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Archive for the ‘particle physics’ category: Page 396

Dec 5, 2019

Fusion: Nuclear physics usually involves high energies, as illustrated by experiments to master controlled nuclear fusion

Posted by in categories: nuclear energy, particle physics

One of the problems is how to overcome the strong electrical repulsion between atomic nuclei which requires high energies to make them fuse. But fusion could be initiated at lower energies with electromagnetic fields that are generated, for example, by state-of-the-art free electron lasers emitting X-ray light. Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) describe how this could be done in the journal Physical Review C.

During two fuse into one new nucleus. In the lab this can be done by , when researchers use reactions to create fast free neutrons for other experiments. On a much larger scale, the idea is to implement controlled fusion of light nuclei to generate power—with the sun acting as the model: its is the product of a series of fusion reactions that take place in its interior.

For many years, scientists have been working on strategies for generating power from fusion energy. “On the one hand we are looking at a practically limitless source of power. On the other hand, there are all the many technological hurdles that we want to help surmount through our work,” says Professor Ralf Schützhold, Director of the Department of Theoretical Physics at HZDR, describing the motivation for his research.

Dec 5, 2019

Scientists have found out why photons from other galaxies do not reach Earth

Posted by in categories: computing, mathematics, particle physics, space

An international group of scientists, including Andrey Savelyev, associate professor of the Institute of Physical and Mathematical Sciences and Information Technologies of the IKBFU, has improved a computer program that helps simulate the behavior of photons when interacting with hydrogen spilled in intergalactic space. Results are published in the scientific journal Monthly Notices of the Royal Astronomical Society.

Andrey Saveliev states, “In the Universe there are extragalactic objects such as blazars, which very intensively generate a powerful gamma-ray flux, part of photons from this stream reaches the Earth, as they say, directly, and part are converted along the way into electrons, then again converted into photons and only then get to us. The problem here is that say that a certain number of photons should reach the Earth, and in fact it is much less.”

Scientists, according to Andrey Savelyev, today have two versions of why this happens. The first is that a , after being converted into an electron (and this, as is known, in contrast to a neutral photon, a charged particle) falls into a , deviates from its path and does not reach the Earth, even after being transformed again into the photon.

Dec 4, 2019

Surprising 1st results from NASA’s sun-skimming spacecraft

Posted by in categories: particle physics, space

CAPE CANAVERAL, Fla. (AP) — NASA’s sun-skimming spacecraft, the Parker Solar Probe, is surprising scientists with its unprecedented close views of our star.

Scientists released the first results from the mission Wednesday. They observed bursts of energetic particles never seen before on such a small scale as well as switchback-like reversals in the out-flowing solar magnetic field that seem to whip up the solar wind.

NASA’s Nicola Fox compared this unexpected switchback phenomenon to the cracking of a whip.

Dec 4, 2019

New Horizons may reach termination shock sooner than expected

Posted by in categories: particle physics, robotics/AI, space

An instrument aboard NASA’s New Horizons is sending back data that could help scientists predict when the unmanned deep-space probe will reach interstellar space. Using the Solar Wind Around Pluto (SWAP) instrument aboard the spacecraft, a team of researchers led by Southwest Research Institute are learning more about how the solar winds change in the outer regions of the solar system.

Though the solar system may look like a big ball of nuclear fire at the center surrounded by a scattering of tiny, solid objects sitting in a lot of very hard vacuum, all that nothingness is permeated by the solar winds – an unceasing flow of ionized particles from the Sun that forms an uneven bubble around our family of planets called the heliosphere.

The outer limit of the heliosphere is where it encounters materials from interstellar space. This is the point where the solar wind slow down to subsonic speeds due to interacting and then is stopped altogether by the interstellar medium. These two points are called, respectively, the termination shock and the heliopause.

Dec 2, 2019

Higgs Boson Mass Explained in New Theory

Posted by in category: particle physics

Three physicists have proposed a new solution to one of the deepest mysteries in particle physics: why the Higgs boson has such a tiny mass.

Dec 2, 2019

Fifth Force of Nature: The Plot Thickens for a Hypothetical “X17” Particle

Posted by in category: particle physics

Fresh evidence of an unknown particle that could carry a fifth force of nature gives the NA64 collaboration at CERN a new incentive to continue searches.

In 2015, a team of scientists spotted an unexpected glitch, or “anomaly,” in a nuclear transition that could be explained by the production of an unknown particle. About a year later, theorists suggested that the new particle could be evidence of a new fundamental force of nature, in addition to electromagnetism, gravity and the strong and weak forces. The findings caught worldwide attention and prompted, among other studies, a direct search for the particle by the NA64 collaboration at CERN.

A new paper (pdf) from the same team, led by Attila Krasznahorkay at the Atomki institute in Hungary, now reports another anomaly, in a similar nuclear transition, that could also be explained by the same hypothetical particle.

Dec 2, 2019

New algorithms to determine eigenstates and thermal states on quantum computers

Posted by in categories: chemistry, computing, information science, particle physics, quantum physics

Determining the quantum mechanical behavior of many interacting particles is essential to solving important problems in a variety of scientific fields, including physics, chemistry and mathematics. For instance, in order to describe the electronic structure of materials and molecules, researchers first need to find the ground, excited and thermal states of the Born-Oppenheimer Hamiltonian approximation. In quantum chemistry, the Born-Oppenheimer approximation is the assumption that electronic and nuclear motions in molecules can be separated.

A variety of other scientific problems also require the accurate computation of Hamiltonian ground, excited and thermal states on a quantum computer. An important example are combinatorial optimization problems, which can be reduced to finding the ground state of suitable spin systems.

So far, techniques for computing Hamiltonian eigenstates on quantum computers have been primarily based on phase estimation or variational algorithms, which are designed to approximate the lowest energy eigenstate (i.e., ground state) and a number of excited states. Unfortunately, these techniques can have significant disadvantages, which make them impracticable for solving many scientific problems.

Dec 1, 2019

The Boötes Void: Is This Evidence Of An Alien Civilization?

Posted by in categories: alien life, existential risks, particle physics

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In 1981 astronomer Robert Kirshner made a shocking intergalactic discovery. 700 million light years from the Earth lies an enormous, barren sphere known as the Boötes Void. Its very existence challenges what we know about the universe and its origins. The Void is at least ten times larger than the rules of modern physics say is reasonably likely. As a structure, the Void verges on the impossible.

Yet, this disturbing formation is consistent with Nikolai Kardashev’s 1962 theory of advanced alien civilizations and their behavior. Could it be home to a hyper-intelligent extraterrestrial species? A void is a massive region of space that holds either minimal or no galaxies. They are created when mass collapses, and is followed by subatomic particle implosions. With a diameter of 330 million light years, the Boötes Void makes up 0.27% of the observable universe. But according to established scientific understanding its huge size is impossible. The Big Bang theory states that the universe is 14 billion years old, and that it has been expanding exponentially since its birth. Given the age of the universe, there has only been enough time for voids to form that are tens of millions of light years across, not hundreds. Stranger still, is just how empty the Bootes Void is.

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Nov 29, 2019

New study shows unique magnetic transitions in quasicrystal-like structures

Posted by in categories: materials, particle physics

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In the world of materials science, many have heard of crystals—highly ordered structures in which atoms are arranged in a tight and periodic manner (in which the atomic arrangement is repeated). But, not many people know about quasicrystals, which are unique structures with strange atomic arrangements. Like crystals, quasicrystals are also tightly arranged, but what’s different about them is the fact that they possess an unprecedented pentagonal symmetry, such that the atomic arrangement is highly ordered but not periodic.

This distinctive feature gives them , like high stability, resistance to heat, and low friction. Since their discovery only about 30 years ago, scientists globally have been trying to understand the properties of quasicrystals, in an effort to make more advancements in materials research. But, this is not easy, as quasicrystals are not prevalent in nature. Luckily, they have been able to make use of structures similar to quasicrystals, called “Tsai-type approximants.” Understanding these structures in detail could give insights into the many properties of quasicrystals. One such property is antiferromagnetism, in which are aligned in a quasiperiodic order, strikingly distinguished from conventional antiferromagnets. This property has never been observed in quasicrystals so far, but the possibility was exciting for materials scientists, as it could be a gateway to a plethora of new applications.

Continue reading “New study shows unique magnetic transitions in quasicrystal-like structures” »

Nov 28, 2019

How a tabletop experiment could test the bedrock of reality

Posted by in categories: particle physics, quantum physics

Here’s a curious thought experiment. Imagine a cloud of quantum particles that are entangled—in other words, they share the same quantum existence. The behavior of these particles is chaotic. The goal of this experiment is to send a quantum message across this set of particles. So the message has to be sent into one side of the cloud and then extracted from the other.

The first step, then, is to divide the cloud down the middle so that the particles on the left can be controlled separately from those on the right. The next step is to inject the message into the left-hand part of the cloud, where the chaotic behavior of the particles quickly scrambles it.

Can such a message ever be unscrambled?