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The quantum door mystery: Electrons that can’t find the exit

What happens when electrons leave a solid material? This seemingly simple phenomenon has, until now, eluded accurate theoretical description. In a new study, researchers have found the missing piece of the puzzle.

Imagine a frog sitting inside a box. The box has a large opening at a certain height. Can the frog escape? That depends on how much energy it has: if it can jump high enough, it could in principle make it out. But whether it actually succeeds is another question. The height of the jump alone isn’t enough—the frog also needs to jump through the opening.

A similar situation arises with inside a solid. When given a bit of extra energy—for example, by bombarding the material with additional electrons—they may be able to escape from the material.

2D devices have hidden cavities that can modify electronic behavior

In the right combinations and conditions, two-dimensional materials can host intriguing and potentially valuable quantum phases, like superconductivity and unique forms of magnetism. Why they occur, and how they can be controlled, is of considerable interest among physicists and engineers. Research published in Nature Physics reveals a previously hidden feature that could explain how and why enigmatic quantum phases emerge.

Using a new terahertz (THz) spectroscopic technique, the researchers revealed that tiny stacks of 2D materials, found in research labs around the world, can naturally form what are known as cavities. These cavities confine light and electrons into even tinier spaces, potentially changing their behavior in drastic ways.

“We’ve uncovered a hidden layer of control in quantum materials and opened a path to shaping light–matter interactions in ways that could help us both understand exotic phases of matter and ultimately harness them for future quantum technologies,” said James McIver, assistant professor of physics at Columbia and lead author of the paper.

Unified Equation: A Berry-Curvature Theory of Quantum Gravity, Entanglement, and Mass Emergence

Many Thanks to Sabine Hossenfelder for giving me puzzles.

What if everything — gravity, light, particles, and even the flow of time — came from a single equation? In Chavis Srichan’s Unified Theory, the universe isn’t built from matter, but from the curvature of entanglement — the twists and turns of quantum information itself. Space, energy, and even consciousness are simply different ways this curvature vibrates.

The One Equation.

At the smallest scale, every motion and interaction follows one rule:

[D_μ, D_ν]Ψ = (i/ħ) [(8πG/c⁴)⟨T_μν(Ψ)⟩ − Λ_q g_μν + λ ∇_μ∇_ν S]Ψ

It means that the “shape” of space itself bends in response to energy and information — and that same bending is quantum mechanics, gravity, and thermodynamics combined.

Mass: When Curvature Loops Back.

Investigating the Individual Performances of Coupled Superconducting Transmon Qubits

The strong requirement for high-performing quantum computing led to intensive research on novel quantum platforms in the last decades. The circuital nature of Josephson-based quantum superconducting systems powerfully supports massive circuital freedom, which allowed for the implementation of a wide range of qubit designs, and an easy interface with the quantum processing unit. However, this unavoidably introduces a coupling with the environment, and thus to extra decoherence sources. Moreover, at the time of writing, control and readout protocols mainly use analogue microwave electronics, which limit the otherwise reasonable scalability in superconducting quantum circuits.

Simplified Sachdev-Ye-Kitaev model simulated on trapped-ion quantum computer

The simulation of strongly interacting many-body systems is a key objective of quantum physics research, as it can help to test the predictions of physics theories and yield new valuable insight. Researchers at Quantinuum, a quantum computing company, recently simulated a simplified version of a well-known theoretical model, the so-called Sachdev-Ye-Kitaev (SYK) model, using a trapped-ion quantum computer and a previously introduced randomized quantum algorithm.

Their simulation, outlined in a paper published on the arXiv preprint server, improves the present understanding of chaotic quantum systems that cannot be simulated using classical computers. In the future, their work could contribute to the simulation of other complex quantum systems and .

“We were interested in the SYK model for two reasons: on one hand it is a prototypical model of strongly interacting fermions in condensed matter physics, and on the other hand it is the simplest toy model for studying in the lab via the holographic duality,” said Enrico Rinaldi, Lead R&D Scientist at Quantinuum and senior author of the paper.

Quantum Companies Join Forces in Italy’s New Quantum Alliance

IonQ and D-Wave, two publicly traded U.S. quantum computing companies, are joining as founding members of Q-Alliance, a new initiative in Lombardy described by organizers as the foundation of “the world’s most powerful quantum hub.”

The alliance, formalized in Como with a memorandum of understanding, is designed to accelerate quantum research and industrial applications as part of Italy’s broader digital transformation agenda, according to a news release. It is backed by the Italian government’s Interministerial Committee for Digital Transition and supported by Undersecretary of State Senator Alessio Butti.

Q-Alliance will serve as an open platform connecting universities, research institutions, and private industry. The program aims to train young researchers through scholarships and internships, promote collaboration across scientific disciplines, and position Italy as a European center for quantum development.

Fano interference of photon pairs from a metasurface

Two-photon interference, a quantum phenomenon arising from the principle of indistinguishability, is a powerful tool for quantum state engineering and plays a fundamental role in various quantum technologies. These technologies demand robust and efficient sources of quantum light, as well as scalable, integrable, and multifunctional platforms. In this regard, quantum optical metasurfaces (QOMs) are emerging as promising platforms for the generation and engineering of quantum light, in particular pairs of entangled photons (biphotons) via spontaneous parametric down-conversion (SPDC). Due to the relaxation of the phase-matching condition, SPDC in QOMs allows different channels of biphoton generation, such as those supported by overlapping resonances, to occur simultaneously. In previously reported QOMs, however, SPDC was too weak to observe such effects.

Quantum networks bring new precision to dark matter searches

Detecting dark matter—the mysterious substance that holds galaxies together—is one of the greatest unsolved problems in physics. Although it cannot be seen or touched directly, scientists believe dark matter leaves weak signals that could be captured by highly sensitive quantum devices.

In a new study published in Physical Review D, researchers at Tohoku University propose a way to boost the sensitivity of quantum sensors by connecting them in carefully designed network structures. These quantum sensors use the rules of quantum physics to detect extremely small signals, making them far more sensitive than ordinary sensors. Using these, accurately detecting the faint clues left behind from dark matter could finally become possible.

The study focuses on , which are tiny electric circuits cooled to very low temperatures. These qubits are normally used as building blocks of quantum computers, but here they act as powerful quantum sensors. Just as a team working together can achieve more than a single person, linking many of these superconducting qubits in an optimized network allows them to detect weak dark matter signals much more effectively than any single sensor could on its own.

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