Well I feel accomplished! Yesterday night I did my last chunk of grading of the spring semester. I had my Statistical Mechanics final exam yesterday morning too. It went better than I expected, considering the fact that I had been doing pretty bad on the partial exams and on some of the homeworks.
There were three problems. The first problem was to consider an ideal spin-0 boson gas. We were asked to find an expression for the chemical potential, and then decided whether you can achieve Bose-Einstein condensation with that system. It was a straight-forward calculation. In the end I found that there could not be any condensation. The second problem was a two-cite Ising model. We were asked to find the susceptibility and the energy variance. At first I started to freak about about the susceptibility, since I had to calculate the average spin. But then I found an expression for the average spin; it was just the derivative of the free energy, which can be found easily with the partition function. Then I completely forgot that I wanted the susceptibility and carried on to the next part. This was my first silly mistake. I had to provided low and high-temperature behavior of the susceptibility and instead provided the analysis for the average spin. Oh well! The last problem was to consider a weakly damped one-dimensional harmonic oscillator. We had to find the spectral densities for the spatial coordinate and the momentum coordinate. I tried something, but to be honest I never fully understood this last part of the course. Partly because I did not cared (and I should have cared), and partly because It was something new and I felt it was a bit rushed (I know, that is a very lame excuse). Overall, I hope to pass the course, at least with the minimum. I have worst things to think about next semester...
But it was not until today early morning, around 2:12 AM, that I realized my second silly mistake. The Electrodynamics final exam had been on the day before yesterday. Again, three problems. The first was an easy question. My professor is an experimentalist, he works with x-rays at the National Synchrotron Light Source. In day during class he asked us what was the wavelength of one photon with an electronvolt of energy. It turns out that this is related to an expression that involves three fundamental constants: Planck's constant h, the speed of light c , and the elementary charge e. The answer is 1239.8 nm. The second problem was to reproduce the calculation of the electromagnetic fields of a charge particle in motion. The idea was to consider a charge moving with constant velocity along the x-axis and to calculate the field at a fixed point along the y axis by considering the fields in the rest frame of the particle and then Lorentz- transforming to the lab frame. It was straight forward. Finally the last problem was about an electric dipole that was rotating along the x-y plane with a given angular frequency and we were asked to calculate the radiation fields and the angular distribution of the radiated power. This expressions involve a unit vector from the source to the observer. Usually this unit vector is a position vector divided by its magnitude. But no sir, the gentlemen writing to you on this cloudy afternoon decided that the unit vector was just the sum of three unit coordinate vectors. For starters that is not even a unit vector! Everything depended on that unit-vector, so of course everything came out wrong; my power distribution was uniform... I did not realized what my mistake was until after a day. What makes me most angry is the fact that I knew it had to be wrong. But I continued on, lying to myself. It all sucks. Oh well, I had been doing better at E&M, so I expect to pass this class too.
Next Tuesday I have my last final, Quantum Mechanics. I hope I do not have to writ about my third silly mistake.
11 May 2007
02 May 2007
Undergraduate orientation
When I was a freshman (not so long ago... well 4 years) I had a class that was suppose to be an orientation for freshmen. What I recall the most from this class was the professor (who was the head of the department at that time) saying a lot "physics is the science, the rest are details" and claiming that this quote was from Einstein. Anyways, now that I look back, I see all that could have been covered on that class.
Something that needed to be covered was to present physics as the interesting and exciting field that it is. I would have talked about all the interesting work going on at the many national laboratories in the US and around the world. I guess from my point of view, physics sounds interesting. After all it might be a matter of whether the students are not to stubborn. In my year most of the students wanted to change to engineering. They all regarded physics as "hard". To this very day, I still get from people that physics is hard when I tell them about me being a physics graduate student.
I would have mentioned some historical background of important discoveries and advances in physics. For example, the Manhattan project provides a very interesting theme to discuss topics like ethics and working conditions. Other examples would include a small survey of Nobel prizes. The history of Quantum Mechanics would have also been a nice interesting topic, mentioning names like Bohr, Schroedinger, Dirac, Heisemberg and Feynman. Biographical talks would be nice too.
At the freshman level, physics is not that fun. I know some people will disagree with me, but I believe that with no calculus it is hard to go into much details. Still, maybe a survey of the many branches of physics and its topics. An example would be Statistical Mechanics and different species of particles (fermions versus bosons), interacting particles, mention of BECs, importance of the electron gas to Solid State physics, even define what Solid State physics is. A little overview of relativity and the different types of wormholes. Problems in high energy physics. All this maybe to the limitation of just mentioning names and dates... but I think that would be enough to motivate the students to stay in physics and try to go as far as possible.
I good freshman year will give the student the idea that the remaining years in college will be rewarding.
Something that needed to be covered was to present physics as the interesting and exciting field that it is. I would have talked about all the interesting work going on at the many national laboratories in the US and around the world. I guess from my point of view, physics sounds interesting. After all it might be a matter of whether the students are not to stubborn. In my year most of the students wanted to change to engineering. They all regarded physics as "hard". To this very day, I still get from people that physics is hard when I tell them about me being a physics graduate student.
I would have mentioned some historical background of important discoveries and advances in physics. For example, the Manhattan project provides a very interesting theme to discuss topics like ethics and working conditions. Other examples would include a small survey of Nobel prizes. The history of Quantum Mechanics would have also been a nice interesting topic, mentioning names like Bohr, Schroedinger, Dirac, Heisemberg and Feynman. Biographical talks would be nice too.
At the freshman level, physics is not that fun. I know some people will disagree with me, but I believe that with no calculus it is hard to go into much details. Still, maybe a survey of the many branches of physics and its topics. An example would be Statistical Mechanics and different species of particles (fermions versus bosons), interacting particles, mention of BECs, importance of the electron gas to Solid State physics, even define what Solid State physics is. A little overview of relativity and the different types of wormholes. Problems in high energy physics. All this maybe to the limitation of just mentioning names and dates... but I think that would be enough to motivate the students to stay in physics and try to go as far as possible.
I good freshman year will give the student the idea that the remaining years in college will be rewarding.
27 April 2007
Hawking goes weightless!
Quantum Crops would like to congratulate Stephen Hawking on his recent weightless experience. I can imagine how much this would mean to professor Hawking, a man that has spent his life studying gravitation, among other things.
Via Reuters.
Via Reuters.
26 April 2007
Who wants to be a theoretical physicist? - Part I
On this post I would like to comment on the "difference" between being a theorist or an experimentalist.
First of all, what the hell do I know about being a theorist or an experimentalist? After all, I am only a first year (almost second year...) graduate student. Well, guess what? I want to do theory. No surprise, since the majority of the students want to do theory when they go to school. The first point is, I am not really sure I want to do theory. That is, my experiences so far consist of field work in laboratories. I really do not know for certain whether I want work with theory. I just like it.
To tell you the truth, I also liked working in the lab. Last summer I had the opportunity to work at SLAC. My project involved putting together an apparatus that assembled water samples for x-ray transmission experiments. It was fun, since I had to manipulate the fluid cells really carefully. I came up with an array of micrometers that slowly assembled the sample. I also went and try them at the Advanced Light Source in Lawrence Berkeley National Laboratory. I know, I am talking about fancy labs, whatever that means. But I was a bit hesitant about working in the lab. My undergraduate years included two semesters of "Intermediate Lab", something that was really depressing. I know that science labs education is a big challenge. My advanced lab experience made me feel really frustrated. Sometimes the experiments were not working; once I even burned one of the detectors. Most of the experiments consisted of a well organized series of steps, that appeared to be really straight forward to carry out in theory. In practice it was not that way. I guess the fun and excitement lies in encountering problems along the way and coming up with solutions. I guess that is how experiments are actually carried out.
There is a little demon inside my head that wants to suggest the following format. Learn about some phenomena (i.e. diffraction). Now device an experiment that will let you measure something (i.e. diameter of a human hair from the diffraction pattern). This type of format will require a considerable amount of equipment, but hey it is just a proposal. Students will learn that the whole process of carrying out an experiment is long and hard. One will have to go not only through the stages of the scientific method but also through the whole design of the experiment.
There is also a little angel inside my head that is suggesting another format for a lab course. How about keeping all this pre-arranged experiments, but having meetings with the professor or the instructor and going through the lab. A quick lecture of the theory behind the phenomena that is to be measure. Also some comments on understanding the instruments and methods used to get the measurements. This way the students will understand better what is actually going on during the experiment. What I am trying to avoid is mindlessly sitting down and pushing buttons to get numbers and just going around with them to get standard deviations and etc.
Having bad experiences with undergraduate labs does not justify that I do not want to become an experimenter... So why do I want to be a theorist?
First of all, what the hell do I know about being a theorist or an experimentalist? After all, I am only a first year (almost second year...) graduate student. Well, guess what? I want to do theory. No surprise, since the majority of the students want to do theory when they go to school. The first point is, I am not really sure I want to do theory. That is, my experiences so far consist of field work in laboratories. I really do not know for certain whether I want work with theory. I just like it.
To tell you the truth, I also liked working in the lab. Last summer I had the opportunity to work at SLAC. My project involved putting together an apparatus that assembled water samples for x-ray transmission experiments. It was fun, since I had to manipulate the fluid cells really carefully. I came up with an array of micrometers that slowly assembled the sample. I also went and try them at the Advanced Light Source in Lawrence Berkeley National Laboratory. I know, I am talking about fancy labs, whatever that means. But I was a bit hesitant about working in the lab. My undergraduate years included two semesters of "Intermediate Lab", something that was really depressing. I know that science labs education is a big challenge. My advanced lab experience made me feel really frustrated. Sometimes the experiments were not working; once I even burned one of the detectors. Most of the experiments consisted of a well organized series of steps, that appeared to be really straight forward to carry out in theory. In practice it was not that way. I guess the fun and excitement lies in encountering problems along the way and coming up with solutions. I guess that is how experiments are actually carried out.
There is a little demon inside my head that wants to suggest the following format. Learn about some phenomena (i.e. diffraction). Now device an experiment that will let you measure something (i.e. diameter of a human hair from the diffraction pattern). This type of format will require a considerable amount of equipment, but hey it is just a proposal. Students will learn that the whole process of carrying out an experiment is long and hard. One will have to go not only through the stages of the scientific method but also through the whole design of the experiment.
There is also a little angel inside my head that is suggesting another format for a lab course. How about keeping all this pre-arranged experiments, but having meetings with the professor or the instructor and going through the lab. A quick lecture of the theory behind the phenomena that is to be measure. Also some comments on understanding the instruments and methods used to get the measurements. This way the students will understand better what is actually going on during the experiment. What I am trying to avoid is mindlessly sitting down and pushing buttons to get numbers and just going around with them to get standard deviations and etc.
Having bad experiences with undergraduate labs does not justify that I do not want to become an experimenter... So why do I want to be a theorist?
14 April 2007
It never pays
Procrastination never pays...
During my spring break, which coincided with "Holy Week", I did little homework and no reading. I really wanted to relaxed. I did worked, but basically I felt like a sloth: slow. Or maybe I should say stupid. Whatever, I was just not processing anything. I did not even finished with taxes, which was very annoying. Taxes were like taking a test on something you never heard about in your life.
But this week, I straighten up. By Friday I had finished the EM homework and had half of the SM homework already written. I guess I have been more motivated since I started reading the Harry Potter and the ... books. They are pretty good, I cannot help but compare myself with Harry in Hogwarts, with physics as magic.
I have also been feeling a bit less stressed out. I did not contacted anyone else regarding summer research. Instead, my plan is to read Frankel's The Geometry of Physics and Zwiebach's A first course in string theory. Both should keep me busy during the summer, before I probably start TAing during July. More on that later, now I should finish my QM and my SM and maybe grade a little.
During my spring break, which coincided with "Holy Week", I did little homework and no reading. I really wanted to relaxed. I did worked, but basically I felt like a sloth: slow. Or maybe I should say stupid. Whatever, I was just not processing anything. I did not even finished with taxes, which was very annoying. Taxes were like taking a test on something you never heard about in your life.
But this week, I straighten up. By Friday I had finished the EM homework and had half of the SM homework already written. I guess I have been more motivated since I started reading the Harry Potter and the ... books. They are pretty good, I cannot help but compare myself with Harry in Hogwarts, with physics as magic.
I have also been feeling a bit less stressed out. I did not contacted anyone else regarding summer research. Instead, my plan is to read Frankel's The Geometry of Physics and Zwiebach's A first course in string theory. Both should keep me busy during the summer, before I probably start TAing during July. More on that later, now I should finish my QM and my SM and maybe grade a little.
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