Showing posts with label Phys.org. Show all posts
Showing posts with label Phys.org. Show all posts

Thursday, May 9

The Entropy of Quantum Entanglement


Bartosz Regula from the RIKEN Center for Quantum Computing and Ludovico Lami from the University of Amsterdam have shown, through probabilistic calculations, that there is indeed, as had been hypothesized, a rule of entropy for the phenomenon of quantum entanglement.


This finding could help drive a better understanding of quantum entanglement, which is a key resource that underlies much of the power of future quantum computers. Little is currently understood about the optimal ways to make effective use of it, despite it being the focus of research in quantum information science for decades.


The second law of thermodynamics, which says that a system can never move to a state with lower entropy, or order, is one of the most fundamental laws of nature, and lies at the very heart of physics. It is what creates the "arrow of time," and tells us the remarkable fact that the dynamics of general physical systems, even extremely complex ones such as gases or black holes, are encapsulated by a single function, its entropy.     READ MORE...

Wednesday, May 8

Quantum Challenge Solved Underground


Radiation from space is a challenge for quantum computers as their computation time becomes limited by cosmic rays. Researchers from Chalmers University of Technology, Sweden, and University of Waterloo in Canada are now going deep underground in the search for a solution to this problem—in a two-kilometer-deep mine.

A recently discovered cause of errors in quantum computers is cosmic radiation. Highly charged particles from space disturb the sensitive qubits and cause them to lose their quantum state, as well as the ability to continue a calculation. 

But now quantum researchers from Sweden and Canada will join forces to find a solution to the problem—in the world's deepest located clean room, two kilometers underground.  READ MORE...

Monday, May 6

7,000-Year-Old Settlement


Together with cooperation partners from the Museum of Vojvodina in Novi Sad (Serbia), the National Museum Zrenjanin and the National Museum Pančevo, a team from the ROOTS Cluster of Excellence has discovered a previously unknown Late Neolithic settlement near the Tamiš River in Northeast Serbia.

"This discovery is of outstanding importance, as hardly any larger Late Neolithic settlements are known in the Serbian Banat region," says team leader Professor Dr. Martin Furholt from the Institute of Prehistoric and Protohistoric Archaeology at Kiel University.

Geophysics reveals a 13-hectare settlement structure
The newly discovered settlement is located near the modern village of Jarkovac in the province of Vojvodina. With the help of geophysical methods, the team was able to fully map its extent in March of this year. It covers an area of 11 to 13 hectares and is surrounded by four to six ditches.     READ MORE...

Tuesday, April 30

The Universe & Dark Matter


Physicists have long theorized that our universe may not be limited to what we can see. By observing gravitational forces on other galaxies, they've hypothesized the existence of "dark matter," which would be invisible to conventional forms of observation.


Pran Nath, the Matthews Distinguished University Professor of physics at Northeastern University, says that "95% of the universe is dark, is invisible to the eye."


"However, we know that the dark universe is there by [its] gravitational pull on stars," he says. Other than its gravity, dark matter has never seemed to have much effect on the visible universe.    READ MORE...

Friday, April 26

New Subatomic Particle Detected


The BESIII collaboration have reported the observation of an anomalous line shape around ppbar mass threshold in the J/ψ→γ3(π+π-) decay, which indicates the existence of a ppbar bound state. The paper was published online in Physical Review Letters.

The proximity in mass to 2mp is suggestive of nucleon-antinucleon bound states, an idea that has a long history. Before the birth of Quark Model, a nucleon-antinucleon bound state was already proposed by Prof. E. Fermi and Prof. C. N. Yang.

There is an accumulation of evidence for anomalous behavior in the proton-antiproton system near the ppbar mass threshold, e.g., J/ψ→γppabr , J/ψ→γπ+π-η' and the proton's effective form factor determined from e+e-→ppbar, exhibiting a narrow peak or a very steep falloff around the ppbar mass threshold, which inspired many speculations and renewed the interests on the nucleon-antinucleon bound state.     READ MORE...

Thursday, April 18

Physics of Complex Fluids


The shearing of fluids—meaning the sliding of fluid layers over each other under shear forces—is an important concept in nature and in rheology, the science that studies the flow behavior of matter, including liquids and soft solids. 

Shear forces are lateral forces applied parallel to a material, inducing deformation or slippage between its layers.

Fluid shear experiments allow the characterization of important rheological properties such as viscosity (resistance to deformation or flow) and thixotropy (decrease in viscosity under the influence of shear), which are important in applications ranging from industrial processes to medicine. 

Studies on the shear behavior of viscoelastic fluids created by introducing polymers into Newtonian fluids have already been conducted in recent years.     READ MORE...

Tuesday, April 9

World's Most Powerful Laser


"Ready? Signal sent!" In the control room of a research center in Romania, engineer Antonia Toma activates the world's most powerful laser, which promises revolutionary advances in everything from the health sector to space.


The laser at the center, near the Romanian capital Bucharest, is operated by French company Thales, using Nobel prize-winning inventions.

France's Gerard Mourou and Donna Strickland of Canada won the 2018 Nobel Physics Prize for harnessing the power of lasers for advanced precision instruments in corrective eye surgery and in industry.

"The sharp beams of laser light have given us new opportunities for deepening our knowledge about the world and shaping it," said the Nobel Academy's citation.    READ MORE...

Monday, March 18

Device Acts Like Superconductivity Switch


In particle colliders that reveal the hidden secrets of the tiniest constituents of our universe, minute particles leave behind extremely faint electrical traces when they are generated in enormous collisions. Some detectors in these facilities use superconductivity—a phenomenon in which electricity is carried with zero resistance at low temperatures—to function.


For scientists to more accurately observe the behavior of these particles, these weak electrical signals, or currents, need to be multiplied by an instrument capable of turning a faint electrical flicker into a real jolt.     READ MORE...

Thursday, March 14

Rich Countries Use More Resources


The extraction of the Earth's natural resources tripled in the past five decades, related to the massive build-up of infrastructure in many parts of the world and the high levels of material consumption, especially in upper-middle and high-income countries.


Material extraction is expected to rise by 60% by 2060 and could derail efforts to achieve not only global climate, biodiversity, and pollution targets but also economic prosperity and human well-being, according to a report published today by the UN Environment Program (UNEP)-hosted International Resource Panel.


The 2024 Global Resource Outlook, developed by the International Resource Panel with authors from around the globe and launched during the sixth session of the UN Environment Assembly, calls for sweeping policy changes to bring humanity to live within its means and reduce this projected growth in resource use by one third while growing the economy, improving well-being, and minimizing environmental impacts.     READ MORE...

Friday, February 16

Artificial Intelligence and Cancer


Artificially intelligent software has been developed to enhance medical treatments that use jets of electrified gas known as plasma. The computer code predicts the chemicals emitted by plasma devices, which can be used to treat cancer, promote healthy tissue growth and sterilize surfaces.


The software learned to predict the cocktail of chemicals coming out of the jet based on data gathered during real-world experiments and using the laws of physics for guidance. This type of artificial intelligence (AI) is known as machine learning because the system learns based on the information provided. The researchers involved in the project published a paper about their code in the Journal of Physics D: Applied Physics.     READ MORE...

Tuesday, February 13

King Tides Swamp Pacific Coast


Mega high tides known as king tides are hitting beaches Feb. 9, giving a glimpse at what future sea level rise could mean for coastal towns and shorelines across California.

The California King Tides Project is asking for people to document the coast for a citizen-science project that aims to give decision-makers a look at how to address sea-level rise in future years.

Many beaches will be swallowed by salt water in the early morning hours Friday, Feb. 9, with tides reaching 6.6 feet high at about 8 a.m.     READ MORE...

Saturday, February 3

Improving Decontamination of Water


Plasma is an ionized gas—that is, a gas containing electrons, ions, atoms, molecules, radicals, and photons. It is often called the fourth state of matter, and surprisingly, it permeates everything. Plasmas, which are artificially generated by transmitting energy to a gas, are found in the fluorescent tubes that light kitchens, but they have also allowed mobile phones to become smaller and smaller.    READ MORE...

Wednesday, December 27

String Theory Requires Extra Dimensions


String theory found its origins in an attempt to understand the nascent experiments revealing the strong nuclear force. Eventually another theory, one based on particles called quarks and force carriers called gluons, would supplant it, but in the deep mathematical bones of the young string theory physicists would find curious structures, half-glimpsed ghosts, that would point to something more. Something deeper.


String theory claims that what we call particles—the point-like entities that wander freely, interact, and bind together to make up the bulk of material existence—are nothing but. Instead, there is but a single kind of fundamental object: the string. These strings, each one existing at the smallest possible limit of existence itself, vibrate. And the way those strings vibrate dictates how they manifest themselves in the larger universe. Like notes on a strummed guitar, a string vibrating with one mode will appear to us as an electron, while another vibrating at a different frequency will appear as a photon, and so on.  READ MORE...

Sunday, December 17

Signs of Life on MARS


A school science experiment is answering questions that are out of this world. While there had been concerns that any evidence of organic matter on Mars might be obscured by the planet's geology, new research suggests this might not be the case.

A group of budding young researchers has helped to demonstrate how evidence of life on Mars could be found.

Students from St Bernard's Convent High School in Westcliff-On-Sea, Essex, assisted scientists from the Natural History Museum and University College London in an experiment to see what evidence any potential ancient life may have left on the red planet.  READ MORE...

Sunday, December 10

Theory Unites Gravity and Quantum Mechanics


A radical theory that consistently unifies gravity and quantum mechanics while preserving Einstein's classical concept of spacetime has been announced in two papers published simultaneously by UCL (University College London) physicists.

Modern physics is founded upon two pillars: quantum theory on the one hand, which governs the smallest particles in the universe, and Einstein's theory of general relativity on the other, which explains gravity through the bending of spacetime. But these two theories are in contradiction with each other and a reconciliation has remained elusive for over a century.

The prevailing assumption has been that Einstein's theory of gravity must be modified, or "quantized," in order to fit within quantum theory. This is the approach of two leading candidates for a quantum theory of gravity, string theory and loop quantum gravity.   READ MORE...

Saturday, December 9

Individual Molecules Entangled


For the first time, a team of Princeton physicists have been able to link together individual molecules into special states that are quantum mechanically "entangled." In these bizarre states, the molecules remain correlated with each other—and can interact simultaneously—even if they are miles apart, or indeed, even if they occupy opposite ends of the universe. This research was recently published in the journal Science.  READ MORE...

Tuesday, October 31

Electron Charge Within Millisecond Coherence Time


Coherence stands as a pillar of effective communication, whether it is in writing, speaking or information processing. This principle extends to quantum bits, or qubits, the building blocks of quantum computing. A quantum computer could one day tackle previously insurmountable challenges in climate prediction, material design, drug discovery and more.  READ MORE...

A team led by the U.S. Department of Energy's (DOE) Argonne National Laboratory has achieved a major milestone toward future quantum computing. They have extended the coherence time for their novel type of qubit to an impressive 0.1 milliseconds—nearly a thousand times better than the previous record.

Wednesday, October 25

Quantum Entanglement & Teleportation


Quantum mechanics is full of weird phenomena, but perhaps none as weird as the role measurement plays in the theory. Since a measurement tends to destroy the "quantumness" of a system, it seems to be the mysterious link between the quantum and classical world. 

And in a large system of quantum bits of information, known as "qubits," the effect of measurements can induce dramatically new behavior, even driving the emergence of entirely new phases of quantum information.

This happens when two competing effects come to a head: interactions and measurement. In a quantum system, when the qubits interact with one another, their information becomes shared nonlocally in an "entangled state." 

But if you measure the system, the entanglement is destroyed. The battle between measurement and interactions leads to two distinct phases: one where interactions dominate and entanglement is widespread, and one where measurements dominate, and entanglement is suppressed.

As reported in the journal Nature, researchers at Google Quantum AI and Stanford University have observed the crossover between these two regimes—known as a "measurement-induced phase transition"—in a system of up to 70 qubits. This is by far the largest system in which measurement-induced effects have been explored.  READ MORE...

Sunday, October 1

Einstein Was Wrong About Gravity


Einstein's theory of gravity—general relativity—has been very successful for more than a century. However, it has theoretical shortcomings. This is not surprising: the theory predicts its own failure at spacetime singularities inside black holes—and the Big Bang itself.

Unlike physical theories describing the other three fundamental forces in physics—the electromagnetic and the strong and weak nuclear interactions—the general theory of relativity has only been tested in weak gravity.

Deviations of gravity from general relativity are by no means excluded nor tested everywhere in the universe. And, according to theoretical physicists, deviation must happen.

Deviations and quantum mechanics
According to a theory initially proposed by Georges Lemaître and widely accepted by the astronomical community, our universe originated in a Big Bang. 

Other singularities hide inside black holes: Space and time cease to have meaning there, while quantities such as energy density and pressure become infinite. These signal that Einstein's theory is failing there and must be replaced with a more fundamental one.

Naively, spacetime singularities should be resolved by quantum mechanics, which apply at very small scales.

Quantum physics relies on two simple ideas: point particles make no sense; and the Heisenberg uncertainty principle, which states that one can never know the value of certain pairs of quantities with absolute precision—for example, the position and velocity of a particle. 

This is because particles should not be thought of as points but as waves; at small scales they behave as waves of matter.  READ MORE...

Sunday, July 23

NASA'S Wind Tunnel


Flying cars. Space tourism. Safe reentry for astronauts coming back from Mars.

These technologies are still science fiction, but some won't be for much longer, according to Charles "Mike" Fremaux, NASA Langley Research Center's chief engineer for intelligent flight systems.

To test these concepts, particularly in regard to public and military safety, NASA Langley is building its first new wind tunnel in over 40 years. The NASA Flight Dynamic Research Facility, a project Fremaux has been pursuing for 25 years, will replace two smaller wind tunnels that are around 80 years old. The center's most recent and largest, the National Transonic Facility, was built in 1980.

"These facilities are really kind of tailor-made for doing a lot of that work," he said at a presentation at the Virginia Air & Space Science Center in Hampton on Tuesday. The talk was part of NASA Langley's Sigma Series community lectures.

"That's not our traditional wheelhouse. We haven't tested anything with a propeller on it in decades."

That's because many new craft will depend on electric vertical takeoff and landing, or "eVTOL," technology. With likely dozens or even hundreds of private vehicles in the airways, research is needed to understand how vehicles will react in real-world conditions.

Fremaux expects some of these technologies will likely be mainstream by 2040 or sooner.

The $43.2 million federal government contract to design and build the 25,000-square-foot facility went to BL Harbert International, a construction company based in Birmingham, Alabama. It is expected to open in early 2025.

The wind tunnel will be 130 feet tall, Fremaux said, comparing its capabilities to those it will replace: The 12-foot, Low-Speed Spin Tunnel built in 1939 and the 20-foot, Vertical Spin Tunnel built in 1940.

One project he worked on using the center's other wind tunnels—there are currently around 16 operating, Fremaux said—was the Stardust Mission in 2006, the first spacecraft to bring back material from outside the moon's orbit.  READ MORE...