Understanding how interconnected neurons exchange information is a key scientific challenge, but existing optical methods are invasive, limiting recording durations. The authors combine microscopy with electrochromic optical recording (ECORE), a label-free technique relying on reversible color changes in a biocompatible medium. They demonstrate the recording of extracellular action potentials from cardiomyocytes with single-cell resolution and a high sensitivity of 6.3 µV. This approach simplifies the optical setup and allows simultaneous imaging, making ECORE accessible to a broader research community.

Remote magnetic tracking is crucial for navigation in GPS-denied environments, but real-world signals are often too weak, noisy, and complex to model reliably. The authors combine quantum diamond magnetometry with a deep-learning algorithm trained solely on experimental data to track an elevator in an urban setting. They show that full-vector magnetic inputs over short time windows yield robust centimeter-scale accuracy across arbitrary sensor frames despite strong noise, with model training requiring less than an hour. This model-free approach provides a practical route to deploying quantum magnetometry for real-time tracking in complex environments.

Superconducting transmon qubits are a cornerstone of solid-state quantum computing, yet their coherence is limited by dielectric loss in planar capacitors and junction electrodes. Here researchers explore to what extent this can be mitigated in mergemon qubits, which employ larger Josephson junctions that contribute most of the required capacitance. Using qubit spectroscopy to detect individual defects on surfaces and within tunnel junctions, the team compares different mergemon qubit designs and finds that careful balancing of junction and electrode geometries allows for long coherence times that are on par with similarly fabricated transmon qubits.

Spin-polarized leptons are prized as probes of how spin shapes matter. Currently they are obtained from large accelerators or laser-driven sources that demand few-femtosecond synchronization and nanocoulomb-class electron beams. Using a laser-driven sheath field, the authors exploit the polarization effects in strong-field quantum electrodynamic processes to spin-polarize the injected electron beam and produce polarized positrons, with the two species separating automatically. This work enhances the experimental feasibility of lepton polarization, relaxes the requirements for the laser and electron beam, and opens a fresh route toward polarized lepton sources.

In the search for dark matter (DM), cavity-based experiments tune a microwave resonator to the unknown oscillation frequency of wavelike DM. Superconducting cavities would make these experiments far more sensitive, but wide-range tuning is needed. The authors mechanically separate the two halves of a Nb${}_3$Sn-coated cavity to realize a tuning range of more than 1 GHz around 8.5 GHz, while the quality factor Q remains above ${10}^6$. Simulations show that radiative losses stay negligible even for large openings, which makes the method a practical route toward wide-band experiments with high-Q cavities, even in significant magnetic fields.

Topological phononic systems could enable backscattering-resistant control of mechanical waves for filters and interconnects in wireless and quantum technologies, but they are limited to low frequencies. The authors realize a gigahertz quantum spin Hall effect in nanoelectromechanical phononic crystals. They resolve the opposite handedness of the counterpropagating pseudospin branches in real space, and demonstrate a helical edge channel traversing two 120° corners without measurable loss. This brings topological phononics into the gigahertz regime, opening opportunities for robust phonon manipulation in integrated gigahertz circuits on a CMOS-compatible piezoelectric platform.

All-optical magnetization switching is attractive for ultrafast, energy-efficient magnetic information technologies, but most nanoscale demonstrations have relied on ferrimagnetic alloys, rather than ferromagnetic multilayers closer to spintronic device architectures. The authors investigate all-optical switching in patterned Pt/Gd/Co/Pt disks with just a little Gd in an otherwise ferromagnetic stack. Switching grows progressively less deterministic as disk diameter decreases, with an unexpected exponential size dependence arising from competition between weak switching bias and finite-size magnetization fluctuations—a fundamental constraint for future devices.

Understanding how interconnected neurons exchange information is a key scientific challenge, but existing optical methods are invasive, limiting recording durations. The authors combine microscopy with electrochromic optical recording (ECORE), a label-free technique relying on reversible color changes in a biocompatible medium. They demonstrate the recording of extracellular action potentials from cardiomyocytes with single-cell resolution and a high sensitivity of 6.3 µV. This approach simplifies the optical setup and allows simultaneous imaging, making ECORE accessible to a broader research community.

Remote magnetic tracking is crucial for navigation in GPS-denied environments, but real-world signals are often too weak, noisy, and complex to model reliably. The authors combine quantum diamond magnetometry with a deep-learning algorithm trained solely on experimental data to track an elevator in an urban setting. They show that full-vector magnetic inputs over short time windows yield robust centimeter-scale accuracy across arbitrary sensor frames despite strong noise, with model training requiring less than an hour. This model-free approach provides a practical route to deploying quantum magnetometry for real-time tracking in complex environments.

Superconducting transmon qubits are a cornerstone of solid-state quantum computing, yet their coherence is limited by dielectric loss in planar capacitors and junction electrodes. Here researchers explore to what extent this can be mitigated in mergemon qubits, which employ larger Josephson junctions that contribute most of the required capacitance. Using qubit spectroscopy to detect individual defects on surfaces and within tunnel junctions, the team compares different mergemon qubit designs and finds that careful balancing of junction and electrode geometries allows for long coherence times that are on par with similarly fabricated transmon qubits.

Spin-polarized leptons are prized as probes of how spin shapes matter. Currently they are obtained from large accelerators or laser-driven sources that demand few-femtosecond synchronization and nanocoulomb-class electron beams. Using a laser-driven sheath field, the authors exploit the polarization effects in strong-field quantum electrodynamic processes to spin-polarize the injected electron beam and produce polarized positrons, with the two species separating automatically. This work enhances the experimental feasibility of lepton polarization, relaxes the requirements for the laser and electron beam, and opens a fresh route toward polarized lepton sources.

In the search for dark matter (DM), cavity-based experiments tune a microwave resonator to the unknown oscillation frequency of wavelike DM. Superconducting cavities would make these experiments far more sensitive, but wide-range tuning is needed. The authors mechanically separate the two halves of a Nb${}_3$Sn-coated cavity to realize a tuning range of more than 1 GHz around 8.5 GHz, while the quality factor Q remains above ${10}^6$. Simulations show that radiative losses stay negligible even for large openings, which makes the method a practical route toward wide-band experiments with high-Q cavities, even in significant magnetic fields.