Articles tagged with "quantum-physics"
Physicists rewrite 200-year-old principle to unlock atomic engines
A research team at the University of Stuttgart, led by physicists Eric Lutz and Milton Aguilar, has fundamentally challenged the 200-year-old Carnot principle, a cornerstone of thermodynamics that sets the maximum efficiency for heat engines operating between two thermal reservoirs. While the Carnot principle, formulated in 1824, applies to macroscopic engines like steam turbines, the researchers demonstrated that it does not hold at the atomic scale where quantum correlations between particles come into play. Their work shows that quantum heat engines can surpass the traditional Carnot efficiency limit by harnessing these correlations, which classical thermodynamics neglects. This breakthrough extends thermodynamic laws to account for quantum effects, revealing that atomic-scale thermal machines can convert both heat and quantum correlations into usable work, thus achieving higher efficiencies than previously thought possible. The findings open new avenues for developing ultra-efficient quantum engines and nanoscale technologies, including tiny molecular motors potentially capable of powering medical nanobots or manipulating materials at the atomic level. Published in Science Advances
energyquantum-enginesthermodynamicsatomic-scalenanobotsquantum-physicsheat-enginesQuantum 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-systemsFirst quantum squeezing achieved with nanoscale particle motion
Researchers at the University of Tokyo have achieved a groundbreaking feat by demonstrating quantum squeezing of the motion of a levitated nanoscale particle. Quantum squeezing reduces the uncertainty in a particle’s position or velocity below the standard quantum limit set by zero-point fluctuations, a fundamental aspect of quantum mechanics. By levitating a glass nanoparticle in a vacuum and cooling it near its ground state, the team managed to measure a velocity distribution narrower than the quantum uncertainty limit, marking the first such observation for nanoscale particle motion. This experiment bridges the gap between microscopic quantum phenomena and larger-scale objects, offering a new platform to explore quantum mechanics at mesoscopic scales. The achievement required overcoming significant challenges, including stabilizing the levitated particle and minimizing environmental noise. The sensitivity of the nanoscale particle to external fluctuations, while initially a hurdle, now provides a powerful system for studying the boundary between classical and quantum physics. Beyond fundamental science, this advance holds promise for practical applications such as ultra-precise quantum sensors that could enable GPS
materialsquantum-physicsnanoscale-particlesquantum-squeezingsensorsquantum-mechanicsnanotechnologyPhysicists create world's first time crystal visible to human eye
Physicists at the University of Colorado Boulder have created the world’s first time crystal visible to the human eye, using liquid crystals—the same materials found in phone displays. Unlike ordinary crystals with repeating spatial patterns, time crystals exhibit a repeating structure in time, with components that move and transform in a continuous cycle. By shining specific light on liquid crystal samples contained between glass plates coated with dye molecules, the researchers induced stable, swirling patterns that repeat over time and can be seen under a microscope or even with the naked eye under special conditions. This breakthrough builds on the theoretical concept proposed by Nobel laureate Frank Wilczek in 2012 and subsequent experimental realizations that were not visible without specialized equipment. The liquid crystal time crystals form through the movement and interaction of molecular “kinks” that behave like particles, creating dynamic, stable patterns resistant to temperature changes. The team envisions practical applications such as advanced anti-counterfeiting measures—embedding “time watermarks” in currency that reveal unique moving patterns
materialstime-crystalliquid-crystalsoptical-devicesanti-counterfeitingquantum-physicsnanotechnologyPhysicists propose tabletop “neutrino laser” to probe ghost particles
MIT physicists have proposed a novel concept for a neutrino laser—a quantum device that could emit coherent, intense beams of neutrinos by synchronizing the radioactive decay of atoms cooled to near absolute zero. The idea involves cooling a gas of radioactive rubidium-83 atoms into a Bose-Einstein condensate, a quantum state where atoms act collectively. This synchronization could accelerate neutrino emission from a process that normally takes months to just minutes, producing a rapid, coherent neutrino beam analogous to the photon emission in conventional lasers. This approach leverages the principle of superradiance, where atoms emit light in unison to amplify the output, applied here to neutrino emission. If realized, the neutrino laser could have significant implications beyond fundamental physics. Because neutrinos interact very weakly with matter, such a beam could enable communication through Earth or deep space without interference, potentially benefiting underground or extraterrestrial communication systems. Additionally, the radioactive decay involved also produces isotopes useful in medical imaging and cancer diagnostics
energyquantum-physicsneutrino-laserradioactive-decayBose-Einstein-condensateparticle-physicssuperradiancePhysicists see heat move as a wave after 90 years of theory
Physicists at MIT have, for the first time, directly observed and filmed the quantum phenomenon known as "second sound," a theory predicted in 1938 but never before visually confirmed. Unlike normal heat diffusion, second sound occurs in superfluid states where heat propagates as a wave, similar to sound, with the surrounding fluid remaining stationary. The team overcame significant experimental challenges by cooling gases to near absolute zero and using lithium-6 atoms, whose resonance frequency shifts with temperature, allowing them to track heat movement via radio wave-induced resonance. This breakthrough enabled real-time visualization of heat waves in a superfluid, marking a major advance in studying quantum states of matter. The ability to observe second sound has important scientific and technological implications. It offers new insights into extreme states of matter such as those found in neutron stars, potentially improving astrophysical models. On Earth, the findings could advance research into high-temperature superconductors, which are crucial for energy-efficient technologies like lossless power transmission and magnetic levitation.
energyquantum-physicssuperfluidityheat-transfersuperconductivitythermal-imagingMIT-researchUltracold cesium atoms challenge rules of physics, refuse to heat up
Researchers at the University of Innsbruck have demonstrated that ultracold cesium atoms can defy the expected process of thermalisation, where systems typically absorb energy and lose order by heating up. By cooling about 100,000 cesium atoms to just billionths of a degree above absolute zero and confining them in one-dimensional microscopic tubes, the team subjected the atoms to repeated laser pulses intended to jolt and heat them. Contrary to classical expectations, after an initial period, the atoms’ momentum distribution ceased to spread even after hundreds of energy kicks, effectively freezing into a stable quantum state with nearly identical velocities rather than dispersing chaotically. This discovery challenges a fundamental assumption in physics that interacting many-particle systems inevitably thermalise and lose coherence. It confirms longstanding theoretical predictions that quantum effects can protect such systems from heating and entropy increase, a phenomenon difficult to observe experimentally due to the complexity of many-body interactions. The ability to prevent thermalisation is crucial for advancing quantum technologies like sensors, memories,
materialsquantum-physicsultracold-atomsentropythermalisationquantum-coherenceenergy-flow90-year-old quantum guitar strings mystery finally explained
Scientists have solved a nearly century-old problem in quantum physics by providing the first exact solution to the damped quantum harmonic oscillator—a quantum analog of a guitar string that gradually loses energy. Traditionally, physicists struggled to describe how quantum systems lose energy without violating Heisenberg’s uncertainty principle, which limits the precision with which certain pairs of physical properties, like position and momentum, can be known simultaneously. Previous models failed because they either broke this principle or could not accurately capture the damping process at the atomic scale. The breakthrough came by considering the atom not in isolation but as part of a many-body system interacting with all other atoms in its environment. Using a sophisticated mathematical technique called the multimode Bogoliubov transformation, the researchers revealed that the atom settles into a multimode squeezed vacuum state. This state carefully balances quantum uncertainties, reducing noise in one property while increasing it in another, thus preserving the uncertainty principle while accurately modeling energy loss. This solution opens new avenues for ultra-precise measurements beyond the
quantum-physicsquantum-mechanicsenergy-dissipationharmonic-oscillatormaterials-scienceatomic-vibrationsquantum-modelingQuantum freezing at room temperature locks nanoparticle at 92% purity
Scientists have achieved a significant breakthrough by freezing the rotational motion of a tiny glass nanoparticle at room temperature to a record quantum purity of 92%. This nanoparticle, though still extremely small, is much larger than typical quantum-scale objects and remains hot internally at several hundred degrees Celsius. Traditionally, observing quantum behavior in larger objects required cooling them near absolute zero and isolating them in vacuum to prevent environmental interference. However, this study bypasses those constraints by focusing solely on the particle’s rotational motion rather than its entire internal energy, enabling quantum ground-state cooling without massive cryogenic setups. The researchers used a slightly elliptical nanoparticle trapped in an electromagnetic field, where it naturally wobbles like a compass needle. By precisely controlling laser light within a high-finesse optical cavity and adjusting mirrors to favor energy removal over addition, they drained nearly all rotational energy, achieving about 0.04 quanta of residual energy. This delicate process also involved managing quantum noise from the lasers to maintain the purity of the
quantum-physicsnanoparticlesmaterials-sciencequantum-optomechanicsroom-temperature-quantum-effectsnanotechnologyquantum-purityQuantum state unlocked in object at room temperature in world-first
Researchers from TU Wien and ETH Zurich have achieved a world-first by unlocking quantum states in glass nanoparticles at room temperature, bypassing the need for ultra-low temperatures typically required in quantum experiments. Their work focused on slightly elliptical nanoparticles smaller than a grain of sand, which were held in electromagnetic fields causing them to rotate around an equilibrium orientation. By using a system of lasers and mirrors capable of both supplying and extracting energy, the team was able to reduce the rotational energy of these particles, effectively bringing their motion close to the quantum ground state despite the particles being several hundred degrees hot. This breakthrough challenges the conventional understanding that quantum states can only be observed in systems cooled near absolute zero to isolate them from environmental disturbances. The researchers emphasized the importance of treating different degrees of freedom separately, which allowed them to manipulate the rotational movement independently and achieve quantum behavior at ambient temperatures. This advancement opens new avenues for studying quantum properties in larger objects and at practical temperatures, potentially accelerating developments in quantum sensing, computation, simulation, and crypt
materialsquantum-physicsnanoparticlesenergy-statesquantum-computingquantum-sensingroom-temperature-quantum-states3D image reveals atomic dance moments before molecule explosion
Scientists at the European XFEL near Hamburg have, for the first time, directly observed the quantum zero-point motion—the intrinsic, smallest possible vibrations of atoms—in a complex molecule just moments before it exploded. Using ultrashort, high-intensity X-ray pulses to ionize a 2-iodopyridine molecule, the team caused it to shatter into charged fragments. By tracking these fragments with a reaction microscope called COLTRIMS, which captures particle trajectories on femtosecond timescales, researchers reconstructed a three-dimensional map of the molecule’s shape and internal atomic motion at the instant of breakup. The observed fragment directions revealed subtle distortions inconsistent with classical flat molecular geometry, indicating coordinated quantum trembling rather than random thermal vibrations. The experiment demonstrated that classical physics alone could not explain the data; only quantum mechanical models matched the observations, confirming the presence of coherent quantum fluctuations in the molecule’s structure. The researchers used statistical methods to reconstruct complete molecular geometries from partial fragment data, enabling a detailed
materialsquantum-physicsmolecular-imagingXFELatomic-motion3D-visualizationquantum-fluctuationsScientists levitate 300 million atoms at room temp for quantum purity
Researchers at ETH Zurich have achieved a significant breakthrough in quantum physics by levitating a nano-cluster composed of three glass spheres, totaling 300 million atoms, at room temperature. Using an optical tweezer—a device that employs polarized laser light in a vacuum—they stabilized the cluster nearly motionless, effectively neutralizing gravity. Despite this, the cluster exhibited zero-point fluctuations, a quantum phenomenon where no object can be perfectly still, oscillating at one million deflections per second with movements measured at a thousandth of a degree. The team attributed 92% of the cluster’s motion to quantum effects, demonstrating an unprecedented level of quantum purity in such a large object without the need for cryogenic cooling. This achievement marks multiple records in precision and scale, as manipulating an object of this size quantum mechanically is notably challenging. Conducted at room temperature, the experiment offers a cost-effective and scalable platform for developing sensitive quantum sensors. These sensors have potential applications in navigation, medical imaging, and fundamental physics research, including
materialsquantum-physicsnano-glass-spheresoptical-tweezerlaser-levitationquantum-sensorsroom-temperature-quantum-effectsChinese scientists detect rare quantum friction in folded graphene
Chinese scientists from the Lanzhou Institute of Chemical Physics, led by Professors Zhang Junyan and Gong Zhenbin, have experimentally observed quantum friction in folded graphene for the first time. By precisely folding graphene layers to create controlled curvature and internal strain, they altered electron behavior at the nanoscale. This strain forced electrons into fixed energy states called pseudo-Landau levels, reducing energy loss as heat and resulting in a nonlinear, sometimes decreasing friction pattern as the number of graphene layers increased. Their findings challenge classical friction models and provide the first direct evidence of quantum friction occurring between two solid surfaces. The research, conducted at ultra-low temperatures using a carefully engineered graphene system, opens new avenues for understanding friction at the atomic scale. The team plans to investigate whether similar quantum friction effects occur in other materials and under more practical conditions. Ultimately, this work could lead to technologies that better manage or minimize energy loss in nanoscale electronics and quantum computing devices by exploiting quantum friction phenomena. The study was published in Nature Communications
materialsgraphenequantum-frictionnanotechnologyenergy-efficiencynanomaterialsquantum-physicsTiny quantum sensor breaks noise limits, could boost MRI, space tech
Researchers at the Niels Bohr Institute (NBI) at the University of Copenhagen have developed a novel tunable quantum sensing system that significantly improves measurement accuracy by overcoming noise limits inherent in conventional optical sensors. This tabletop device leverages large-scale entanglement by pairing a multi-photon light state with a large atomic spin ensemble, enabling frequency-dependent squeezing of light. This approach reduces quantum noise across a broad frequency range by dynamically adjusting the phase and amplitude of light, which traditional systems cannot achieve without large-scale infrastructure. The innovation addresses both back-action noise—disturbances caused by the measurement process—and detection noise, enhancing sensor sensitivity beyond the standard quantum limit. Unlike previous frequency-dependent squeezing applications that require extensive optical resonators (around 300 meters long), the NBI team’s compact system achieves similar performance on a tabletop scale. Potential applications include improved detection of time variations, acceleration, and magnetic fields, with significant implications for biomedical imaging such as enhancing MRI resolution for earlier neurological disorder diagnosis, as well
quantum-sensingoptical-sensorsquantum-noise-reductiontunable-quantum-systembiomedical-technologyspace-technologyquantum-physicsQuantum 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-scienceQuantum tunneling time cracked: Electrons barely pause before escaping
A recent study has resolved the long-standing question of how long quantum tunneling takes by introducing a novel phase-resolved attoclock technique. Quantum tunneling, where electrons pass through energy barriers they normally couldn't cross, occurs on attosecond timescales, making direct measurement extremely challenging. Traditional attoclock methods, which use rotating elliptical laser fields to infer tunneling times from electron emission angles, have produced inconsistent results due to complex interpretations and distortions. The new approach employs perfectly circularly polarized laser light combined with precise control of the carrier-envelope phase (CEP), allowing researchers to track the exact peak of the electric field that triggers electron escape, thereby eliminating non-time-dependent distortions and improving measurement reliability. Using this refined method, the researchers found that electrons do not experience any measurable delay during tunneling; they essentially "barely pause" before escaping the atom. Instead, the key factor influencing electron emission is the strength of the atom’s hold on the electron prior to tunneling, not the tunneling duration itself. This finding challenges previous assumptions about tunneling dynamics and has significant implications for modeling ultrafast atomic and molecular processes. Additionally, the study suggests that the phase-resolved attoclock technique is stable and precise enough to be adapted for real-time chemical analysis, potentially advancing applications in ultrafast spectroscopy and quantum technologies.
materialsquantum-tunnelingattoclock-techniqueelectron-dynamicslaser-physicsquantum-physicsultrafast-measurementZEUS: US facility fires world’s most powerful laser at 2 petawatts
energylaser-technologymaterials-sciencequantum-physicsplasma-sciencescientific-discoveryhigh-field-science