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May 18, 2024

A New Dimension of Quantum Materials: Topological Phonons Discovered in Crystal Lattices

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

An international research team has shown that phonons, the quantum particles behind material vibrations, can be classified using topology, much like electronic bands in materials. This breakthrough could lead to the development of new materials with unique thermal, electrical, and mechanical properties, enhancing our understanding and manipulation of solid-state physics.

An international group of researchers has found that quantum particles, which play a key role in the vibrations of materials affecting their stability and other characteristics, can be classified through topology. Known as phonons, these particles represent the collective vibrational patterns of atoms within a crystal structure. They create disturbances that spread like waves to nearby atoms. Phonons are crucial for several properties of solids, such as thermal and electrical conductivity, neutron scattering, and quantum states including charge density waves and superconductivity.

The spectrum of phonons—essentially the energy as a function of momentum—and their wave functions, which represent their probability distribution in real space, can be computed using ab initio first principle codes. However, these calculations have so far lacked a unifying principle. For the quantum behavior of electrons, topology—a branch of mathematics—has successfully classified the electronic bands in materials. This classification shows that materials, which might seem different, are actually very similar.

May 18, 2024

Researchers realize multiphoton electron emission with non-classical light

Posted by in categories: particle physics, quantum physics

Strong field quantum optics is a rapidly emerging research topic, which merges elements of non-linear photoemission rooted in strong field physics with the well-established realm of quantum optics. While the distribution of light particles (i.e., photons) has been widely documented both in classical and non-classical light sources, the impact of such distributions on photoemission processes remains poorly understood.

May 17, 2024

Tracing the history of perturbative expansion in quantum field theory

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

Perturbative expansion is a valuable mathematical technique which is widely used to break down descriptions of complex quantum systems into simpler, more manageable parts. Perhaps most importantly, it has enabled the development of quantum field theory (QFT): a theoretical framework that combines principles from classical, quantum, and relativistic physics, and serves as the foundation of the Standard Model of particle physics.

May 17, 2024

Scientists Test for Quantum Gravity

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

The tension between quantum mechanics and relativity has long been a central split in modern-day physics. Developing a theory of quantum gravity remains one of the great outstanding challenges of the discipline. And yet, no one has yet been able to do it. But as we collect more data, it shines more light on the potential solution, even if some of that data happens to show negative results.

That happened recently with a review of data collected at IceCube, a neutrino detector located in the Antarctic ice sheet, and compiled by researchers at the University of Texas at Arlington. They looked for signs that gravity could vary even a minuscule amount based on quantum mechanical fluctuations. And, to put it bluntly, they didn’t find any evidence of that happening.

Continue reading “Scientists Test for Quantum Gravity” »

May 17, 2024

Ask Ethan: Are we expanding along with the Universe?

Posted by in category: particle physics

Overturned that picture entirely. The Universe, on the largest of cosmic scales, wasn’t static and unchanging at all, but rather was dynamically expanding.

If that’s true, and the Universe is expanding, then what else is expanding along with it? Is our galaxy expanding? What about the Solar System, planet Earth, or even the atoms in our own body? That’s the topic of this week’s inquiry courtesy of Jim Robison, who asks:

“We are part of the expanding universe. Does that mean we are expanding with it? Is the distance between the Earth and the Sun expanding, or between San Francisco and New York? Is the distance between the atoms in my body expanding? Is that why I need a larger belt?”

May 17, 2024

What is ‘time’ for quantum particles?

Posted by in categories: particle physics, quantum physics

In an amazing phenomenon of quantum physics known as tunneling, particles appear to move faster than the speed of light. However, physicists from Darmstadt believe that the time it takes for particles to tunnel has been measured incorrectly until now. They propose a new method to stop the speed of quantum particles.

In classical physics, there are hard rules that cannot be circumvented. For example, if a rolling ball does not have enough energy, it will not get over a hill, but will turn around before reaching the top and reverse its direction. In quantum physics, this principle is not quite so strict: a particle may pass a barrier, even if it does not have enough energy to go over it. It acts as if it is slipping through a tunnel, which is why the phenomenon is also known as quantum tunneling. What sounds magical has tangible technical applications, for example in flash memory drives.

In the past, experiments in which particles tunneled faster than light drew some attention. After all, Einstein’s theory of relativity prohibits faster-than-light velocities. The question is therefore whether the time required for tunneling was “stopped” correctly in these experiments. Physicists Patrik Schach and Enno Giese from TU Darmstadt follow a new approach to define “time” for a tunneling particle. They have now proposed a new method of measuring this time. In their experiment, they measure it in a way that they believe is better suited to the quantum nature of tunneling.

May 17, 2024

20-Year-Old Molecular Prediction Comes True — Chemists Have Finally Succeeded in Synthesizing an Unusual and Elusive Molecule

Posted by in categories: chemistry, particle physics

The first and the best-known metallocene is ‘ferrocene’, which contains a single iron atom. Sandwich complexes are now standard topics in inorganic chemistry textbooks, and the bonding and electronic structure of metallocenes are covered in undergraduate chemistry courses. These sandwich molecules are also significant in industry, where they serve as catalysts and are utilized in the creation of unique metallopolymers.

Nobody knows exactly how many sandwich molecules there are today, but the number is certainly in the thousands. And they all have one thing in common: a single metal atom located between two flat rings of carbon atoms. At least that was what was thought up until 2004, when a research group from the University of Seville made a startling discovery.

The Spanish research team succeeded in synthesizing a sandwich molecule that contained not one but two metal atoms. For a long time, this ‘dimetallocene’ containing two zinc atoms remained the only example of its kind until a group in the UK succeeded last year in synthesizing a very similar molecule that contained two beryllium atoms. But now, Inga Bischoff, a doctoral student in Dr. André Schäfer’s research team at Saarland University, has taken things one big step further. She has managed to synthesize in the laboratory the world’s first ‘heterobimetallic’ sandwich complex – a dimetallocene that contains two different metal atoms.

May 16, 2024

Scientists demonstrate the survival of quantum coherence in a chemical reaction involving ultracold molecules

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

If you zoom in on a chemical reaction to the quantum level, you’ll notice that particles behave like waves that can ripple and collide. Scientists have long sought to understand quantum coherence, the ability of particles to maintain phase relationships and exist in multiple states simultaneously; this is akin to all parts of a wave being synchronized. It has been an open question whether quantum coherence can persist through a chemical reaction where bonds dynamically break and form.

May 16, 2024

Researchers call for a new measurement of time for tunneling particles

Posted by in categories: particle physics, quantum physics

In an amazing phenomenon of quantum physics known as tunneling, particles appear to move faster than the speed of light. However, physicists from Darmstadt believe that the time it takes for particles to tunnel has been measured incorrectly. They propose a new method to stop the speed of quantum particles.

May 16, 2024

World’s Purest Silicon Paves the Way for Next-Gen Quantum Computers

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

A major breakthrough in quantum computing has been achieved with the development of ultra-pure silicon, setting the stage for the creation of powerful, scalable quantum computers.

More than 100 years ago, scientists at The University of Manchester changed the world when they discovered the nucleus in atoms, marking the birth of nuclear physics.

Fast forward to today, and history repeats itself, this time in quantum computing.

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