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Category: physics – Page 166

INCITE program awards supercomputing time to 56 projects to accelerate science and engineering research

The U.S. Department of Energy’s (DOE) Office of Science announced allocations of supercomputer access to 56 high-impact computational science projects for 2023 through its Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program. These awards, which will pursue transformational advances in science and engineering, account for 60% of the available time on the leadership-class supercomputers at DOEs Argonne and Oak Ridge national laboratories.

The projects will support a broad range of large-scale research campaigns to advance knowledge in areas ranging from astrophysics to sustainable energy technologies to materials design and discovery.

Jointly managed by the Argonne Leadership Computing Facility (ALCF) and the Oak Ridge Leadership Computing Facility (OLCF), the INCITE program is the primary means by which the facilities fulfill their mission to advance open science by providing the scientific community with access to their powerful supercomputing resources. The ALCF and OLCF are DOE Office of Science user facilities.

CERN Courier Nov/Dec 2022

As LHC Run 3 gets into its stride and the first results at a new energy frontier roll in (p5), all eyes are on what’s next: the High-Luminosity LHC (HL-LHC), scheduled to start operations in 2029. Civil engineering for the major upgrade is complete (p7) and new crystal collimators for HL-LHC operations are to be put to the test during the current run (p35). Looking beyond the LHC, how best to deal with the millions of cubic metres of excavation materials from a future circular collider? (p9), and a new project to explore the use of high-temperature superconductors for FCC-ee (p8). The HL-LHC and proposed future colliders also feature large in the recent US Snowmass community planning exercise (p23).

The Gold In Our Galaxy May Be 10 Billion Years Old, Say Scientists

The hundreds of gold-rich stars discovered in our Milky Way galaxy may have come from smaller galaxies that merged 10 billion years ago, according to new simulations by a supercomputer.

Using the ATERUI II supercomputer in the Center for Computational Astrophysics at the National Astronomical Observatory of Japan, scientists at Tohoku University and the University of Notre Dame developed new simulations of galaxy formation with the highest resolution yet.

The paper was published this week in the Monthly Notices of the Royal Astronomical Society.

What is the shape of the universe?

The universe may seem shapeless because it is so vast, but it does have a form that astronomers can observe. So, what is it shaped like?

Physicists think the universe is flat. Several lines of evidence point to this flat universe: light left over from the Big Bang, the rate of expansion of the universe at different locations, and the way the universe “looks” from different angles, experts told Live Science.

Predicting Black Hole Radio-Wave Hot Spots

Characterized by just three parameters—mass, spin, and charge—black holes could be considered one of the Universe’s simpler astrophysical objects. Yet, the number of open problems related to how the dark behemoths behave also marks them as one of the most enigmatic. One puzzle is why the plasma around black holes glows so brightly. Now, in 3D simulations of the magnetic fields within this plasma, Benjamin Crinquand of Princeton University and colleagues think they have found the answer: the breaking and reconnecting of magnetic-field lines [1]. The simulations predict that, under certain conditions, magnetic-field instabilities can induce radio-wave hot spots that rotate around the shadow of the black hole. This prediction could be tested by future versions of the Event Horizon Telescope (EHT)—the network of radio dishes used to capture the first black hole images (see Research News: First Image of the Milky Way’s Black Hole).

There are several mechanisms that physicists think could be behind a black hole’s light. One of those is so-called accretion power, where friction-like forces in the infalling plasma heat the plasma, leading to the emission of photons. Models of this process predict constant emission signals, which doesn’t seem to fit with observations of high-intensity bursts of gamma rays from black holes.

Another possibility—and the one that Crinquand and his colleagues consider—is that the energy needed to create this light is extracted from the magnetic field that threads through the plasma. When the lines associated with this field break apart and then reconnect—a process known as magnetic reconnection—magnetic-field energy can convert into plasma-kinetic energy that is then emitted as photons. This model would not replace the accretion one, but act in tandem with it.

Famous Stephen Hawking theory about black holes confirmed

One of Stephen Hawking’s most famous theories has been confirmed to be correct, thanks to space-time ripples caused by the merger of the two distant black holes.

The black hole area theorem, which Hawking derived from Einstein’s theory of general relativity in 1971, states that the surface area of a black hole cannot decrease over time. This rule is of importance to physicists because it appears to set time to run in a certain direction: the second law of thermodynamics, which states that the entropy, or disorder, of a closed system must always rise. Because the entropy of a black hole is proportional to its surface area, both must always increase.

The researchers’ confirmation of the area law, according to the new study, appears to suggest that the properties of black holes are crucial hints to the hidden laws that control the universe. Surprisingly, the area law appears to contradict another of the famous physicist’s proven theorems: that black holes should evaporate over incredibly long time scales, suggesting that determining the source of the conflict between the two theories might reveal new physics.

Black holes don’t always power gamma-ray bursts, new research shows

Gamma-ray bursts (GRBs) have been detected by satellites orbiting Earth as luminous flashes of the most energetic gamma-ray radiation lasting milliseconds to hundreds of seconds. These catastrophic blasts occur in distant galaxies, billions of light years from Earth.

A sub-type of GRB known as a short-duration GRB starts life when two neutron stars collide. These ultra-dense stars have the mass of our sun compressed down to half the size of a city like London, and in the final moments of their life, just before triggering a GRB, they generate ripples in space-time—known to astronomers as gravitational waves.

Until now, space scientists have largely agreed that the “engine” powering such energetic and short-lived bursts must always come from a newly formed black hole (a region of where gravity is so strong that nothing, not even light, can escape from it). However, new research by an international team of astrophysicists, led by Dr. Nuria Jordana-Mitjans at the University of Bath, is challenging this scientific orthodoxy.

The mathematics that makes us realize we don’t know much: Behavior of spin glasses

Spin glasses are alloys formed by noble metals in which a small amount of iron is dissolved. Although they do not exist in nature and have few applications, they have nevertheless been the focus of interest of statistical physicists for some 50 years. Studies of spin glasses were crucial for Giorgio Parisi’s 2021 Nobel Prize in Physics.

The scientific interest of spin glasses lies in the fact that they are an example of a complex system whose elements interact with each other in a way that is sometimes cooperative and sometimes adversarial. The mathematics developed to understand their behavior can be applied to problems arising in a variety of disciplines, from ecology to machine learning, not to mention economics.

Spin glasses are , that is, systems in which individual elements, the spins, behave like small magnets. Their peculiarity is the co-presence of ferromagnetic-type bonds, which tend to align the spins, with antiferromagnetic-type bonds, which tend to orient them in opposite directions.

Scientists Tested Einstein’s Relativity on a Cosmic Scale, And Found Something Odd

Everything in the Universe has gravity – and feels it too. Yet this most common of all fundamental forces is also the one that presents the biggest challenges to physicists.

Albert Einstein’s theory of general relativity has been remarkably successful in describing the gravity of stars and planets, but it doesn’t seem to apply perfectly on all scales.

General relativity has passed many years of observational tests, from Eddington’s measurement of the deflection of starlight by the Sun in 1919 to the recent detection of gravitational waves.

Build Your Own Universe

Physicists agree, one day it may be possible for a person to create a universe. It won’t happen tomorrow, but the idea is in the works. There’s already one problem with the idea: If a universe is created, physicists say they wouldn’t know how to communicate with it.