I suddenly feel very privileged. There is such a deficit in students for scientific/engineering courses in Germany, as soon as you made the Abitur you are guaranteed to get into almost all of the universities for those subjects.
[QUOTE=Swebonny;39504817]Completely forgot about that. Yeah basår works as well. However I think you still have to perform well to get a Teknisk fysik spot, because I imagine loads of the basår students are going to pick Tfys.[/QUOTE]
[QUOTE=booster;39504978]Frankly, the only thing I'm worried about considering a basår is that I don't know if i'll get any student benefits.
Would any of you Swedes know any more in that area? Because if I don't get any student benefits that year, I'm gonna be knee deep in shit trying to get the money to last.[/QUOTE]
Took basår to get where I am (didn't have math E and physics B). It's not very hard, the system is more like a normal high school rather than uni. Also to get into teknisk fysik (immediately, no reserve) I had slightly under C as average (thank you, surprisingly hard final exams compared to former years out of nowhere) so you definitely don't need high marks.
Most people at my basår were scared to death of barely managing that year, so it was like, 2 people excluding me that even thought of taking teknisk fysik.
As for CSN benefits, I got it no problem. As long as you are studying they'll pay (though I can't remember if I got the same 2700SEK/month as now at a normal programme or if I got less).
Just be sure to not be a lazy ass at high school and get placed down in Södertälje, going from north of Stockholm to Södertälje and back again every single weekday for a year was a pain (about 3.5 hours a day in total, assuming the trains didn't have problems).
If not, take the högskole prov, it's not that hard to get in apparently, easier than getting that insane 22.1 that is required to get in anyway.
[editline]7th February 2013[/editline]
Also word of advice: They'll tell you the basår is hard and it gets easier afterwards. It doesn't, in fact it gets much harder (teknisk fysik, at least). First day of Thermodynamics will probably make you want to quit, but after the initial shock it turns out to be easy (relatively at least).
[QUOTE=acds;39505898]Took basår to get where I am (didn't have math E and physics B). It's not very hard, the system is more like a normal high school rather than uni. Also to get into teknisk fysik (immediately, no reserve) I had slightly under C as average (thank you, surprisingly hard final exams compared to former years out of nowhere) so you definitely don't need high marks.
Most people at my basår were scared to death of barely managing that year, so it was like, 2 people excluding me that even thought of taking teknisk fysik.
As for CSN benefits, I got it no problem. As long as you are studying they'll pay (though I can't remember if I got the same 2700SEK/month as now at a normal programme or if I got less).
Just be sure to not be a lazy ass at high school and get placed down in Södertälje, going from north of Stockholm to Södertälje and back again every single weekday for a year was a pain (about 3.5 hours a day in total, assuming the trains didn't have problems).
If not, take the högskole prov, it's not that hard to get in apparently, easier than getting that insane 22.1 that is required to get in anyway.
[editline]7th February 2013[/editline]
Also word of advice: They'll tell you the basår is hard and it gets easier afterwards. It doesn't, in fact it gets much harder (teknisk fysik, at least). First day of Thermodynamics will probably make you want to quit, but after the initial shock it turns out to be easy (relatively at least).[/QUOTE]
The subject all in all is something I'd love to work with, so I'm definitely going to give it my best shot.
I am currently reading up on the physics courses (10 books) by my own, and oh man would this be easier with a teacher to explain it to you.
It sure is going to be an adventure.
Also, just to confirm. With the basår, the complete education is something like 7(+1?) years right?
[editline]7th February 2013[/editline]
Can't believe acds just gave me more info on basår than my tutor did in 2 years :v:
[QUOTE=booster;39507627]The subject all in all is something I'd love to work with, so I'm definitely going to give it my best shot.
I am currently reading up on the physics courses (10 books) by my own, and oh man would this be easier with a teacher to explain it to you.
It sure is going to be an adventure.
Also, just to confirm. With the basår, the complete education is something like 7(+1?) years right?
[editline]7th February 2013[/editline]
Can't believe acds just gave me more info on basår than my tutor did in 2 years :v:[/QUOTE]
Depends on what you want to do, if you are going teknisk fysik it's a civil ingenjör programme, which means 5 years (3 years + 2 of master degree), which would make it 6 years in total with basår. Other programmes I don't really know. Also don't know about student loans and basår, but I don't see why it shouldn't work.
Yeah a good professor is great, we have a guy called Manneberg in Classical Physics and you barely even need to re-read your notes because he explains it so well you'll get it the first time (they aren't all like that though, sadly).
For you people currently at KTH, how difficult is it to find student housing in Stockholm? I heard there was some massive queue or whatever and I was hoping it was at least a little bit overexaggerated.
I'm also wondering the same thing, where do I begin if I want to find housing in Umeå?
Just had an interview for Physics with Astrophysics at York, I had to prove that the derivative of ln x=1/x and then generalise F=ma without the assumption of constant mass. Think it went ok; the maths was fine and I got the physics bit eventually.
Housing in Stockholm is really scarce. You can probably find one, but unless you got a good deal of money it will be hard. Not impossible though. Also the further out you go the easier.
Today I had a Calc II part 2 test which was easy as shit. Tangent plane to the surface given a F(x, y)=z at a point and then to draw the area of stuff like x^2+y^2 < 2 (I think he was bored and couldn't be arsed to come up with something, because that isn't exactly Calc2 level, is it?).
Now that I think of it, we've had very little actual physics in the last few pages. Anyway for people wanting to do engineering at uni (can't speak for physics), expect some very different kind of problems. Our final thermodynamics exam had questions like "What is the potential energy of a skyscraper?", "If all windows had a perfect vacuum between the two glass panels, how many Watthours would be saved every year?" and "A coal plant outputs X kWh per day, if all coal burned in a year was used to create a cube, what would the length of the side of the cube be?" (no data other than what's in the question). Basically be ready for educated guessing (at least in the first year physics courses at my programme).
[QUOTE=DeEz;39508072]For you people currently at KTH, how difficult is it to find student housing in Stockholm? I heard there was some massive queue or whatever and I was hoping it was at least a little bit overexaggerated.[/QUOTE]
Not sure about student housing. I know if you as a Stockholmer is looking for a house, queuing can take years.
But looking at things like this, makes it seem like there are loads of student housing.
[url]http://www.studentlya.nu/search?field_hyran_value=All&field_manadsavgift_value%255Bmin%255D=1000&field_manadsavgift_value%255Bmax%255D=9000&field_rum_value%255Bmin%255D=1&field_rum_value%255Bmax%255D=100&field_storlek_value%255Bmin%255D=11&field_storlek_value%255Bmax%255D=200&field_lan_tid=1596[/url]
[editline]7th February 2013[/editline]
This thread has been taken over by the Swedes.
[QUOTE=Yahnich;39508010]i spent my day doing laplace transformations to solve diff equations
tnx laplace transformations ur a bro[/QUOTE]
Spent the day doing the exact same thing (and some astrophysics). I find it so much easier than fucking around with ansatz.
I will finish off my bachelor's degree in physics in a few months. The last class I have to take now is right back where I started - Classical Mechanics.
Are we allowed to ask for help with physics problems in this thread?
[QUOTE=acds;39509434]Now that I think of it, we've had very little actual physics in the last few pages. Anyway for people wanting to do engineering at uni (can't speak for physics), expect some very different kind of problems. Our final thermodynamics exam had questions like "What is the potential energy of a skyscraper?", "If all windows had a perfect vacuum between the two glass panels, how many Watthours would be saved every year?" and "A coal plant outputs X kWh per day, if all coal burned in a year was used to create a cube, what would the length of the side of the cube be?" (no data other than what's in the question). Basically be ready for educated guessing (at least in the first year physics courses at my programme).[/QUOTE]
This surprises me. What would be the best way to prepare myself to be better at guessing?
[QUOTE=ArgvCompany;39515229]This surprises me. What would be the best way to prepare myself to be better at guessing?[/QUOTE]
Practice a bit. For me it all seemed impossible the first day, then I slept and the morning after it just clicked and it was super easy (most anyway), yet some people that know the whole book by heart couldn't even do the easiest problem (this is one thing where study time is kinda useless). You also need some general knowledge, like how much the average nuclear reactor outputs or how much an average human body gives off (they do [B]not[/B] have to be exact, but you should be able to guess decently within the right order of magnitude at least).
Hard to explain exactly how to get good at it because it's different for everyone, but with some practice it will "click" and then you'll wish the whole exam was like that.
The idea behind that is that you need to be able to solve problems, not just repeat memorized formulas, as that is almost more important. Our classical physics exam will be purely problem solving for example, we are allowed to bring anything we want but another person or communication device. The book? Yup. Whole library? No problem. Computer? As long as communication capabilities are disconnected, you can (though computers might be forbidden this year, as they had equipment to pick up wifi, but people could still cheat with bluetooth apparently). This also means that the problems will be much harder than what we got in thermodynamics though.
Gentlemen, I'd like to propose a theory I've been considering for a couple of weeks now.
When Einstein formuled his theory of general relativity, he defined time to be an intrinsic property of space, perhaps as a 4th dimension of sorts (to form what we know as 4-dimensional space-time). I don't know the specifics, but it comes down to the following: an object of great mass will distort space, in turn distorting the passage of time - the greater the mass and the closer the distance to the center of mass, the slower the passage of time. This has been confirmed by precise measurements.
Now, here's my theory. Instead of time being a property (an extra dimension, if you will) of space, let's consider it the result of a sub-atomic particle. If a sub-atomic particle were responsible for the passage of time, I would call it a chroniton, give it the symbol χ (the Greek letter, pronounced /ki/ in English) and classify it as a boson (a force carrier, like photons and the theoretical gravitons and Higgs bosons and the like).
This theory hinges on the idea that chronitons behave similarly to Higgs bosons, in that they form a field (so, a chroniton field) with which particles interact. The idea behind the Higgs field is that particles that interact with it gain mass. The more a particle attracts Higgs bosons, the more mass it has (or such is the general idea).
Since it's been established that mass (gravity) slow the rate of passage of time, and gravity attracts things, I'd say that chroniton particles are also attracted by gravity. So the higher the density of this chroniton field, the slower the passage of time.
It's completely possible all of this is complete bogus and that time is indeed simply the 4th dimension of space as we know it, but I think it would be interesting to search for something like this, nonetheless.
Went to a physics lecture today that a guy in our uni is doing for anyone interested. Guy who did it said he worked out how to fix Maxwell's equations, and is about to publish a paper on it. Got offered a preprint of the paper, too.
Sometimes I kinda wish my degree was physics, not mechanical engineering.
[QUOTE=Raygen;39515730]Gentlemen, I'd like to propose a theory I've been considering for a couple of weeks now.
When Einstein formuled his theory of general relativity, he defined time to be an intrinsic property of space, perhaps as a 4th dimension of sorts (to form what we know as 4-dimensional space-time). I don't know the specifics, but it comes down to the following: an object of great mass will distort space, in turn distorting the passage of time - the greater the mass and the closer the distance to the center of mass, the slower the passage of time. This has been confirmed by precise measurements.
Now, here's my theory. Instead of time being a property (an extra dimension, if you will) of space, let's consider it the result of a sub-atomic particle. If a sub-atomic particle were responsible for the passage of time, I would call it a chroniton, give it the symbol χ (the Greek letter, pronounced /ki/ in English) and classify it as a boson (a force carrier, like photons and the theoretical gravitons and Higgs bosons and the like).
This theory hinges on the idea that chronitons behave similarly to Higgs bosons, in that they form a field (so, a chroniton field) with which particles interact. The idea behind the Higgs field is that particles that interact with it gain mass. The more a particle attracts Higgs bosons, the more mass it has (or such is the general idea).
Since it's been established that mass (gravity) slow the rate of passage of time, and gravity attracts things, I'd say that chroniton particles are also attracted by gravity. So the higher the density of this chroniton field, the slower the passage of time.
It's completely possible all of this is complete bogus and that time is indeed simply the 4th dimension of space as we know it, but I think it would be interesting to search for something like this, nonetheless.[/QUOTE]
I don't see how a particle could have to do with time being passed. Is there a particle for each of our 3 spatial dimensions?
Does anybody know of any resource that'll teach me up to and including all the laws and stuff of quantum mechanics/general relativity/etc? Started with khan academy this year just to get ahead with mathematics, but I cant seem to find anything that does the same with physics. Best Ive found so far is Roger Penrose The Road to Reality, but from the little ive read seems like its too much to fit into one book. Im trying to work towards an understanding of String Theory, before actually studying the subject in uni.
[editline]asd[/editline]
[quote]I don't know about different languages but for us Demtröder was always the best:
[url]http://www.amazon.de/Atoms-Molecules...0335780&sr=1-1[/url]
I had it in German though.[/quote]
Thanks
[QUOTE=ArgvCompany;39515229]This surprises me. What would be the best way to prepare myself to be better at guessing?[/QUOTE]
You are not supposed to calculate numbers. When you are asked for the potential energy of a skyscraper you assume a density function, gravitational pull, maybe the base area and then write down the integral along the height, everything else is stupid.
[editline]8th February 2013[/editline]
[QUOTE=Waterpi;39516525]Does anybody know of any resource that'll teach me up to and including all the laws and stuff of quantum mechanics/general relativity/etc? Started with khan academy this year just to get ahead with mathematics, but I cant seem to find anything that does the same with physics. Best Ive found so far is Roger Penrose The Road to Reality, but from the little ive read seems like its too much to fit into one book. Im trying to work towards an understanding of String Theory, before actually studying the subject in uni.[/QUOTE]
I don't know about different languages but for us Demtröder was always the best:
[url]http://www.amazon.de/Atoms-Molecules-Photons-Introduction-Molecular-/dp/3642102972/ref=sr_1_1?s=books-intl-de&ie=UTF8&qid=1360335780&sr=1-1[/url]
I had it in German though.
[editline]8th February 2013[/editline]
[QUOTE=Uber|nooB;39515960]Went to a physics lecture today that a guy in our uni is doing for anyone interested. Guy who did it said he worked out how to fix Maxwell's equations, and is about to publish a paper on it. Got offered a preprint of the paper, too.
Sometimes I kinda wish my degree was physics, not mechanical engineering.[/QUOTE]
What's there to fix? They all work in their respective fields!?
[editline]8th February 2013[/editline]
[QUOTE=paindoc;39514531]Are we allowed to ask for help with physics problems in this thread?[/QUOTE]
I insist!
I'm a second year Applied Physics student. I'm also not very good at it :v: (Well, I'd be better if I wasn't so lazy...)
Radiation is my favourite subject, and optics is my least. Mainly because we weren't trusted with lasers.
Browse ebay. Importing certain lasers may be illegal in your country, importing the KIT to build them however.. is not.
[QUOTE=Killuah;39517269]Browse ebay. Importing certain lasers may be illegal in your country, importing the KIT to build them however.. is not.[/QUOTE]
Oh, I have a laser somewhere up in the loft, but I find the whole idea of not trusting university students with lasers is somewhat stupid, but that's my university for you.
I think that's a pretty smart move. I wouldn't trust the 3rd semester me with a laser. Hell I can't trust my present self with a laser.
[editline]8th February 2013[/editline]
Some weeks ago a friend of mine and I tried out his new shiny laser imported from Czech Republic
"See if you can hit that trafic sign"
Well I don't know how but he somehow he mistook the safety patrol that was walking around the building next to that sign for the sign itself and hit him spot on in the eyes.
Lucky him, or if you think about it lucky us, he had sunglasses.
[QUOTE=Yahnich;39518129]spent the day fighting with matlab
matlab do you even linfit[/QUOTE]
Man, [B]FUCK[/B] matlab (though I'm starting to like it now, maybe just Stockholm syndrome).
[QUOTE=Killuah;39516893]What's there to fix? They all work in their respective fields!?[/QUOTE]
Yeah, I'm confused what there is to fix about them.
Why not Mathematica?
[QUOTE=Killuah;39518774]Why not Mathematica?[/QUOTE]
Why not say fuck to Mathematica too? Well fair enough, fuck Mathematica too.
[QUOTE=booster;39504978]Frankly, the only thing I'm worried about considering a basår is that I don't know if i'll get any student benefits.
Would any of you Swedes know any more in that area? Because if I don't get any student benefits that year, I'm gonna be knee deep in shit trying to get the money to last.[/QUOTE]
This might help you (It's from a handbook published in 2011, so it's most likely up-to-date).
[url]http://f2.braxupload.se/1a8hfc.dsc00597.jpg[/url]
Some people may still know me (even though I'm not visiting this forums that often anymore - Too busy with physics). In 2006 I started studying physics and right now I'm have already passed the first year (of roughly 3-4) of study of my PhD.
My experiment is about optical atomic clocks.
[b]History and principles of clocks[/b]
You know clocks like mechanical pendulum clocks: The pendulum oscillates like 2 times a second and if you count the number of oscillations per second you know how much time has left.
Well there are many other types of clocks like quartz clocks (many million oscillations per second: MHz) or even atomic clocks based on Caesium which currently define the duration of the second (Billion oscillations per second: 9.191 GHz).
The idea of atomic clocks is that an atomic transition only depends on natural constants and every oscillator (atom) is equal (for all times). In contrast a quartz-clock or pendulum clock depends on how well it has been manufactured. So in principle you have a very precise definition of time, right?
Well the number of oscillations is one thing but how well you can measure the frequency (and therefore time) and and with what uncertainty determines the quality of your clock. For the Caesium atomic clock the fundamental limit is already reached. This limit can be avoided by going to higher frequencies, because measuring billion oscillations per second and being off by +/-1 oscillations is something different than measuring 100 trillion oscillations and being off by +/-1 oscillations.
[b]Optical atomic clocks[/b]
Optical atomic clocks are based on optical atomic frequencies (Several 100 THz or 100 Trillion oscillations per second). This means your "pendulum" is oscillating at frequencies of visible light!
So in principle you have a laser and probe an optical atomic transition ("look if the freuency is right") and count the amount of oscillations.
But there are a few things you have to consider:
* The laser you use has to be "ultra stable"
* The atomic transition you want to probe has to have a small linewidth (which means it decays very very slowly, so during your measurements/interaction time it does not change/decay).
* The atoms should be at rest/move very slowly because of the Doppler effect (Like with a police car passing you with sirens on the pitch of the siren changes. a moving atom sees another frequency of the laser than a non-moving atom)
[u]Ultrastable laser[/U]
To stabilize the laser you generally use a so called resonator. This is simply a device consisting of two highly reflecting mirrors in a fixed distance. If you now shine in light into the resonator, it passes the first mirror and is reflected between both mirrors several times (for state of the art ultra stable resonators like we have for our "clock laser" this is in the range of 100,000 times up to a billion times). The thing is now that the frequency of light which fits into this resonator is determined by the distance of the mirrors and the uncertainty of this frequency is determined by the amount of reflectivity of the mirrors! And as less this distance changes as more stable your laser will be! For state of the art resonators the distance between the mirrors [u]does not change more than a proton radius[/u]! For a resonator of 10 cm length this means that you want to keep the distance between the earth and sun (~ 150 billion km) constant to 0.01 mm!
This stability is achieve by using special materials with ultra low thermal expansion as separator between the mirrors, ultra high vacuum environments, passive and active thermal shieldings and/or cryogenic cooled systems.
With this a laser frequency of e.g. 655 THz (a number with 15 digits) can be stabilized to be instable by 0.1 Hz or even less (for short times like seconds)! Because you have some unavoidable drifts over longer time-scales you still need atoms as absolute frequency reference to correct this ultra stable laser.
[u](Ultra) cold atoms[/u]
The atoms are generally laser cooled to temperatures close to the absolute zero point of temperature (0 Kelvin or simply 0 K). We use Magnesium atoms and cool them (with several complicated steps I don't want to mention here right now) to 10 µK (which is 0.00001 K above absolute zero). We do not reach record-breaking low temperatures (it's possible to be 1000 times colder with other atoms) but it's not that important for a clock. Even though that moving atoms cause a so called "broadening" of the atomic resonance (caused by the Doppler Effect, which is a very very huge effect) we have a trick to circumvent this problem: We tightly trap the atoms in a space not greater than a few 100 nm! This is possible in so called optical lattices (simply a laser-beam reflected into itself causing interference minima and maxima in which you can trap atoms). Without this tight confinement the ultra small transition we want to probe (in the regime of Hz to mHz and below = 1 Hz to 0.001 Hz) would be broadened to several kHz and up to MHz (= completely useless for a stable clock). But this confinement suppresses the Doppler effect and allows us to stabilize our ultra stable laser accurately and stable to an atomic frequency.
[b]But why?[/b]
Well why do we want to measure time that accurate? There are several fundamental physical theories that predict that physical constants actually are not constant and change over time. To verify or falsify this you either measure that constant at the beginning of the universe till now with a pendulum clock (which has to be stable over that time period but that's another thing though) or you use optical atomic clocks, wait for a few days/weeks/months and and get the same result (or even better). Also an optical atomic clock runs differently fast because of General Relativity and that already on the cm-level. So in principle you can measure the gravitational differences (Geodesy) by lifting your clock... And many many more (GPS uses atomic clocks for example).
[b]tl;dr[/b]
And that's it: A laser stabilized to an atomic transition so this clock would have gone wrong less than a second compared to the age of the universe allowing to test fundamental physics, geodesy and other cool stuff.
I'm actually really torn on whether to take a PhD or not. On one hand, researching and shit is cool, on the other it's 4 more years, I don't really want to spend the rest of my life researching, and you don't get paid much (30000SEK/month here, but you also lose 4 years of experience which are a pretty big deal).
Plenty of time to chose, but you can't know what route to take too soon.
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