Raimar Sandner

C++QED: a framework for simulating open quantum dynamics

Raimar — 2011-10-15T01:18:48+01:00

The C++QED-framework was developed by András Vukics. I will be using this framework for the work on my PhD-thesis, so I presented a poster on this topic at the summer school "Cold gases with long range interactions" in Les Houches.

Spatial Pauli blocking of spontaneous emission in optical lattices

Raimar — 2011-10-15T00:54:36+01:00

Here is a Poster I have presented at the Ultra-Cold Matter Workshop in Windsor, and the recently published Phys. Rev. A article.

Linux support for Broadcom 4331 wireless chip (Macbook Pro 8,1)

Raimar — 2011-09-04T12:06:31+01:00

Linux support for the Broadcom 4331 wireless chip used to be poor. This chip has vendor- and device id 14e4:4331 and identifies as

$ lspci | grep 4331
03:00.0 Network controller: Broadcom Corporation Device 4331 (rev 02)

As of this writing, there is no driver in the kernel, and with ndiswrapper there are many random system lock-ups. As a result, Macbook Pro 8,1 (8,2 ...?) users running Linux couldn't use the internal wireless chip. Recently, the situation has improved thanks to three patches submitted by Rafał Miłecki and Larry Finger. The driver is announced for kernel version 3.2, but if you don't want to wait for this kernel it is possible to compile and use the relevant module with older kernels.

kbibtex-0.3 packages for Ubuntu

Raimar — 2011-06-24T21:04:58+01:00

I have built packages of the new kbibtex version 0.3 based on KDE 4 for Ubuntu Lucid, Maverick and Natty in my ppa. Please report any problems you encouter with these packages which are not application bugs directly to me (see contact).

Mathematica: "Indeterminate expression 0^0 encountered."

Raimar — 2011-04-28T00:09:36+01:00

Mathematica treats the expression 0^0 (that is Power[0,0]) as indeterminate. That might be mathematically accurate, but sometimes it is extremely useful to define 0^0=1. Interestingly enough, when evaluated with a as a symbol, Mathematica simplifies a^0 to 1 without conditions on a. Of course you could always add If-statements to your code to capture the special case 0^0 and make it behave the way you want, but there is an easier solution:

Unprotect[Power];
Power[0,0]=1;
Protect[Power];

After this, 0^0 will evaluate to 1. If you need this in numerical calculations, you should define Power[0 | 0., 0 | 0.] = 1;, which also includes the case 0.^0..

An instance of nm-applet is already running.

Raimar — 2010-11-15T20:37:41+01:00

This error message displayed by the Gnome NetworkManager applet can be very misleading. In some cases, nm-applet claims that another instance of itself is running even when this is obviously not true. In fact, any other client registered with NetworkManager will trigger this error message when you try to start nm-applet. For example, this could be a running instance of knetworkmanager, or even the KDE daemon kded4 (check if systemsettings -> Startup and Shutdown -> Service Manager -> NetworkManager User Settings Service is enabled).

Tele2 (AT) mit Fritz!Box Fon 7170, Umstellung Annex B -> Annex A

Raimar — 2010-10-10T23:34:24+01:00

Der Router, der von Tele2 mitgeliefert wird (Tilgin VOOD), ist so ziemlich der benutzerunfreundlichste Router, den ich je hatte. Wenn er mal eingerichtet ist und läuft ist er zwar relativ zuverlässig, aber das Webinterface ist ein Graus, und beim Hochfahren verschluckt er sich schon mal, hat dann keine DSL-Verbindung aufgebaut und muss nochmal neu gestartet werden. Außerdem habe ich keine Möglichkeit entdeckt, mich direkt auf dem Router einzuloggen bzw. alternative Firmwares aufzuspielen oder ähnliches. Zum Glück habe ich noch eine inzwischen schon recht betagte Fritz!Box Fon 7170, die bisher hinter der Vood als normaler client angeschlossen war und hauptsächlich für das Voip für Telefonate nach Deutschland zuständig war. Mit einer modifizierten Firmware (freetz) hat sie sich außerdem um den OpenVPN Tunnel in die Uni gekümmert. Dabei hat die Fritz!Box natürlich auch ein DSL Modem und kann sich um das WLAN kümmern. Sie ist dem VOOD haushoch überlegen, erst recht wenn sie mit einem freetz image läuft. Um sie als DSL-Modem in Österreich zu verwenden, muss man ihr allerdings zunächst Annex A beibringen.

Diploma thesis

Raimar — 2010-07-22T13:15:05+01:00

I have finished my diploma thesis.

Mathematica 7 Qt style

Raimar — 2010-03-29T22:58:06+01:00

Mathematica had a rather ugly looking user interface on Ubuntu Karmic 64bit, but it was all right on a Gentoo 32bit system. I don't know the reason for this, but I managed to improve the situation on Ubuntu. I forced mathematica to use the system Qt libraries and specified the Qt style in the mathematica launcher script.

nanoblogger: navigation bar always visible

Raimar — 2010-03-27T02:53:28+01:00

I wanted the navigation bar (the thing on the left with "articles", "categories" etc.) on this homepage to be visible also for archive pages and permanent links. This is how to convince nanoblogger to do it.