Lifeboat Foundation

Realizing Majorana bound states (MBS) in condensed matter systems is a key challenge on the way toward topological quantum computing. As a promising platform, one-dimensional magnetic chains on conventional superconductors were theoretically predicted to host MBS at the chain ends. We demonstrate a novel approach to design of model-type atomic-scale systems for studying MBS using single-atom manipulation techniques. Our artificially constructed atomic Fe chains on a Re surface exhibit spin spiral states and a remarkable enhancement of the local density of states at zero energy being strongly localized at the chain ends. Moreover, the zero-energy modes at the chain ends are shown to emerge and become stabilized with increasing chain length. Tight-binding model calculations based on parameters obtained from ab initio calculations corroborate that the system resides in the topological phase. Our work opens new pathways to design MBS in atomic-scale hybrid structures as a basis for fault-tolerant topological quantum computing.

Majorana fermions —particles being their own antiparticles—have recently attracted renewed interest in various fields of physics. In condensed matter systems, Majorana bound states (MBS) with a non-Abelian quantum exchange statistics have been proposed as a key element for topological quantum computing (2–4). One of the most promising platforms to realize MBS are one-dimensional (1D) helical spin systems being proximity-coupled to a conventional s-wave superconductor (5–9). In such a surface-confined system, the MBS can directly be investigated by local probe techniques such as scanning tunneling microscopy/spectroscopy (STM/STS). Previously reported experiments aiming at the direct visualization and probing of the MBS have focused on self-assembled magnetic chains on superconducting Pb substrates (10–15).

The US Department of Energy will fund the most sensitive search yet for theorized dark matter particles. It will sit over a mile underground, in a nickel mine near the Canadian city of Sudbury, according to a release.

The proposed Super Cryogenic Dark Matter Search at SNOLAB, or SuperCDMS SNOLAB, would be a detector held at near absolute zero that would be sensitive enough to detect the elusive dark matter with silicon and germanium atoms. It joins a long line of other experiments hunting for “weakly interacting massive particles,” or WIMPs, the most popular dark matter particle candidate.

Throughout the universe, there exist hints of unaccounted-for mass. Galaxies rotate too quickly at their edges, and the seemingly empty regions beside clusters of colliding galaxies warp the shape of space around them as if there were stuff there. The most popular solution to solve this mystery are WIMPs, particles that interact too weakly with regular matter to be detected by our telescopes or any other observing equipment.

Continue reading “The US Will Fund Another Super-Sensitive and Expensive Dark Matter Experiment” »

One of the Unit Telescopes of ESO’s Very Large Telescope (VLT) is producing an artificial star — a guide star — in the skies above the Atacama desert, above the flowing Milky Way.

The Four Laser Guide Star Facility (4LGSF) shines four 22-watt laser beams into the sky to create artificial guide stars by making sodium atoms in the upper atmosphere glow so that they look just like real stars. The artificial stars allow the adaptive optics systems to compensate for the blurring caused by the Earth’s atmosphere and so that the telescope can create sharp images.

Ironically, my more popular posts are ones furthest from my passion and core interests. They are larks—never intended to go viral. This is about one of them…

Apart from family, I typically steer clear of religious topics. I identify with a mainstream religion, but it is completely beside the purpose of Lifeboat Foundation, and it is a personal affair.^[1]

Yet, here we discuss a religious topic, after all. Let’s get started…

Question

Continue reading “Does Mystery of Quantum Physics Prove God Exists?” »

One of the greatest obstacles to producing energy via fusion on Eearth is the formation and growth of small magnetic field imperfections in the core of experimental fusion reactors. These reactors, called tokamaks, confine hot ionized gas, or plasma. If the imperfections persist, they let the energy stored in the confined plasma leak out; if allowed to grow, they can lead to sudden termination of the plasma discharge. Recent simulations of tokamak discharges with fast, energetic ions have shown that the structure of the magnetic field can either stabilize or destabilize these magnetic imperfections, or “tearing” instabilities. The result depends on the helical structure of the field as it winds around the tokamak.

Energetic ions, ubiquitous in fusion plasmas, can be a strong stabilizing or destabilizing force. The choice depends on the magnetic shear in the plasma. Understanding the physics driving the onset of the instabilities can lead to their avoidance, a “zero tolerance” approach, vital for ITER’s stable operation. ITER is a key step between today’s fusion research and tomorrow’s fusion power plants. Also, the results explain many experimental observations of tearing instabilities that limit the maximum heat energy that can be contained.

Advanced tokamaks achieve high-thermal-energy plasmas by injecting beams of hot ions that collide with, and thereby heat, the background plasma. Burning plasma experiments that create energy from fusion reactions, such as ITER, will also have a significant population of hot alpha particles, the byproduct of fusion. The effects that energetic ions have on the benign instabilities, such as the sawtooth instability, which causes the temperature near the plasma core to flatten, and the toroidal Alfvén eigenmode, which intuitively is a “vibration” (wobble) of the magnetic field lines, have been known for some time.

Continue reading “Eliminating small instabilities in tokamaks before they become disruptions” »

Yale physicists have uncovered hints of a time crystal—a form of matter that “ticks” when exposed to an electromagnetic pulse—in the last place they expected: a crystal you might find in a child’s toy.

The discovery means there are now new puzzles to solve, in terms of how time crystals form in the first place.

Ordinary crystals such as salt or quartz are examples of three-dimensional, ordered spatial crystals. Their atoms are arranged in a repeating system, something scientists have known for a century.

From tunneling through impenetrable barriers to being in two places at the same time, the quantum world of atoms and particles is famously bizarre. Yet the strange properties of quantum mechanics are not mathematical quirks—they are real effects that have been seen in laboratories over and over.

One of the most iconic features of quantum mechanics is “entanglement”—describing particles that are mysteriously linked regardless of how far away from each other they are. Now three independent European research groups have managed to entangle not just a pair of particles, but separated clouds of thousands of atoms. They’ve also found a way to harness their technological potential.

When particles are entangled they share properties in a way that makes them dependent on each other, even when they are separated by large distances. Einstein famously called entanglement “spooky action at a distance,” as altering one particle in an entangled pair affects its twin instantaneously—no matter how far away it is.

Continue reading “A new physics discovery could change the game for quantum computing” »

Researchers have built a new dynamic model showing how hydrogen produced with concentrated solar thermal energy can be made more continuously through a novel seasonal control strategy with ceria (CeO₂) particles buffering the effect of variation in solar radiation.

A paper, “Dynamic Model of a Continuous Hydrogen Production Plant Based on CeO₂ Thermochemical Cycle,” presented at the SolarPACES2017 Annual Conference, proposes using ceria particles not only as the redox reactant in hydrogen production, but also for heat storage and heat transfer media (or medium) to control the temperatures.

Hydrogen can be produced by splitting water (H₂O into H₂ and oxygen) at very high temperatures using concentrated solar thermal (CST) — avoiding today’s use of fossil fuels for hydrogen production. Using mirrors reflecting focused sunlight onto a receiver, CST can generate very high temperatures for thermochemical processes in a solar reactor, up to 2,000°C, and can store solar energy thermally so it can dispatch the energy when needed.

Four lasers beam out from one of the Unit Telescopes of ESO’s Very Large Telescope (VLT), guiding your eyes to the Small and Large Magellanic Clouds beneath them.

The Four Laser Guide Star Facility (4LGSF) shines four 22-watt laser beams into the sky to create artificial guide stars by making sodium atoms in the upper atmosphere glow so that they look just like real stars. The artificial stars allow the adaptive optics systems to compensate for the blurring caused by the Earth’s atmosphere and so that the telescope can create sharp images.