# Search results

1. ### Is the real world deterministic?

Do you know of any theory or evidence that shows the real world is (or is not) deterministic? By "deterministic" I mean: If we give exactly the same initial conditions to any system in the world, does it evolve to the same state?
2. ### Bound states and Current density

The current density vanishes for a bound state. I would like to know the proof and its physical significance. I appreciate the responses in advance!
3. ### Energy unit

I have seen in text that it used an unfamiliar unit for fine-structure energy difference in a species. The unit was: cm^-1. I need these energies to do some statistical calculations in exp(-beta*E). Can anyone tell me how can I convert this unit or convert beta to this unit? Thanks!
4. ### Constraints in Hamilton's equations

My question is about the constraints in Hamiltonian viewpoint. I mean, where the constraints are put into the Hamilton's equations. Constraints are usually studied in Lagrange's equations in text books (such as Jose and Goldstein). However, I couldn't find anything about constraints in...
5. ### The angle between two 3D lines

Can anyone tell me how can I calculate the angle between two lines in 3D. I need in my codings. I know it has a simple solution. but I really have mixed up!!! Thanks.
6. ### Statistical physics

Hi. I need some useful and conceptual book in advanced statistical physics. I can understand the mathematics in some famous book such as Pathria, but I have trouble understanding some concepts in that area. Any suggestion?!!! Thanks in advance. Somy
7. ### A question on group theory

Hi all. I'm studying Wybourne book on group theory. I didn't understand this expression: U(p,q) I know what U(p+q,C) and U(n) means, but I'm unfamiliar with the notation of the above statement. Thanks in advance. Somy:smile:
8. ### Heisenberg Hamiltonian

Hi. Can anyone tell me what exactly the "Heisenberg Hamiltonian" is??? I found it in an article related to: the renormalization group. Thanks in advance. Somy:smile:
9. ### An emergency question

an emergency question!!! Hi all. I just wanted the proof of this statement via group theory: det(AB)=det(A)det(B) thanks in advance. somy:smile:
10. ### Action at a distance

Hi all. I want to know what do they mean by "action at distance". I know the concept of field(!!!) and the meaning of "space geometry effects". I wanted to know something about the history of this concept. Thank you. Somy :smile:
11. ### Distinction between experiment and theory

As you know we use the experimental methods to confirm our theories. so we measure some quantities to have a sense about the errors may occure. In some of these experiments we do not measure the considered quantity but another quantity that later relates to the desired one with ANOTHER THEORY...
12. ### Wave and particle.

I have a question about these concepts: I know that we can see both the wave and particle properties in all paricles and wave. but... when we call a "being" , "wave" or "particle". where is the distinction??? thanks in advance. Somy :smile:
13. ### Pauli exclution principles.

I had a question about the pauli principle. Well, I know that it classify the particles into two groups named bosons and fermions and says that they have symmetrical or antisymetrical wave functions. My question is this: How did he say these? I mean, was it assumption that came true or just a...
14. ### New images

New images from Titan!!! Have you seen new images of Titan???!!! http://saturn.jpl.nasa.gov/multimedia/images/image-details.cfm?imageID=1310 [Broken] http://www.esa.int/SPECIALS/Cassini-Huygens/SEMC8Q71Y3E_1.html#subhead2
15. ### Problem with this renormalize quantum theory

Hi. I have a problem with this quantum theory, that is going to make me crazy!!!: Why we are allowed to renormalize every function after we find the solution. I mean, how we are sure that we have found all the solution exists. Thanks in advance. Somy :smile:
16. ### Examinations

Hi all. My semester examinations are starting. Well I did all my best in this term so I really want to get some excelent results. Would you give me any useful advise in order to do my best. Thanks a lot. Somy
17. ### A question about electromagnetic wave function

Hi there. We always put the time dependent part of the wave functions as e^(iwt). Of course there is a reason!!! but I don't know it. Can you help me??? Thanks in advance. Somy :smile:
18. ### How does EPR and entanglement theory are related?

So silly question!!! but how does EPR and entanglement theory are related??? I mean the history and its cocepts of similarities. Thanks in advance. Somy :smile:
19. ### Addition of angular momentum

Hi there. I was just confused with this addition of angular momentum!!! Any useful help or link about the mathematical consepts??? Thanks in advance. Somy :smile:
20. ### The history of string theory.

I just wanted to know about the history of the string theory development. I mean the klein's (or someone else!!!) interpretation about the charge that resulted in assumption of higher order dimentions of space. I just wanted to know the historical story of it. Any link will be usefull...
21. ### A funny problem

A funny problem!!! Hi everyone. I'm a teacher assistant. and my students always copy their assignments from each other!!! :mad: I suggested to do a new experiment :biggrin: I want to find the original one who is the source of the coppies!!! I have noticed that there are just two or three...
22. ### Cosmological constant

Can anyone explain the relation between quantum field theory and relativity. I mean the "cosmological constant". Tanks a lot.
23. ### Science searching motors?

Hi. I just wanted to ask you about the powerfull searching engine in scientific fields (specially physics!!!). Thanks a lot. Somy :smile:
24. ### Vector potential of B

vector potential of magnetic field Hi everyone. I have a question about the vector potential of magnetic field, A: we just set the divergance(A)=0 inorder to define the potential. I just wanted to know why we are allowed to do this. Thanks a lot. Somy :smile:

I have noticed a formula in which Cn (the probability density of the nth state ) was somthing like this: Cn=1/ih*(...) The probability of this state is then negative. Can someone tell me about the physical interpretation of negative probability? Thanks a lot. :smile:
26. ### A question about mickelson& morli experiment

Hi there! I'm not sure about the dictation of the names!!! But can anyone explain the method of their experiment on the existence of ether. Thanks a lot. Somy :smile:
27. ### A historical question

a historical question!!! I have a question about galileo's experiment on top of the pizza !!! (maybe it seems a bit silly!!!) Can anyone tell me how did he say from this experiment that: mass of gravity and inertia are identical??? Thanks a lot. Somy :smile:
28. ### Bessel function

Hi there ; I wanted you to help me with a problem. Well, I'm now studying griffiths' quantum book and now I'm trying the three dimentional schrodinger equation. I just wanted to know more about bessel functions. Can anyone give me a link for it? Some useful book will be good too. Thanks a...
29. ### Area problem.

assume that we have an area of 20*30 meters, and we want to cut it to some parts of specified areas. I want to know when is it possible? Of course the first assumpsion should be: the sum of the areas should not exceed the total area. I know we need another assumpsion. What is it??? And if...
30. ### A question about the linear product

A question about the "linear product" Hi everyone; As you know, we assume the answer of the dot product as a complex number: <a|b> Also, we have the property: <a|b>=<b|a>* I just want to know how can we say this, or is it just a definition??? Thanks a lot. Somy :smile: