Articles tagged with "quantum-entanglement"
Hidden quantum spin liquid behavior confirmed in a new kagome crystal
The article reports a significant advancement in confirming the existence of quantum spin liquids (QSLs), an exotic state of matter where electron spins remain in a fluctuating, entangled state even near absolute zero, defying typical magnetic order. Historically elusive due to their lack of clear experimental signatures, QSLs have been difficult to conclusively identify. The research team focused on materials with a kagome lattice—a triangular atomic pattern known to frustrate magnetic order and potentially host QSLs. Previously, unusual magnetic excitations observed in the kagome material herbertsmithite hinted at QSL behavior, but it was unclear if these were unique to that compound. To address this, the researchers synthesized high-quality single crystals of a different kagome material, Zn-barlowite, and used inelastic neutron scattering at very low temperatures to probe its spin dynamics. They discovered that the fundamental excitations in Zn-barlowite were not conventional magnons but fractionalized spinons, a hallmark of strong quantum ent
materialsquantum-spin-liquidkagome-latticemagnetic-materialsquantum-entanglementcrystal-synthesiscondensed-matter-physicsNew quantum method lets drones, robots talk in 'signal lost' zones
Researchers at Virginia Tech have developed a novel quantum communication method enabling AI-driven machines—such as drone swarms and robotic teams—to coordinate and share information without transmitting traditional signals. This approach leverages quantum entanglement, a phenomenon where pairs of qubits remain interconnected so that changes to one instantly affect the other, regardless of distance, without sending signals through space. The team created a framework called entangled quantum multi-agent reinforcement learning (eQMARL), where each agent holds entangled qubits and modifies them based on environmental interactions. Other agents detect these changes locally, allowing coordination without direct data exchange, which is especially valuable in environments where communication is unreliable or jammed, such as disaster zones. Testing showed that eQMARL outperforms classical AI and non-entangled quantum methods in limited-communication scenarios, offering promising applications for coordinating autonomous systems in “signal lost” zones like wildfire management or search-and-rescue operations. Despite its potential for ultra-secure communication that bypasses conventional networks
roboticsdronesquantum-communicationAImulti-agent-systemsquantum-entanglementdisaster-responseSingle-atom setup settles Einstein–Bohr challenge with new clarity
A research team at the University of Science and Technology of China (USTC), led by Pan Jianwei, has experimentally realized a century-old thought experiment originally proposed by Albert Einstein in 1927, which challenged the foundations of quantum mechanics. Using a highly sensitive single-atom interferometer with a trapped rubidium atom cooled near absolute zero, they recreated Einstein’s idea of detecting a photon’s path by measuring the recoil of a movable slit. Their results confirmed Niels Bohr’s counterargument: attempting to determine the photon’s trajectory destroys the interference pattern, demonstrating the fundamental incompatibility of certain quantum properties in a single measurement. This experiment provides one of the clearest modern validations of Bohr’s interpretation of quantum mechanics. Beyond settling this historic debate, the experiment offers a precise platform to explore more subtle quantum phenomena such as coherence loss and entanglement with the environment. By controlling the atom’s confinement and thus the photon’s momentum uncertainty, the team could tune the visibility of interference fringes, aligning
materialsquantum-physicssingle-atom-interferometerquantum-mechanicsquantum-entanglementquantum-sensorsquantum-communicationPhysicists Create a Thermometer for Measuring ‘Quantumness’
Physicists have developed a novel method to detect quantum phenomena such as superposition and entanglement by observing "anomalous" heat flow, which appears to contradict the classical second law of thermodynamics. Traditionally, heat flows spontaneously from hotter to colder bodies, as stated by Clausius in 1850. However, at the quantum scale, heat can flow from colder to hotter systems due to quantum mechanical effects, without violating the fundamental thermodynamic principles. This quantum heat flow can be harnessed as a sensitive, non-destructive thermometer for measuring "quantumness" in physical systems. The technique involves coupling a quantum system to an information-storing system and a heat sink capable of absorbing energy. By measuring the temperature increase of the heat sink, researchers can infer the presence of quantum superposition or entanglement in the system. This approach not only provides a practical tool for verifying quantum resources in quantum computing but also deepens the understanding of the interplay between thermodynamics and information theory.
energyquantum-physicsthermodynamicsheat-flowquantum-entanglementquantum-computingquantum-measurementQuantum entanglement offers clues to nature’s fast energy flow
Researchers at Rice University have found evidence that quantum entanglement can accelerate energy transfer in natural processes such as photosynthesis. Their simulations demonstrated that when energy starts in an entangled, delocalized state across multiple molecular sites, it moves faster to the acceptor site compared to starting localized at a single site. This speed advantage persisted even in the presence of environmental noise and across various parameters, suggesting that nature may exploit quantum coherence and entanglement to enhance the efficiency and robustness of energy flow in biological systems. The study used a simplified molecular model with donor and acceptor regions and included environmental effects like vibrations that influence energy transfer. The findings imply that natural systems might use quantum effects as a blueprint to optimize energy transfer speed, which could inspire new design principles for artificial light-harvesting technologies, such as more efficient solar cells. The researchers propose that experimental tests on controllable quantum platforms, like trapped-ion systems, could further validate their results. Overall, the work bridges quantum physics and biology, highlighting
energyquantum-entanglementphotosynthesisenergy-transfersolar-technologyquantum-physicsartificial-light-harvesting-systemsScientists create quantum 'telephones' to connect long-distance atoms
Researchers at the University of New South Wales (UNSW) in Australia have successfully created quantum entanglement between two distant phosphorus atoms embedded in silicon, marking a significant advancement in quantum computing. Using electrons as a bridge, they established entangled states between the nuclear spins of atoms separated by up to 20 nanometers. This breakthrough was demonstrated through a two-qubit controlled-Z logic operation, achieving a nuclear Bell state with a fidelity of approximately 76% and a concurrence of 0.67. The findings, published in the journal Science, suggest that nuclear spin-based quantum computers can be developed using existing silicon technology and manufacturing processes. The key innovation lies in using electrons—capable of “spreading out” in space—to mediate communication between atomic nuclei that were previously isolated like people in soundproof rooms. By enabling these nuclei to “talk” over a distance via electron exchange interactions, the researchers effectively created quantum “telephones” that allow long-distance entanglement. This method is robust
quantum-computingsilicon-microchipsquantum-entanglementsemiconductor-technologyspin-qubitsnuclear-spinquantum-communicationQuantum breakthrough promises real-time humanoid robot control
Researchers from Shibaura Institute of Technology, Waseda University, and Fujitsu have developed a quantum computing-based method to improve humanoid robot posture control by leveraging quantum entanglement. Their approach uses qubits to represent the position and orientation of robot joints, with entanglement mirroring the interconnected movement of real joints. By combining quantum circuits for forward kinematics with classical computing for inverse kinematics, the hybrid system reduces computational complexity, cutting errors by up to 43% and speeding up calculations compared to traditional methods. Tests on Fujitsu’s quantum simulator and a 64-qubit quantum computer confirmed these improvements, enabling realistic full-body movement calculations for robots with 17 joints that would otherwise require excessive computing power and time. This breakthrough is significant for the future of humanoid robots, especially those working closely with humans, as it enables smoother, more lifelike, and real-time motion control without oversimplifying joint models. The method is already compatible with current noisy intermediate-scale quantum (N
robotquantum-computinghumanoid-robotsinverse-kinematicsquantum-entanglementrobotics-controlquantum-simulationA strange quantum battery concept reveals the second law of entanglement
Researchers have demonstrated for the first time that quantum entanglement—a fundamental and mysterious connection between particles—can be manipulated reversibly, akin to energy in classical thermodynamics. This breakthrough was achieved by introducing the concept of an "entanglement battery," a quantum system that stores and supplies entanglement during transformations without loss. By allowing entanglement to flow in and out of this battery, the researchers resolved a long-standing challenge in quantum information science: the inability to perfectly reverse entanglement transformations under the traditional framework of local operations and classical communication (LOCC), which typically degrade entanglement. The study shows that in the asymptotic limit of many identical entangled states, transformations between different entangled states can be performed reversibly with rates determined by the relative amounts of entanglement, analogous to thermodynamic cycles involving energy and entropy. This framework not only advances the fundamental understanding of entanglement but also has practical implications for quantum computing, secure communication, and quantum networks. Furthermore
energyquantum-batteryquantum-entanglementquantum-informationthermodynamicsquantum-computingquantum-networksScientists probe whether gravity and space-time alter quantum world
A recent study by researchers from Stevens Institute of Technology, University of Illinois, and Harvard University explores how quantum networks can be used to investigate the effects of curved space-time on quantum theory, probing the intersection of Einstein’s General Theory of Relativity and quantum mechanics. Their work, published in PRX Quantum, introduces a protocol leveraging entangled W-states and quantum teleportation to distribute quantum effects across network nodes, enabling experimental tests of quantum theory under gravitational influences. This approach could provide new insights into whether gravity alters quantum mechanics, addressing a longstanding challenge in physics. The researchers highlight that while quantum mechanics effectively describes atomic and subatomic behavior, it remains unclear how or if gravity modifies these quantum effects, especially given the differences from classical physics at larger scales. Quantum networks, beyond their anticipated role in creating a global quantum internet and ultra-secure communications, offer a novel platform to experimentally study fundamental physics in curved space-time—something classical computing cannot achieve. This research opens pathways toward testing and potentially unifying quantum
quantum-networksquantum-mechanicsquantum-gravityquantum-internetquantum-entanglementquantum-computingquantum-technologyEuropean quantum scientists flip excitons like light switches
Researchers from the University of Innsbruck, in collaboration with universities in Dortmund, Bayreuth, and Linz, have developed a novel technique to control dark excitons in semiconductor quantum dots using chirped laser pulses and magnetic fields. Excitons are quasiparticles formed when an electron is excited to a higher energy state, leaving behind a positively charged hole; the electron and hole pair orbit each other due to Coulomb attraction. Excitons are categorized as bright or dark based on their interaction with light: bright excitons can absorb or emit photons, while dark excitons, likely due to differing spin configurations, do not interact optically and thus have longer lifetimes, making them promising for energy storage and quantum information applications. The team demonstrated the ability to switch bright excitons into dark excitons and vice versa, effectively using dark excitons as a quantum memory by storing quantum states in a non-radiative form and reactivating them later with laser pulses. This controlled manipulation opens new avenues
materialsquantum-dotsexcitonssemiconductorenergy-storageoptoelectronicsquantum-entanglementScientists isolate lone spinon in breakthrough for quantum magnetism
Scientists have achieved a significant breakthrough in quantum magnetism by isolating a lone spinon, a quasiparticle previously thought to exist only in pairs. Spinons arise as quantum disturbances in low-dimensional magnetic systems, particularly one-dimensional spin chains, where flipping a single electron spin creates a ripple that behaves like a particle carrying spin ½. Historically, spinons were observed only in pairs, reinforcing the belief that they could not exist independently. However, a new theoretical study by physicists from the University of Warsaw and the University of British Columbia demonstrated that a single unpaired spin can move freely through a spin-½ Heisenberg chain, effectively acting as a solitary spinon. This theoretical finding gained experimental support from recent work led by C. Zhao, published in Nature Materials, which observed spin-½ excitations in nanographene-based antiferromagnetic chains consistent with lone spinon behavior. The ability to isolate and understand single spinons has profound implications for quantum science, as spinons are closely
quantum-magnetismspinonsquantum-materialsmagnetic-materialsquantum-computingnanographenequantum-entanglementQuantum embezzlement is hiding in known one-dimensional materials: Study
A recent study by researchers at Leibniz University Hannover in Germany has demonstrated that the phenomenon of quantum embezzlement—previously thought to exist only in idealized, infinite quantum systems—can actually occur in real, finite one-dimensional materials known as critical fermion chains. Quantum embezzlement is a unique form of entanglement where one system can supply entanglement to another, enabling state changes without itself being altered, analogous to borrowing resources without depletion. The study found that these critical fermion chains, which are highly entangled systems at phase transition points, satisfy the strict criteria for universal embezzlement, meaning they can assist in creating any entangled state across various scenarios. Importantly, the researchers showed that this embezzlement property is not limited to infinite systems (the thermodynamic limit) but also emerges in large, finite fermion chains that could be experimentally realized. This suggests that quantum embezzlement is not merely a theoretical curiosity but a physical effect
quantum-materialsfermion-chainsquantum-entanglementquantum-information-transferquantum-physicsquantum-embezzlementmaterials-science