http://www.quantenblog.net Hendrik Weimer's Quantenblog en-US Sat, 28 Jun 2008 12:32:24 UT 120 http://www.quantenblog.net/images/logo.png http://www.quantenblog.net Hendrik Weimer's Quantenblog http://www.quantenblog.net/physics/rydberg-paper Rydberg atoms are atoms with a large principle quantum number. One possibility to create them is to excite ground state atoms with lasers. They are very sensitive to electric fields, so if you bring them close together they will experience very strong interactions due to static or induced electric dipoles.We have now put a paper onto the arXiv, where we investigate the properties of the strongly interacting regime. We have found some interesting links between Rydberg physics and concepts originally coming from condensed matter physics. Read more Sat, 28 Jun 2008 12:32:24 UT http://www.quantenblog.net/free-software/liberation-fonts Ever wondered why a Word document you received looks garbled when opening it in OpenOffice.org under GNU/Linux? Most likely, this is not a bug in OOo's conversion algorithms, but a problem of missing fonts. Most Word documents use fonts like "Arial" or "Times New Roman", which are copyrighted by Microsoft. While Microsoft used to distribute these so-called "core fonts" for non-Windows users, they no longer do so. There are still places where you can get them legally, but of course this is not a free-as-in-speech solution. Therefore, these fonts are not available by default in many GNU/Linux distros.While the individual glyphs of a fonts can be copyrighted, their metrics (i.e., their spatial dimensions) cannot be, and therefore one can create a free set of fonts that look different than their proprietary counterparts, but otherwise behave the same when it comes to things like linebreaking, hyphenation, etc. Red Hat has done just that, and some time ago released the Liberation fonts.However, due to licensing issues not all major GNU/Linux distros included the Liberation fonts. But after a long wait and the persistent work by several people these issues have finally been settled and the Liberation fonts have been accepted into the Debian archive. Other distros are expected to follow suit soon. Read more Tue, 24 Jun 2008 06:33:49 UT http://www.quantenblog.net/security/pseudonymity-anonymity A paper (also available here) published yesterday in Nature analyzes moving patterns of humans based on position data provided by a European mobile network operator. While the paper itself is very interesting and provides new insights it also raises serious privacy concerns, and maybe even legal troubles for the telco in question. Read more Fri, 06 Jun 2008 06:43:42 UT http://www.quantenblog.net/misc/monitor-internet-censorship You have probably heard already of Tor, a tool for surfing the internet anonymously. It can also be used to evade censorship, but less known is the fact that you can turn the tables and monitor internet censorship in various parts of the world. Not only that, you can use Tor to visit websites pretending you come from almost any country. Read more Sat, 12 Apr 2008 15:36:40 UT http://www.quantenblog.net/free-software/ooxml-poi-patent-ambush Yesterday, Microsoft and Milan-based Sourcesense announced they collaborate to contribute code to Apache POI, a Java library for manipulating Microsoft Office files. This collaboration has two possible consequences: either it will turn POI into the greatest patent laundry of all time, or it will help Microsoft to launch a patent ambush on the project. Feel free to decide which one is more likely. Read more Thu, 27 Mar 2008 08:19:02 UT http://www.quantenblog.net/physics/libquantum-0.9.1 libquantum 0.9.1 has been released. The new release adds an interface for time-evolution of arbitrary Hamiltonians using a fourth-order Runge-Kutta algorithm. The license has been changed to GPLv3 and several bugs have been fixed. Further information can be found on the libquantum website. Mon, 03 Sep 2007 07:13:29 UT http://www.quantenblog.net/physics/work-heat As some of you may know, I wrote my diploma thesis on transport in quantum thermodynamics. Related to this work, we now put up a paper on arXiv, describing how to incorporate the concepts of work and heat, which are well-known from the classical world, into the quantum realm.It turns out that if you do it properly, you get some remarkable consequences, like a machine that both works and does not at the same time. These strange things arise (hardly surprising) from non-commuting observables in quantum mechanics. Read more Wed, 22 Aug 2007 06:32:42 UT http://www.quantenblog.net/security/german-computer-crime-law Last Friday, a new law on computer crime came into effect in Germany. The newly introduced Section 202c of the German penal code created much buzz around the net since it prohibits the distribution of certain computer programs assisting in committing data espionage.Although I think the law is bad and creates an uncanny area of uncertainty it is not the end of all security research done in Germany. In fact, much of the current outcry is overblown and counter-productive, as it contributes to spreading FUD about the issue. Read more Mon, 13 Aug 2007 20:07:16 UT http://www.quantenblog.net/free-software/nexuiz Okay, I promise I won't mention every article I write for OS Reviews on my blog, but here is an exception. I just put up an article about Nexuiz, which is definitely the best first-person shooter I've ever played. And of course it's free as in speech! Tue, 29 May 2007 07:13:08 UT http://www.quantenblog.net/misc/sco-delisting Most of you probably remember the delisting trouble SCO got into because they failed to timely file their 10-K back in 2005. The same story will show up again soon, but this time for another reason: the stock price is too low to meet Nasdaq's requirements. Read more Fri, 13 Apr 2007 07:21:20 UT