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Geodesic approach links quantum physics and gravitation

It is something like the “Holy Grail” of physics: unifying particle physics and gravitation. The world of tiny particles is described extremely well by quantum theory, while the world of gravitation is captured by Einstein’s general theory of relativity. But combining the two has not yet worked—the two leading theories of theoretical physics still do not quite fit together.

There are many ideas for such a unification—with names like string theory, loop quantum gravity, canonical quantum gravity or asymptotically safe gravity. Each of them has its strengths and weaknesses. What has been missing so far, however, are observable predictions for measurable quantities and experimental data that could reveal which of these theories actually describes nature best. A new study from TU Wien published in Physical Review D may now have brought us a small step closer to this ambitious goal.

Quantum Spin Ice Is Real: Physicists Confirm Exotic State of Matter

Researchers have uncovered clear evidence of exotic quantum excitations inside a rare 3D spin liquid, validating decades of theory. An international research group led by Pengcheng Dai of Rice University has now verified the presence of emergent photons and fractionalized spin excitations within

Bridging the gap between molecules and materials in quantum chemistry with localized active spaces

Emerging materials between molecules and materials demand new modeling approaches. Here, the authors present a localized active space approach that enables accurate and efficient band structure calculations to capture long-range charge and energy transfer in correlated materials.

New levitating sensors could pave way to dark matter detection and quantum sensing

A new type of sensor that levitates dozens of glass microparticles could revolutionize the accuracy and efficiency of sensing, laying the foundation for better autonomous vehicles, navigation and even the detection of dark matter.

Using a camera inspired by the human eye, scientists from King’s College London believe they could track upwards of 100 floating particles in what could be one of the most sensitive sensors to date.

Levitating sensors typically isolate small particles to observe and quantify the impact of outside forces like acceleration on them. The higher the number of particles which could be disturbed and the greater their isolation from their environment, the more accurate the sensor can be.

Scientists advance quantum signaling with twisted light technology

A tiny device that entangles light and electrons without super-cooling could revolutionize quantum tech in cryptography, computing, and AI.

Present-day quantum computers are big, expensive, and impractical, operating at temperatures near-459 degrees Fahrenheit, or “absolute zero.” In a new paper, however, materials scientists at Stanford University introduce a new nanoscale optical device that works at room temperature to entangle the spin of photons (particles of light) and electrons to achieve quantum communication—an approach that uses the laws of quantum physics to transmit and process data. The technology could usher in a new era of low-cost, low-energy quantum components able to communicate over great distances.

“The material in question is not really new, but the way we use it is,” says Jennifer Dionne, a professor of materials science and engineering and senior author of the paper just published in Nature Communications describing the novel device. “It provides a very versatile, stable spin connection between electrons and photons that is the theoretical basis of quantum communication. Typically, however, the electrons lose their spin too quickly to be useful.”

Synchrotron radiation sources: Toolboxes for quantum technologies

Synchrotron radiation sources generate highly brilliant light pulses, ranging from infrared to hard X-rays, which can be used to gain deep insights into complex materials.

An international team has published an overview of synchrotron methods for the further development of quantum materials and technologies in the journal Advanced Functional Materials.

Using concrete examples, they show how these unique tools can help to unlock the potential of quantum technologies such as quantum computing, overcome production barriers and pave the way for future breakthroughs.

Scientists Teleport Entanglement Across Two Linked Quantum Networks in Historic First

Researchers at Heriot-Watt University have introduced a prototype quantum network that merges two smaller networks into a single, reconfigurable eight-user system capable of routing — and even teleporting — entanglement on demand. For many years, physicists have imagined a quantum internet: a glo

Single-photon teleportation achieved between distant quantum dots for the first time

An international research team involving Paderborn University has achieved a crucial breakthrough on the road to a quantum internet. For the first time ever, the polarization state of a single photon emitted from a quantum dot was successfully teleported to another physically separated quantum dot.

This means that the properties of one photon can be transmitted to another via teleportation. This is a particularly vital step for future quantum communication networks. For example, the scientists used a 270m free-space optical link for their experiments. The results have now been published in the journal Nature Communications.

Detecting strong-to-weak symmetry breaking might be impossible, study shows

When a system undergoes a transformation, yet an underlying physical property remains unchanged, this property is referred to as “symmetry.” Spontaneous symmetry breaking (SSB) occurs when a system breaks out of this symmetry when it is most stable or in its lowest-possible energy state.

Recently, physicists realized that a new type of SSB can occur in open quantum systems, systems driven by quantum mechanical effects that can exchange information, energy or particles with their surrounding environment. Specifically, they realized that the symmetry in these systems can be “strong” or “weak.”

A strong symmetry entails that both the open system and its surrounding environment individually obey the symmetry. In contrast, a weak symmetry takes place when the system and the environment only follow a symmetry when they are taken together.

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