Quantum entanglement realized between distant large objects

Light propagates through the atomic cloud shown in the center and then falls onto the SiN membrane shown on the left. As a result of interaction with light the precession of atomic spins and vibration of the membrane become quantum correlated. This is the essence of entanglement between the atoms and the membrane. Credit: Niels Bohr Institute

A team of researchers from the University of Copenhagen’s Niels Bohr Institute has successfully entangled two very distinct quantum particles. The findings, which were reported in Nature Physics, have various possible applications in ultra-precise sensing and quantum communication.

Quantum communication and quantum sensing are both based on entanglement. It’s a quantum link between two items that allows them to act as if they’re one quantum object.

Researchers were able to create entanglement between a mechanical oscillator—a vibrating dielectric membrane—and a cloud of atoms, each serving as a small magnet, or «spin,» according to physicists. By joining these disparate entities with photons, or light particles, they were able to entangle. The membrane—or mechanical quantum systems in general—can be used to process quantum information, and the membrane—or mechanical quantum systems in general—can be used to store quantum information.

Professor Eugene Polzik, the project’s leader, says: «We’re on our way to pushing the boundaries of entanglement’s capabilities with this new technique. The larger the objects, the further away they are, and the more different they are, the more intriguing entanglement becomes from both a basic and an applied standpoint. Entanglement between highly diverse things is now conceivable thanks to the new result.»

Imagine the position of the vibrating membrane and the tilt of the total spin of all atoms, similar to a spinning top, to explain entanglement using the example of spins entangled with a mechanical membrane. A correlation occurs when both items move randomly yet are observed travelling right or left at the same moment. The so-called zero-point motion—the residual, uncorrelated motion of all matter that occurs even at absolute zero temperature—is generally the limit of such correlated motion. This limits our understanding of any of the systems.

Eugene Polzik’s team entangled the systems in their experiment, which means they moved in a correlated way with more precision than zero-point motion. «Quantum mechanics is a double-edged sword—it gives us amazing new technology, but it also restricts the precision of measurements that would appear simple from a classical standpoint,» explains Micha Parniak, a team member. Even if they are separated by a large distance, entangled systems can maintain perfect correlation, a fact that has perplexed academics since quantum physics’ inception more than a century ago.

Christoffer stfeldt, a Ph.D. student, elaborates: «Consider the many methods for manifesting quantum states as a zoo of diverse realities or circumstances, each with its own set of features and potentials. If, for example, we want to construct a gadget that can take advantage of the many attributes they all have and perform different functions and accomplish different tasks, we’ll need to invent a language that they can all understand. For us to fully utilise the device’s capabilities, the quantum states must be able to communicate. This entanglement of two zoo elements has demonstrated what we are presently capable of.»

Quantum sensing is an example of distinct perspectives on entangling different quantum things. Different objects have different levels of sensitivity to external pressures. Mechanical oscillators, for example, are employed in accelerometers and force sensors, while atomic spins are used in magnetometers. Entanglement permits only one of the two entangled objects to be measured with a sensitivity not restricted by the object’s zero-point fluctuations when only one of the two is subject to external perturbation.

The approach has the potential to be used in sensing for both small and large oscillators in the near future. The first detection of gravity waves, performed by the Laser Interferometer Gravitational-wave Observatory, was one of the most significant scientific breakthroughs in recent years (LIGO). LIGO detects and monitors extremely faint waves produced by deep-space astronomical events such as black hole mergers and neutron star mergers. The waves can be seen because they shake the interferometer’s mirrors. However, quantum physics limits LIGO’s sensitivity since the laser interferometer’s mirrors are likewise disturbed by zero-point fluctuations. These variations produce noise, which makes it impossible to see the tiny movements of the mirrors induced by gravitational waves.

It is theoretically possible to entangle the LIGO mirrors with an atomic cloud and so cancel the reflectors’ zero-point noise in the same manner that the membrane noise is cancelled in the current experiment. Due to their entanglement, the mirrors and atomic spins have a perfect correlation that can be used in such sensors to almost eliminate uncertainty. It’s as simple as taking data from one system and applying what you’ve learned to the other. In this method, one may simultaneously learn about the position and momentum of LIGO’s mirrors, entering a so-called quantum-mechanics-free subspace and moving closer to unlimited precision in motion measurements. A model experiment demonstrating this principle is on the way at Eugene Polzik’s laboratory.

Link original: https://www.sciandnature.com/2022/01/quantum-entanglement-realized-between.html?fbclid=IwAR2RyzFbzEcknG2KeoBoJo7TY4wzVHpjKqFRjbI57OxqMVexRiObG-wwh8c


China’s New Quantum Computer Has 1 Million Times the Power of Google’s

It appears a quantum computer rivalry is growing between the U.S. and China.

Physicists in China claim they’ve constructed two quantum computers with performance speeds that outrival competitors in the U.S., debuting a superconducting machine, in addition to an even speedier one that uses light photons to obtain unprecedented results, according to a recent study published in the peer-reviewed journals Physical Review Letters and Science Bulletin.

China has exaggerated the capabilities of its technology before, but such soft spins are usually tagged to defense tech, which means this new feat could be the real deal.

China’s quantum computers still make a lot of errors

The supercomputer, called Jiuzhang 2, can calculate in a single millisecond a task that the fastest conventional computer in the world would take a mind-numbing 30 trillion years to do. The breakthrough was revealed during an interview with the research team, which was broadcast on China’s state-owned CCTV on Tuesday, which could make the news suspect. But with two peer-reviewed papers, it’s important to take this seriously. Pan Jianwei, lead researcher of the studies, said that Zuchongzhi 2, which is a 66-qubit programmable superconducting quantum computer is an incredible 10 million times faster than Google’s 55-qubit Sycamore, making China’s new machine the fastest in the world, and the first to beat Google’s in two years.

The Zuchongzhi 2 is an improved version of a previous machine, completed three months ago. The Jiuzhang 2, a different quantum computer that runs on light, has fewer applications but can run at blinding speeds of 100 sextillion times faster than the biggest conventional computers of today. In case you missed it, that’s a one with 23 zeroes behind it. But while the features of these new machines hint at a computing revolution, they won’t hit the marketplace anytime soon. As things stand, the two machines can only operate in pristine environments, and only for hyper-specific tasks. And even with special care, they still make lots of errors. «In the next step we hope to achieve quantum error correction with four to five years of hard work,» said Professor Pan of the University of Science and Technology of China, in Hefei, which is in the southeastern province of Anhui.

China’s quantum computers could power the next-gen advances of the coming decades

«Based on the technology of quantum error correction, we can explore the use of some dedicated quantum computers or quantum simulators to solve some of the most important scientific questions with practical value,» added Pan. The circuits of the Zuchongzhi have to be cooled to very low temperatures to enable optimal performance for a complex task called random walk, which is a model that corresponds to the tactical movements of pieces on a chessboard.

The applications for this task include calculating gene mutations, predicting stock prices, air flows in hypersonic flight, and the formation of novel materials. Considering the rapidly increasing relevance of these processes as the fourth industrial revolution picks up speed, it’s no exaggeration to say that quantum computers will be central in key societal functions, from defense research to scientific advances to the next generation of economics.

Link Original: https://interestingengineering.com/chinas-new-quantum-computer-has-1-million-times-the-power-of-googles?fbclid=IwAR1IuvBdu_2k4RU0ueeA_j5dnWZkwz1N0DsmyfErtrRvBTzVs971unoo1ZQ


PARTICULAS FANTASMAS

Los científicos a menudo se refieren al neutrino como la «partícula fantasma. «Los neutrinos fueron una de las partículas más abundantes en el origen del universo y lo siguen siendo hoy en día. Las reacciones de fusión en el sol producen vastos ejércitos de ellos, que vierten sobre la Tierra todos los días. Trillones pasan a través de nuestros cuerpos cada segundo, luego vuelan a través de la Tierra como si no estuviera allí.Aunque fue postulado por primera vez hace casi un siglo y detectado por primera vez hace 65 años, los neutrinos permanecen envueltos en el misterio debido a su reticencia a interactuar con la materia», dijo Alessandro Lovato, un físico nuclear del Departamento de Energía de los Estados Unidos (DO E) Laboratorio Nacional Argonne.Lovato es miembro de un equipo de investigación de cuatro laboratorios nacionales que ha construido un modelo para abordar uno de los muchos misterios acerca de los neutrinos – cómo interactúan con los núcleos atómicos, sistemas complicados hechos de protones y neutrones («núcleo ns») unidos por la fuerza fuerte. Este conocimiento es esencial para desentrañar un misterio aún más grande — por qué durante su viaje a través del espacio o la materia los neutrinos se transforman mágicamente de uno en otro de tres posibles tipos o «sabores. «Para estudiar estas oscilaciones, se han llevado a cabo dos series de experimentos en el Laboratorio Nacional de Accelerator Fermi (MiniBooNE y NOvA). En estos experimentos, los científicos generan una intensa corriente de neutrinos en un acelerador de partículas, luego los envían a detectores de partículas durante un largo período de tiempo (MiniBooNE) o a quinientas millas de la fuente (NOvA).Conociendo la distribución original de los sabores de neutrinos, los experimentalistas recogen datos relacionados con las interacciones de los neutrinos con los núcleos atómicos en los detectores. A partir de esa información, pueden calcular cualquier cambio en los sabores de neutrinos a lo largo del tiempo o la distancia. En el caso de los detectores MiniBooNE y NOvA, los núcleos son del isótopo carbono-12, que tiene seis protones y seis neutrones.»Nuestro equipo entró en escena porque estos experimentos requieren un modelo muy preciso de las interacciones de los neutrinos con los núcleos detectores en un gran rango de energía», dijo Noemi Rocco, una posdoctora de la división de Física de Argonne y Fermilab. Dada la esquividad de los neutrinos, lograr una descripción completa de estas reacciones es un desafío formidable.El modelo de física nuclear del equipo de interacciones de neutrinos con un solo nucleón y un par de ellos es el más preciso hasta ahora. «El nuestro es el primer enfoque para modelar estas interacciones a un nivel tan microscópico», dijo Rocco. «Los enfoques anteriores no eran tan finos. «Uno de los hallazgos importantes del equipo, basado en los cálculos llevados a cabo en la supercomputadora Mira ahora retirada en la Argonne Leadership Computing Facility (ALCF), fue que la interacción del par de nucleones es crucial para modelar las interacciones de neutrinos con nu Clei con exactitud. El ALCF es una instalación de usuario de la Oficina de Ciencia DOE.»Cuanto más grandes son los núcleos en el detector, mayor es la probabilidad de que los neutrinos interactúen con ellos», dijo Lovato. «En el futuro, planeamos extender nuestro modelo a datos de núcleos más grandes, a saber, los de oxígeno y argón, en apoyo de experimentos planeados en Japón y los EE. UU.».Rocco añadió que «Para esos cálculos, nos basaremos en computadoras ALCF aún más potentes, el sistema Theta existente y la próxima máquina exascale, Aurora. «Los científicos esperan que, eventualmente, surja una imagen completa de oscilaciones de sabor tanto para neutrinos como para sus antipartículas, llamados «antineutrinos». «Ese conocimiento puede arrojar luz sobre por qué el universo se construye a partir de materia en lugar de antimateria — una de las preguntas fundamentales sobre el universo.

Link Original:Quantum Physics News


Liquid’ light shows social behaviour

Could photons, light particles, really condense? And how will this «liquid light» behave? Condensed light is an example of a Bose-Einstein condensate: The theory has been there for 100 years, but University of Twente researchers have now demonstrated the effect even at room temperature. For this, they created a micro-size mirror with channels in which photons actually flow like a liquid. In these channels, the photons try to stay together as group by choosing the path that leads to the lowest losses, and thus, in a way, demonstrate «social behavior.» The results are published in Nature Communications.

A Bose-Einstein condensate (BEC) is typically a sort of wave in which the separate particles can not be seen anymore: There is a wave of matter, a superfluid that typically is formed at temperatures close to absolute zero. Helium, for example, becomes a superfluid at those temperatures, with remarkable properties. The phenomenon was predicted by Albert Einstein almost 100 years ago, based on the work of Satyendra Nath Bose; this state of matter was named for the researchers. One type of elementary particle that can form a Bose-Einstein condensate is the photon, the light particle. UT researcher Jan Klärs and his team developed a mirror structure with channels. Light traveling through the channels behaves like a superfluid and also moves in a preferred direction. Extremely low temperatures are not required in this case, and it works at room temperature.


The structure is the well-known Mach-Zehnder interferometer, in which a channel splits into two channels, and then rejoins again. In such interferometers, the wave nature of photons manifests, in which a photon can be in both channels at the same time. At the reunification point, there are now two options: The light can either take a channel with a closed end, or a channel with an open end. Jan Klärs and his team found that the liquid decides for itself which path to take by adjusting its frequency of oscillation. In this case, the photons try to stay together by choosing the path that leads to the lowest losses—the channel with the closed end. You could call it «social behavior,» according to researcher Klärs. Other types of bosons, like fermions, prefer staying separate.

The mirror structure somewhat resembles that of a laser, in which light is reflected back and forth between two mirrors. The major difference is in the extremely high reflection of the mirrors: 99.9985 percent. This value is so high that photons don’t get the chance to escape; they will be absorbed again. It is in this stadium that the photon gas starts taking the same temperature as room temperature via thermalization. Technically speaking, it then resembles the radiation of a black body: Radiation is in equilibrium with matter. This thermalization is the crucial difference between a normal laser and a Bose-Einstein condensate of photons.
In superconductive devices at which the electrical resistance becomes zero, Bose-Einstein condensates play a major role. The photonic microstructures now presented could be used as basic units in a system that solves mathematical problems like the Traveling Salesman problem. But primarily, the paper shows insight into yet another remarkable property of light.

Link Original: https://www.scientiststudy.com/2021/10/liquid-light-shows-social-behaviour.html?fbclid=IwAR3x_CZFiidVuOYU4vCFOltF7S54q8WLrTudDchyEf5Q-ZgyHEiOX3js7k8


Light Photographed As A Wave And A Particle For The First Time

Scientists have long known that light can behave as both a particle and a wave—Einstein first predicted it in 1909. But no experiment has been able to show light in both states simultaneously. Now, researchers at the École Polytechnique Fédérale de Lausanne in Switzerland have taken the first ever photograph of light as both a wave and a particle. The key was a new experimental technique that uses electrons to capture the light’s movement. The work was published today in the journal Nature Communications.

To get this snapshot, the researchers shot laser pulses at a nanowire. The wavelengths of light moved in two different directions along the metal. When the waves ran into each other, they look liked a wave standing still, which is effectively a particle.

In order to see how the waves were moving, the researchers shot a beam of electrons at the nanowire, like dropping dye in a river to see the currents. The particles in the light wave changed the speed at which the electrons moved. That enabled the researchers to capture an image just as the waves met.

“This experiment demonstrates that, for the first time ever, we can film quantum mechanics – and its paradoxical nature – directly,” said Fabrizio Carbone, one of the authors of the study, in a press release. Carbone hopes that a better understanding of how light functions can jumpstart the field of quantum computing.

Link Original: https://www.popsci.com/light-photographed-wave-and-particle-first-time/?utm_campaign=trueAnthem%3A%20Trending%20Content&utm_medium=trueAnthem&utm_source=facebook&fbclid=IwAR1bnEcplHEvfb3UOKE8iYXeYqoC_JI1OWMhVKc2tbL4oQ9uvxfW5mkM1BQ


Pupil size surprisingly linked to differences in intelligence

What can you tell by looking into someone’s eyes? You can spot a glint of humor, signs of tiredness, or maybe that they don’t like something or someone. 

But outside of assessing an emotional state, a person’s eyes may also provide clues about their intelligence, suggests new research. A study carried out at the Georgia Institute of Technology shows that pupil size is «closely related» to differences in intelligence between individuals. 

The scientists found that larger pupils may be connected to higher intelligence, as demonstrated by tests that gauged reasoning skills, memory, and attention. In fact, the researchers claim that the relationship of intelligence to pupil size is so pronounced, that it came across their previous two studies as well and can be spotted just with your naked eyes, without any additional scientific instruments. You should be able to tell who scored the highest or the lowest on the cognitive tests just by looking at them, say the researchers.

The pupil-IQ link

The connection was first noticed across memory tasks, looking at pupil dilations as signs of mental effort. The studies involved more than 500 people aged 18 to 35 from the Atlanta area. The subjects’ pupil sizes were measured by eye trackers, which use a camera and a computer to capture light reflecting off the pupil and cornea. As the scientists explained in Scientific American, pupil diameters range from two to eight millimeters. To determine average pupil size, they took measurements of the pupils at rest when the participants were staring at a blank screen for a few minutes.

Another part of the experiment involved having the subjects take a series of cognitive tests that evaluated «fluid intelligence» (the ability to reason when confronted with new problems), «working memory capacity» (how well people could remember information over time), and «attention control» (the ability to keep focusing attention even while being distracted). An example of the latter involves a test that attempts to divert a person’s focus on a disappearing letter by showing a flickering asterisk on another part of the screen. If a person pays too much attention to the asterisk, they might miss the letter. 

The conclusions of the research were that having a larger baseline pupil size was related to greater fluid intelligence, having more attention control, and even greater working memory capacity, although to a smaller extent. In an email exchange with Big Think, author Jason Tsukahara pointed out, «It is important to consider that what we find is a correlation — which should not be confused with causation.»

The researchers also found that pupil size seemed to decrease with age. Older people had more constricted pupils but when the scientists standardized for age, the pupil-size-to-intelligence connection still remained.

Why are pupils linked to intelligence?

The connection between pupil size and IQ likely resides within the brain. Pupil size has been previously connected to the locus coeruleus, a part of the brain that’s responsible for synthesizing the hormone and neurotransmitter norepinephrine (noradrenaline), which mobilizes the brain and body for action. Activity in the locus coeruleus affects our perception, attention, memory, and learning processes.

As the authors explain, this region of the brain «also helps maintain a healthy organization of brain activity so that distant brain regions can work together to accomplish challenging tasks and goals.» Because it is so important, loss of function in the locus coeruleus has been linked to conditions like Alzheimer’s disease, Parkinson’s, clinical depression, and attention deficit hyperactivity disorder (ADHD).

The researchers hypothesize that people who have larger pupils while in a restful state, like staring at a blank computer screen, have «greater regulation of activity by the locus coeruleus.» This leads to better cognitive performance. More research is necessary, however, to truly understand why having larger pupils is related to higher intelligence. 

In an email to Big Think, Tsukahara shared, «If I had to speculate, I would say that it is people with greater fluid intelligence that develop larger pupils, but again at this point we only have correlational data.»

Do other scientists believe this?

As the scientists point out in the beginning of their paper, their conclusions are controversial and, so far, other researchers haven’t been able to duplicate their results. The research team addresses this criticism by explaining that other studies had methodological issues and examined only memory capacity but not fluid intelligence, which is what they measured.

Link Original: https://bigthink.com/surprising-science/pupil-size-intelligence


Quantum Biology May Help Solve Some of Life’s Greatest Mysteries

In one of the University of Sheffield’s physics labs, a few hundred photosynthetic bacteria were nestled between two mirrors positioned less than a micrometer apart. Physicist David Coles and his colleagues were zapping the microbe-filled cavity with white light, which bounced around the cells in a way the team could tune by adjusting the distance between the mirrors. According to results published in 2017, this intricate setup caused photons of light to physically interact with the photosynthetic machinery in a handful of those cells, in a way the team could modify by tweaking the experimental setup.1

That the researchers could control a cell’s interaction with light like this was an achievement in itself. But a more surprising interpretation of the findings came the following year. When Coles and several collaborators reanalyzed the data, they found evidence that the nature of the interaction between the bacteria and the photons of light was much weirder than the original analysis had suggested. “It seemed an inescapable conclusion to us that indirectly what [we were] really witnessing was quantum entanglement,” says University of Oxford physicist Vlatko Vedral, a coauthor on both papers.

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Birds Have a Mysterious ‘Quantum Sense’. For The First Time, Scientists Saw It in Action

Seeing our world through the eyes of a migratory bird would be a rather spooky experience. Something about their visual system allows them to ‘see’ our planet’s magnetic field, a clever trick of quantum physics, and biochemistry that helps them navigate vast distances.


Now, for the first time ever, scientists from the University of Tokyo have directly observed a key reaction hypothesised to be behind birds’, and many other creatures’, talents for sensing the direction of the planet’s poles.

Importantly, this is evidence of quantum physics directly affecting a biochemical reaction in a cell – something we’ve long hypothesised but haven’t seen in action before. 

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Aqua-Fi: Underwater WiFi developed using LEDs and lasers

Aquatic internet that sends data through light beams could enable divers to instantly transmit footage from under the sea to the surface.

The internet is an indispensable communication tool, connecting tens of billions of devices worldwide, and yet we struggle to connect to the web from under water. «People from both academia and industry want to monitor and explore underwater environments in detail,» explains the first author, Basem Shihada. Wireless internet under the sea would enable divers to talk without hand signals and send live data to the surface.

Underwater communication is possible with radio, acoustic and visible light signals. However, radio can only carry data over short distances, while acoustic signals support long distances, but with a very limited data rate. Visible light can travel far and carry lots of data, but the narrow light beams require a clear line of sight between the transmitters and receivers.

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Scientists Demonstrate “Liquid Light” at Room Temperature for the First Time

Researchers from Italy and Canada have made liquid light at room temperatures for the first time. The work paves the way for studying quantum hydrodynamics further and for future applications of this new type of matter in electronics devices.

A STRANGE FORM OF MATTER

Thanks to technological advances, scientists now have various ways of manipulating matter. Often times, these result in discovering new types of matter that posses unique properties — like the famous metallic hydrogen and the bizarre time crystal. The discovery of such materials leads to a wide range of potential applications in electronics. One of these is the so-called “liquid light,” a strange matter which researchers from the CNR NANOTECH Institute of Nanotechnology in Italy and the Polytechnique Montréal in Canada recently formed at room temperature for the first time.

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