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Category: quantum physics – Page 22

Mirrorless laser: Physicists propose a new light source

A team of physicists from the University of Innsbruck and Harvard University has proposed a fundamentally new way to generate laser light: a laser without mirrors. Their study, published in Physical Review Letters, shows that quantum emitters spaced at subwavelength distances can constructively synchronize their photon emission to produce a bright, very narrow-band light beam, even in the absence of any optical cavity.

In conventional lasers, mirrors are essential to bounce light back and forth, stimulating coherent emission from excited atoms or molecules, and thus light amplification. But in the new “mirrorless” concept, the atoms interact directly through their own electromagnetic dipole fields, given that interatomic spacing is smaller than the emitted light’s wavelength. When the system is pumped with enough energy, these interactions cause the emitters to lock together and radiate collectively—a phenomenon called superradiant emission.

The team led by Helmut Ritsch found that this collective emission generates light that is both highly directional and spectrally pure, with a single narrow spectral line, in cases where only a fraction of emitters are excited by a laser and the rest of atoms remain unpumped. Since this passive emitter fraction is not broadened by the driving laser or power broadening, it effectively acts as an for the active emitters, in analogy with a conventional laser where the optical resonator and the gain medium are separate physical entities.

Electrons can now be controlled to build smarter quantum devices

Auburn University scientists have developed a new class of materials that lets researchers precisely control free electrons, a breakthrough that could reshape the future of computing and chemical manufacturing.

Their study introduces a material system that allows fine-tuned control over how electrons behave within matter, potentially paving the way for faster computers, smarter machines, and more efficient industrial processes.

Memristors achieve stable resistance values tied to fundamental constants of nature

Researchers at Forschungszentrum Jülich, together with international collaborators, have demonstrated for the first time that memristors—novel nanoscale switching devices—can provide stable resistance values directly linked to fundamental constants of nature. This paves the way for electrical units such as electrical resistance to be traced back far more simply and directly than it has been possible to date. By contrast, conventional, quantum-based measurement technology is so demanding that it can only be carried out in a few specialized laboratories worldwide.

The paper is published in the journal Nature Nanotechnology.

Since 2019, all base units of the International System of Units (SI)—including the meter, second, and kilogram—have been based on fundamental natural constants. For example, the kilogram, which was once based on the “prototype kilogram,” is now linked to Planck’s constant h. A meter is defined by the speed of light, and a second by the oscillation of the cesium atom.

Topological insulator maintains quantum spin Hall effect at higher temperatures

Topological insulators could form the basis for revolutionary electronic components. However, as they generally only function at very low temperatures, their practical application has been severely limited to date. Researchers at the University of Würzburg have now developed a topological insulator that also works at higher temperatures. Their results are published in Science Advances.

A topological insulator can be imagined as a material that is a perfect insulator on the inside—it does not conduct electricity there. At its edges, however, it behaves like an almost lossless “electron highway.” Electrons can move along these paths with almost no loss.

To deepen the analogy: these highways have separate lanes for electrons with different “spins”—a kind of intrinsic angular momentum. Electrons with “spin-up” move in one direction, electrons with “spin-down” in the opposite direction. This strict traffic regulation prevents collisions and thus . The phenomenon behind this is known as the quantum spin Hall effect (QSHE)—an effect that was also first experimentally proven at the University of Würzburg.

Distributed quantum sensor network achieves ultra-high resolution near Heisenberg limit

Precise metrology forms a fundamental basis for advanced science and technology, including bioimaging, semiconductor defects diagnostics, and space telescope observations. However, the sensor technologies used in metrology have so far faced a physical barrier known as the standard quantum limit.

A promising alternative to surpass this limit is the distributed quantum sensor—a technology that links multiple spatially separated sensors into a single, large-scale quantum system, thereby enabling highly . To date, efforts have primarily focused on enhancing precision, while the potential for extending this approach to has not yet been fully demonstrated.

Dr. Hyang-Tag Lim’s research team at the Center for Quantum Technology, Korea Institute of Science and Technology (KIST), has demonstrated the world’s first ultra-high-resolution distributed quantum sensor network. The study is published in the journal Physical Review Letters.

This Quantum Electron Breakthrough Could Make Computers Faster Than Ever Before

Auburn University scientists have developed a new class of materials that allow precise control over free electrons, potentially transforming computing and chemical manufacturing. Imagine a future where factories produce new materials and chemical compounds more quickly, more efficiently, and at

Quantum Echo: Nobel Prize in Physics Goes to Quantum Computer Trio (Two from Google) Who Broke Through Walls Forty Years Ago

Editor’s Note: EDRM is proud to publish Ralph Losey’s advocacy and analysis. The opinions and positions are Ralph Losey’s copyrighted work. All images in the article are by Ralph Losey using AI. This article is published here with permission.]

The Nobel Prize in Physics was just awarded to quantum physics pioneers John Clarke, Michel H. Devoret, and John M. Martinis for discoveries they made at UC Berkeley in the 1980s. They proved that quantum tunneling, where subatomic particles can break through seemingly impenetrable barriers, can also occur in the macroscopic world of electrical circuits. So yes, Schrödinger’s cat really could die.

Scientists Develop “Unbreakable” Quantum Sensor Built to Survive 30,000 Atmospheres

Boron nitride sensors enable quantum measurements under crushing pressure, redefining high-pressure physics. The quantum world is already full of mysteries, but what happens when this strange domain of subatomic particles is subjected to immense pressure? Studying quantum behavior in such conditi

Microtubule-Stabilizer Epothilone B Delays Anesthetic-Induced Unconsciousness in Rats

Suggests microtubules play an important role in consciousness. Answer probably lies within them. I really hope for the possibility of what some call “mind uploading” or transfer of consciousness to a stronger medium like artificial neurons made out of better materials. But first, we must get a far better understanding of why consciousness exist. These kinds of experiments are a pre-requisite to that.

Study: Sana Khan, Yixiang Huang, Derin Timuçin, Shantelle Bailey, Sophia Lee, Jessica Lopes, Emeline Gaunce, Jasmine Mosberger, Michelle Zhan, Bothina Abdelrahman, Xiran Zeng and Michael C. Wiest.

Volatile anesthetics reversibly abolish consciousness or motility in animals, plants, and single-celled organisms (Kelz and Mashour, 2019; Yokawa et al., 2019). For humans, they are a medical miracle that we have been benefiting from for over 150 years, but the precise molecular mechanisms by which these molecules reversibly abolish consciousness remain elusive (Eger et al., 2008; Hemmings et al., 2019; Kelz and Mashour, 2019; Mashour, 2024). The functionally relevant molecular targets for causing unconsciousness are believed to be one or a combination of neural ion channels, receptors, mitochondria, synaptic proteins, and cytoskeletal proteins.

The Meyer–Overton correlation refers to the venerable finding that the anesthetic potency of chemically diverse anesthetic molecules is directly correlated with their solubility in lipids akin to olive oil (S. R. Hameroff, 2018; Kelz and Mashour, 2019). The possibility that general anesthesia might be explained by unitary action of all (or most) anesthetics on one target protein is supported by the Meyer–Overton correlation and the additivity of potencies of different anesthetics (Eger et al., 2008). Together these results suggest that anesthetics may act on a unitary site, via relatively nonspecific physical interactions (such as London/van der Waals forces between induced dipoles).

Cytoskeletal microtubules (MTs) have been considered as a candidate target of anesthetic action for over 50 years (Allison and Nunn, 1968; S. Hameroff, 1998). Other membrane receptor and ion channel proteins were ruled out as possible unitary targets by exhaustive studies culminating in Eger et al. (2008). However, MTs (composed of tubulin subunits) were not ruled out and remain a candidate for a unitary site of anesthetic action. MTs are the major components of the cytoskeleton in all cells, and they also play an essential role in cell reproduction—and aberrant cell reproduction in cancer—but in neurons, they have additional specialized roles in intracellular transport and neural plasticity (Kapitein and Hoogenraad, 2015). MTs have also been proposed to process information, encode memory, and mediate consciousness (S. R. Hameroff et al., 1982; S. Hameroff and Penrose, 1996; S. Hameroff, 2022). While classical models predict no direct role of MTs in neuronal membrane and synaptic signaling, Singh et al. (2021a) showed that MT activities do regulate axonal firing, for example, overriding membrane potentials. The orchestrated objective reduction (Orch OR) theory proposes that anesthesia directly blocks quantum effects in MTs necessary for consciousness (S. Hameroff and Penrose, 2014). Consistent with this hypothesis, volatile anesthetics do bind to cytoskeletal MTs (Pan et al., 2008) and dampen their quantum optical effects (Kalra et al., 2023), potentially contributing to causing unconsciousness.

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