Quantum Diaries

Sometimes I wonder what physics will bring me in terms of hard cash. This question may play a larger role in my subconsciousness than I realized. Saturday night I dreamed that me and my fellow PhD students from the summer school I am right now were calculating how a normal wave would traverse a medium of liquid argon. We found out that this wave has a rather complicated equation of motion, in which heavy objects are not seen, but light objects are lifted. In this dream I had the plan to rob a jewellery using liquid argon. All my colleagues agreed, so we went to a nice shop and pumped it until it was filled with liquid argon. One of my colleagues bashed a hole in the ceiling by throwing the guard. A small flame of a lighter was enough to set off a wave in the liquid argon, blowing all the shiny jewellery through the hole into our van. I felt that I had brought physics and making money together in an efficient way. Waking up was a weird experience, I noticed myself checking the room for illegal jewellery. It made me think that a physicist could make a good living in crime.

[Disclaimer: This is not a overview of the history of physics. This is an overview of MY history in physics.]

It occurred to me in the last couple of years that the history of physics had involved an inflation of the names of the different theories. As soon as the new model arises it old one, on which it is based, is suddenly “Classical” and “Standard”, the modern theory gets fancy names like “Quantum” and “New”. Today, we were confronted with the problems in the Standard Model. The Standard Model describes the fundamental particles and forces and is therefore of not to be neglected importance to particle physicists. It took me roughly six years to get a grasp on the Standard Model, only to find out that is incomplete. We need lot’s of New Physics and Super Symmetry to “fix” the Standard Model. Darn.
When starting on physics, one starts typically by looking on processes that take place in our human-frame. Things have masses of 1 to 1000 kg and move at speeds of zero to 1000 km/h. An exercise to go with this would be to calculate the braking distance of a 800-kg car that drives on a highway. I won’t deny the possible advantage of knowing this number, but unfortunately this kind of physics hardly compares to the physics in university. In the Netherlands, high school physics ends with radio-active decays. Pierre and Marie got a Noble Prize for the discovery of these decays in the 1890’s.
The first Monday of the first year in university the students get to meet Einstein’s Theory of Special Relativity (TSR). Irreversibly sending everything you learned in high school to the classical era. In this class speeds are pimped towards the speed of light (c=229 792 458 m / s). From TSR it becomes clear that at very high speeds space and time act together in a four-dimensional space-time. At those speeds all sorts of weird things happen: object have different size and masses from different viewpoints and mass and energy are equal except for a factor of c-squared. (You can think of the formula, I suppose.) We have now arrived to 1905, when the TRS was published.
In the next year you are taken further form our day-to-day life during the courses Quantum Mechanics I and II. QM is relevant for very small masses, such as for electrons (the mass of the electron is 0.00000000000000000000000000000091 kg). The central message is that real particles have some calculable probability to be in a specific place. Here, my imagination left me. Luckily, I am not the only one, my teacher quoted Pauli (I think) when he said “When I close one eye, I see a wave. When I close the other, I see a particle. When I open both my eyes, I go crazy”. Do not try to draw/understand/imagine this, it doesn’t work. Nice.
In the third year, you are ready to really learn that the language spoken in physics in math. It took me many hours of total despair, but then you see Maxwell’s formula’s of electrodynamics (1873) in Einstein’s space-time conventions. I can really appreciate the beauty of it, but maybe not that day right away.
Congrats, if you are

Quantum joke: "Sir, do you have any idea how fast you were driving?" "No, but I can tell you exactly where I was"

still with me, you are now ready to hear about the Standard Model and its shortcomings. But I have to get back to my PhD-class, so I will definitely come back to that. Maybe I also want to convince you that there different ways to look at the world. And all of them are equally interesting and complete in their own way.

Last weekend I met some 40 new people. When meeting new people, I find it almost impossible to not be biased. In the Netherlands all primary school teachers are well-dressed girls. People from Russia can drink massive amounts of vodka. Men in the financial sector are handsome and rich. Doctors are stubborn and save lives. Physicists are nerdy men.

Luckily, I am not the only one who has prejudices (I always love it when I can use a Jane Austen-word in real life) every now and then. When having the socially accepted introductionary talk, it is OK to make a joke about expected behaviour of your partner of conversation. “So you are a doctor? I feel much saver now.” This will may withdraw a polite smile, as doctors probably hear that kind of remark more often than they want.

But how do you react if the person in front of you does something completely a-typical? For a not so random example, what to say if a blond girl works in high energy physics for a laboratory you read about in papers and in Dan Brown’s Angels and Demons. I have heard many things: “Wauw, you must be much smarter than you look like”, “Isn’t that a male-thing?”, “I always found physics pretty horrible in high school”, “What does your boyfriend think about that?” and “If you would have been my physics teacher in school, I might have liked it”. The last one was nice. Over the past six years, remarks have gone from rather negative (“all your colleagues are nerds then?”) to rather positive (“interesting, no really!”). From that I guardedly conclude that our image is improving.

At the end of this weekend a Russian lady, who did not drink vodka by the way, told me that I had changed her view on nuclear physicists. Always happy to help!

it is a funny comic; but why are there only men in this picture?

As long as the LHC is not running, the ATLAS experiment is taking data runs to measure cosmic muons. Muons are the heavier brothers of the electron.  Every second 3000 of these muons pass through ATLAS leaving at least one hit in the detector. Because a muon is so heavy, it can penetrate though the 100 meters of rock above ATLAS, other particles are absorbed and therefore almost never seen in the detector. We know the paths of the muons are straight. We can use this knowledge to calibrate the detector. Very useful indeed.

On the left, you see a muon flying though the middle part of the SCT. It obviously leaves more that one YES (yellow dot) in the detector. On the right side, you see the same track, but through the disks. It only leaves one or two hits.

The part of the ATLAS detector I will be working at is the Semi Conductor Detector (SCT). This detector is built up from modules with small strips in them. These strips give a signal when a charged particle (such as a muon) passes by. This is a binary signal: YES (a particle) or NO. In order to measure as many of the particles produced in the LHC collisions later on, the detector has two regions: the middle part (barrel, cylindrical shaped) and circular disks on each side. As everything is installed by now, it is not my job to design or construct the detector, but to calibrate it. Here the muons come into play.

When a muon passes through the barrel part of the detector, the change that it leaves a YES in only one point of the detector is rather small. (See the figure.) When looking at the disks, the change of leaving only one YES is quite big.The thing is, that we have very complicated software that searches for tracks in the jungle of many hits that may come from a single event. As you can basically draw any straight line through a single point, this is not very informative. You need at least two points to determine a straight line (a line is therefore a 2D object). So, with only one hit, the software cannot find a track, with two hits it is stillambiguous and with three hits it starts to work.

Because I have been interested in the disks for the last few weeks, I have gone through many many files looking for tracks that left enough hits to find straight paths and analyse these. The good thing to report here is that some analysis can be done and it is good fun to be working with real data. Because statistics are low, I expect errors to be big. I will keep you informed.

My earliest memory that has something to do with politics is the Fall of the Berlin Wall in 1989. I was five at the time, and I remember that my parents sat in front of the television stating over and over that this was a day of international importance. And that my future would be so much different from theirs at my age. My dad traveled to Berlin not to long after that and brought us a piece of the Wall in a plastic box. It was pink on one side. Maybe, we all should throw a German party this year at November 17, to celebrate twenty years after the Fall.

Het Oostblok (The Eastern Bloc), as the countries behind the Wall are still referred to, still give me a feeling of far-awayness. I expected the Danube to be very grand, cold and dirty. I expected Budapest to be very crowded, grey and harsh. A city in Hungary is probably very hot in summer and extremely cold in winter. Arriving to Budapest I found out that the city is indeed grey, but almost empty, and spacious because of the Danube, which is (luckily) broad, cold and brownish. The city is beautiful in a faded glory kind of way.

Just north of town one of the Danube’s Szigets (Islands) in turned into a festival arena once a year. We spend a week surrounded by (Balkan) music, beer and people from all over Europe. The nice thing about a festival is that you have the change to go and listen to music you usually would not hear. The concert of The Prodigy was by far the most forceful. One of my friends mistook my face of wild panic for crude pleasure, just before I ran for coverage. It made me think about that time when my father mistook my expression of utmost incomprehension for surprise when we were listening to his African drum beats and he told me that this was improvised. I had not guessed differently. Seen from a large dustbin, the Prodigy concert was good, by the way.

Back at the Nikhef, I have to say I enjoyed the combination of Eastern Europe obscurity and music. I will defenetely be back.

The future came a little bit closer today: this morning I opened my email and found the email by the CERN’s General Director. The LHC will start up in 2009. Last year at October 21st the LHC was start-up for the first time. Everything went extremely well, the protons made their rounds in both ways and the first collisions were almost a fact when one of magnets quenched and actually jumped out of its concrete foot. Only an enormous force can make a 35 ton magnet jump, so the “accident” (as this disaster is euphemistically referred to) must have been pretty spectacular. It took a few weeks to found out what happend. And it took a year to fix it and test the rest of the magnets. Any suspected magnets were fixed, the tunnel will be cleared shortly. We will be good to go in the next few months.

If I am asked by non-physics friends “why it is taking so long”, I compare the construction of the LHC with telling the brothers Wright in the beginning of last century to build a Boeing 747 and fly it. It takes them 20 years to design, construct and finalize the plane. When they decide to make it fly, it actually takes off. Everybody is astonished. After a short flght, something appears to be wrong and the plane crashes. A year later they make it fly. Pretty amazing, I would say.

The delays of start-up should not make us loose our spirits. The fact that the experiments work so well, that we can use the Grid and managed to surfive the accusation that we want to turn the Universe inside out, should be enough reason to be very enthousiastic. If the LHC will run properly from 2009, even at lower energy, I think we can be very proud that humanity has accomplished something beyond the imagination of our fellow humans of  30 years ago. With the risk of sounding soggy, I believe that the combined effort of people and governments from all over the world to fight for something as abstract as scientific truth, is something very beautiful.

I would like to use this opportunity to thank the GD for making my day.

By studying animals, you can learn a lot about biology. But also about physics. I wanted to write about my cat for some time now and I write this on a very sad moment: our cat Willem (after the first king of Holland) has been found in the canal and is no longer with us.

Willem was extremely fat. In this way he could himself warm in winter and cool in summer. Fat is an excellent insualtor for heat. Futhermore he had a lot of fur. This is probably for the  same reasons, air is also a good insulator. Besides, it is nice if people pet you, which they do more often if you have fur. If Willem jumped from the side to our boat (we live on a boat) he would put his tail straight up in the air for balance. The rotation angle of the tip of his tail is much bigger than from his body, so a deflection is much easier noticed. By standing on four legs, he made it much more difficult to push him over.  From a physics point of view, I cannot say anything about the stripes, but I always found it very hard to see him if he was hiding underneath the cars.

If you have a pet, I invite you to play my game once. Why do they do certain things? Why are things as they are? Nature works very beautifully.

Next week we will be hiking the Swiss mountain slopes close to Zermatt and the Matterhorn. I have been to Zermatt once before as a kid, and the only thing I remember about it was a guy who guided his 50 goats through the streets. A Japanese family wanted to take my picture with a goat. The goat bit a hank of my hair, I am sure the pictures were hilarious.

Being a grown up now, I want to enjoy Zermatt in a serious and more sustainable fashion: I decided to plan my trip. This is something rather new for me. Usually I read a novel on the plane and get staggered by the fact that I can’t pay with euro’s on arrival. So my decision arose a problem: where do people plan a trip? On howtodothings.com I ended up making a IQ test and on loneyplanet they suggest that you think before you act. Thanks..

This asks for a more rigorous approach: after all, I am a scientist. Like the ATLAS detector, it is really hard to understand and analyse that whole thing at once. So this planning should contain a setup for travelling back and forth to Swiss, the days in between and a risk analysis of the things that may change this program. When you think about it, there is an overwhelming variaty of things that may happen in the mountains. What if I fall in love with goat guy? Would my boyfriend allow me in the car after such a betrayal? Do I need to bring an extra car just in case?

Concluding remark: I am completely inadequate holiday planner.

Every year tens of people die climbing the Matterhorn. I guess this only adds to its almost scary beaty.

Hereby I would like to introduce a new kind of event: the MIP event. (For the non-physicists among you, the word “event” has the direct association of “collision in accelerator” to it.) (For the non-detector people among you, a MIP is also a minimum ionising particle, like a cosmic muon.) The definition of the More Important than Physics (MIP) event is highly personal and may change as a function of time.

As physics is work for me, I would like to point out that there are of course enough things that compete with physics for my attention and time. These are all fun things: My boyfriend, my friends, my horse, skiing, Amsterdam night life etc. Combining all these comes down to combinatorial trial-and-error. Sometimes I end up with a sustainable schedule. But physics is there and has a high priority in both time and brain CPU.

In the last weeks, I have assigned the MIP status to two events. The first one was not happy and I won’t go into that one, but the second was a colleague’s wedding. The party took place at the water, we danced, had a beer and drove home. Although it was on a Tuesday, the physicists probably outnumbered other people and I needed to stay sober, I did think about physics at all. Definitely a MIP event.

As a particle physicist in Europe, I will be travelling back and forth to CERN a lot. This blog is brought to you by Easyjet, by enriching my schedule with tree hours of delay in the wonderful “shopping lounge” of the M gate at Schiphol. It is getting so boring that my neighbor actually is trying to read over my shoulder right now. I don’t think he reads English, because he doesn’t stop as I write this.

There is a guy sitting in the lounge with a lap top with a CERN sticker on it. That is extremely nerdy; I want that too! His sitting in the lounge all of a sudden seems a lot less like a lost for time then mine. He is probably doing something outragingly intelligent right now. I need a sticker to look that smart as well.

Next time, when you are at Schiphol, look out for the blond girl with a lap top with a CERN sticker on it. I will be in course of changing my Facebook profile..