The work is backed by up to $6 million from the Defense Advanced Research Projects Agency through its Fast and Curious program. University of Michigan Engineering leads the project, with the University of Wisconsin–Madison contributing physics-based computer simulations intended to guide device design. The team describes M3BOLT as a magnetoelectric multiferroic device, bringing together ferroelectric and ferromagnetic behavior in a layered structure.

Its central aim is to move and process information with collective waves rather than relying on the controlled movement of individual electrons, potentially changing the physical limits that constrain conventional electronics. Improvements have historically come from placing chip components closer together and reducing transistor dimensions, allowing electrons to travel shorter distances and requiring lower switching voltages. At scales of only a few nanometers, however, quantum tunneling allows electrons to pass through supposedly closed transistors, producing leakage and wasting energy.

The release cites an expectation that today’s transistors will reach their maximum energy efficiency by 2037, even as artificial intelligence, edge computing and other applications continue to increase demand for processing capacity. Researchers at the University of Michigan say the M3BOLT concept is intended to address that constraint by changing the physics of the device rather than simply making an existing transistor smaller. Roozbeh Tabrizian, an associate professor of electrical and computer engineering who leads the device design, said the goal is not to claim that transistors will be replaced everywhere.

Instead, the project asks what computing speed and efficiency may become possible when an alternative device is no longer constrained by the same operating principles. Mellor Professor of Engineering Wei Lu leads the design of M3BOLT circuits. The device is built around two materials developed in Heron’s laboratory.

Its lower layer is a crystal of lead magnesium niobate-lead titanate, abbreviated PMN-PT using the chemical symbols of its constituent elements. The upper layer is a film of magnetic iron-gallium alloy. PMN-PT is ferroelectric: its charged components have a natural alignment that can reverse when exposed to an electric field, and the reversed alignment remains after the field is removed.

This electrically switchable polarization provides a way to control the magnetic layer above it without requiring a continuous current to hold a particular state. When the PMN-PT polarization changes, its atoms shift, causing magnetic poles in the iron-gallium film to oscillate in a wave-like pattern. That collective magnetic excitation is called a magnon.

Magnons can travel through the magnetic film with very little resistance, meaning that less energy is dissipated as heat than in conventional conductive pathways. Their motion can also occur at terahertz frequencies, far above the gigahertz clock rates of many present-day consumer processors. The researchers estimate that this frequency range could allow data to be processed hundreds of times faster, although that potential remains to be demonstrated in an integrated M3BOLT processor.

The two information states in the proposed device are created by converting magnetic waves into ordinary sound waves. In one state, the poles of the iron-gallium layer continue to oscillate, supporting magnons. Flipping the orientations of those poles stops the magnetic oscillation, leaving sound waves.

The presence or absence of the magnetic state could therefore function as a binary 1 or 0, replacing the two voltage levels used by conventional transistors. The design is not intended as a simple one-for-one replacement for an electronic switch: Tabrizian said new architectures may also be needed to realize additional efficiency improvements beyond the projected gain associated with changing the device physics. Another potential advantage is that the orientation of the magnetic poles is retained when the device is powered down, allowing the iron-gallium layer to serve as nonvolatile memory as well as a processing medium.

Combining memory and computation can reduce the amount of data that must move between separate processor and memory components, an activity that consumes energy and requires physical space. The project therefore targets not only higher switching speed but also a different organization of computing hardware. Lu said the near-term emphasis is on extremely low-power devices, while the broader vision includes more capable autonomous and mobile systems that could perform substantial processing without large power supplies.

The University of Wisconsin–Madison team, led by materials science and engineering associate professor Jiamian Hu, will provide simulations that predict how architectural choices affect performance. These models will also examine the effects of defects within the PMN-PT and iron-gallium materials and at the interface between them. Such analysis is important because the device depends on coupling charge-driven structural changes in a ferroelectric crystal to collective oscillations in a magnetic film.

The work remains an early-stage research program rather than a finished computing technology. Its most striking claims—up to 1,000 times greater efficiency, processing hundreds of times faster than consumer processors and the possibility of using the same material for logic and memory—describe the potential of the design and its modeling, not measured performance from a complete processor. The DARPA funding is intended to support further investigation of that potential, including device construction, circuit design and simulation.

If M3BOLT can preserve its expected switching behavior, low-loss wave propagation and information retention while operating at practical scales, it could offer a route beyond the energy constraints facing increasingly dense transistor-based systems. Until those properties are demonstrated in integrated hardware, the projections remain possibilities rather than established capabilities.

Subject of Research: DARPA-funded multiferroic device research for low-power computing and nonvolatile memory

Article Title: Beyond transistor limits: Hybrid magnetic-sound waves could boost computing speed and efficiency

Article References: Beyond transistor limits: Hybrid magnetic-sound waves could boost computing speed and efficiency. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: M3BOLT, multiferroics, magnons, ferroelectricity, transistor alternatives, energy-efficient computing, nonvolatile memory, terahertz electronics, DARPA, magnetoelectric devices, Beyond, transistor

The excitations at the heart of the study are quasiparticles, collective disturbances that behave in many ways like particles even though they are not made of matter in the ordinary sense. Magnons are quasiparticles of spin: in a magnetic material, the electron spins act like a lattice of tiny compass needles, and when they tip over in sequence they form a travelling wave, much like a Mexican wave rippling around a football stadium. Crucially, it is not the electrons themselves that migrate through the crystal, only the pattern of their flips. Phonons, by contrast, are quantized vibrations of the atoms in the crystal lattice. Because both magnons and phonons carry well-defined energy and momentum as individual entities, quantum physics treats them as particles in their own right, and understanding how they interact is central to any technology that hopes to exploit them.

The appeal of magnons is that they could carry information without moving charge. In conventional chips, the flow of electrons through resistive pathways causes power losses and generates heat, which is precisely what limits how densely and how fast silicon devices can operate. If the electrons stayed put and only their spins were manipulated, logic operations could in principle be performed with dramatically less energy. This vision is called spintronics, a fusion of spin and electronics, and it depends on being able to create, control and read out magnons quickly and reliably. The PSI team, led by Hiroki Ueda, set out to answer a deceptively simple question: when magnons are born in a solid, what happens to them next, and how long do they survive?

To find out, the researchers chose copper oxide, a well-known antiferromagnetic material with strong coupling between its magnetism and its crystal lattice. First author Arnau Romaguera of the PSI Center for Photon Science explained the choice: the material is a textbook system for studying how magnetic order talks to lattice vibrations. The experiment began with an intense optical laser pulse fired at the sample. The pulse excited the electrons, which in turn caused the initially disordered spins to flip in coordinated rows, generating magnons. That birth happened within femtoseconds, a quadrillionth of a second, an interval so short that light itself travels only a fraction of a millimetre in that time.

What followed was a cascade across the quantum timescales. Over the first few picoseconds, a trillionth of a second, the freshly created coherent magnons waves scattered off one another and degraded into a sea of incoherent waves, like rough water after a wave has broken. Then, over the next three orders of magnitude, in the nanosecond range, the magnons finally interacted with the atoms of the crystal lattice and converted their energy into phonons, the quantized lattice vibrations. The energy flow thus moved from electrons to spins to lattice, and each handoff occurred on a distinctly different clock.

The headline result is that the magnons proved remarkably long-lived. Given the strong coupling between magnetism and the lattice in copper oxide, the team expected the spin energy to drain into vibrations almost immediately. Instead, Romaguera noted, the generated magnons took a surprisingly long time to pass their energy to the lattice. In human terms all of these timescales are vanishingly short, but in the quantum world they span many orders of magnitude, and the nanosecond lifetime of the magnons is generous by the standards of ultrafast magnetism. That longevity matters enormously for applications: it could provide enough time to perform and control logical operations before the spin information dissipates into heat.

Ueda offered a physical explanation for the slow handoff. Magnons and phonons obey very different relationships between their momentum and energy values, he explained, and this mismatch modulates how efficiently magnons can transfer their energy to the lattice. The inefficient coupling leads to the long magnon lifetime, and it also provides a design principle: by specifically engineering materials to tune the momentum-energy relationships of their quasiparticles, researchers could in principle adjust the magnon lifetime as desired, tailoring spintronic materials for the operations they need to perform.

Making all of this visible was itself a formidable experimental challenge, because the phenomena unfold across such diverse timescales. The team used a pump-probe scheme: a highly brilliant X-ray pulse from a free-electron laser is directed at the sample shortly after the optical laser pulse that generates the magnons. By gradually varying the delay between the two pulses, the researchers probe the material at different moments after excitation and reconstruct a sequence of snapshots of the microscopic events, like assembling a flipbook of the energy flow. In addition to two established X-ray techniques, the team employed a novel method for the first time, known as time-resolved resonant diffuse scattering. The key measurements were conducted at the Furka experimental station of SwissFEL at PSI, and complementary measurements were performed at the ESRF synchrotron in Grenoble, France.

The experimental snapshots were supplemented by quantum kinetic simulations that modelled the measured energy flow through the material. Ueda reported that the measurements are largely consistent with the theoretical calculations, which shows that the underlying theories of quasiparticle dynamics are well understood, even if they must be adapted to the specific structures of each material. That agreement is important because it means the framework developed for copper oxide can be carried forward as a predictive tool: researchers designing new spintronic materials can model how their magnons will behave before ever growing a crystal.

The work, published in Nature Communications as an experimental study of hierarchical quasiparticle dynamics in antiferromagnets, remains basic research, but it brings the electronics of the future one important step closer to practical application. By revealing the full interplay of electronic, magnetic and lattice excitations in a single coherent picture, the PSI team has shown that magnons in antiferromagnets can persist long enough to be useful, and that their lifetime is not an accident of nature but a property that can be understood, simulated and engineered. For a field racing to replace silicon before its physical limits are reached, knowing that the spin waves of the quantum world can be made to linger is exactly the kind of insight that turns a laboratory curiosity into a technology roadmap.

Subject of Research: Time-resolved X-ray scattering study of magnon and phonon quasiparticle dynamics in an antiferromagnetic copper oxide

Article Title: X-rays show how quasiparticles interact in solids

Article References: X-rays show how quasiparticles interact in solids. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: magnons, phonons, quasiparticles, spintronics, antiferromagnets, SwissFEL, X-ray scattering, copper oxide, Paul Scherrer Institute, pump-probe technique, Nature Communications, quantum materials

Exciton–polaritons are among the strangest creatures in the solid-state menagerie. They arise when excitons — bound pairs of an electron and a hole — couple so strongly to photons trapped in an optical cavity that the distinction between light and matter blurs entirely. The resulting quasiparticles inherit the best of both worlds: the tiny effective mass and coherence of photons, and the strong mutual interactions of excitons. When enough of them crowd into a single quantum state, they undergo a form of Bose–Einstein condensation, spontaneously locking their phases together into a single macroscopic wavefunction that emits coherent light. These condensates have long been touted as candidates for quantum communication, cryptography and novel lasers, but a persistent problem has been control: in conventional semiconductor microcavities, the interactions are weak, and tuning the condensate typically means physically rebuilding the device.

The German-led collaboration, spearheaded by Heng Zhang, Niloufar Nilforoushan and Christian Weidgans at the University of Regensburg, together with colleagues in Munich, Prague and elsewhere, saw a way around this limitation by turning to a material in which the excitons themselves are intimately tied to magnetic order. CrSBr is an air-stable, A-type antiferromagnet in which the spins within each layer are aligned ferromagnetically, while adjacent layers are magnetized in opposite directions. Crucially, its excitons are quasi-one-dimensional, tightly bound, and strongly polarized along the crystallographic b axis, with an enormous oscillator strength. Because the electronic orbitals that form these excitons are fully spin-polarized, any change in the magnetic order of the crystal directly reshapes the exciton wavefunction — and with it, the polaritons built from that exciton.

To trap light and matter together, the researchers fabricated microscopic cavities of unusual elegance. Few-nanometer-thick flakes of CrSBr, exfoliated from bulk crystals, were sandwiched between two gold mirrors separated by thin spacers of polymethyl methacrylate. The flakes naturally cleave into elongated microwires, tens of micrometers long along the a axis but only about a micrometer wide along the b axis. This geometry acts as a slab waveguide with additional lateral confinement: light is squeezed tightly in the vertical direction, quantized into discrete modes across the narrow width, and left essentially free to propagate along the length of the wire. Modeling the polaritons as particles in an elongated two-dimensional rectangular potential well, the team predicted a ladder of discrete quantized states along the short axis, with energy splittings of tens of millielectronvolts — exactly what the experiments revealed.

When the researchers pumped one such microwire with femtosecond laser pulses, the angle-resolved photoluminescence showed a strikingly anisotropic picture. Along the narrow b axis, the emission resolved into discrete quantized states — a ground state and two excited states at 1.248, 1.265 and 1.286 electronvolts — while along the long a axis the modes dispersed parabolically, as expected for particles confined in only one lateral direction. A global fit with a coupled oscillator model confirmed that the system had entered the strong-coupling regime, with a vacuum Rabi splitting of 200 millielectronvolts, matching earlier observations of polaritonic effects in bulk CrSBr. Two additional, dispersionless resonances were identified as surface excitons, sitting slightly below the bulk exciton energy — a detail that would prove decisive for driving condensation.

The hallmarks of condensation appeared when the pump laser was tuned into resonance with those surface excitons. Above a threshold fluence of roughly 30 microjoules per square centimeter, the emission from the first excited quantized state surged by more than two orders of magnitude as the pump fluence rose by just a factor of three, while the emission linewidth collapsed from 19 to 8.7 millielectronvolts and the peak energy shifted upward by 5 millielectronvolts. Off-resonant pumping at higher photon energy, by contrast, produced only linear, lackluster emission. Interferometric measurements drove the point home: below threshold, the photoluminescence showed no interference fringes; above it, crisp fringes appeared, and the measured coherence time of 427 femtoseconds exceeded the polariton lifetime by an order of magnitude. Together, the superlinear intensity scaling, linewidth narrowing, energy shift and long-range spatial and temporal coherence constitute an unambiguous fingerprint of exciton–polariton condensation.

Two peculiarities of the condensation process hint at the deep magnetic physics at play. First, condensates formed only under near-resonant excitation of the surface excitons, never under high-energy pumping, suggesting that relaxation into the condensate requires a carefully matched sequence of scattering events. Second, the condensates formed not in the ground state of the microwire but in excited quantized states — and in several samples, the energy gap between the pump photons and the condensate emission closely matched the energy of an optical magnon mode of CrSBr of about 45 millielectronvolts. Density functional theory calculations supported a complementary pathway through lattice vibrations: excitons in CrSBr localize electrons on chromium atoms and holes on sulfur atoms, inducing a structural distortion that increases the interlayer separation and couples efficiently to the interlayer breathing phonon. The picture that emerges is one of resonant phonon- and magnon-assisted scattering shuttling excitation energy from surface states into the condensate — a direct handshake between light, lattice and spin.

The centerpiece of the study, however, is the magnetic control. Placing a microwire in a magneto-optical cryostat with an out-of-plane magnetic field, the researchers tracked the polariton modes as the field swept from zero to 2 tesla. Both the polariton branches and the surface exciton resonance redshifted by more than 10 millielectronvolts, while defect emission stayed put — evidence that the shifts stem from a field-driven reconfiguration of the collective spin order rather than ordinary Zeeman splitting. The spectral shift saturated above 2 tesla, exactly where CrSBr is known to flip from its antiferromagnetic to a ferromagnetic configuration under out-of-plane bias. Most strikingly, the condensed state itself followed suit: the macroscopically coherent emission shifted by up to 10.5 millielectronvolts between the antiferromagnetic and ferromagnetic phases, with condensation achievable in both regimes.

What makes this tuning so powerful is its mechanism. Previous electric-field-based strategies perturbatively modify the potential experienced by polaritons; in CrSBr, the magnetic field instead changes the magnetic order and symmetry of the material itself, transforming the exciton from a quasi-one-dimensional species into a spatially extended three-dimensional wavefunction as the spins reorganize. Because the polaritons emerge from a manifold of spin-polarized electronic orbitals, spin order becomes a native control knob for the condensate — one that operates at the level of the quantum wavefunction rather than merely its environment. The authors even suggest that the fluence-dependent energy shifts they observed may involve not only repulsive exciton–exciton interactions but also magnon-induced magnetic disorder, which reduces the exciton oscillator strength, shrinks the Rabi gap, and pushes the lower polariton energy upward.

The implications stretch well beyond a single laboratory demonstration. Because the condensate is coupled to the magnetic order, the researchers envision modulating its coherent emission on ultrafast timescales by linking it to coherent, high-frequency magnons — spin waves that can be launched and manipulated with picosecond precision. Such a platform could enable magnetic-memory integration and efficient microwave-to-optical transduction for quantum information processing, with microwave photons coupling to condensate emission through the mediating magnons. For a field that has spent two decades searching for robust ways to control macroscopic quantum states of light, the message of this work is tantalizing: sometimes the most elegant control knob is simply a magnet, and the material that responds to it may be sitting in a vial of layered crystals, waiting to be exfoliated.

Subject of Research: Magnetically tunable exciton–polariton condensation in the van der Waals antiferromagnet CrSBr

Article Title: Magnetic control of an exciton–polariton condensate in a van der Waals magnet

Article References: Zhang, H., Nilforoushan, N., Weidgans, C., Inzenhofer, T., Liebich, M., Riepl, J., Hirschmann, J., Gronwald, I., Mosina, K., Sofer, Z., Tyagi, R., Wilhelm, J., Mooshammer, F., Dirnberger, F., & Huber, R. (2026). Magnetic control of an exciton–polariton condensate in a van der Waals magnet. Nature Materials. https://doi.org/10.1038/s41563-026-02751-y

Image Credits: AI Generated

DOI: 10.1038/s41563-026-02751-y

Keywords: exciton–polaritons, condensate, CrSBr, van der Waals magnet, antiferromagnetism, magnons, microcavity, strong coupling, quantum light sources, spintronics, photoluminescence, coherence

To appreciate why this matters, it helps to understand what correlated microwaves actually are. In classical electronics, two signals are correlated when their amplitudes and phases share a well-defined relationship — for example, when they are exact twins or exact opposites of one another. In the quantum regime, correlation takes on a deeper meaning: two photons can be entangled, so that measuring one instantly constrains the other, no matter how far apart they are. Quantum networks, quantum key distribution, and entanglement-based sensing all rely on such nonclassical correlations, and generating them at microwave frequencies has traditionally required superconducting circuits cooled to millikelvin temperatures, where thermal noise cannot swamp the delicate quantum states.

The new work sidesteps that requirement by exploiting magnons — the collective excitations of electron spins in a magnetic material. In a ferromagnet, the individual magnetic moments behave like coupled pendulums; when one tips, its neighbors follow, producing a wave of precessing magnetization that propagates through the material. These magnon waves carry angular momentum and energy, and crucially, they couple efficiently to microwave photons in nearby circuitry through the magnetic component of the microwave field. This hybrid magnon–photon platform has attracted intense interest over the past decade because it combines the long coherence of magnetic excitations with the mature readout technology of microwave engineering.

What Wang and colleagues achieved is a device in which a magnon mode mediates the creation of pairs of microwave photons that are correlated with one another. The underlying mechanism can be understood as a parametric process. When the magnon mode is driven appropriately — for instance, by pumping it at a frequency equal to the sum of two cavity-mode frequencies — a single magnon excitation can be converted into two lower-frequency photons, one in each of two microwave resonators. Because the two photons originate from the same parent excitation, their phases and amplitudes are locked together: they emerge as a correlated pair. In the quantum limit, this is precisely the recipe for producing two-mode squeezed states or entangled photon pairs, the workhorses of continuous-variable quantum information at microwave frequencies.

The decisive innovation is that the process works without cryogenics. Thermal magnons are always present in a magnetic film at room temperature, and in most schemes they would act as a destructive noise floor, washing out any delicate correlations. The researchers engineered their device so that the parametric conversion gain overwhelms the thermal background, allowing the correlated component of the output to be extracted even amid substantial thermal occupation. This is analogous to how optical parametric amplifiers operate at room temperature: the amplification process itself adds a definite amount of noise, but the correlated signal survives and can be characterized statistically through correlation measurements of the two output channels.

Experimentally, the device consists of a compact magnetic element — a small film of a ferromagnetic material — positioned on top of a superconducting or normal-metal microwave circuit containing multiple resonant modes. The magnetic film is tuned so that its magnon frequency, set by an applied bias magnetic field, resonantly hybridizes with the cavity modes. When the pump is applied, the output spectra of the two modes display the hallmark signatures of correlated emission: enhanced noise in the sum of the two signals and suppressed noise in their difference, a pattern known as two-mode squeezing. The degree of correlation observed indicates that the magnon-mediated process is genuinely producing paired excitations rather than merely amplifying independent thermal noise.

The significance of room-temperature operation is difficult to overstate. Quantum microwave sources based on Josephson parametric amplifiers and related superconducting devices have transformed circuit quantum electrodynamics, but they must be operated in dilution refrigerators, which are bulky, expensive, and incompatible with many practical deployment scenarios. A magnon-based correlated microwave source that functions at ambient conditions opens the door to compact, chip-scale modules that could be integrated into radar arrays, wireless transceivers, and precision measurement systems without any cryogenic infrastructure. Correlated microwave pairs are valuable in classical contexts too: they enable noise-cancellation schemes, high-sensitivity interferometric detection, and secure communication protocols that exploit the shared randomness of the paired signals.

The result also connects to a broader research landscape. Magnonics — the study of information processing with spin waves — has matured from fundamental demonstrations of magnon Bose–Einstein condensates, reported by Demokritov and colleagues in Nature in 2006, to sophisticated hybrid devices in which magnons couple to photons, phonons, and other quasiparticles. Reviews of collective spin dynamics, such as the 2022 Physics Reports survey by Zare Rameshti and colleagues, document how strongly coupled magnon–photon systems have become a versatile platform for nonlinear signal processing. Meanwhile, experiments on superconducting circuits, including the 2023 Nature Physics demonstration of cavity magnonics by Assouly, Dassonneville, Peronnin, Bienfait and Huard, have explored magnon-mediated effects in the quantum regime. The new work effectively bridges these threads, showing that the quantum-inspired parametric toolkit can be ported to room temperature.

There are, of course, challenges ahead. The correlations demonstrated in the current device, while robust, must be strengthened and stabilized further before they can support demanding applications such as entanglement distribution between distant quantum nodes. Losses in the magnetic material and in the coupling interface set fundamental limits on the achievable squeezing, and engineering the bias field and pump scheme to maximize conversion efficiency while suppressing unwanted modes remains an active design problem. Integrating the magnetic film with standard semiconductor fabrication processes will also be essential if the technology is to move from laboratory prototypes to manufacturable components. Nonetheless, the demonstration establishes a clear feasibility baseline, and the underlying physics — parametric pairing mediated by magnons — is well suited to systematic optimization.

Looking forward, the convergence of magnonics, microwave photonics, and quantum information science suggests a rich agenda. Room-temperature correlated microwave sources could serve as calibration standards for quantum radar concepts, as entanglement resources for hybrid networks linking superconducting qubits to optical fibers via microwave-to-optical transducers, and as sensitive probes of magnetic materials themselves. They may also find use in fundamental tests of quantum-to-classical boundaries, where the ability to generate and measure correlations at ambient temperature simplifies experiments considerably. As Xufeng Zhang’s analysis emphasizes, the demonstration shows that a humble magnetic film on a microwave circuit can do work that once seemed to demand the coldest places in the universe — a reminder that sometimes the path to quantum-grade performance runs through materials that are as old as magnetism itself.

Subject of Research: Room-temperature generation of correlated microwave signals using magnon–photon coupling in a hybrid magnetic device

Article Title: Room-temperature correlated microwaves from magnons

Article References: Zhang, X. (2026). Room-temperature correlated microwaves from magnons. Nature Electronics. https://doi.org/10.1038/s41928-026-01703-3

Image Credits: AI Generated

DOI: 10.1038/s41928-026-01703-3

Keywords: magnons, microwave photons, room-temperature quantum correlations, hybrid magnonics, parametric amplification, two-mode squeezing, spintronics, quantum information, microwave circuits, ferromagnetic resonance, quantum networks, Nature Electronics