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Archive for the ‘particle physics’ category: Page 178

Mar 16, 2023

How Big Is a Proton? Neutrinos Weigh In

Posted by in category: particle physics

The team’s measurement of the proton’s radius was 0.73 femtometer, even smaller than the 0.84-femtometer electric charge radius. In either case, it is almost 10,000 times smaller than a hydrogen atom.

To be clear, this apparent 13 percent shrinkage is not a blow to the electric charge radius measurements and not as shocking as it may seem. The two measurements are complementary and work together to offer a big picture view of the little proton. Because they measure different distributions of matter, the discrepancy does not challenge our understanding of the proton the same way its previous 4 percent shrinkage did. Instead it adds to that understanding.

“The thing that makes this measurement really interesting is not whether or not it agrees with the electron measurements of the electromagnetic proton radius but the fact that it didn’t have to agree at all,” says Deborah Harris, co-spokesperson for the MINERvA experiment. This is because the way neutrinos interact with up quarks versus down quarks is very different from how quarks interact with electrons. Instead of an electromagnetic interaction, neutrinos interact via a different force called the weak force. (But don’t let its name fool you—the weak force is quite strong across subatomic distances!)

Mar 16, 2023

Faint gravitational waves may be from primordial fractures time

Posted by in categories: particle physics, quantum physics

With each of these splittings, the universe completely remolded itself. New particles arose to replace ones that could exist only in extreme conditions previously. The fundamental quantum fields of space-time that dictate how particles and forces interact with each other reconfigured themselves. We do not know how smoothly or roughly these phase transitions took place, but it’s perfectly possible that with each splitting, the universe settled into multiple identities at once.

This fracturing isn’t as exotic as it sounds. It happens with all kinds of phase transitions, like water turning into ice. Different patches of water can form ice molecules with different orientations. No matter what, all the water turns into ice, but different domains can have differing molecular arrangements. Where those domains meet walls, or imperfections, fracturing will appear.

Physicists are especially interested in the so-called GUT phase transition of our universe. GUT is short for “grand unified theory,” a hypothetical model of physics that merges the strong nuclear force with electromagnetism and the weak nuclear force. These theories are just beyond the reach of current experiments, so physicists and astronomers turn to the conditions of the early universe to study this important transition.

Mar 16, 2023

A Better Production Line for Atom Arrays

Posted by in categories: information science, particle physics

A new algorithm can organize hundreds of atoms into pristine patterns—including a honeycomb lattice, a fractal called a Sierpiński triangle, and a lion’s head.

Mar 16, 2023

The experimental observation of quantum avalanches in a many-body localized system

Posted by in categories: particle physics, quantum physics

Strongly correlated systems are systems made of particles that strongly interact with one another, to such an extent that their individual behavior depends on the behavior of all other particles in the system. In states that are far from equilibrium, these systems can sometimes give rise to fascinating and unexpected physical phenomena, such as many-body localization.

Many-body localization occurs when a system made of interacting particles fails to reach even at high temperatures. In many-body localized systems, particles thus remain in a state of non-equilibrium for long periods of time, even when a lot of energy is flowing through them.

Theoretical predictions suggest that the instability of the many-body localized phase is caused by small thermal inclusions in the strongly interacting system that act as a bath. These inclusions prompt the delocalization of the entire system, through a mechanism that is known as avalanche propagation.

Mar 16, 2023

Building an understanding of quantum turbulence from the ground up

Posted by in categories: computing, particle physics, quantum physics

Most people only encounter turbulence as an unpleasant feature of air travel, but it’s also a notoriously complex problem for physicists and engineers. The same forces that rattle planes are swirling in a glass of water and even in the whorl of subatomic particles. Because turbulence involves interactions across a range of distances and timescales, the process is too complicated to be solved through calculation or computational modeling—there’s simply too much information involved.

Scientists have attempted to tackle the issue by studying the that occurs in superfluids, which is formed by tiny identical whirls called quantized vortices. A key question is how turbulence happens on the and how is it linked to turbulence at larger scales.

Researchers at Aalto University have brought that goal closer with a new study of quantum wave turbulence. Their findings, published in Nature Physics, demonstrate a new understanding of how wave-like motion transfers from macroscopic to microscopic length scales, and their results confirm a theoretical prediction about how the energy is dissipated at small scales.

Mar 16, 2023

‘Counterportation’: Quantum breakthrough paves way for world-first experimental wormhole

Posted by in categories: computing, cosmology, particle physics, quantum physics

One of the first practical applications of the much-hyped but little-used quantum computing technology is now within reach, thanks to a unique approach that sidesteps the major problem of scaling up such prototypes.

The invention, by a University of Bristol physicist, who gave it the name “counterportation,” provides the first-ever practical blueprint for creating in the lab a wormhole that verifiably bridges space, as a probe into the inner workings of the universe.

By deploying a novel computing scheme, revealed in the journal Quantum Science and Technology, which harnesses the basic laws of physics, a small object can be reconstituted across space without any particles crossing. Among other things, it provides a “smoking gun” for the existence of a physical reality underpinning our most accurate description of the world.

Mar 15, 2023

Fundamental constants: Is the universe fine-tuned for life?

Posted by in categories: alien life, evolution, information science, particle physics

Imagine a universe with extremely strong gravity. Stars would be able to form from very little material. They would be smaller than in our universe and live for a much shorter amount of time. But could life evolve there? It took human life billions of years to evolve on Earth under the pleasantly warm rays from the Sun after all.

Now imagine a with extremely weak gravity. Its matter would struggle to clump together to form stars, planets and—ultimately—living beings. It seems we are pretty lucky to have gravity that is just right for life in our universe.

This isn’t just the case for gravity. The values of many forces and in the universe, represented by some 30 so-called fundamental constants, all seem to line up perfectly to enable the evolution of intelligent life. But there’s no theory explaining what values the constants should have—we just have to measure them and plug their numbers into our equations to accurately describe the cosmos.

Mar 15, 2023

Is the universe fine-tuned for life?

Posted by in categories: alien life, particle physics

For decades, various physicists have theorized that even the slightest changes in the fundamental laws of nature would make it impossible for life to exist. This idea, also known as the “fine-tuned universe” argument, suggests that the occurrence of life in the universe is very sensitive to the values of certain fundamental physics. Alter any of these values (as the logic goes), and life would not exist, meaning we must be very fortunate to be here.

But can this really be the case, or is it possible that life can emerge under different physical constants, and we just don’t know it? This question was recently tackled by Luke A. Barnes, a postdoctoral researcher at the Sidney Institute for Astronomy (SIA) in Australia. In his book, “A Fortunate Universe: Life in a Finely Tuned Cosmos,” he and Sydney astrophysics professor Geraint F. Lewis argued that a fine-tuned universe makes sense from a standpoint.

The authors also summarized these arguments in an invited contribution paper, which appeared in the Routledge Companion to Philosophy of Physics (1st ed.) In this paper, titled “The Fine-Tuning of the Universe for Life,” Barnes explains how “fine-tuning” consists of explaining observations by employing a “suspiciously precise assumption.” This, he argues, has been symptomatic of incomplete theories throughout history and is a common feature of modern cosmology and .

Mar 15, 2023

Is the ‘fine-tuned universe’ an illusion?

Posted by in categories: alien life, particle physics

For decades physicists have been perplexed about why our cosmos appears to have been precisely tuned to foster intelligent life. It is widely thought that if the values of certain physical parameters, such as the masses of elementary particles, were tweaked, even slightly, it would have prevented the formation of the components necessary for life in the universe—including planets, stars, and galaxies. But recent studies, detailed in a new report by the Foundational Questions Institute, FQXi, propose that intelligent life could have evolved under drastically different physical conditions. The claim undermines a major argument in support of the existence of a multiverse of parallel universes.

“The tuning required for some of these physical parameters to give rise to life turns out to be less precise than the tuning needed to capture a station on your radio, according to new calculations,” says Miriam Frankel, who authored the FQXi report, which was produced with support from the John Templeton Foundation. “If true, the apparent fine tuning may be an illusion,” Frankel adds.

Over the last few decades, the subject of fine tuning has attracted some of the sharpest minds in physics. By probing the ’s physical laws and precisely pinning down the values of physical constants—such as the masses of elementary particles and the strengths of forces—physicists have discovered that surprisingly small variations in these values would have rendered the universe lifeless. This led to a puzzle: why are physical conditions seemingly tailored towards human existence?

Mar 15, 2023

CMS collaboration homes in on Higgs boson’s lifetime

Posted by in category: particle physics

The Higgs boson doesn’t stick around for long. Once it is created in particle collisions, the famed particle lives for a mere less than a trillionth of a billionth of a second or, more precisely, 1.6 × 10-22 seconds. According to theory, that is, for so far experiments have only been able to set bounds on the value of the particle’s lifetime or to determine this property with a large uncertainty. Until now. In a new study, the CMS collaboration reports a value for the particle’s lifetime that has a small enough uncertainty to confirm that the Higgs boson does have such a short lifetime.

Measuring the Higgs boson’s lifetime is high on the wish list of particle physicists, because an experimental value of the lifetime would allow them not only to better understand the nature of the particle but also to find out whether or not the value matches the value predicted by the Standard Model of particle physics. A deviation from the prediction could point to new particles or forces not predicted by the Model, including new particles into which the Higgs boson would decay.

But it isn’t easy to measure the Higgs boson’s lifetime. For one, the predicted lifetime is too short to be measured directly. A possible solution entails measuring a related property called the mass width, which is inversely proportional to the lifetime and represents the small range of possible masses around the particle’s nominal mass of 125 GeV. But this isn’t easy either, as the predicted mass width of the Higgs boson is too small to be easily measured by experiments.