Hendrik Weimer's Quantenblog

Having fun with science and technology.

  • libquantum 1.0.0 and 1.1.0 released

    Posted: 2008-09-09 06:27

    Two new versions of libquantum have been released. The 1.1.0 development release adds support for exact diagonalization, while the 1.0.0 stable release contains only bug fixes. Further information can be found on the libquantum website.

  • libquantum 0.9.1 released

    Posted: 2007-09-03 07:13

    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.

  • Read Scientific Papers from Anywhere

    Posted: 2007-01-03 12:56

    Accessing scientific papers online is great because it spares you the way to the library. Unfortunately, most journals make their articles available only to paying subscribers (contrary to Open Access). So if you want to read an article at home or while on a conference you have a problem. This posting shows you how to access it anyway just by clicking on the download link in a journal. Read more

  • Qinf: A Free Quantum Information Suite for Maxima

    Posted: 2008-10-22 20:17

    I have dropped Mathematica in favor of Maxima some time ago in order to escape from obscure bugs remaining unfixed and licensing troubles, and have not regretted it since. Now I just came across Qinf, which is a free (as in GPLv2) quantum information suite for Maxima. While the package is still under development it already contains quite a lot useful functions like partial traces, entropy calculation, operator expansion. So if you use Qinf instead of another package relying on a proprietary CAS, you can prevent your code from being trapped.

  • Listen to Quantum Computer Music

    Posted: 2010-04-13 18:55

    I spent some time playing around with libquantum, the free quantum simulation library, and created two musical compositions that represent the inner workings of a quantum computer. So if you'd like to know what a quantum computer sounds like, here's your chance!

    Read more

  • Academic Journals Resolve Copyright Conflict over Wikipedia

    Posted: 2008-10-06 18:43

    The American Physical Society (APS) is one of the most important publishers in physics, well-known for its Physical Review journals, including their flagship Physical Review Letters. Like most other publishers, APS requires authors to transfer copyright, meaning you may not use the materials elsewhere without permission from the APS. This created trouble for some researchers who wanted to put their research on Wikipedia and other open content sites because the APS refused to permit them to do so. Fortunately, the APS has now changed their copyright policy, thus resolving the issue.

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  • US Government Works Still Protected Internationally

    Posted: 2009-01-20 18:52

    Recently on debian-legal someone asked whether you may freely distribute works created by a US government entity in other countries than the US. Well, I've asked a guy working on international copyright law, and unfortunately the answer was "no". Even though these works do not enjoy copyright protection in the US, they are still protected in other countries.

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  • OpenOffice tops 20% market share

    Posted: 2010-02-02 06:33

    The guys at Webmasterpro have published a study that analyzes the install base of various office packages among German users. While Microsoft Office comes out top (72%), open source rival OpenOffice is already installed on 21.5% of all PCs and growing.

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  • OpenJDK in Debian

    Posted: 2008-07-29 12:02

    Over a year after Sun's initial release of OpenJDK as free software, Debian successfully managed to build a version of OpenJDK using only free software. Apparently, the hard part was bootstrapping OpenJDK with the GNU Java compiler gcj. And it seems they did a very good job, as there are hardly any drawbacks compared to the proprietary version.

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  • Nexuiz: Best First-Person Shooter Ever

    Posted: 2007-05-29 07:13

    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!

  • Meet me on Diaspora

    Posted: 2011-09-01 03:17

    I thought I let you know here that I've recently joined Diaspora, the privacy-enabled open source social network. I'll continue using this blog for longer posts, but short notices will rather go there. My Diaspora handle is hweimer@diasp.org.

  • MS launching a Patent Ambush on Free Software?

    Posted: 2008-03-27 08:19

    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.

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  • Liberation Fonts Increase Document Interoperability

    Posted: 2008-06-24 06:33

    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 font 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.

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  • Google Chrome in Debian

    Posted: 2010-05-05 19:41

    Google's Chrome browser has been accepted in Debian under the unbranded Chromium name. Currently, it's in the experimental distribution, but as it does not depend on other stuff from experimental, installation is not a big problem. Now I can finally get serious with Web Sockets programming!

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  • Getting PSfrag-ged EPS files to work with Inkscape

    Posted: 2009-08-13 06:35

    When preparing figures for papers or other scientific content I routinely use PSfrag for inserting LaTeX commands. Sometimes I would like to edit the result with Inkscape to add some fancy stuff, but unfortunately most of the time Inkscape cannot open the created EPS file. I have written a short guide describing how to finally get it to work.

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  • Copyright 2006--2011 Hendrik Weimer. This document is available under the terms of the GNU Free Documentation License. See the licensing terms for further details.