Traditional microscale levitation systems often employ optical or electrical methods to suspend particles, requiring highly sophisticated and sensitive apparatuses. Far from the lab bench’s fragile environments, macroscopic magnetic levitation systems offer a compelling alternative. These systems operate at room temperature and are far more resilient against environmental perturbations such as vibrations or air currents. Magnetically levitated macroscopic rotors, unlike microscale atomic particles, must contend with Earth’s gravitational pull directly, making them uniquely suitable for practical applications like gravimetry – the precise measurement of gravitational fields – as well as foundational inquiries into the crossover between classical physics and quantum phenomena. However, persistent physical challenges have historically limited their performance.

A key limitation in magnetic levitation systems stems from eddy-current damping. When a conductor moves through a non-uniform magnetic field, circulating currents, known as eddy currents, arise within the material. These currents generate secondary magnetic fields that oppose the rotor’s movement, effectively acting as friction and thereby dissipating energy and disrupting precision measurements. Although eddy-current damping serves useful purposes in various industrial applications, such as power tool brakes and train systems, it represents a formidable barrier for researchers aiming to measure physical effects with ultra-high sensitivity. Overcoming this obstacle has remained a long-standing challenge in rotor levitation technology.

Recently, researchers from the Okinawa Institute of Science and Technology (OIST) have unveiled a novel approach that elegantly circumvents eddy-current damping, marking a significant breakthrough for macroscopic levitating rotors. The team, led by professor Jason Twamley and including PhD student Daehee Kim, developed a graphite rotor disk paired with rare-earth magnets, arranged with perfect axial symmetry to eliminate the usual eddy-current friction during rotation. Rather than reducing damping by material modifications alone, this approach leverages fundamental geometric and electromagnetic principles to achieve near frictionless rotation in an idealized setup, as verified through comprehensive mathematical modeling, numerical simulations, and experimental validation.

The conventional wisdom surrounding eddy currents dictates that any movement of a conductive object in a varying magnetic field generates opposing currents that drain energy and cause drag. However, the OIST team found a profound exception: if the object’s rotation axis perfectly aligns with the symmetry axis of the magnetic field, the rotor experiences no change in magnetic flux during spin. Because the flux remains constant, eddy currents cannot form in response to rotation, effectively nullifying this source of damping. Their experiments used a centimeter-scale disk made solely of graphite, a diamagnetic conductor with favorable levitation properties and low mass, maximizing the levitative force without adding heavier composite materials.

This research builds on earlier developments by the OIST Quantum Machines Unit, who previously engineered composite graphite plates embedded in silica and wax matrices to reduce eddy-current damping. While that design confined eddy currents within microscopic grains of graphite, greatly reducing friction, the inclusion of wax compromised the levitative strength, limiting the device’s utility when weight was added—such as mirrors or other components needed for rotation tracking and measurement tasks. The new purely graphite rotor eliminates these constraints, combining strong magnetic suspension with an intrinsic evasion of eddy-current losses.

Achieving ultra-low friction in a levitated rotor is a paramount goal because it directly correlates with the device’s sensitivity to subtle forces and its potential to approach quantum mechanical behavior. The OIST rotor can be spun up with minimal energy loss, making it a candidate for high-precision gyroscopes capable of detecting infinitesimal rotational changes. Conversely, the rotor can be gradually spun down and cooled, aiming to reach the quantum regime where macroscopic superposition and quantum gravity effects might be observed. Such experiments could provide unprecedented insights into the foundation of quantum physics as it bridges to classical phenomena.

Realizing the ideal system relies heavily on precise engineering. Any imperfections in the rotor disk or asymmetries in the magnetic field can reintroduce flux variations, triggering eddy currents and damping. The researchers emphasize that the limiting factors now become mechanical machining precision and ambient air friction, which can be minimized by operating under near-perfect vacuum conditions. Advances in magnet fabrication and refined machining techniques will further enhance the symmetry and stability of the levitated rotor, pushing the boundaries of measurable precision to scales of mere millimeters or even beyond.

From a practical standpoint, this breakthrough paves the way for next-generation sensors and instruments that operate with unprecedented sensitivity and stability at room temperature. Unlike microscale levitation systems that demand intricate lasers or cryogenic environments, the OIST rotor’s macroscopic magnetic levitation operates in accessible laboratory conditions and remains robust against environmental noise. This combination makes it an attractive candidate for diverse applications, including precise inertial navigation, gravimetric mapping, and fundamental physics experiments that test the limits of wave-particle duality and the nature of vacuum gravity.

Looking forward, the implications of achieving near-zero eddy-current damping in magnetically levitated rotors span scientific disciplines. Precise measurement apparatuses based on this technology could be deployed aboard spacecraft or satellites, where microgravity environments enhance operational stability and where extreme sensitivity is needed for probing dark matter interactions, gravitational waves, or subtle deviations in fundamental constants. The platform may also enable experimental tests of rotational quantum superposition states at scales never before possible, potentially shedding light on how classical macroscopic objects transition to quantum behavior.

The OIST team’s comprehensive study was published in Communications Physics in October 2025, marking a milestone in macroscopic quantum rotor development. By blending rigorous theoretical analysis with hands-on experimental insights, they have demonstrated a path forward that blends elegant physics with practical engineering to eradicate one of the longest-standing obstacles in magnetic rotor levitation research. Their work exemplifies how precision engineering guided by fundamental electromagnetic theory can unlock new frontiers of measurement and quantum science accessible at room temperature and human-friendly scales.

In summary, the creation of a diamagnetically levitated graphite rotor that completely sidesteps eddy-current damping effects represents a landmark achievement. This advances the state-of-the-art from complex, fragile microscale levitation setups toward robust, scalable macroscopic systems with ultra-low frictional losses. Such systems hold promise not only for refined classical sensing applications but also for pioneering quantum mechanical research. The elegant exploitation of axial symmetry to suppress rotational eddy currents unlocks a realm where frictionless, nearly ideal macroscopic rotors operate, merging the dream of levitation with the rigorous demands of experimental physics in unprecedented ways.

Subject of Research: Not applicable

Article Title: A magnetically levitated conducting rotor with ultra-low rotational damping circumventing eddy loss

News Publication Date: 10-Oct-2025

Web References:

• Communications Physics: https://doi.org/10.1038/s42005-025-02318-4

References:

Kim, D., Twamley, J., et al. (2025). “A magnetically levitated conducting rotor with ultra-low rotational damping circumventing eddy loss,” Communications Physics. https://doi.org/10.1038/s42005-025-02318-4

Image Credits: Adrian Skov (OIST)

Keywords: Magnetic levitation, eddy-current damping, diamagnetic rotor, graphite disk, rare earth magnets, quantum regime, ultra-low friction, gyroscope, quantum machines, precision sensors, axial symmetry, vacuum gravity

Quantum physics continually defies our classical understanding of the universe, revealing phenomena that challenge fundamental intuitions. A groundbreaking study by researchers at the University of Geneva (UNIGE) has unveiled a remarkable advancement: the ability to perform joint quantum measurements on particles separated by vast distances without necessitating their physical convergence. This achievement fundamentally relies on the intricate phenomenon known as quantum entanglement, which intertwines particles in such a way that their quantum states remain inseparably linked regardless of spatial separation. The implications of this discovery are profound, potentially revolutionizing quantum communication, distributed quantum computing, and our fundamental approach to quantum measurements.

At the heart of modern quantum theory lies the ability to accurately measure and manipulate the states of atomic and subatomic particles. Unlike classical physics, quantum systems exhibit properties such as superposition and entanglement, which do not have analogs in the macroscopic world. However, the act of measurement in quantum mechanics is fraught with subtleties. The measurement apparatus itself is governed by quantum laws, making it inherently challenging to extract information without inadvertently altering the system’s state. This reflexive nature of quantum measurements complicates not only theoretical understanding but also technological applications, where precise readouts of quantum information are critical.

The UNIGE research team, comprising physicists Jef Pauwels, Alejandro Pozas Kerstjens, Flavio Del Santo, and Nobel laureate Nicolas Gisin, has delved into the largely unexplored realm of joint quantum measurements distributed across multiple particles located remotely. Traditionally, joint measurements required physical interaction between particles to combine their quantum information resources. Such interactions are cumbersome, especially when particles are separated by significant distances, impeding scalability in quantum technologies. The team’s novel approach leverages entanglement as a resource shared among separate measurement devices, enabling them to collectively perform what is effectively a joint measurement without physically bringing particles together.

Quantum entanglement, often described as a mysterious "invisible thread," establishes instantaneous correlations between quantum particles regardless of the distance that separates them. When two or more particles are entangled, the measurement of one instantaneously affects the state of the other(s), a feature Einstein famously dubbed "spooky action at a distance." The team’s insight was that this intrinsic nonlocality could be harnessed not only to observe but to perform joint measurements across systems deployed remotely. This reframes entanglement from just a curious phenomenon to a crucial operational tool in distributed quantum measurement networks.

However, the complexity does not end there. Different measurements vary in their “entanglement cost,” or the quantity and configuration of entangled particles required to perform them accurately in a distributed manner. Some measurements demand high levels of entanglement spread over many particles and devices, while others can be executed with minimal entanglement resources. To tackle this intricate landscape, the researchers devised a comprehensive classification framework—a “catalogue”—that meticulously maps out which measurements fall into which entanglement resource categories. This systematic approach offers a blueprint for optimizing measurement strategies according to available entanglement, enabling efficient design of quantum protocols.

The ramifications of this research stretch far beyond academic interest. In quantum communication, for example, securing and decoding information encoded in photons is fundamental. The ability to perform joint measurements remotely without physically transferring particles could enhance protocols for quantum key distribution and quantum networks, offering more robust, scalable, and less vulnerable architectures. This distributed measurement paradigm circumvents many practical challenges associated with physically moving quantum particles, such as losses and decoherence, thereby improving fidelity and range.

Furthermore, the advancement holds enormous potential in quantum computing. Unlike traditional computers where data is centrally processed, next-generation quantum computers may operate as networks of smaller distributed processors. Here, reading out computation results requires coordinated joint measurements across disparate quantum nodes. The Geneva team’s remote joint measurement protocols can eliminate the need for centralization by enabling each processor to measure its subsystem locally while still reconstructing the global outcome through entanglement-assisted correlations. This decentralization could pave the way for scalable modular quantum computing systems, mitigating hardware bottlenecks and minimizing error propagation.

Delving deeper, the study addresses the fundamental question of how quantum information is localized and manipulated through measurements distributed over multiple parties. Traditionally, the “localization” of information implied bringing subsystems together physically. The new entanglement-based framework redefines localization cost in terms of entanglement consumption, bridging abstract quantum theory with practical resource management. By quantifying the entanglement cost for performing different classes of measurements, the research offers a resource-aware perspective that could guide future experimental setups and quantum protocol designs.

The implications extend to the philosophical and foundational domains of quantum mechanics as well. The ability to perform joint measurements remotely invites fresh perspectives on nonlocality, measurement independence, and the very nature of quantum reality. The transition from viewing measurements as local acts to global operations mediated by shared entanglement challenges existing conceptual frameworks and may inspire novel interpretations and theoretical developments.

One of the notable challenges remains technological implementation. While the theoretical framework and classification catalog are formidable achievements, realizing these remote joint measurements in laboratory settings involves overcoming significant obstacles, including generating high-quality entanglement, maintaining coherence over long distances, and synchronizing quantum devices precisely. Nonetheless, the Geneva team emphasizes the achievable nature of these goals and expresses intent to explore these avenues experimentally, marking a promising step toward tangible quantum systems exploiting their theoretical breakthroughs.

This research has been published in the prestigious journal Physical Review X and is poised to influence numerous disciplines within quantum science. By advancing our mastery of quantum measurements and entanglement resources, the work effectively lays down operational foundations that will likely underpin future quantum communication networks and distributed quantum computer architectures.

As Alejandro Pozas Kerstjens summarizes, “Our findings not only deepen our conceptual grasp of the measurement problem but open exciting new pathways for designing quantum protocols where spatial separation no longer limits collaborative measurement capabilities. This is a significant stride toward fully decentralized quantum technologies where information processing and readout transcend physical boundaries through entanglement.”

The intersection of theory and application in this study highlights an exciting period in quantum research. As scientists continue to unlock the capabilities of entanglement and refine measurement techniques, the era of practical, widespread quantum networks and distributed quantum machines comes ever closer to reality. The Geneva team’s contribution marks a pivotal advancement in this journey, emphasizing that in quantum physics, distance indeed may no longer be an obstacle but a resource to be harnessed.

Subject of Research: Not applicable

Article Title: Classification of Joint Quantum Measurements Based on Entanglement Cost of Localization

News Publication Date: 14-Apr-2025

Web References: 10.1103/PhysRevX.15.021013

Keywords

Quantum entanglement, joint quantum measurements, distributed quantum computing, quantum communication, entanglement cost, quantum measurement classification, nonlocality, quantum protocols, remote measurement, quantum networks, quantum information theory, quantum measurement resource theory

A key development in this quest has been reported by a team led by Xiaoyang Zhu, the Howard Family Professor of Nanoscience at Columbia University. Their groundbreaking study, published on April 3, adds over a dozen novel quantum states to what is rapidly becoming a richly populated quantum zoo. Zhu expressed surprise at both the quantity and the novelty of the states unearthed during their research efforts.

Significantly, some of these newly identified states hold the promise of providing the foundational elements necessary for the creation of a topological quantum computer, a theoretical construct that could revolutionize computational power. Unlike current quantum computers, which operate using superconducting materials that are adversely affected by magnetic fields, the states discovered in Zhu’s studies can be synthesized without the need for external magnets. This breakthrough is primarily attributed to the unique properties of twisted molybdenum ditelluride, the exceptional material harnessed in their experiments.

The underlying principles that govern many of these new quantum states are intricately intertwined with the Hall effect—a phenomenon first described in 1879. The classical Hall effect illustrates how electrons, when subject to a magnetic field, tend to aggregate along the edges of a metallic strip, resulting in a voltage differential that is directly proportional to the strength of the magnetic field. However, in the quantum realm, particularly at ultra-low temperatures and within two-dimensional confines, this behavior evolves from linearity into quantized jumps that correlate with the electron’s charge.

Delving deeper into the quantum regime reveals an extraordinary aspect known as the fractional quantum Hall effect, which enables electrons to manifest fractional charges, such as -½ or -⅓. This counterintuitive effect showcases the ability of multiple electrons to act in unison, collectively generating quasiparticles with charges that are not simply multiples of an electron’s elementary charge. This intriguing discovery earned Horst Stormer, a Columbia Professor Emeritus, a Nobel Prize in Physics in 1998.

The community of researchers has long sought to uncover the fractional quantum Hall effect, which has surfaced across a variety of materials. A pivotal moment occurred in 2023, when Xiaodong Xu, a physicist at the University of Washington linked with Columbia’s Energy Frontier Research Center on Programmable Quantum Materials, made strides by identifying an anomalous fractional quantum Hall effect in layers of twisted molybdenum ditelluride. Xu’s findings, established alongside experiments at Cornell and Shanghai Jiao Tong University, illuminated two previously elusive fractional quantum anomalous Hall (FQAH) states.

A deeper investigation into these materials led to the realization that twisted layers of molybdenum ditelluride exhibit topological properties that create favorable electron arrangements. This quantum twist not only facilitates the formation of fractional Hall charges but also generates an internal magnetic field, rendering the necessity for external magnets obsolete. In the summer prior to the publication of Zhu’s latest research, Yiping Wang, a postdoctoral fellow at the Max-Planck NYC Center and primary author of the study, obtained samples from Xu’s lab.

During her experimental work on these samples utilizing a pump-probe spectroscopy technique—a method developed in collaboration with co-author Eric Arsenault—Wang made an astonishing discovery. Her results revealed a spectrum of fractional charge peaks, some of which correspond to theoretically predicted values crucial for the construction of topological quantum computers, notably including non-Abelian anyons. This discovery not only paves the way for deeper explorations into the new states but also showcases the pump-probe technique as a remarkably sensitive method for detecting new quantum states of matter.

Zhu emphasized the importance of these new discoveries, noting that they not only elucidate the ground-state configurations of these materials but also open avenues for studying the dynamical changes that occur when these states are manipulated. "We feel as though we’ve entered a new dimension," Wang remarked, conveying the excitement and potential that accompany the exploration of correlation and topology within these quantum systems. Their results elicit enthusiasm for further investigations, as the team hopes their findings will stimulate others within the scientific community to embark on their own explorations.

The journey to fully understand the implications and potential applications of these newly identified quantum states is just beginning. As researchers peel back the layers of complexity surrounding twisted molybdenum ditelluride and its entourage of emergent states, one thing becomes clear: the quantum zoo, teeming with possibilities, is an expanding frontier where the next groundbreaking discoveries may await.

Policymakers, educators, and students alike hold a vested interest in the implications of research like this, as the development of topological quantum computers could usher in a new era of efficiency and reliability in quantum computing technology. The findings put forth by Zhu and his team offer not just insights into quantum mechanics but also a glimpse into a fascinating future where our understanding of the quantum realm could transform technology in ways we can only begin to imagine.

The importance of collaboration in this field cannot be overstated. Teams working across institutions, such as those involved in the research at Columbia and the University of Washington, exemplify the collective effort needed to advance the frontier of quantum materials research. As researchers continue to share insights and techniques, the pace of discovery is likely to accelerate, revealing even more about the intricate tapestry that defines the quantum world.

In conclusion, the current study and its novel contributions to the field not only showcase the potential of twisted materials in revealing new quantum states but also highlight the excitement that comes from the unexpected. With each new discovery adding to our quantum zoo, the scientific community remains poised to uncover the rich tapestry of phenomena that lies just beyond the horizon.

Subject of Research: Exploration of novel quantum states in twisted molybdenum ditelluride and their relationship to topological quantum computing.
Article Title: Hidden states and dynamics of fractional fillings in twisted MoTe2 bilayers
News Publication Date: 3-Apr-2025
Web References: Nature Article
References: DOI: 10.1038/s41586-025-08954-8
Image Credits: Columbia University

Keywords

Quantum states, Quantum Hall effect, Discovery research, Topology, Materials testing, Spectroscopy.