Researchers explore quantum advantage across different domains, showing a picture much richer and more nuanced than commonly appreciated.
Category: quantum physics – Page 18
Physicists say quantum mechanics may not need imaginary numbers after all
Physicists from Heinrich Heine University Düsseldorf (HHU) have examined a fundamental property of quantum mechanics in collaboration with the German Aerospace Center (DLR). In the scientific journal Physical Review Letters, they show that this theory does not necessarily need to be formulated with imaginary numbers – real numbers can in fact also be used.
Quantum mechanics is the branch of physics that explains how matter and energy behave at the atomic and subatomic scale. Developed in the early 1900s by pioneers including Max Planck, Niels Bohr, Werner Heisenberg, and Erwin Schrödinger, it has become one of the most successful scientific theories ever created.
The theory accurately describes a wide range of microscopic phenomena. These include the famous double slit experiment, in which particles also display wave like behavior, and quantum tunneling, where particles have a probability of passing through a barrier even when they do not have enough energy to overcome it in the classical sense. Other key quantum effects, such as entanglement and coherence, now form the foundation of emerging technologies including quantum computing and quantum communication.
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World’s first ‘zinc oxide spin qubit’ could advance scalable quantum devices
A research team led by SKKU professor Hosung Seo of the Department of Quantum Information Engineering and the SKKU Advanced Institute of Nanotechnology, working with the University of Wisconsin–Madison and the University of Washington, has identified—for the first time—an atomic defect structure in the zinc oxide (ZnO) semiconductor with outstanding properties for use as a “spin qubit,” a core building block of future quantum computers, quantum communications and quantum sensors.
The results are published in PRX Quantum.
Electron spins trapped at point defects in solid-state crystals can operate at room temperature and retain quantum information for long periods, making them a leading platform not only for quantum computing but also for quantum communications and ultrasensitive quantum sensing. The nitrogen-vacancy (NV) center in diamond has been the most prominent candidate, but diamond is difficult to grow into large-area, high-quality crystals and is poorly suited to standard semiconductor fabrication, posing major obstacles to the integration and mass production of quantum devices.
Long-lived ytterbium states could sharpen quantum computing and atomic clocks
Researchers from the University of Amsterdam and the University of New South Wales have answered a question that has been around for decades: whether ions of the metal ytterbium can enter certain long-lived, nearly stable states and, if so, for how long. The measured long-lived states may find applications in quantum computers and atomic clocks.
Many modern atomic clocks and quantum computers have so-called trapped ions at their core. Ions, electrically charged atoms, can be in many different states, all with different amounts of energy. Because of their charge, these ions can be suspended in empty space and kept in place using electromagnetic fields. The operation of the clock or computer then relies on precisely controlling which energy state an ion occupies.
Researchers from the University of Amsterdam and the University of New South Wales have now discovered that the ytterbium ion (Yb⁺), a leading candidate for both technologies, can remain in previously unexplored states for surprisingly long periods.
Quantum dots reveal hidden light waves on metal surfaces
Photographs can reveal things that are otherwise impossible for the naked eye to see, be they distant galaxies or microscopic cells. Researchers at Osaka Metropolitan University have developed a practical and versatile imaging technique that makes another usually invisible phenomenon visible: surface plasmon polaritons (SPPs), light waves that travel along metal surfaces.
The new method, published in the journal Nano Letters, could boost the development of next-generation optical and plasmonic technologies.
SPPs are electromagnetic waves that travel along the boundary between a metal and a dielectric material, such as air or glass. Unlike ordinary light, which spreads freely through three-dimensional space, SPPs remain tightly confined to this interface, allowing them to be guided and manipulated at the nanoscale. This unique property makes them fundamental to emerging technologies including ultrasensitive sensors, optical circuits and quantum devices.
Quantum Zeno effect could freeze computations as qubit systems scale up
The promise of quantum computing is to solve complex problems faster and more energy-efficiently than today’s supercomputers—from optimizing logistics to simulating molecules. This goal is coming within reach as the number of qubits—the computational units of quantum computing—increases.
But in addition to the technological challenges of scaling, there is another, less-considered issue: In the New Journal of Physics, researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) demonstrate that, in extreme cases, the so-called quantum Zeno effect can nearly halt computational processes as the number of qubits increases—a dreaded phenomenon comparable to a traditional computer “freezing.”
“The quantum Zeno effect is a previously overlooked obstacle to a certain class of quantum computers,” says Dr. Gernot Schaller, head of Quantum Technologies at HZDR’s Institute of Theoretical Physics. These so-called adiabatic quantum computers operate according to a special principle: Their qubits are always in their ground state, the lowest energy state. To solve a computational problem, the qubits’ energy landscape is gradually altered—slowly enough for them to adapt continuously and follow the changing ground state. Once the transformation is complete, the ground state immediately encodes the solution to the problem.
Algorithms create foundry-ready photonic circuits
Photonic microchips can process data at extremely high speeds and are embedded in a wide variety of today’s technologies. Researchers at the Max Planck Institute for the Science of Light (MPL) and Harvard University have now succeeded in developing three functional components for such chips that are up to 500 times smaller than conventional designs. The researchers used inverse design, a computer algorithm, to achieve this. The results are published in Nature Communications.
Photonic microchips are among the key technologies of modern data processing. Their miniaturization and extremely fast data processing relative to electronic components make them essential building blocks in telecommunications, large-scale AI data centers, precision measurement and quantum technologies. Light is guided through micrometer-wide waveguides across chips only a few millimeters wide.
Photonic microchips incorporate various components, such as grating couplers, which couple light between fibers and the chip, and ring resonators, tiny circular structures that temporarily store light and strongly increase light intensity inside the chip.
Prize honors discovery of altermagnetism as a third fundamental class of magnetism
One of Europe’s highest distinctions in condensed matter physics has been awarded for a discovery that is reshaping our understanding of magnetism: The 2026 Europhysics Prize of the European Physical Society (EPS) Condensed Matter Division goes to Professor Jairo Sinova of Johannes Gutenberg University Mainz (JGU), Dr. Libor Šmejkal and Professor Tomas Jungwirth for their discovery of altermagnetism—a previously unknown fundamental class of magnetism.
The prize recognizes their work establishing that nature hosts a third elementary form of collinear magnetism in addition to ferromagnetism and antiferromagnetism. The discovery overturns a century-old understanding of magnetic order and has opened an entirely new research field with major implications for quantum materials, condensed matter physics and future information technologies.
“This award recognizes a fundamental discovery that challenged one of the most established paradigms in condensed matter physics,” said Sinova, director of the Spin Phenomena Interdisciplinary Center (SPICE) at Mainz University. “Discovering that an entirely new magnetic phase had remained hidden for more than 100 years demonstrates that even the most mature scientific fields can still hold fundamental surprises.”
