instead of the symmetric Lorentzian lineshapes of probe molecules in the gas phase or in solution phase.

Intermolecular vibrational energy transfer via microcavity strong light-matter coupling

4 days 7 hours ago
Strong coupling between cavity photon modes and donor/acceptor molecules can form polaritons (hybrid particles made of a photon strongly coupled to an electric dipole) to facilitate selective vibrational energy transfer between molecules in the liquid phase. The process is typically arduous and hampered by weak intermolecular forces. In a new report now published on Science, Bo Xiang, and a team of scientists in materials science, engineering and biochemistry at the University of California, San Diego, U.S., reported a state-of-the-art strategy to engineer strong light-matter coupling. Using pump-probe and two-dimensional (2-D) infrared spectroscopy, Xiang et al. found that strong coupling in the cavity mode enhanced the vibrational energy transfer of two solute molecules. The team increased the energy transfer by increasing the cavity lifetime, suggesting the energy transfer process to be a polaritonic process. This pathway on vibrational energy transfer will open new directions for applications in remote chemistry, vibration polariton condensation and sensing mechanisms.
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