Lifeboat Foundation

Researchers find that a phenomenon called multifractality manifests in the conductance fluctuations of a 2D electron gas as the gas undergoes a topological phase transition.

Fractals are geometric patterns that repeat themselves across different length scales. Such patterns are ubiquitous, appearing in the outlines of snowflakes, in swirls of turbulent fluids, and in graphs tracing the highs and lows of financial markets. Now Aveek Bid and his colleagues at the Indian Institute of Science in Bangalore show that fractals can also emerge in the electrical-conductance fluctuations of a 2D electron gas in graphene as the electron gas transitions between two topological phases [1]. The results confirm predictions made earlier this year [2].

Subject a 2D electron gas to a strong perpendicular magnetic field, and its Hall conductance—the conductance perpendicular to an induced current—takes on certain discrete values. But during a transition from one discrete value to another, this conductance can exhibit fluctuations. Bid and his colleagues measured these fluctuations in the 2D electron gases of two graphene-based devices. Using detailed data analysis, they determined that the conductance fluctuations contained patterns that could be accurately described by a multifractal—a fractal that scales spatially in several different ways.

Simulations indicate that postmerger gravitational waves from coalescing neutron stars could allow researchers to hear the phase transitions between exotic states of matter.

Linking acoustic and seismic signals from meteorite strikes to orbiter images is a step toward mapping the planet’s interior.

Predictions indicate that disorder induced by immobile imperfections does not prevent organisms from moving collectively as a group.

Improved fabrication methods for qubits made from erbium-doped silicon waveguides give these qubits the key prerequisites for becoming a contender for future quantum computers.

From superconducting circuits to single atoms, there are many quantum-bit—or “qubit”—systems to choose from when building a quantum computer. New to the game are qubits made from individual erbium atoms implanted in silicon waveguides. Each of these qubits can be controlled and measured with telecom-wavelength light, making the platform practical to implement. But the platform has unfavorable properties that have put that implementation on hold. Now Andreas Reiserer of the Max Planck Institute of Quantum Optics in Germany and his colleagues have improved the qubit’s fabrication and detection methods, such that it is viable for near-future use in quantum computing technologies [1]. The results suggest that erbium-doped silicon waveguides could make more promising qubits than previously thought.

One problem with previous erbium-doped silicon waveguides came from the uneven clustering of erbium atoms around impurities in the waveguide. This clustering meant that the erbium atoms had different transition frequencies, making it difficult to simultaneously address multiple atoms and to perform basic operations between them—a necessary component of quantum information processing.

“Dicamba drift”—the movement of the herbicide dicamba off crops through the atmosphere—can result in unintentional damage to neighboring plants. To prevent dicamba drift, other chemicals, typically amines, are mixed with dicamba to “lock” it in place and prevent it from volatilizing, or turning into a vapor that more easily moves in the atmosphere.

Now, new research from the lab of Kimberly Parker, an assistant professor of energy, environmental and chemical engineering at Washington University in St. Louis’ McKelvey School of Engineering, has shed new light on this story by demonstrating for the first time that these amines themselves volatilize, often more than dicamba itself.

Their findings were published Sept. 23 in the journal Environmental Science and Technology.

When a volcanic eruption occurs in an inhabited area, rapid and accurate lava flow forecasts can save lives and reduce infrastructure and property losses. To ensure that current lava forecasting models can provide outputs fast enough to be useful in practice, they unfortunately must incorporate physical simplifications that limit their accuracy.

To aid evacuation plans, forecast models must predict a lava flow’s speed, direction, and extent. These attributes are intimately connected to how the lava solidifies as it cools. Yet to achieve real-time speed, most current models assume that a flow has a uniform temperature. This is a major simplification that directly influences modeled rates of cooling; generally, lava flows are much cooler at their boundaries, where they are in contact with air or the ground, than they are internally.

Aiming to strike a better compromise between speed and realism, David Hyman and a team developed a 2D, physics-based lava flow model called Lava2d. They extended the traditional, vertically averaged treatment of a lava packet by considering it as three distinct regions: the portion near the lava-air boundary, the portion near the lava-ground boundary, and the fluidlike central core. The top and bottom regions of a modeled flow cool based on the physics of heat transfer to the air and ground, while the temperature in the center remains uniform, as in prior approaches. This setup enables the model to account for a temperature gradient without requiring a computationally expensive 3D approach.

The finding is a turning point in cancer research.

Two major studies published in Nature.

Continue reading “Major breakthrough in cancer research: Papers reveal ‘dark matter’ that contributes to disease’s growth” »

This harkens back to the first time he spoke about Twitter as a town square.

Elon Musk, CEO of Tesla, has now confirmed he is buying Twitter. The billionaire has tweeted a letter of sorts addressed to the advertisers who use Twitter. In the letter, Musk explains why he bought Twitter and that most of the speculation surrounding the purchase has been wrong.

Twitter is important to civilization

Continue reading “Elon Musk tweets that the social media platform he’s buying is important to civilization” »