The concept of time crystals, first theorized by Nobel Laureate Frank Wilczek in 2012, has fascinated physicists for over a decade. Unlike conventional crystals, which derive their shimmering patterns from repeating arrangements in space, time crystals exhibit a novel kind of order that persists in time. These exotic phases of matter occupy their lowest energy state yet perpetually cycle through motion without external energy input, defying traditional thermodynamic expectations. Though the existence of time crystals was experimentally demonstrated in 2016, their direct interface with other physical systems remained elusive—until now.

Mäkinen and his team employed radiofrequency pumping to generate magnons, quasiparticles representing collective spin excitations in magnetic systems, into an ultracold superfluid of Helium-3. This superfluid environment, kept near absolute zero, provides an ideal medium for sustaining fragile quantum phenomena. When the radiofrequency pump was discontinued, the magnons self-organized into a coherent time crystal that astonishingly maintained its oscillations for up to 100 million cycles. This longevity extends over several minutes, a significant enhancement compared to the typical coherence times of quantum states, opening new vistas for stable quantum memory.

One of the most remarkable aspects of this research lies in the coupling of the time crystal to a mechanical oscillator situated nearby. As the time crystal gradually faded, it established a dynamic connection with the mechanical oscillator, with characteristics dictated by the oscillator’s own frequency and amplitude. This optomechanical interaction is akin to phenomena exploited in gravitational wave detectors such as the Laser Interferometer Gravitational-Wave Observatory (LIGO), where mechanical motion is sensitively influenced by light within an optical cavity.

The analogy to cavity optomechanics offers profound implications. Just as optomechanical systems manipulate photons and mechanical vibrations to detect infinitesimal signals, the coupling of time crystals to mechanical modes could enable the encoding and readout of quantum information with exceptional fidelity. By minimizing energy dissipation in the mechanical oscillator and tuning its vibrational frequency, the researchers anticipate achieving operational regimes close to the quantum ground state, where the boundary between classical and quantum worlds blurs.

This innovative approach transforms time crystals from isolated curiosities into functional components in hybrid quantum systems. The ability to externally modulate the properties of a time crystal marks a departure from previous understandings, where perpetual motion in such systems was preserved only under strict isolation. Mäkinen explains that external observations or energy injections typically disrupt the fragile motion of time crystals, making their external control a formidable challenge. This study breaks new ground by demonstrating controlled interaction without destroying the time crystal’s coherence.

The implications for quantum computing are particularly compelling. Time crystals exhibit coherence times orders of magnitude longer than those of conventional quantum bits presently deployed. This longevity could translate into more robust quantum memory elements, capable of holding quantum information without rapid decoherence. Additionally, time crystals may serve as frequency combs—precisely spaced spectral lines crucial for high-accuracy frequency references in sensors and metrological devices. This dual utility could significantly enhance the performance and scalability of quantum technologies.

To achieve these results, the Aalto team utilized state-of-the-art facilities within the Low Temperature Laboratory, which functions as part of OtaNano, Finland’s premier research infrastructure specializing in nano-, micro-, and quantum technologies. Additionally, computational models and simulations were conducted using Aalto Science-IT’s advanced calculational resources, underscoring the interdisciplinary and high-tech nature of this research.

The study, published in Nature Communications on October 16, 2025, represents a milestone for quantum physics and materials science. It showcases how bridging time crystals with mechanical oscillators creates a new platform reminiscent of optomechanical systems but operating under markedly different physical principles. Such platforms hold promise not only for future quantum computers but also for revolutionary sensors that operate with near-perfect precision at the quantum limit.

Furthermore, this research opens up new theoretical inquiries about the fundamental physics of time translation symmetry breaking, the hallmark of time crystals. The experimental observation of coupling and controllability invites fresh exploration of how macroscopic quantum coherence can be maintained, manipulated, and exploited. It also paves the way for integrating time crystalline systems with existing quantum architectures, potentially enabling hybrid devices that leverage the best qualities of diverse quantum phenomena.

Ultimately, the successful demonstration that perpetual quantum motion can influence and be influenced by external mechanical modes is testament to the advancing maturity of quantum engineering. By precisely tuning the interaction between magnons in a superfluid and a macroscopic oscillator, researchers are not only elucidating the physics of exotic states but also innovating pathways toward quantum technologies that once belonged purely to theoretical speculation.

In the coming years, this pioneering work suggests an exciting convergence of condensed matter physics, quantum information science, and optomechanics. Such fusion may yield unprecedented sensors, memory devices, and computational platforms that harness the full weirdness and power of quantum mechanics—crafted upon the fragile yet persistent dance of time crystals.

Subject of Research: Quantum physics, time crystals, optomechanics, superfluid magnons, quantum computing applications.

Article Title: Continuous time crystal coupled to a mechanical mode as a cavity-optomechanics-like platform.

News Publication Date: 16-Oct-2025.

Web References: doi.org/10.1038/s41467-025-64673-8

Image Credits: Mikko Raskinen/Aalto University.

Keywords: Time crystal, quantum coherence, optomechanics, magnons, superfluid Helium-3, quantum computing, quantum sensors, frequency combs, ultracold physics, hybrid quantum systems, quantum memory, cavity optomechanics.

The scanning tunneling microscope stands at the heart of this achievement. With its atomically-sharp metallic needle, the STM can resolve individual atoms on surfaces by detecting currents generated from electrons tunneling between the tip and the sample. However, while it has been known that STM can sense electron spin states, directly accessing nuclear spins has posed a formidable challenge due to their relatively weak magnetic moments and the indirect nature of their interactions with the electrons. The Delft team ingeniously exploited the subtle hyperfine interactions—delicate quantum couplings between the nucleus and electron spins—to infer nuclear spin orientations by observing changes in the tunneling current.

Electron spins in atoms typically fluctuate on extremely short timescales, often mere nanoseconds, making real-time detection and control difficult. Nuclear spins, by contrast, can be far more stable, but their weak signals have long eluded rapid measurement. Surprisingly, the researchers found that the nuclear spin of the targeted atom remained stable for several seconds before flipping states. This timescale, orders of magnitude longer than electron spin lifetimes, allowed the team to monitor the nuclear spin transitions live on their computer screens, truly witnessing quantum behavior unfold in real time.

The real novelty of the experiment lies in the concept of single-shot readout—rapidly and reliably determining the nuclear spin state from a single measurement without averaging over multiple trials. Previous techniques often required repeated measurements to infer nuclear spin behavior, because the signal-to-noise level was prohibitively low or the measurement process itself disturbed the spin state. By tuning the STM setup and leveraging the hyperfine interaction, the Delft scientists detected fluctuations in the tunneling current that directly corresponded to the nuclear spin flipping between two distinct quantum states. This capability not only advances fundamental quantum measurement techniques but sets the stage for future quantum control schemes, where nuclear spins can serve as qubits or sensors.

This work reveals that nuclear spins, despite their small magnetic moment, have lifetimes suitable for quantum information tasks. While electron spins decohere within nanoseconds under typical conditions, nuclear spins act as robust quantum memories, persisting for seconds or longer. Capturing their dynamics on such timescales with an STM—an instrument traditionally used for imaging surfaces—reveals unprecedented atomic-scale information and control, which was previously thought impossible.

The implications for quantum sensing are profound. Nuclear spins tethered to surface atoms can function as ultra-sensitive probes of magnetic and electric fields, chemical environments, or even mechanical strains, all at the atomic scale. This capability surpasses traditional macroscopic sensors, promising advances in nanoscale materials science, condensed matter physics, and even the detection of elusive phenomena such as dark matter or novel quantum phases.

Achieving this feat required overcoming several technical hurdles. The STM tip must be exquisitely stable and sensitive to detect the minute current variations caused by nuclear spin flips, all while avoiding perturbation of the spin state. The research team employed rapid measurement protocols, coupled with sophisticated data analysis, to distinguish genuine nuclear spin signals from noise and other electronic fluctuations. Their success paves the way for the development of STM-based quantum sensors that can operate as scalable platforms for quantum simulation or computing.

The interplay of electron and nuclear spins within a single atom, long studied theoretically, now finds concrete expression through this experiment. The so-called hyperfine interaction, a quantum mechanical coupling arising from contact and dipolar effects between the electron cloud and the atomic nucleus, acts as the conduit transmitting nuclear spin information to the electron states detectable by STM. By harnessing this subtle yet fundamental interaction, researchers can now observe and manipulate nuclear spins with unprecedented precision.

Looking ahead, the researchers envision leveraging single-shot nuclear spin readout for quantum state preparation and error correction protocols, essential for robust quantum computing. On a practical level, this capability could enable the design of novel quantum devices where nuclear spins serve as stable information storage nodes or sensors integrated directly at the atomic scale. Furthermore, the experimental framework provides a testbed for exploring quantum coherence, decoherence mechanisms, and spin dynamics in complex materials.

This landmark study, conducted under the lead of Professor Sander Otte, marks a crucial step in the frontier of quantum measurement science. By illuminating the “silent” spins of atomic nuclei, the Delft team has expanded our toolkit for probing and harnessing the quantum world. As the field progresses, such techniques promise to transform our understanding of matter and underpin next-generation quantum technologies.

In summary, this research not only captures a fundamental quantum phenomenon—nuclear spin flips—in real time but also establishes STM as a versatile platform for quantum sensing and manipulation at the atomic scale. The ability to observe and control nuclear spins with such fidelity offers exciting possibilities in physics, materials science, and quantum engineering. As quantum technology races forward, these findings stand as a testament to the ingenuity and precision now achievable in experimental quantum science.

Subject of Research: Not applicable
Article Title: Single-shot readout of the nuclear spin of an on-surface atom
News Publication Date: 21-Aug-2025
Web References: https://www.nature.com/articles/s41467-025-63232-5
References: DOI: 10.5281/zenodo.15518772
Image Credits: Scixel

Keywords

Nuclear spin, quantum spin flipping, scanning tunneling microscope, single-shot readout, hyperfine interaction, quantum measurement, atomic scale sensing, quantum sensing, quantum information, electron spin, decoherence, quantum simulation

Superradiant phase transition arises when multiple groups of quantum particles synchronize their fluctuations to form a coherent state, effectively transitioning into a new state of matter. The researchers conducted their experiments using a crystal made from erbium, iron, and oxygen, which was cooled to an astonishing minus 457 degrees Fahrenheit while being subjected to an intense magnetic field of up to 7 tesla. This magnetic field is over 100,000 times stronger than Earth’s own magnetic force, demonstrating the extreme conditions under which such quantum phenomena might be explored.

Prominent in the research was Dasom Kim, a doctoral student at Rice, who led the investigative team. Kim explained that while the theory around SRPT suggested it could arise from interactions between quantum vacuum fluctuations and matter fluctuations, their work demonstrated that this transition could be initiated through the coupling of two distinct magnetic subsystems—the spins of iron and erbium ions within the crystal structure. This innovative approach effectively sidestepped the limitations imposed by the so-called "no-go theorem" that has long hampered experimental verification of such quantum theories.

The spins of electrons and particles play a crucial role in quantum mechanics, comparable to tiny arrows that exert a magnetic pull. When these spins align, they produce intricate magnetic patterns, much like waves rippling across a surface. This collective magnetic excitation is termed a magnon, representing a fundamental aspect of the interactions at play in quantum systems. Observing the formation of magnons under these conditions was essential to the team’s findings.

Using sophisticated spectroscopic techniques, researchers captured distinct signatures of the SRPT in their experiments. They noted that as they approached the superradiant phase, the energy signatures of specific spin modes displayed definitive changes; particularly, one mode’s energy dissipated while another’s exhibited a marked shift, or kink. These observations closely mirrored theoretical predictions of what should happen when entering the superradiant phase, instilling great confidence in the accuracy and integrity of the results.

The implications of this discovery extend far beyond academic interest. The ability to observe and understand collective quantum states during a superradiant phase transition holds transformative potential for the development of next-generation technologies. For instance, near this critical transition, the researchers discovered that the quantum system became capable of stabilizing quantum-squeezed states, which dramatically reduce quantum noise. This capability is crucial for enhancing the precision of quantum measurements, which is essential for advancing the functionalities of quantum sensors and computational devices.

The theoretical groundwork for this research was laid by Sohail Dasgupta, another graduate student at Rice, who worked alongside associate professor Kaden Hazzard, a co-author on the study. Dasgupta built on a mathematical model created by Motoaki Bamba, a professor at Yokohama National University. This collaboration highlights the fusion of experimental and theoretical physics, showcasing how theoretical predictions can be experimentally validated under the right conditions—a rare yet exhilarating experience for physicists.

Professor Hazzard emphasized the significance of this breakthrough, noting that it exemplifies the application of quantum optics concepts within solid materials. "This opens a new pathway for creating and manipulating phases of matter guided by the principles of cavity quantum electrodynamics," he remarked. Such advancements could lead to the emergence of novel materials with tailored properties conducive to quantum applications.

The crystal employed in these studies is merely one instance of a broader category of materials. The findings pave the way for further investigations into quantum phenomena across various materials with comparable magnetic interactions. By establishing a form of SRPT driven through the coupling of internal matter fluctuations, the researchers have forged a fresh perspective in the field of quantum physics, providing a framework to understand and exploit inherent quantum interactions in materials.

Professor Junichiro Kono, who serves as the corresponding author of the study and is the Karl F. Hasselmann Professor in Engineering at Rice, conveyed the importance of their findings. "Demonstrating SRPT through the coupling of two internal fluctuations is a significant milestone in quantum physics. It establishes a new understanding of how matter can act in a quantum realm," Kono stated. This work not only confirms a prediction that has lingered for decades but also highlights the possibilities for future exploration and advancements in quantum technologies.

As scientific inquiry continues to transcend established boundaries, the implications of the superradiant phase transition extend significantly into practical applications. The collective quantum states observed during such a transition could revolutionize the efficiency and capability of various quantum technologies, affecting areas from computing to sensor development. The enhanced measurement precision made possible by these states promises to elevate the fidelity of quantum experiments, laying a strong foundation for future innovation.

With the support of several prominent funding organizations—including the U.S. Army Research Office and the National Science Foundation—the researchers underline the collaborative effort involved in this cutting-edge work. This research was a cooperative endeavor among scientists from multiple institutions and disciplines, underscoring the nature of scientific advancement as a collective achievement rather than an individual pursuit.

This breakthrough in the observation of superradiant phase transitions not only enriches the tapestry of our understanding of quantum mechanics but also delineates clear pathways for the development of new technologies that harness quantum phenomena. The ability to fully comprehend and manipulate these quantum states marks a defining moment in physics, with potential ramifications that could alter the landscape of technological capabilities for years to come.

As we enter this exciting new chapter in the exploration of quantum behavior, the findings from Rice University stand as a testament to the perseverance and ingenuity of researchers dedicated to pushing the limits of human understanding. The journey has only just begun; as we strive to unlock more about the quantum world, the prospects for innovation are indeed limitless.

Subject of Research: Superradiant phase transition, quantum particles, and their implications in technology
Article Title: Observation of the magnonic Dicke superradiant phase transition
News Publication Date: April 11, 2025
Web References: Science Advances, Rice University News
References: Kim, D., et al. (2025). Observation of the magnonic Dicke superradiant phase transition. Science Advances. DOI: 10.1126/sciadv.adt1691
Image Credits: Photo by Jorge Vidal/Rice University

Keywords

Superradiance, quantum computing, quantum communication, quantum sensing, phase transition, quantum mechanics, optical properties, magnetic materials, experimental physics, collective excitation, spin dynamics, magnetic interactions.