Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: particle physics – Page 543

Back in the first moment of the universe, everything was hot and dense and in perfect balance. There weren’t any particles as we’d understand them, much less any stars or even the vacuum that permeates space today. The whole of space was filled with homogeneous, formless, compressed stuff.

Then, something slipped. All that monotonous stability became unstable. Matter won out over its weird cousin, antimatter, and came to dominate the whole of space. Clouds of that matter formed and collapsed into stars, which became organized into galaxies. Everything that we know about started to exist.

So, what happened to tip the universe out of its formless state? [How Quantum Entanglement Works (Infographic)].

Read more

Today the collaboration for the LHCb experiment at CERN’s Large Hadron Collider announced the discovery of two new particles in the baryon family. The particles, known as the Xi_b’- and Xi_b*-, were predicted to exist by the quark model but had never been seen before. A related particle, the Xi_b*, was found by the CMS experiment at CERN in 2012. The LHCb collaboration submitted a paper reporting the finding to Physical Review Letters.

Like the well-known protons that the LHC accelerates, the new particles are baryons made from three quarks bound together by the strong force. The types of quarks are different, though: the new X_ib particles both contain one beauty (b), one strange (s), and one down (d) quark. Thanks to the heavyweight b quarks, they are more than six times as massive as the proton. But the particles are more than just the sum of their parts: their mass also depends on how they are configured. Each of the quarks has an attribute called “spin”. In the Xi_b’- state, the spins of the two lighter quarks point in the opposite direction to the b quark, whereas in the Xi_b*- state they are aligned.

“Nature was kind and gave us two particles for the price of one,” said Matthew Charles of the CNRS’s LPNHE laboratory at Paris VI University. “The Xi_b’- is very close in mass to the sum of its decay products: if it had been just a little lighter, we wouldn’t have seen it at all using the decay signature that we were looking for.”

Read more

Electronegativity is one of the most well-known models for explaining why chemical reactions occur. Now, Martin Rahm from Chalmers University of Technology, Sweden, has redefined the concept with a new, more comprehensive scale. His work, undertaken with colleagues including a Nobel Prize-winner, has been published in the Journal of the American Chemical Society.

The theory of is used to describe how strongly different atoms attract electrons. By using electronegativity scales, one can predict the approximate charge distribution in different molecules and materials, without needing to resort to complex quantum mechanical calculations or spectroscopic studies. This is vital for understanding all kinds of materials, as well as for designing new ones. Used daily by chemists and materials researchers all over the world, the concept originates from Swedish chemist Jöns Jacob Berzelius’ research in the 19th century and is widely taught at high-school level.

Now, Martin Rahm, Assistant Professor in Physical Chemistry at Chalmers University of Technology, has developed a brand-new scale of electronegativity.

Read more

The production of entropy, which means increasing the degree of disorder in a system, is an inexorable tendency in the macroscopic world owing to the second law of thermodynamics. This makes the processes described by classical physics irreversible and, by extension, imposes a direction on the flow of time. However, the tendency does not necessarily apply in the microscopic world, which is governed by quantum mechanics. The laws of quantum physics are reversible in time, so in the microscopic world, there is no preferential direction to the flow of phenomena.

One of the most important aims of contemporary scientific research is knowing exactly where the transition occurs from the quantum world to the classical world and why it occurs — in other words, finding out what makes the production of entropy predominate. This aim explains the current interest in studying mesoscopic systems, which are not as small as individual atoms but nevertheless display well-defined quantum behavior.

Read more

A scientific collaboration has released a concept design for the Large Hadron Collider’s successor, an enormous new experiment that would sit inside a hundred-kilometer (62-mile) tunnel.

The design concept plans for two Future Circular Colliders, the first which would begin operation perhaps in 2040. The ambitious experiments would hunt for new particles with collision energies 10 times higher than those created by the Large Hadron Collider (LHC). The concept design is the first big milestone achieved by the scientific collaboration.

Read more

Australia’s New South Wales scientists have adapted single atom technology to build 3D silicon quantum chips – with precise interlayer alignment and highly accurate measurement of spin states. The 3D architecture is considered a major step in the development of a blueprint to build a large-scale quantum computer.

They aligned the different layers in their 3D device with nanometer precision – and showed they could read out qubit states with what’s called ‘single shot’, i.e. within one single measurement, with very high fidelity.

“This 3D device architecture is a significant advancement for atomic qubits in silicon,” says Professor Simmons.

Read more

One mysterious number determines how physics, chemistry and biology work. But controversial experimental hints suggest it’s not one number at all.

By Michael Brooks

IT IS a well-kept secret, but we know the answer to life, the universe and everything. It’s not 42 – it’s 1/137.

This immutable number determines how stars burn, how chemistry happens and even whether atoms exist at all. Physicist Richard Feynman, who knew a thing or two about it, called it “one of the greatest damn mysteries of physics: a magic number that comes to us with no understanding”.

Read more