last week i was in leiden, attending a workshop on post-quantum crytpography and quantum algorithms at the lorentz center. it was a collection of talks and working in smaller groups, where we discussed certain topics, such as quantum attacks on ideal lattices in more detail, trying to find a way to use quantum computers to speed up attacks against primitives of post-quantum cryptography. as this is somewhat close to my research – i work on analyzing a quantum algorithm with pawel wocjan and am working on lattices and lattice reductions – i was very happy to attend this meeting. especially since there were not just some mathematicians, but also a lot of experts on various aspect of quantum computers and quantum algorithms. now i also know a lot more about quantum computing, both from the theoretical side – like having been explained grover’s algorithm, which is another of the fundamental quantum algorithms next to the period-finding algorithm family starting with shor’s algorithm – and the practical side – what the current technology with regard to building quantum computers is, and how people writing compilers for quantum computers can suffer and how complicated it can be to turn a “simple” algorithm into a circuit. i think this was one of the most productive workshops i’ve ever attended.
unfortunately, i neither took my camera with me (the little one i had with me last week, since it is somewhat broken (the sd card slot won’t keep the card anymore, similar to what is described here), nor did i really had time to take any pictures, as i spend most awake hours doing mathematics. i took a few shots with my mobile phone on the excursion/conference dinner on wednesday, which happend to be on a boat going through grachten around leiden and the city and also happened to be a very decicious and very spicy asian food buffet. and later, there was a great dessert buffet. one of the best and original conference dinners i had for quite some time :)

last weekend we travelled to dresden. with perfect weather, we (re-)explored the city and parts of the sächsische schweiz. we first started with a hop-on/hop-off sightseeing tour which led us among other things to the blue wonder, schwebebahn dresden, the funicular railway, the “balcony of dresden” (luisenhof), the dresden-neustadt station’s entrance hall and the “toilet cinema”. some impressions from these places can be seen below:

here are also some shots from during the night, mainly showing dresden downtown:

finally, we did an excursion to the sächsische schweiz, namely to the bastei and the adjacent neurathen castle. from there, we descended down to rathen and took a paddle wheeler from there back to dresden. here are some impressions. (you can see “our” paddle wheeler in the photos above, it was the “pillnitz”.)

as you can see, we had a great time with perfect weather. most of the time during the excursion, there wasn’t a single cloud on the sky!

yesterday we were on an excursion, which led us from our home to some nice places between lake constance and schaffhausen with a final stop in baden before we returned home.

we first traveled to tägerwilen to look at a small design settlement with eight houses, where different materials were used. unfortunately, the weather wasn’t very great at that point, and it was not very easy to take good pictures there anyway… afterwards, we walked over to gottlieben and waited for our boat.

we traveled by boat on lake constance and the rhine to schaffhausen. the weather was still not great, it was cloudy, but at least it wasn’t raining. when approaching schaffhausen, the clouds started to rip apart.

in schaffhausen, the clouds began to clear up. we explored the old town a bit.

finally, we walked up to the munot, a fortification built during the 16th century. from there we had a great view – some of the above photos were taken from there or from the way up/down.

finally, we proceeded by train to waldshut to drink coffee, and continued by train to baden to eat dinner. at least, that was what we planned to do in baden. turns out that the city center is essentially dead from 6 pm on, except fast food “restaurants” or pubs. we had to walk quite some distance outside of the city center to find something to eat; we ended up in an italian restaurant chain near the kantonsschule. on the way back, two of us who had to travel westwards wanted to take bus 3, which would have allowed them to arrive home earlier than if they would take the later bus which would be perfect for us. bus 3 is supposed to leave at the same stop. unfortunately, unknown to us and also to google maps, apple maps, map.search.ch etc., there are two stops called “kantonsschule”. at the time we located the second stop on a map, their bus was already gone… really great. anyway, we eventually got back to the main station, and were able to depart in direction of our beds after this long day…

yesterday, when the weather was surprisingly beautiful, we were outside. me, mostly hanging around with my telephoto lens, watching the kittens play, hide, and explore.

later, on the inside, i took some photos of the older cats as well, while they were waiting for food:

they had to wait a bit longer. first, we did some cooking: a vegetarian zürcher geschnetzeltes (based on dinki) with rösti. won’t be the last time we had that :)

today was the first time that miukumauku was lying on our bed with another one of our cats and both ended up licking at each other. this is the best sign that the cats start to accept each other. what a beautiful moment that was!

today, while being in bauma, we saw a steam locomotive from the dampfbahn-verein zürcher oberland. they usually operate on sundays from may through october between hinwil and bauma. (and yes, it’s on our to-do list!)
here are two snapshots of the train:

on sunday afternoon, miukumauku met her two sisters the first time since they were separated from their mother. it is interesting to see how different the kittens already behave. the two sisters play and live together, while miukumauku has to survive on her own, together with three adult cats who are not the most social ones. the two play a lot, while miukumauku first watched them a lot, tries to play along, but doesn’t really dare to jump on the others, to really play with them. on the other hand, miukumauku also stays closer to her home, knows where she lives, returns from time to time, while the other kittens run around, and just explore every door they can find.
another interesting thing is that apparently, miukumauku doesn’t want to be left alone. when in the evening we were sitting outside, eating, with the kittens back inside, miukumauku was making a huge noise and tried to get outside. when we’re inside, she’s quite different, watching open doors and windows with interest, looking through, but usually staying inside or close to the opening, only walking a few meters, exploring a bit, usually with me standing nearby.

after some years of using it, i finally decided to leave facebook. i was never a huge fan of facebook, even though during some times, i used it rather intensely. over time, facebook changed. most of the time, not for good. facebook tried to create a own sub-internet, trying to convince users to only use this sub-net, ignoring the rest of the net. a recent peak was their (again, forced) introduction of email addresses for all their user, replacing user specified email addresses on the users’ profiles by the facebook one. besides that, facebook is spying on their users. a lot, in many regards. facebook is tracking their users while they use the web (using many websites which use the “like” button “correctly”). facebook evaluates all communication done over facebook. facebook is trying to keep track on how we live, offline and online, by keeping track of our position. facebook is trying to obtain information about us by trying to convince our friends to add stuff about us – for example revealing our correct name. and worst of all, facebook is trying to undermine many basic principles of data protection, including european data protection laws.
for me, there is almost no reason left to stay with facebook – except that it allows to keep track of people from all around the world, stay in contact with them; people i met at conferences, at places where i was living, during school, etc.
this is quite important, as it is not very easy to keep track of many people who don’t have a (permanent) blog, website, or email address. which is the case for the vast majority of people. for that reason, i will keep my account – at least for some time, maybe until a better alternative comes around. but i will not feed it with any information. i will only use it as a kind of “business card”, which points to spielwiese, and contains a working email address of mine. i might use it to retrieve contact data of other people, or see what they are doing, in case they still actively use facebook. but i won’t add any more content to facebook. no more posts, no more comments, no more photos, no more “like”s.
and in case you want to contact me, send me an email. or comment in my blog. but please avoid sending me messages via facebook :-)

yesterday, when flying back from spain via frankfurt airport, we noticed a microphone dangling from the ceiling near to our gate, a38. i guess big brother is not (only) watching, but listening… (maybe it is related to this?)

yesterday we went on an excursion. first, we visited an old ehgraben in züri niederdorf, which is a small trench between rows of houses which was used to dispose of feces during the middle ages. nowadays one can visit it and read the provided information panels. afterwards, we proceeded to the lindenhofkeller, containing celtic, roman and medieval remains.

afterwards, we continued to the sewage treatment center in werdhölzli, zürich. we had a guided tour through the process of treating waste water from the zürich region and its conversion into “clean” water. certainly very interesting! it is also interesting to see what kind of stuff the mechanic filtering finds. among toys, dentures and mobile phones one can find base stations for mobile phones, credit cards, cash, id cards, remotes, pocket calculators, etc. quite amazing.

finally, in the evening, we had a barbecue.