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Category: particle physics – Page 45

TEMPO molecule enhances stability and performance of perovskite solar cells

Perovskite solar cells are among the most promising candidates for the next generation of photovoltaics: lightweight, flexible, and potentially very low-cost. However, their tendency to degrade under sunlight and heat has so far limited widespread adoption. Now, a new study published in Joule presents an innovative and scalable strategy to overcome this key limitation.

A research team led by the École Polytechnique Fédérale de Lausanne (EPFL), in collaboration with the University of Applied Sciences and Arts of Western Switzerland (HES⁠-⁠SO) and the Politecnico di Milano, has developed a bulk passivation technique that involves adding the molecule TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) to the perovskite film and applying a brief infrared heating pulse lasting just half a second.

This approach enables the repair of near-invisible crystalline defects inside the material, boosting solar cell efficiency beyond 20% and maintaining that performance for several months under operating conditions. Using positron annihilation spectroscopy—a method involving antimatter particles that probe atomic-scale defects—the researchers confirmed a significant reduction in vacancy-type defects.

Superconducting quantum processors help understand quantum transport

Thus, a complete understanding of quantum transport requires the ability to simulate and probe macroscopic and microscopic physics on equal footing.

Researchers from Singapore and China have utilized a superconducting quantum processor to examine the phenomenon of quantum transport in unprecedented detail.

Gaining deeper insights into quantum transport—encompassing the flow of particles, magnetization, energy, and information through quantum channels—has the potential to drive significant innovations in next-generation technologies such as nanoelectronics and thermal management.

Quantum simulator realizes strongly interacting Mott-Meissner phases in bosonic flux ladders

When exposed to periodic driving, which is the time-dependent manipulation of a system’s parameters, quantum systems can exhibit interesting new phases of matter that are not present in time-independent (i.e., static) conditions. Among other things, periodic driving can be useful for the engineering of synthetic gauge fields, artificial constructs that mimic the behavior of electromagnetic fields and can be leveraged to study topological many-body physics using neutral atom quantum simulators.

Researchers at Ludwig-Maximilians-Universität, Max Planck Institute for Quantum Optics and Munich Center for Quantum Science and Technology (MCQST) recently realized a strongly interacting phase of matter in large-scale bosonic flux ladders, known as the Mott-Meissner phase, using a neutral atom quantum simulator. Their paper, published in Nature Physics, could open new exciting possibilities for the in-depth study of topological quantum matter.

“Our work was inspired by a long-standing effort across the field of neutral atom quantum simulation to study strongly interacting phases of matter in the presence of magnetic fields,” Alexander Impertro, first author of the paper, told Phys.org. “The interplay of these two ingredients can create a variety of quantum many-body phases with exotic properties.

A newly discovered type of superconductor is also a magnet

Magnets and superconductors go together like oil and water—or so scientists have thought. But a new finding by MIT physicists is challenging this century-old assumption.

In a paper appearing in the journal Nature, the physicists report that they have discovered a “chiral superconductor”—a material that conducts electricity without resistance, and also, paradoxically, is intrinsically magnetic. What’s more, they observed this exotic superconductivity in a surprisingly ordinary material: graphite, the primary material in pencil lead.

Graphite is made from many layers of graphene—atomically thin, lattice-like sheets of carbon atoms—that are stacked together and can easily flake off when pressure is applied, as when pressing down to write on a piece of paper. A single flake of graphite can contain several million sheets of graphene, which are normally stacked such that every other layer aligns. But every so often, graphite contains tiny pockets where graphene is stacked in a different pattern, resembling a staircase of offset layers.

Controlling quantum motion and hyper-entanglement

Manuel Endres, professor of physics at Caltech, specializes in finely controlling single atoms using devices known as optical tweezers. He and his colleagues use the tweezers, made of laser light, to manipulate individual atoms within an array of atoms to study fundamental properties of quantum systems. Their experiments have led to, among other advances, new techniques for erasing errors in simple quantum machines; a new device that could lead to the world’s most precise clocks; and a record-breaking quantum system controlling more than 6,000 individual atoms.

One nagging factor in this line of work has been the normal jiggling motion of atoms, which make the systems harder to control. Now, reporting in the journal Science, the team has flipped the problem on its head and used this to encode .

“We show that atomic motion, which is typically treated as a source of unwanted noise in quantum systems, can be turned into a strength,” says Adam Shaw, a co-lead author on the study along with Pascal Scholl and Ran Finkelstein.

Photon manipulation near absolute zero: New record for processing individual light particles

Scientists at Paderborn University have made a further step forward in the field of quantum research: for the first time ever, they have demonstrated a cryogenic circuit (i.e. one that operates in extremely cold conditions) that allows light quanta—also known as photons—to be controlled more quickly than ever before.

Specifically, these scientists have discovered a way of using circuits to actively manipulate made up of individual photons. This milestone could substantially contribute to developing modern technologies in quantum information science, communication and simulation. The results have now been published in the journal Optica.

Photons, the smallest units of light, are vital for processing quantum information. This often requires measuring a ’s state in real time and using this information to actively control the luminous flux—a method known as a “feedforward operation.”

Quantum computing and photonics discovery potentially shrinks critical parts by 1,000 times

Researchers have made a discovery that could make quantum computing more compact, potentially shrinking essential components 1,000 times while also requiring less equipment. The research is published in Nature Photonics.

A class of quantum computers being developed now relies on light particles, or photons, created in pairs linked or “entangled” in quantum physics parlance. One way to produce these photons is to shine a laser on millimeter-thick crystals and use optical equipment to ensure the photons become linked. A drawback to this approach is that it is too big to integrate into a computer chip.

Now, Nanyang Technological University, Singapore (NTU Singapore) scientists have found a way to address this approach’s problem by producing linked pairs of photons using much thinner materials that are just 1.2 micrometers thick, or about 80 times thinner than a strand of hair. And they did so without needing additional optical gear to maintain the link between the , making the overall set-up simpler.

Laser Cooling is Optimized for Efficiency

A new laser-based cooling scheme approaches the maximum efficiency that is theoretically achievable.

Much of the progress in 20th-century physics has centered around understanding the interaction between light and matter. The availability of well-controlled light sources—lasers—enabled experimental exploration of controlled light–matter interactions and, specifically, methods to cool atoms close to absolute zero temperatures [1, 2]. Several laser-cooling methods, such as Doppler cooling and resolved sideband cooling, are used routinely to prepare controlled quantum states of atoms. Brennen de Neeve of the Swiss Federal Institute of Technology (ETH) Zurich and his colleagues now show just how efficient a laser-cooling process can be [3] (Fig. 1). They demonstrate a laser-cooling method that uses a “spin-dependent force” to transfer motional entropy from the atom into the entropy of its internal degrees of freedom.

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