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Research team uses tunable laser to develop straightforward broadband spectroscopy method with Hz-level precision

Since the first demonstration of the laser in the 1960s, laser spectroscopy has become an essential tool for studying the detailed structures and dynamics of atoms and molecules. Advances in laser technology have further enhanced its capabilities. There are two main types of laser spectroscopy: frequency comb-based laser spectroscopy and tunable continuous-wave (CW) laser spectroscopy.

DUNE scientists observe first neutrinos with prototype detector at Fermilab

In a major step for the international Deep Underground Neutrino Experiment, scientists have detected the first neutrinos using a DUNE prototype particle detector at the US Department of Energy’s Fermi National Accelerator Laboratory.


The prototype of a novel particle detection system for the international Deep Underground Neutrino Experiment successfully recorded its first accelerator neutrinos.

A Simpler Path to Fusion: The Promise of Spherical Tokamak Technology

Some experts believe that the future of fusion in the U.S. may be found in compact, spherical fusion vessels. A smaller tokamak is seen as a potentially more economical solution for fusion energy. The challenge lies in fitting all necessary components into a limited space. Recent research indicates that removing one key component used to heat the plasma could create the additional space required.

Scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), the private company Tokamak Energy, and Kyushu University in Japan have proposed a design for a compact, spherical fusion pilot plant that heats the plasma using only microwaves. Typically, spherical tokamaks also use a massive coil of copper wire called a solenoid, located near the center of the vessel, to heat the plasma. Neutral beam injection, which involves applying beams of uncharged particles to the plasma, is often used as well. But much like a tiny kitchen is easier to design if it has fewer appliances, it would be simpler and more economical to make a compact tokamak if it has fewer heating systems.

The new approach eliminates ohmic heating, which is the same heating that happens in a toaster and is standard in tokamaks. “A compact, spherical tokamak plasma looks like a cored apple with a relatively small core, so one does not have the space for an ohmic heating coil,” said Masayuki Ono, a principal research physicist at PPPL and lead author of the paper detailing the new research. “If we don’t have to include an ohmic heating coil, we can probably design a machine that is easier and cheaper to build.”

Remnants of quark model in lattice QCD simulation in the Coulomb gauge

Aiming at the relation between QCD and the quark model, we consider projections of gauge configurations generated in quenched lattice QCD simulations in the Coulomb gauge on a 16 $$^{\textrm{3}}$$3 $$\mathrm \times $$ × 32, $$\mathrm \beta $$ β = 6.0 lattice. First, we focus on a fact that the static quark-antiquark potential is independent of spatial gauge fields. We explicitly confirm this by performing $$\textbf{A}$$ A = 0 projection, where spatial gauge fields are all set to zero. We also apply the $$\textbf{A}$$ A = 0 projection to light hadron masses and find that nucleon and delta baryon masses are almost degenerate, suggesting vanishing of the color-magnetic interactions.

2D layer of phosphorus pentamers shows semiconductor properties on silver surface

Phosphorus is an exciting element: It is essential for the survival of organisms and promises numerous electronic applications. With this in mind, researchers at the University of Basel have synthesized two-dimensional layers containing rings of five phosphorus atoms (phosphorus pentamers (cyclo-P5)) on a silver surface.

For the first time, they have been able to investigate their electronic properties using combined atomic force and scanning tunneling spectroscopy. They found that the atomic phosphorus pentamer layer retains its semiconductor properties and forms a special electronic interface where the layer joins the silver surface (p-type semiconductor-metal Schottky junction).

This shows that phosphorus pentamers on the silver surface fulfill a basic requirement for applications in field-effect transistors, diodes or solar cells, as recently reported by the research team in the scientific journal Nature Communications (“Probing charge redistribution at the interface of self-assembled cyclo-P5 pentamers on Ag(111)”).