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Performance of the spin qubit shuttling architecture for a surface code implementation

Berat Yenilen, Arnau Sala, Hendrik Bluhm, Markus Müller, and Manuel Rispler, Quantum 10, 2219 (2026). Qubit shuttling promises to advance some quantum computing platforms to the qubit register sizes needed for effective quantum error correction (QEC), but also introduces additional errors whose impact must be evaluated. The established method to investigate the performance of QEC codes in a realistic scenario is to employ a standard noise model known as circuit-level noise, where all quantum operations are modeled as noisy. In the present work, we take this noise model and single out the effect of shuttling errors by introducing them as an additional so-called error location. This hardware abstraction is motivated by the SpinBus architecture and allows a systematic numerical investigation to map out the resulting two-dimensional parameter space. To this end, we take the Surface code and perform large scale simulations, most notably extracting the threshold across said two-dimensional parameter space. We study two scenarios for shuttling errors, depolarization on the one hand and dephasing on the other hand. For a purely dephasing shuttling error, we find a threshold of several percent, provided that all other operations have a high fidelity. The qubit overhead needed to reach a logical error rate of $10^{-12}$ (known as the “teraquop” regime [23] increases only moderately for shuttling error rates up to about 1% per shuttling operation. The error rates at which practically useful, i.e. well below threshold error correction is predicted to be possible are comfortably higher than what is expected to be achievable for spin qubits. Our results thus show that it is reasonable to expect shuttling operations to fall below threshold already at surprisingly large error rates. With realistic efforts in the near term, this offers positive prospects for spin qubit based quantum processors as a viable avenue for scalable fault-tolerant error-corrected quantum computing.

Exploring the shapes of exotic nuclei

In the conventional diagram of an atom, the center depicts a nucleus—a spherical cluster of protons and neutrons. But that sphere is a simplification: nuclei can deform into exotic shapes that appear more like a pear, football or Frisbee. Understanding why and when nuclei distort is crucial for predicting and modeling how they will behave.

Researchers at Lawrence Livermore National Laboratory (LLNL) have developed a new detector, CHICOX (Compact Heavy Ion Counter version X), that opens up a new era of extremely sensitive studies of nuclear shapes.

“Nuclear theorists are working toward a comprehensive, predictive model of nuclei and how they behave. The data we measure with CHICOX are a good test of these models,” said LLNL scientist Daniel Rhodes.

Cosmic-ray particles help probe powerful electric fields inside thunderstorms

An instrument built to study cosmic rays has turned out to be a powerful tool for investigating thunderstorms. Earlier observations with the GRAPES-3 muon telescope revealed that thunderclouds can develop electrical potential differences far greater than those ever measured directly. But they also uncovered a puzzle: the instrument detected many more thunderstorm events in the eastern part of its field of view than in the western part. A new study by the same team, published in the Journal of Cosmology and Astroparticle Physics, has now explained why.

The asymmetry does not mean that thunderstorms are actually more common to the east. Instead, it arises from the way the geomagnetic field affects the cosmic rays traveling through Earth’s magnetosphere, making GRAPES-3 more sensitive to thunderstorms from some directions than others. The result strengthens the case for using these cosmic-ray particles as a natural probe of thunderstorm electricity.

Cosmic rays are a continuous flux of extremely high-energy particles arriving at Earth from outer space. Most primary cosmic rays are protons. Because they are electrically charged, their trajectories are deflected by Earth’s magnetic field. When they enter the atmosphere, they collide with atomic nuclei in the air, generating showers of secondary particles.

Google DeepMind develops invisible watermarks for AI-designed proteins

Watermarks have long protected everything from bank notes and fine art to digital photographs and software, helping prove authenticity and trace an object’s origin. Their main function is to protect copyright and verify authenticity.

That same traceability is needed in synthetic biology, where AI is now a useful research tool. To address this, Google DeepMind has introduced SynthIDBio, a method for embedding invisible signatures directly into biological sequences and 3D structures without interfering with their function.

AI is actively designing new functional proteins and predicting their three-dimensional shapes. But along with the benefits come a host of potential problems. These include biosecurity risks, such as the potential misuse of AI-designed biological molecules, and the spread of fake or misleading scientific data.

Hidden ‘funnels’ let complex systems slip between stable states

Many systems in nature can settle into several different stable states, with the final state depending on their starting conditions. However, the boundaries separating these states are often far more complicated than they first appear.

Through new research published in Physical Review Letters, researchers in Ireland and Germany, led by Serhiy Yanchuk at University College Cork, have shown that these boundaries can contain narrow, hidden pathways, allowing systems to reach stable states from starting points that simpler models would rule out entirely.

Counteranions reshape molecular packing to tune magnetism in copper complexes

Magnetic properties in molecular materials depend not only on the molecular components themselves but also on their solid-state organization. In charged π-electronic systems, electrostatic and dispersion forces can organize molecules into distinct ion-pairing structures.

Oppositely charged species may form charge-by-charge assemblies, whereas like-charged π-electronic units can, under favorable intermolecular interactions, overcome electrostatic repulsion and form stacked dimers. Because intermolecular spin–spin interactions are sensitive to the proximity and relative orientation of paramagnetic units, controlling the assembly pattern provides a route to modulating magnetic behavior.

Yet solid-state intermolecular spin–spin interactions in CuII complexes of π-electronic macrocycles have been reported only in limited cases.

Webb provides crash course on planet-shattering collisions

In the early history of our solar system, scientists theorize that a Mars-sized object called Theia smashed into the infant Earth, vaporizing massive amounts of rock and blasting it into space. Some of that material coalesced into the moon, where NASA’s Artemis program is returning humans, preparing for Mars and shaping the future of space exploration.

That long-ago, violent collision reshaped our home planet. Astronomers have used NASA’s James Webb Space Telescope to examine a class of young stellar systems that show signs of similar upheavals, providing clues to the amount of energy in their collisions. The results offer insights into the composition and evolution of these chaotic systems.

The team’s findings were published Thursday in The Astrophysical Journal.

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