Physics Today Daily Edition
<em>Nature Physics</em> editorial charges physicists with failure to explain the LIGO advance properly
Science: On 24 February, 65 scientists sent US Senate leaders a letter concerning a provision in an energy bill currently under consideration. The provision requires the federal government to treat the use of forest biomass for power production as carbon neutral, as long as the trees from the forests are replaced and the forests continue to grow trees. Philip Duffy, president of the Woods Hole Research Center in Massachusetts, and the other letter cosigners say the calculation does not take into account the effects that tree removal, processing, consumption, and replanting have on the carbon balance.
Nature: Conventional soldering requires heat, but as electronic devices get smaller and more sensitive, that heat can damage the materials used. Now Martin Thuo of Iowa State University in Ames and his colleagues have taken advantage of a phenomenon known as undercooling or supercooling to create tiny droplets of a metal that is normally solid at room temperature. The droplets are encased in a solid shell. To use them as solder, the researchers simply put the droplets into place and then crush them. As the metal is released, it quickly cools and solidifies. By varying details of the production, Thuo's team was able to create particles that range in diameter from 4 nm to 5 µm and can be stored for months without breaking down. The next step is finding a metal that has a higher melting point, because many electronics generate heat that can melt the solder.
IEEE Spectrum: In 1994, Peter Shor of MIT developed an algorithm for using a quantum computer to factor large numbers, a necessary step for decrypting data. Seven years later, Isaac Chuang of MIT and his colleagues created the first quantum system that could run Shor's algorithm, although their system could factor only the number 15. Now Chuang's team has developed a five-qubit system that can factor 15 and be scaled up to factor larger numbers. The researchers used a quantum computer prototype called an ion trap, in which a string of ions held in place by an electric field and manipulated by laser pulses serves as the qubits. As long as the trap can hold the ions in place, the number of qubits can be increased.