Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: computing – Page 665

Researchers in the Department of Physics of ETH Zurich have measured how electrons in so-called transition metals get redistributed within a fraction of an optical oscillation cycle. They observed the electrons getting concentrated around the metal atoms within less than a femtosecond. This regrouping might influence important macroscopic properties of these compounds, such as electrical conductivity, magnetization or optical characteristics. The work therefore suggests a route to controlling these properties on extremely fast time scales.

The distribution of electrons in , which represent a large part of the periodic table of chemical elements, is responsible for many of their interesting properties used in applications. The magnetic properties of some of the members of this group of materials are, for example, exploited for data storage, whereas others exhibit excellent electrical conductivity. Transition metals also have a decisive role for novel materials with more exotic behaviour that results from strong interactions between the electrons. Such materials are promising candidates for a wide range of future applications.

In their experiment, whose results they report in a paper published today in Nature Physics, Mikhail Volkov and colleagues in the Ultrafast Laser Physics group of Prof. Ursula Keller exposed thin foils of the transition metals titanium and zirconium to short laser pulses. They observed the redistribution of the electrons by recording the resulting changes in optical properties of the metals in the extreme ultraviolet (XUV) domain. In order to be able to follow the induced changes with sufficient temporal resolution, XUV pulses with a duration of only few hundred attoseconds (10-18 s) were employed in the measurement. By comparing the experimental results with theoretical models, developed by the group of Prof. Angel Rubio at the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, the researchers established that the change unfolding in less than a femtosecond (10-15 s) is due to a modification of the electron localization in the vicinity of the metal atoms.

Read more | >

[Tadao Hamada] works for Fujitsu Tokki, a subsidiary of the more famous Fujitsu. In 1956, Fujitsu decided to compete with IBM and built a relay-based computer, the FACOM128. The computer takes up 70 square meters and weighs about 3 tons. By 1959, they’d learned enough to make a FACOM128B model that was improved. [Hamada’s] job is to keep one of these beasts operational at Fujitsu’s Numazu plant. According to the Japanese Computer Museum, it may be the oldest working computer.

Read more | >

A paper posted online this month has settled a nearly 30-year-old conjecture about the structure of the fundamental building blocks of computer circuits. This “sensitivity” conjecture has stumped many of the most prominent computer scientists over the years, yet the new proof is so simple that one researcher summed it up in a https://twitter.com/BooleanAnalysis/status/1145837576487612416
”}" href="https://twitter.com/BooleanAnalysis/status/1145837576487612416" rel="nofollow noopener noreferrer" target="_blank">single tweet.

“This conjecture has stood as one of the most frustrating and embarrassing open problems in all of combinatorics and theoretical computer science,” wrote Scott Aaronson of the University of Texas, Austin, in a blog post. “The list of people who tried to solve it and failed is like a who’s who of discrete math and theoretical computer science,” he added in an email.

The conjecture concerns Boolean functions, rules for transforming a string of input bits (0s and 1s) into a single output bit. One such rule is to output a 1 provided any of the input bits is 1, and a 0 otherwise; another rule is to output a 0 if the string has an even number of 1s, and a 1 otherwise. Every computer circuit is some combination of Boolean functions, making them “the bricks and mortar of whatever you’re doing in computer science,” said Rocco Servedio of Columbia University.

Read more | >

It’s an intruiging technology. All it takes to set up is burying a sensor in the plant’s dirt, and it works for living and non-living things alike. Given that the experience is going to be wildly different depending on the plant, it’s not like this would be useful for doing anything with accuracy. But for doing weird, unique things (while fondling plants) it’s perfect.

In this era of Kinect, Wii, and Leap, everyone wants to capitalize on motion control. Disney still likes physical peripherals, like houseplants for example.

Read more | >

On the heels of my latest New York Times OpEd, which is in print today on page 4 of the NYT Sunday Review, I’m excited to share my brand new book: The Futuresist Cure: Notes From the Front Lines of #Transhumanism. It’s a collection of my best essays on the future, many re-adapted, and many which have helped shape our movement. It’s #FREE today on Amazon in #Kindle. Or get the paperback version. There’s a foreword by the late Jacque Fresco. Download the book for FREE today!

Enter your mobile number or email address below and we’ll send you a link to download the free Kindle App. Then you can start reading Kindle books on your smartphone, tablet, or computer — no Kindle device required.

Read more | >

Like a misshapen potato chip, our home galaxy is warped. A new 3D map brings the contorted structure of the Milky Way’s disk into better view, thanks to measurements of special stars called Cepheids, scientists report in the Aug. 2 Science.

Making 3D measurements of the galaxy requires estimating how far away stars are from Earth, typically a matter of guesswork. But unlike other stars, Cepheids vary in brightness over time in a particular way that can be used to determine a precise distance to each star.

Although the Milky Way’s disk is usually depicted as flat, previous observations had revealed that the galaxy is curved at its edges. The new study shows that that the Milky Way is even more warped than scientists had thought, says astronomer Dorota Skowron of the Astronomical Observatory of the University of Warsaw. If you took a spaceship into deep space and looked back at our galaxy, says Skowron, “you could see by eye” that it’s misshapen.

Read more | >

The Pentagon is hitting pause on awarding its $10 billion cloud computing contract until the Defense Department examines whether the process was rigged in favor of Amazon, according to Business Insider.

“Keeping his promise to Members of Congress and the American public, Secretary Esper is looking at the Joint Enterprise Defense Infrastructure (JEDI) program,” a Pentagon spokesperson said in a statement Thursday. “No decision will be made on the program until he has completed his examination.”

The contract was supposed to be awarded sometime this month.

Read more | >

This week’s podcast features an interview with Ray LaPierre, who heads up the department of engineering physics at McMaster University in Canada. Ray talks to fellow Canadian Hamish Johnston about his research in semiconductor nanowires, in particular for use in photonics and quantum computers, and also shares his experiences of working at JDS Uniphase during the telecoms boom.

Physics World’s Anna Demming also joins the podcast to describe a flurry of new results in the emerging field of twistronics – where two layers of graphene are stacked on top of each other but twisted at a slight angle to each other. The discovery last year that bilayer graphene can become a superconductor if the two graphene layers are twisted at the so-called magic angle of 1.1º won Physics World’s 2018 Breakthrough of the Year, and since then the race has been on to investigate other angle-dependent properties of twisted bilayer graphene. Anna describes how different research teams are now trying to work out what causes these intriguing effects.

We also talk to industry editor Margaret Harris about the importance of technology and engineering for scientific progress. Margaret shares her own “light-bulb” moment, when she realized that new laser technology could have saved hours of experimental time during her PhD, and also highlights several articles in the latest Physics World Focus on Instruments and Vacuum that highlight how breakthrough scientific discoveries rely on developments in the enabling technologies – including the first images of a black hole that were revealed in April.

Read more | >

The phenomenon known as “tunneling” is one of the best-known predictions of quantum physics, because it so dramatically confounds our classical intuition for how objects ought to behave. If you create a narrow region of space that a particle would have to have a relatively high energy to enter, classical reasoning tells us that low-energy particles heading toward that region should reflect off the boundary with 100% probability. Instead, there is a tiny chance of finding those particles on the far side of the region, with no loss of energy. It’s as if they simply evaded the “barrier” region by making a “tunnel” through it.

It’s very important to note that this phenomenon is absolutely and unquestionably real, demonstrated in countless ways. The most dramatic of these is sunlight— the Sun wouldn’t be able to fuse hydrogen into helium without quantum tunneling— but it’s also got more down-to-earth technological applications. Tunneling serves as the basis for Scanning Tunneling Microscopy, which uses the tunneling of electrons across a tiny gap between a sharp tip and a surface to produce maps of that surface that can readily resolve single atoms. It’s also essential for the Josephson effect, which is the basis of superconducting detectors of magnetic fields and some of the superconducting systems proposed for quantum computing.

So, there is absolutely no debate among physicists about whether quantum tunneling is a thing that happens. Physicists get a bit twitchy without something to argue over, though, and you don’t have to dig into tunneling (heh) very far to find a disputed question, namely “How long does quantum tunneling take?”

Read more | >