Quantum mechanics exam (want to solve by myself)

[Matiasss]

Hi

i am studying for an exam (after failing the first one) on Quantum mechanics that is in one month from now. I use the lecture notes from the teacher. It includes the following topics and 25 exercises per chapter:

Formalism of classical physics
state vectors and operators
position and momentum observables
quantum dynamics
harmonic osc
angular momentum
central potential
density operator
time independent perturbation theory

My problem is that i try to solve the problems and almost always without success. It tooks to me a lot of time also to understand the solution. It feels de-motivating to me because i want to solve and review all the problems in the lecture notes but in the other hand it takes me a lot of time to solve them. Also the feeling that i am not solving the exercises by myself is bad.
Sometimes the maths blocks me but is not the biggest issue. I must say this course is very mathematical.

I am doing an Msc in Electrical Engineering (semiconductor devices) and my Bsc is also in EE but without modern physics background.
I am researching experimentally semiconductor detectors and i must complete the theory background (Yes, i know is strange to start experiments w/o theory).

any suggestions how to push forward ? may i just read and understand the solutions and continue with next excersies? my problem is that i stuck my self in the first or second problem in the chapter and start thinking that physics is not for me :(thanks

 

[Orodruin]

Definitely do not simply read it the problem solutions. If you do this you are never going to reach proficiency in solving problem yourself. My suggestion is to start by looking at the problem, if you do not understand how to solve it, go back to your textbook (note that textbooks are usually superior to lecture notes unless the lecture notes are very ambitious, in particular if you are having trouble). The material should be designed to help you solve the corresponding problems. If there is something conceptual you do not understand, visit Physics Forums and ask for clarification. If not, attempt to solve your problem. When/if you get stuck, come here to ask in the homework forums. Make sure to fill in the homework template and show us whatyou have tried. Once done, look at the provided solution to compare and see if you can get any new insights.

 

[micromass]

A month is really not a lot of time. I get the impression you started this way too late. As a consequence, there is nothing much you can do except to try to solve the problems and hope you make it.

 

[Orodruin]

Also, one thing that should go without saying: You should start by actually reading the course material before starting the problems, in particular if it has been some time since the lectures.

 

[Matiasss]

Definitely do not simply read it the problem solutions. If you do this you are never going to reach proficiency in solving problem yourself. My suggestion is to start by looking at the problem, if you do not understand how to solve it, go back to your textbook (note that textbooks are usually superior to lecture notes unless the lecture notes are very ambitious, in particular if you are having trouble). The material should be designed to help you solve the corresponding problems. If there is something conceptual you do not understand, visit Physics Forums and ask for clarification. If not, attempt to solve your problem. When/if you get stuck, come here to ask in the homework forums. Make sure to fill in the homework template and show us whatyou have tried. Once done, look at the provided solution to compare and see if you can get any new insights.

Thanks. I am actually using Cohen-Tanoduji book. Regarding the lecture notes, you are right. There are lot of difficult problems there (my teacher also told me that) but he also said that going through a lot of books could be difficult because i need to be focused.

 

[micromass]

Also, one thing that should go without saying: You should start by actually reading the course material before starting the problems, in particular if it has been some time since the lectures.

I don't know, I always found it fun to start the problems immediately. Obviously I fail a lot of time, or it takes too much effort. But then after reading the course material, I could solve them. This way makes the theory much more motivated and fun. But I guess everybody has his own methods.

 

[Orodruin]

I don't know, I always found it fun to start the problems immediately. Obviously I fail a lot of time, or it takes too much effort. But then after reading the course material, I could solve them. This way makes the theory much more motivated and fun. But I guess everybody has his own methods.

Yes, I did that too, but I was also not very representative and understood most of the theory directly from lectures. If, as the OP, you do not know where to start, I do not think jumping to the problems will be effective. That is mainly effective when you are able to get somewhere with the problems.

 

[Matiasss]

Thanks for the response "micromass" and "Orodruin".

Is not the first time i am sitting and trying to prepare for the exam. During the semester i have read the theory, solve a couple of problems (not a lot), and then studied to the first term exam that i failed to pass. One month should be enough, my problem is that i get stuck. Sometimes with very basic maths or physics that maybe i don't remember well because i took a break between my Bsc and my Msc studies.

I read the theory first of all. Then try to solve problems.

 

[Orodruin]

Sometimes with very basic maths or physics that maybe i don't remember well because i took a break between my Bsc and my Msc studies.

I think this is a very common problem. The point is that at university level physics, you need to remember what you did in the first year in order to progress. People do forget and, in some cases, barely passed calculus in the first place. The mistake many do is to tell themselves "I have passed this course so I never need to look at that material again" and this inevitably leads to problems in higher courses. You simply cannot take a proper quantum mechanics course unless you remember your linear algebra and calculus and I think that time spent in reviewing these subjects in general is time well spent unless you feel confident that your abilities in these subjects are sufficient.

 

[Matiasss]

I understand and agree with you. In my case i succeeded in the mathematical and classical physics very well in my Bsc.
Sometimes it occurs to me that i stuck with a problem and i don't release it until i understand ALL the things... and i don't continue with the following exercises.