Walter Kohn...

Image Source: NobelPrize.org 

Topics: Chemistry, Computational Physics, Condensed Matter Physics, Density Function Theory*, Nobel Prize, Quantum Mechanics

“Why, man, he doth bestride the narrow world

Like a Colossus; and we petty men

Walk under his huge legs, and peep about

To find ourselves dishonourable graves.”

― William Shakespeare, Julius Caesar

LOS ANGELES (JTA) –Nobel Prize winner Walter Kohn, who fled Nazi-ruled Austria one month before the start of World War II, has died.

Kohn died on April 19 at his home in Santa Barbara. He was 93.

Kohn received the 1998 Nobel Prize in Chemistry, which he shared with British-born scientist John Pople. His research, which spanned the fields of physics and chemistry, applied quantum mechanics and advanced mathematics to explain complex chemical reactions.

His studies also formed the basis for the creation of innovative materials custom designed for medicines and for advances in electronics.

In the fall of 1939, Kohn left his native Vienna on one of the last transports of children to England, where he was interned as an “enemy alien.” The following year he was shipped to Canada, where he subsequently joined the Canadian army as an infantryman.

His parents, Salomon and Gittel Kohn, died in Auschwitz.

* Density functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases. Using this theory, the properties of a many-electron system can be determined by using functionals, i.e. functions of another function, which in this case is the spatially dependent electron density. Hence the name density functional theory comes from the use of functionals of the electron density. DFT is among the most popular and versatile methods available in condensed-matter physics, computational physics, and computational chemistry. Wikipedia

Jewish Telegraphic Agency: Walter Kohn, Nobel Prize winner in chemistry, dies at 93

"Walter Kohn - Facts". Nobelprize.org. Nobel Media AB 2014. Web. 4 May 2016. < http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1998/kohn-facts.html >

"Walter Kohn - Biographical". Nobelprize.org. Nobel Media AB 2014. Web. 4 May 2016. < http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1998/kohn-bio.html >

3-D Eta Carinae...

Source: Technology Review

Topics: 3D Printing, Astrophysics, Computational Physics, NASA

TECHNOLOGY REVIEW: In 1843, a relatively unknown star in the constellation of Carina in the southern hemisphere suddenly erupted becoming the second brightest star in the sky after Sirius. This object, called Eta Carinae, gradually decreased in brightness until it faded from view entirely some 40 years later. Since then, it has varied in brightness in a rough a five-year cycle.

Eta Carinae is curious because this variation in brightness occurs over a wide range of wavelengths and timescales. In 1998, for example, it suddenly flared up and doubled in brightness.

The explosion in the 1840s left Eta Carinae surrounded by a spectacular cloud of dust known as the Homunculus Nebula. Astronomers have long known that this eruption did not destroy the star involved, which they thought must sit at the center of this cloud.

About 10 years ago, however, they discovered that this cloud contains two stars in a highly elliptical five-year orbit. This orbit, they decided, must be the cause of the periodic changes in brightness.

But exactly why Eta Carinae is so variable over such a wide range of wavelengths is something of a mystery. Today, Thomas Madura from the NASA Goddard Space Flight Centre in Greenbelt, Maryland, and a few pals provide a detailed insight into the nature of the star system using supercomputer simulations of the way they interact.

Physics arXiv:
3D Printing Meets Computational Astrophysics: Deciphering the Structure of Eta Carinae's Inner Colliding Winds
Thomas I. Madura, Nicola Clementel, Theodore R. Gull, Chael J.H. Kruip, Jan-Pieter Paardekooper