Lifeboat Foundation

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.

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.

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.

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.

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.

Strongly interacting systems play an important role in quantum physics and quantum chemistry. Stochastic methods such as Monte Carlo simulations are a proven method for investigating such systems. However, these methods reach their limits when so-called sign oscillations occur. This problem has now been solved by an international team of researchers from Germany, Turkey, the USA, China, South Korea and France using the new method of wavefunction matching. As an example, the masses and radii of all nuclei up to mass number 50 were calculated using this method. The results agree with the measurements, the researchers now report in the journal “Nature.”

All matter on Earth consists of tiny particles known as atoms. Each atom contains even smaller particles: protons, neutrons and electrons. Each of these particles follows the rules of quantum mechanics. Quantum mechanics forms the basis of quantum many-body theory, which describes systems with many particles, such as atomic nuclei.

One class of methods used by nuclear physicists to study atomic nuclei is the ab initio approach. It describes complex systems by starting from a description of their elementary components and their interactions. In the case of nuclear physics, the elementary components are protons and neutrons. Some key questions that ab initio calculations can help answer are the binding energies and properties of atomic nuclei and the link between nuclear structure and the underlying interactions between protons and neutrons.

A team of researchers affiliated with several institutions in Israel has used a Floquet quantum detector to constrain axion-like dark matter, hoping to reduce its parameter space. In their paper published in the journal Science Advances, the group describes their approach to constraining the theoretical dark matter particle as a means to learning more about its properties.

Despite several years of effort by physicists around the world, dark matter remains a mystery. Most physicists agree that it exists, but thus far, no one has been able to prove it. One promising theory involving the existence of interacting massive particles has begun to lose its luster, and some teams are looking for something else. In this new effort, the researchers seek axions, or axion-like particles. Such dark matter particles have been theorized to be zero-spin and able to possess any number of combinations of mass and interaction strength. The team sought to constrain the features of axion-like particles to reduce the number of possibilities of their existence and thereby increase the chances of proving their existence.

The researchers used a shielded glass cell filled with rubidium-85 and xenon-129 atoms. They fired two lasers at the cell—one to polarize the rubidium atoms’ electronic spin and the xenon’s nuclear spin, and the other to measure spin changes. The experiment was based on the idea that the oscillating field of the axions would impact on the xenon’s spin when they are close in proximity. The researchers then applied a magnetic field to the cell as a means of blocking the spin of the xenon to within a narrow range of frequencies, allowing them to scan the possible oscillation frequencies that correspond to the range of the axion-like particles. Under this scenario, the Floquet field is theorized to have a frequency roughly equal to the difference between the nuclear magnetic resonance (NMR) and the electron paramagnetic resonance, and their experiment closes that gap.

Strongly interacting systems play an important role in quantum physics and quantum chemistry. Stochastic methods such as Monte Carlo simulations are a proven method for investigating such systems. However, these methods reach their limits when so-called sign oscillations occur.

This problem has now been solved by an international team of researchers from Germany, Turkey, the U.S., China, South Korea and France using the new method of wavefunction matching. As an example, the masses and radii of all nuclei up to mass number 50 were calculated using this method. The results agree with the measurements, the researchers now report in the journal Nature.

All matter on Earth consists of tiny particles known as atoms. Each atom contains even smaller particles: protons, neutrons and electrons. Each of these particles follows the rules of quantum mechanics. Quantum mechanics forms the basis of quantum many-body theory, which describes systems with many particles, such as atomic nuclei.

Exploring the complex domain of subatomic particles, researchers at the The Institute of Mathematical Science (IMSc) and the Tata Institute of Fundamental Research (TIFR) have recently published a novel finding in the journal Physical Review Letters. Their study illuminates a new horizon within quantum chromodynamics (QCD), shedding light on exotic subatomic particles and pushing the boundaries of our understanding of the strong force.