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Physicists have observed a novel quantum effect termed “hybrid topology” in a crystalline material. This finding opens up a new range of possibilities for the development of efficient materials and technologies for next-generation quantum science and engineering.

The finding, published on April 10th in the journal Natur e, came when Princeton scientists discovered that an elemental solid crystal made of arsenic (As) atoms hosts a never-before-observed form of topological quantum behavior. They were able to explore and image this novel quantum state using a scanning tunneling microscope (STM) and photoemission spectroscopy, the latter a technique used to determine the relative energy of electrons in molecules and atoms.

This state combines, or “hybridizes,” two forms of topological quantum behavior—edge states and surface states, which are two types of quantum two-dimensional electron systems. These have been observed in previous experiments, but never simultaneously in the same material where they mix to form a new state of matter.

The BESIII collaboration have reported the observation of an anomalous line shape around ppbar mass threshold in the J/ψ→γ3(π+π-) decay, which indicates the existence of a ppbar bound state. The paper was published online in Physical Review Letters.

Microscopic magnetic fields induced by rotating atoms.

POSTECH researchers have created a technique for controlling polaritons, which could lead to advancements in optical displays and various optoelectronic devices.

A research team consisting of Professor Kyoung-Duck Park and Hyeongwoo Lee, an integrated PhD student, from the Department of Physics at Pohang University of Science and Technology (POSTECH) has pioneered an innovative technique in ultra-high-resolution spectroscopy. Their breakthrough marks the world’s first instance of electrically controlling polaritons—hybridized light-matter particles—at room temperature.

Novel Characteristics of Polaritons.

The findings affirm a 90-year-old theory about how electrons can assemble without atoms.

A future quantum network of optical fibers will likely maintain communication between distant quantum computers. Sending quantum information rapidly across long distances has proved difficult, in part because most photons don’t survive the trip. Now Viktor Krutyanskiy of the University of Innsbruck, Austria, and his colleagues have more than doubled the success rate for sending photons that are quantum mechanically entangled with atoms to a distant site [1]. Instead of the previous approach of sending photons one at a time and waiting to see if each one arrives successfully, the researchers sent photons in groups of three. They believe that sending photons in larger numbers should be feasible in the future, allowing much faster transmission of quantum information.

Quantum networks require entanglement distribution, which involves sending a photon entangled with a local qubit to a distant location. The distribution system must check for the arrival and for the entanglement of each photon at the remote site before another attempt can be made, which can be time consuming. For a 100-km-long fiber, the light travel time combined with losses in the fiber and other inefficiencies limit the rate for this process to about one successful photon transfer per second using state-of-the-art equipment.

For faster distribution, Krutyanskiy and his colleagues trapped three calcium ions (qubits) in an optical cavity and performed repeated rounds of their protocol: in rapid sequence, each ion was triggered to emit an entangled photon that was sent down a 101-km-long, spooled optical fiber. In one experiment, the team performed nearly 900,000 of these “attempts,” detecting entangled photons at the far end 1906 times. The effective success rate came out to 2.9 per second. The team’s single-ion success rate was 1.2 per second.

A signal from the decay products of a meson—a quark and an antiquark—comes from two subatomic particles and not one, as previously thought.

Electrons—the infinitesimally small particles that are known to zip around atoms—continue to amaze scientists despite the more than a century that scientists have studied them. Now, physicists at Princeton University have pushed the boundaries of our understanding of these minute particles by visualizing, for the first time, direct evidence for what is known as the Wigner crystal—a strange kind of matter that is made entirely of electrons.

But a team of researchers has recently developed a novel fabrication technique —the use of chemical solutions to peel off thin layers from their parent compounds, creating atomically thin sheets—that looks set to deliver on the ultra-thin substance’s promise finally.

The researchers describe their fabrication technique in a study published in Nature.

In the world of ultra-thin or ‘two-dimensional’ materials—those containing just a single layer of atoms—transition metal telluride (TMT) nanosheets have, in recent years, caused great excitement among chemists and materials scientists for their particularly unusual properties.