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Category: quantum physics – Page 6

Doping triggers tunable charge density wave in 2D antiferromagnetic semiconductor

Researchers at the National University of Singapore (NUS) have observed a doping-tunable charge density wave (CDW) in a single-layer semiconductor, Chromium(III) selenide (Cr2Se3), extending the CDW phenomenon from metals to doped semiconductors.

CDWs are intriguing electronic patterns widely observed in metallic two-dimensional (2D) transition metal chalcogenides (TMCs). The study of CDW provides insights into emergent orders in , where electron correlations play a non-negligible role. However, most reported TMCs exhibiting CDW are intrinsic metals, and tuning their carrier density is predominantly accomplished through intercalation or atomic substitution. These approaches may introduce impurities or defects that complicate the understanding of the underlying mechanisms.

A research team led by Professor Chen Wei from the Department of Physics and the Department of Chemistry at NUS, synthesized single-layer semiconducting Cr2Se3 and demonstrated the CDW phenomenon using scanning tunneling microscopy (STM).

Routing photonic entanglement toward a quantum internet

Imagine the benefits if the entire internet got a game-changing upgrade to speed and security. This is the promise of the quantum internet—an advanced system that uses single photons to operate. Researchers at Tohoku University have developed a new photonic router that can direct single and quantum entangled photons with unprecedented levels of efficiency. This advancement in quantum optics brings us closer to quantum networks and next-generation photonic quantum technologies becoming an everyday reality.

The findings were published in Advanced Quantum Technologies on September 2, 2025.

Photons are the backbone of many emerging quantum applications, from secure communication to powerful quantum computers. To make these technologies practical, photons must be routed quickly and reliably, without disturbing the delicate quantum states they carry.

Information could be a fundamental part of the universe, and may explain dark energy and dark matter

For more than a century, physics has been built on two great theories. Einstein’s general relativity explains gravity as the bending of space and time.

Quantum mechanics governs the world of particles and fields. Both work brilliantly in their own domains. But put them together and contradictions appear—especially when it comes to black holes, dark matter, and the origins of the cosmos.

My colleagues and I have been exploring a new way to bridge that divide. The idea is to treat information—not matter, not energy, not even spacetime itself—as the most fundamental ingredient of reality. We call this framework the quantum memory matrix (QMM).

Physicists Find a New Way Around Quantum Limits

Physicists in Australia and the United Kingdom have found a way to reshape quantum uncertainty, offering a new method that bypasses the limits set by the well-known Heisenberg uncertainty principle. Their discovery could lay the groundwork for next-generation sensors with extraordinary precision, with potential uses in navigation, medical imaging, and astronomy.

The Heisenberg uncertainty principle, first introduced in 1927, states that it is impossible to know certain pairs of properties, such as a particle’s position and momentum, with unlimited accuracy at the same time. In practice, this means that increasing precision in one property inevitably reduces certainty in the other.

In a study published in Science Advances, researchers led by Dr. Tingrei Tan of the University of Sydney Nano Institute and School of Physics demonstrated how to design an alternative trade-off, one that allows position and momentum to be measured simultaneously with exceptional accuracy.

“Quantum Computing Works at Room Temperature”: Physics Breakthrough Terrifies Tech Giants While Computing Revolution Explodes

Researchers have long faced a significant hurdle in the development of practical quantum devices: the requirement for ultra-cold environments to maintain

New tensor network-based approach could advance simulation of quantum many-body systems

The quantum many body problem has been at the heart of much of theoretical and experimental physics over the past few decades. Even though we have understood the fundamental laws that govern the behavior of elementary particles for almost a century, the issue is that many interesting phenomena are the result of the complex collective behavior of many interacting quantum particles. In the words of condensed matter theorist Philip W. Anderson: “More is different.”

Since simulating models with this many degrees of freedom exactly is entirely intractable computationally, approximations such as have been widely used to gain insight into their behavior. However, this approach requires that the theory is close to non-interacting, which renders it unusable in many cases of physical interest.

More recently, an approach based on insights from has shown great promise for tackling these non-perturbative regimes. It was understood that the low-energy quantum states of local models display relatively little entanglement compared to generic quantum states, a feature that is exploited in tensor network methods.

Device-independent method certifies genuinely entangled subspaces in photonic and superconducting systems

In a study published in Reports on Progress in Physics, researchers have achieved device-independent characterization of genuinely entangled subspaces (GESs) in both optical and superconducting quantum systems, completing the self-checking of the five-qubit error correction code space.

In quantum information, genuinely multipartite entangled states require the existence of entanglement correlations between any two subsystems within the system. The GES constituted by the states has application value especially in designing quantum error-correcting codes. By encoding in the subspace, it can prevent error propagation caused by local decoherence.

Scientists have constructed a new Bell inequality based on the stabilizer framework constructed, and the entangled subspace can be universally characterized by using it. Any quantum state (including mixed states) within this subspace could maximally violate this inequality, providing a theoretical basis for the self-testing of genuine entangled subspaces.

Breakthrough: Quantum Entanglement Achieved Between The Hearts of Two Atoms

Quantum entanglement – once dismissed by Albert Einstein as “spooky action at a distance” – has long captured the public imagination and puzzled even seasoned scientists.

But for today’s quantum practitioners, the reality is rather more mundane: entanglement is a kind of connection between particles that is the quintessential feature of quantum computers.

Though these devices are still in their infancy, entanglement is what will allow them to do things classical computers cannot, such as better simulating natural quantum systems like molecules, pharmaceuticals, or catalysts.

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