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Universal pattern revealed in quantum matter

When different materials transition from one phase to another, such as water coming to a boil or a magnet losing its ability to attract metals, something remarkable can happen: They begin to behave identically, following the same mathematical rules. “Physicists call this trait universality—the messy, microscopic details wash out and only a few essential features survive,” explains Jason Alicea, William K. Davis Professor of Theoretical Physics. The math underlying these universal traits is commonly described by a theoretical framework called conformal field theory.

Reporting in the journal Nature, a collaboration between the experimental group of Caltech’s Manuel Endres, professor of physics, and Alicea’s theory group, together with theorists at Université Paris-Saclay and the Technical University of Munich, performed first-of-their-kind experiments on two different conformal field theories using quantum simulators, which are simplified versions of quantum computers tailored for specific tasks.

Using new technology developed for these quantum simulators, the team reports the first direct measurement of energy levels in synthetic quantum matter as predicted by the Ising and tricritical Ising conformal field theories. (Ising refers to Ernst Ising, a physicist who, in the 1920s, solved an early model of magnetism.) Both theories describe universal behavior that emerges when a quantum system—exhibiting exotic traits such as entanglement and superposition—is placed at a tipping point between two states, one of which is more ordered than the other.

Gentle chemical glow helps scientists capture sharper images of living cells

We reach for brighter, better lighting for sharper pictures, whether we’re photographing a puppy or a microscopic cell. In most cases, the light comes from outside the object being photographed. A recent study explored a different approach, using the cells’ own chemical glow to illuminate their internal structures. This new experimental framework, called REID, lets microscopes capture super-sharp, high-resolution details of cell structures by bypassing the need for harsh external lasers that can sometimes damage the cells being imaged.

Chemical reactions inside cells are normally very dim, but researchers discovered that swapping a common chemical co-reactant for a biological buffer called Bis-Tris boosted the cellular glow by 1,000 times. This let them capture sharp, unblurred images in just 20 milliseconds. The REID framework combined computer algorithms with electricity-triggered, chemical and biological (BL) luminescence to sharpen images down to 100 nanometers.

The team tested REID’s sensitivity, or how little of a biomarker it could still detect, using the cancer marker CEA, and compared it with standard fluorescence microscopy. They found that although the REID setup was less efficient at producing light, it was eight times more sensitive at detecting the cancer marker than the standard technique. The findings are published in Nature.

Turning a quantum battery’s environmental sensitivity into an advantage

Quantum batteries, devices that store energy by exploiting quantum mechanical phenomena, could, in principle, be charged faster and more efficiently than classical ones. Despite their potential, connecting these batteries to chargers is known to create quantum correlations that can trap some energy inside the combined battery-charger system. This can reduce useful work, or the energy available to complete a task that can be extracted from the battery alone.

Researchers at the University of Insubria & INFN, University of Genova & CNR-SPIN and University of Milan recently proposed a new design strategy that could potentially increase the usable energy of quantum batteries. Their approach, outlined in a paper in Physical Review Letters, involves connecting both a battery and its charger to a shared environment that is continuously monitored.

“Quantum technologies—including quantum batteries—are usually designed under the assumption that the environment is the enemy,” the authors told Phys.org.

Supramolecular nanofibers paired with nanohole substrate improve exciton transport in organic solid

Self-assembling, anthracene-based supramolecular nanofibers can enable excitons to migrate hundreds of nanometers, according to a new experimental finding by researchers at Science Tokyo. Coupling these nanofibers with a plasmonic gold nanohole substrate further doubles exciton diffusivity. By mitigating the limited diffusivity of singlet excitons in organic semiconductors, this approach offers a new strategy for improving optoelectronic technologies.

For decades, one of the biggest challenges in organic optoelectronics has been the limited diffusivity of excitons. Created when light is absorbed, excitons diffuse through the semiconducting material before they can dissociate into free charge carriers to generate electricity. However, excitons in conventional organic semiconductors typically diffuse only up to 5–20 nm before recombining, limiting the performance of optoelectronic devices.

Now, researchers from the Institute of Science Tokyo (Science Tokyo) in Japan have managed to overcome this long-standing limitation by combining molecular self-assembly with plasmonic nanotechnology. The breakthrough comes from a study conducted by a collaborative research team comprising Professor Martin Vacha and Associate Professor Yoshimitsu Sagara from Science Tokyo and Dr. Takatoshi Fujita from the National Institute for Quantum Science and Technology in Japan. The findings are published in the journal Nano Letters.

3D-printed ceramic waveguide lasers could surpass the power of glass fiber lasers by 10 times

At the bottom of the ocean, optical fibers transmit telecommunications and internet data around the world. Waveguides make that feat possible by channeling and amplifying the light—and therefore the data within—over enormous distances.

The technology goes beyond undersea cables. Waveguiding optics are among the most important advances in photonics since the invention of the laser. They are fundamental to the structure of glass fiber lasers, which are used for high-power national security applications like counter-drone laser systems and missile defense.

Astronomers catch hot birth of galaxy cluster more than 11 billion light-years away

Astronomers have detected an enormous cloud of gas tens of millions of degrees hot surrounding one of the most extreme structures known in the early universe. The study offers one of the clearest views yet of a galaxy cluster in the making. Using more than 600,000 seconds of observations with NASA’s Chandra X-ray Observatory, the team found diffuse, extended X-ray emission around a quasar embedded in a dense concentration of galaxies more than 11 billion light-years away. The paper describing the results was published in Astronomy & Astrophysics on July 24.

Thousands of galaxies gravitationally bound together in a crowded region are collectively called a galaxy cluster. They can form through gravitational collapse and mergers with smaller structures. When gas is accreted into a reservoir of hot gas—the intracluster medium (ICM)—that fills the gaps between galaxies in a cluster, the infalling gas undergoes shock heating, reaching temperatures of tens to hundreds of millions of Kelvin. The hot gas is primarily detected through X-ray emission.

Astronomers understand this hot gas well in mature, nearby clusters. But they want to know when and how this hot gas envelope first started forming, when the universe was young.

Laser de-icing system helps nuclear power plants improve maintenance of a critical safety system

University of South Florida engineers have developed an innovative laser-based technology that is helping nuclear power plants solve a complex maintenance challenge affecting a critical reactor safety system. After four years of research, design, and testing, the custom system has been successfully tested at two Tennessee Valley Authority nuclear plants.

The technology, created by Ahmad Vaselbehagh, professor of mechanical and aerospace engineering, and postdoctoral research associate Ty Hagan, addresses a longstanding maintenance issue involving specialized ice condensers used in certain nuclear power plants in the United States, Japan, and Finland. During routine inspections, plant operators must individually lift and weigh thousands of baskets filled with borated ice that help cool and depressurize the containment building in the unlikely event of severe accidents.

Over time, the process used to replenish the ice can cause neighboring baskets to freeze together, preventing workers from lifting and inspecting them individually. TVA challenged researchers to develop a safer, more efficient way to separate the baskets without damaging equipment or requiring labor-intensive manual work.

Search in strange quark sector reveals new particle possibilities

Despite science’s best efforts to classify the vast menagerie of subatomic particles discovered over the past few decades, some exotic varieties defy explanation. Now, nuclear physicists at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility have found evidence of two unexpected structures that could help better sort the zoo of exotic particles.

These structures may provide new insights into a perplexing family of objects known as XYZ states don’t fit cleanly into the prevailing model of particles made of quarks, the elementary building blocks of nature, and, for the first time, researchers at Jefferson Lab observed two such signals produced by a beam of high-energy photons interacting with a proton target.

The results, reported by the Gluonic Excitations (GlueX) Collaboration in Experimental Hall D at Jefferson Lab, were recently published in the journal Physical Review Letters and could go a long way in unraveling how one of the universe’s fundamental forces plays a role in the formation of matter.

Neutron capture experiment sheds light on ancient stardust

Niobium-94, an isotope of niobium with 41 protons and 53 neutrons, is a critical crossroads in the complex nuclear processes that forge heavy elements under the intense pressures and temperatures of dying stars. In an article published in Physical Review Letters, the n_TOF Collaboration reports the first-ever measurement of the probability of niobium-94 taking one of the paths at this crossroads—that is, undergoing neutron capture.

This new result provides insight into a persistent puzzle over the composition of ancient stardust. This type of stardust, known as presolar grains, survived the formation of the sun and did not get incorporated into our solar system. Some of these grains can now be found on Earth, having been brought down by primitive meteorites. Through analyzing these presolar grains, researchers can get a snapshot of the nuclear makeup of our galaxy as the heavy elements were being formed. The puzzle for researchers is that the presolar grains contain more molybdenum-94 than can be explained by theoretical models.

To investigate this problem, researchers looked at niobium-94, which is very similar to molybdenum-94 but with one less proton and one extra neutron. Within a dying star, where the extreme environment allows heavy elements to form, niobium-94 is at a crossroads. It may undergo beta decay to become molybdenum-94 or neutron capture to become niobium-95. Understanding how these two processes compete in this environment is crucial for gaining insight into why there are such mysteriously large amounts of molybdenum-94 in presolar grains.

Quantum simulators gain quantitative error bars in 51-ion test

In the coming years, increasingly larger and more powerful quantum systems are expected to tackle problems that are difficult or impossible to solve using conventional computers. However, the more powerful quantum simulations become, the more difficult it is to independently verify their results. Where classical simulation is still feasible, results can be cross-checked directly; beyond that regime, other methods are needed.

Researchers led by Tristan Kraft of the Technical University of Munich and Peter Zoller of the University of Innsbruck and the Institute for Quantum Optics and Quantum Information at the Austrian Academy of Sciences, together with Barbara Kraus of the Technical University of Munich, have now demonstrated how a quantum simulator can be experimentally characterized and how the uncertainties that arise in the process can be translated into quantitative error limits for its results.

The approach was demonstrated by a team led by Manoj Joshi and Christian Roos using an ion-trap quantum simulator containing up to 51 ions.

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