Acoustic manipulation of small particles is important for various applications, particularly in the life sciences, yet understanding higher-order acoustic forces and torques on larger, nonspherical particles has remained unexplored. This work reveals two interesting phenomena: a lateral acoustic recoil force, and a stable acoustic lift for an anisotropically shaped particle in a sound-wave field. The authors’ discovery offers fresh functionalities for acoustic manipulation and sorting of anisotropic particles, including biomolecules and cells.

Rapid developments in film-based hybrid magnonic systems call for probing magnetization dynamics at smaller scales, with both amplitude and phase information. Here the stroboscopic technique is promising, but popular spectroscopic wavelengths in or near the UV-visible range face challenges in coherent modulation at the same target frequency (often gigahertz). The authors demonstrate that an IR-wavelength (1550 nm) strobe can be used for spatial imaging of spin waves, by exploiting the Faraday and magneto-optical Kerr effects. Their setup probes a spin wave’s wavefront and intensity simultaneously, while being compact enough for a tabletop system with optical-fiber components.

Metamaterials have emerged as a promising platform to achieve on-demand shape morphing, yet so far it has been difficult to design metamaterials with more than one shape change. This study meets this challenge by introducing a sequential design strategy, where each shape change is achieved by local geometric constraints. As a result, metamaterials with multiple shape changes of arbitrary complexity can be designed. These findings highlight an inherent trade-off between design freedom and design constraints and pave the way towards multishape metamaterials with potential applications in e.g. soft robotics, mechanical computing, and mechanical self-assembly.

Piezoelectric devices are traditionally analyzed in the quasistatic regime with the magnetic fields ignored. However, the surface magnetic fields can be significant at GHz frequencies and provide a natural interface to nanoscale spin systems. The authors show via scaling arguments that the surface magnetic field scales with the square of the operation frequency, and demonstrate its existence in a proof-of-concept experiment by showing excess absorption of a focused surface acoustic wave induced by magnon mode. This approach leads to enhanced spin detection sensitivity of piezoelectric devices, and also indicates the feasibility of single-spin electrical readout at cryogenic temperatures.

Quantum computers are sensitive to sources of noise in their surroundings. In this work the authors design, implement, and demonstrate a technique that can overcome noise from the nuclei of the atoms hosting a semiconductor spin qubit. The team uses the geometrical properties of qubits to design noise-canceling control sequences and experimentally demonstrate high-fidelity quantum operations.

This study’s modeling of superconducting quantum processors reveals that, contrary to popular belief, three-body ZZZ stray couplings can surpass parasitic ZZ interactions, posing a serious threat to gate fidelity and crosstalk. Even more striking, strongly decoupled qubits—long thought to be ideal—can be more problematic than loosely coupled ones, even when idle. These findings overturn traditional design principles and force us to rethink next-generation architectures for quantum processors.

Carbon nanotubes (CNTs) are known for their exceptional electronic properties, but defects often induce scattering and thus hinder performance. Taking inspiration from CNTs’ electronic band structure, this study introduces phononic CNTs for controlling surface acoustic waves (SAWs). Phononic CNTs support two distinct, chiral SAW bands and exhibit strong resistance to scattering, enabling efficient SAW propagation. With their broad bandwidth, antireflection properties, and minimal loss, these tubes offer a promising solution for application in high-performance acoustics and phononics.

DNA flexibility is a key determinant of biological function, but the inability to directly measure the bending energy at short, biophysically relevant length scales leaves this quantity poorly understood. The authors measure DNA bending directly, by tethering a ferromagnetic nanoparticle probe to an individual DNA molecule, applying a magnetic field, and reading out a diamond magnetic field sensor. Wide-field imaging of quantum defects near the surface of the diamond enables measurement of the DNA bending torque.

Magnonic crystals, artificial magnetic media with periodically modulated properties, are a powerful tool for processing microwave signals, but generally require several millimeters of periodic structure. The authors present an innovative approach to circumvent this issue through a magnonic waveguide covered by a VO${}_2$ stripe with a shaped microgroove. Simulations show that such a structure does not manifest noticeable spin-wave reflection, but still demonstrates a rejection band in its transmission characteristic. The obtained findings pave a clear way forward to microminiaturizing spin-wave devices, where features of magnonic crystals are exploited.

Spintronic devices known as metallic nonlocal spin valves are leading candidates for next-generation low-resistance hard disk drive read heads but suffer from low signal. This work addresses this challenge through a wide-ranging study of the use of tuned-interface-resistance Al-O barriers, realizing 500-fold enhancement in spin signal even in the ultrathin Al limit. Despite this boost, spin signals still fall short of theoretical predictions, uncovering a universal spin polarization vs. resistance-area product relationship, over twelve orders of magnitude in the resistance-area product.

N-$V$ diamond magnetic microscopes enable high-resolution imaging across a wide range of physical and engineering disciplines, but the applications were restricted to a narrow measurable frequency range, and the field of view size was limited when imaging ac magnetic fields. This work overcomes these challenges to achieve a 1.5 $\times$ 1.5 mm${}^2$ field of view size, and applies a quantum frequency mixing technique to enable a wide range of detectable frequencies, from 0 to 70 MHz and beyond. This result can lead to new capabilities to better understand and diagnose problems in electronics components, study material properties, and even improve quantum computing technology.

Twin-field quantum key distribution exploits single-photon interference to provide long-haul secure communication. However, real-time phase tracking between optical signals sent from opposite ends of the communication link is necessary to realize this scheme. Here the authors show that it is feasible to apply independent optical frequency combs in a quantum communication field trial, using a coherent dual-band stabilization technique. A practical finite-size-secure-key rate of 0.53 bit/s is recorded over a 546-km link connecting two major cities in China. This study represents a significant setup toward the integration of long-distance fiber links into quantum networks.

Single-photon detectors are integral to many photonic quantum technologies, but take tens of nanoseconds to recover after each detection event. This study models the form of the count-rate saturation for bunched, Poissonian, and antibunched light sources and demonstrates the form’s effect on the recovery of detector efficiency. The authors also show how this effect suppresses the ability to accurately measure multiphoton correlation with bunched light. These insights highlight the importance of accurate detector calibration as higher-rate sources continue to be developed for real-world quantum technologies.

Nanoscale sensing of electromagnetic signals in aqueous environments is crucial for applications ranging from advanced materials research to biological systems. Employing optically trapped fluorescent nanodiamonds (FNDs) containing nitrogen-vacancy centers, the authors perform spin-relaxometry measurements in solution, demonstrating nanomolar-level sensitivity to the paramagnetic ion Gd${}^{3+}$. They also develop a theoretical framework that successfully captures all three of the distinct phases observed in the data. Their work highlights the potential of optically trapped FNDs to advance nanoscale sensing of free paramagnetic ions and molecules in biologically relevant environments.

Limited coherence times pose one of the biggest challenges for quantum computing with electron-spin qubits. One promising strategy to enhance the coherence of silicon spin qubits is purification of the semiconducting host material, to remove isotopes with nuclear spins. This study shows that the residual hyperfine interactions with atoms in the barrier material act as an additional source of hyperfine noise, limiting the coherence times even for present-day purification levels of ${}^{28}Si$. Thus we should not focus solely on the silicon to improve silicon qubits.

This Letter presents an innovative approach to perfect microwave absorption, offering significant potential to reduce electromagnetic interference and enhance secure communication. Unlike traditional methods that rely on conductive materials, the authors’ technique leverages non-Hermitian physics by arranging dielectric slabs in nonuniform patterns to achieve tunable broadband absorption (up to 1.5 GHz) across specific frequencies, enabling precise control over absorption characteristics. This advance in wave manipulation is expected to impact electromagnetic absorption technologies, and perhaps could be extended to terahertz and other frequency regimes.

The interplay of Rashba spin-orbit coupling and magnetism in ultrathin ferromagnet–heavy metal bilayers is crucial for advancing spintronics, but remains challenging to elucidate. This Letter identifies distinct temperature- and bias-dependent magnetic phenomena near the Curie temperature, driven by the competition between exchange interactions and interfacial Rashba effects. Utilizing the anomalous Hall effect and magneto-optical measurements, the authors demonstrate the emergence of Rashba magnetism, a state with unique magnetic and electronic properties. These findings yield pathways to optimizing interfacial spin-orbit phenomena for efficient spin-orbitronic devices.

Nonlinearity is a critical property of nanomechanical resonators, and methods for its control are in high demand, especially as it can enrich device dynamics and extend functionality. The authors show that the coupling between flexural and torsional modes in a cantilever-like nanomechanical resonator makes it possible to tune the effective nonlinearity displayed by each mode, over a wide range in situ. The intermode nonlinearity seems to be much stronger than the intramode one, in flat resonators of high width-to-thickness ratio. This approach might augment multimode atomic force microscopy, nanomechanical quantum nondemolition measurements, phononic frequency-comb generation, and more.

Metamaterials have emerged as a promising platform to achieve on-demand shape morphing, yet so far it has been difficult to design metamaterials with more than one shape change. This study meets this challenge by introducing a sequential design strategy, where each shape change is achieved by local geometric constraints. As a result, metamaterials with multiple shape changes of arbitrary complexity can be designed. These findings highlight an inherent trade-off between design freedom and design constraints and pave the way towards multishape metamaterials with potential applications in e.g. soft robotics, mechanical computing, and mechanical self-assembly.

Piezoelectric devices are traditionally analyzed in the quasistatic regime with the magnetic fields ignored. However, the surface magnetic fields can be significant at GHz frequencies and provide a natural interface to nanoscale spin systems. The authors show via scaling arguments that the surface magnetic field scales with the square of the operation frequency, and demonstrate its existence in a proof-of-concept experiment by showing excess absorption of a focused surface acoustic wave induced by magnon mode. This approach leads to enhanced spin detection sensitivity of piezoelectric devices, and also indicates the feasibility of single-spin electrical readout at cryogenic temperatures.

Quantum computers are sensitive to sources of noise in their surroundings. In this work the authors design, implement, and demonstrate a technique that can overcome noise from the nuclei of the atoms hosting a semiconductor spin qubit. The team uses the geometrical properties of qubits to design noise-canceling control sequences and experimentally demonstrate high-fidelity quantum operations.

This study’s modeling of superconducting quantum processors reveals that, contrary to popular belief, three-body ZZZ stray couplings can surpass parasitic ZZ interactions, posing a serious threat to gate fidelity and crosstalk. Even more striking, strongly decoupled qubits—long thought to be ideal—can be more problematic than loosely coupled ones, even when idle. These findings overturn traditional design principles and force us to rethink next-generation architectures for quantum processors.

Carbon nanotubes (CNTs) are known for their exceptional electronic properties, but defects often induce scattering and thus hinder performance. Taking inspiration from CNTs’ electronic band structure, this study introduces phononic CNTs for controlling surface acoustic waves (SAWs). Phononic CNTs support two distinct, chiral SAW bands and exhibit strong resistance to scattering, enabling efficient SAW propagation. With their broad bandwidth, antireflection properties, and minimal loss, these tubes offer a promising solution for application in high-performance acoustics and phononics.

Acoustic manipulation of small particles is important for various applications, particularly in the life sciences, yet understanding higher-order acoustic forces and torques on larger, nonspherical particles has remained unexplored. This work reveals two interesting phenomena: a lateral acoustic recoil force, and a stable acoustic lift for an anisotropically shaped particle in a sound-wave field. The authors’ discovery offers fresh functionalities for acoustic manipulation and sorting of anisotropic particles, including biomolecules and cells.

DNA flexibility is a key determinant of biological function, but the inability to directly measure the bending energy at short, biophysically relevant length scales leaves this quantity poorly understood. The authors measure DNA bending directly, by tethering a ferromagnetic nanoparticle probe to an individual DNA molecule, applying a magnetic field, and reading out a diamond magnetic field sensor. Wide-field imaging of quantum defects near the surface of the diamond enables measurement of the DNA bending torque.

Magnonic crystals, artificial magnetic media with periodically modulated properties, are a powerful tool for processing microwave signals, but generally require several millimeters of periodic structure. The authors present an innovative approach to circumvent this issue through a magnonic waveguide covered by a VO${}_2$ stripe with a shaped microgroove. Simulations show that such a structure does not manifest noticeable spin-wave reflection, but still demonstrates a rejection band in its transmission characteristic. The obtained findings pave a clear way forward to microminiaturizing spin-wave devices, where features of magnonic crystals are exploited.

Spintronic devices known as metallic nonlocal spin valves are leading candidates for next-generation low-resistance hard disk drive read heads but suffer from low signal. This work addresses this challenge through a wide-ranging study of the use of tuned-interface-resistance Al-O barriers, realizing 500-fold enhancement in spin signal even in the ultrathin Al limit. Despite this boost, spin signals still fall short of theoretical predictions, uncovering a universal spin polarization vs. resistance-area product relationship, over twelve orders of magnitude in the resistance-area product.

N-$V$ diamond magnetic microscopes enable high-resolution imaging across a wide range of physical and engineering disciplines, but the applications were restricted to a narrow measurable frequency range, and the field of view size was limited when imaging ac magnetic fields. This work overcomes these challenges to achieve a 1.5 $\times$ 1.5 mm${}^2$ field of view size, and applies a quantum frequency mixing technique to enable a wide range of detectable frequencies, from 0 to 70 MHz and beyond. This result can lead to new capabilities to better understand and diagnose problems in electronics components, study material properties, and even improve quantum computing technology.

Twin-field quantum key distribution exploits single-photon interference to provide long-haul secure communication. However, real-time phase tracking between optical signals sent from opposite ends of the communication link is necessary to realize this scheme. Here the authors show that it is feasible to apply independent optical frequency combs in a quantum communication field trial, using a coherent dual-band stabilization technique. A practical finite-size-secure-key rate of 0.53 bit/s is recorded over a 546-km link connecting two major cities in China. This study represents a significant setup toward the integration of long-distance fiber links into quantum networks.

Single-photon detectors are integral to many photonic quantum technologies, but take tens of nanoseconds to recover after each detection event. This study models the form of the count-rate saturation for bunched, Poissonian, and antibunched light sources and demonstrates the form’s effect on the recovery of detector efficiency. The authors also show how this effect suppresses the ability to accurately measure multiphoton correlation with bunched light. These insights highlight the importance of accurate detector calibration as higher-rate sources continue to be developed for real-world quantum technologies.

Nanoscale sensing of electromagnetic signals in aqueous environments is crucial for applications ranging from advanced materials research to biological systems. Employing optically trapped fluorescent nanodiamonds (FNDs) containing nitrogen-vacancy centers, the authors perform spin-relaxometry measurements in solution, demonstrating nanomolar-level sensitivity to the paramagnetic ion Gd${}^{3+}$. They also develop a theoretical framework that successfully captures all three of the distinct phases observed in the data. Their work highlights the potential of optically trapped FNDs to advance nanoscale sensing of free paramagnetic ions and molecules in biologically relevant environments.

Rapid developments in film-based hybrid magnonic systems call for probing magnetization dynamics at smaller scales, with both amplitude and phase information. Here the stroboscopic technique is promising, but popular spectroscopic wavelengths in or near the UV-visible range face challenges in coherent modulation at the same target frequency (often gigahertz). The authors demonstrate that an IR-wavelength (1550 nm) strobe can be used for spatial imaging of spin waves, by exploiting the Faraday and magneto-optical Kerr effects. Their setup probes a spin wave’s wavefront and intensity simultaneously, while being compact enough for a tabletop system with optical-fiber components.

Limited coherence times pose one of the biggest challenges for quantum computing with electron-spin qubits. One promising strategy to enhance the coherence of silicon spin qubits is purification of the semiconducting host material, to remove isotopes with nuclear spins. This study shows that the residual hyperfine interactions with atoms in the barrier material act as an additional source of hyperfine noise, limiting the coherence times even for present-day purification levels of ${}^{28}Si$. Thus we should not focus solely on the silicon to improve silicon qubits.