# Search results

1. ### Programs Phd and family

Its an integrated programme starting in august.
2. ### Programs Phd and family

How much leave do phd scholars in physics get annualy? Is it it not possible to do research work at home,incase the student is ill and wants to be in his comfort zone during bad times? Btw if i choose a theoretical physics topic will i be free from learning computer related stuff with...
3. ### Mathematica Minimization help in mathematica

The soln does satisfy the constraint,but since i have included e\inequality constraints as well,why are some solutions on the boudary.Should,nt they be within in? c1+c2+...c9=2200
4. ### Mathematica Minimization help in mathematica

Sorry i forgot to add the following additional constraint: c2+c3+c4+c5+c6+c7+c8+c9=2200 try it now
5. ### Mathematica Minimization help in mathematica

My dear friend i too got the same thing but are you blind to not notice that it gives only trivial values,that is the c values are just the values of the less then equality.
6. ### Courses Life course of physicists

Hey Mr sick scientist! How dare you equate an innocent human being with noise just because they are less smarter then you are. Don't you realize that you too, are a result of lot of noisy activity in the brain.
7. ### Black hole microstates and string theory

Can someone give me a Pop science explanation of what do strings and Branes have got to do with black hole entropy. The no of degrees of freedom or the no of microstates of the black hole corresponding to a given macrostate is given by exp(S),where S is entropy of black hole which is related to...
8. ### Mathematica Minimization help in mathematica

Hi i am finding difficulty in minimzing the following in mathematica. Can someone try it out and share with me the results. Its urgent. Its a constrained minimization problem in 8 variables c2,c3...c9 Can it be tried out in MATLAB or maple? NMinimize[{1.383 c2^2 + 1.377 c3^2 + 1.2618`...
9. ### Physics To old to do physics?

Hi Guys Thanks for all the comments. It will go a long way in me coming to a correct decision.
10. ### Physics To old to do physics?

sure,i know many who have completed phd at that age,maybe in other areas like astronomy etc.. I have not heard anyone complete a phd in theoretical suff(strings,LQG etc..) at an age older then 26-27
11. ### Physics To old to do physics?

Hi everyone Will i be to OLD ,if i obtain a Phd in Theoretical physics at the age of 29? I will be 24 when i get started with the phd program ,and its no way going to take less then 5 years as i am an electronics/telecom engineering graduate and have to...
12. ### Linear optimization problem.

First let me clarify this is not a homework question. This part has cropped up as part of a small project i am doing on Cosmic microwave background. How would i go about minimizing the function f(x_{1},x_{2}...x_{n})=\Sigma*x_{i}*a_{i} subject to the constraint: \Sigma x_{i}*(2*i+1)=constant...
13. ### Legendre poly in Fotran 90

Is it possible to evaluate a legendre polynomial p(n,x) using the recurrence relation p(n,x)=p(n-1,x)*x-p(n-2,x) in fotran 90 {there are some other terms which i left out for brevity]
14. ### Equation cropping up in Kronig Penny model

Homework Statement how does one solve the following equation to obtain E as a function of K. Homework Equations cos(k*a)=P*sin(u*a)/u*a + cos(u*a), where u=sqrt(2*m*E)/h-bar The Attempt at a Solution theres no way this can be solved analytically,however how to go...
15. ### Partioning natural numbers

if you read carefully you will find a striking resemblance of the number theoretical problem and quantum statistics,wherin \Pi(M,N) gives the number of microstates asscociated with N harmonic oscillators having total energy MhV. i read something similar in Zweibachs string theory.
16. ### Partioning natural numbers

In How many ways can one write a natural number M as a sum of N whole numbers? Consider the two conditions; 1)the numbers appearing in the sum are distinct. 2)the numbers appearing in the sum are not necessary distinct. eg1:eight can be written as a sum of 6 whole numbers as shown below...
17. ### Gibbs distribution

In canonical ensemble all energy values are permitted. The distribution of energies of system at temp T follows Gibbs Distribution. My question is simple. Why is it that all energies are permitted?? forget the mathematical derivation. How to understand it physically. Does it not take the...
18. ### Degeneracy and orthogonality

Fine but how do you go about the proof? forget about in the wavemechanics just a general proof in bra-ket notation,showing that degenerate states are orthonormal.
19. ### Degeneracy and orthogonality

Homework Statement Are all electronis states orthonormal? I mean the degenerate states ie [n,l,m>states corresponding to same energy for example can one write [2,0,0>=a[2,1,-1>+b[2,1,0>+c[2,1,+1> Homework Equations The Attempt at a Solution for example can one write...
20. ### Derivation of maxwells equation

http://en.wikipedia.org/wiki/Image:On_Physical_Lines_of_Force.pdf
21. ### Derivation of maxwells equation

When i did my undergraduate course in electromagnetism i never heard of or never told by the professors of "the Physical lines of force" the classical paper by J.C Maxwell. I want to know why is that students are not taught(or encouraged) to go through this classic,why is that maxwell...
22. ### Nucleon potential

Which authors do you recommend?? BTW what potential is used to model the interaction between neutron and proton in deuterium nucleus? should'nt it be the Yukawa potential. If so does the equation admit solutions that are similar to that of electron in hydrogen atom for the theta-phi part .The...
23. ### Nucleon potential

What PEP has got to do? Plz make it more clear. What do you mean by edge?
24. ### Nucleon potential

Why is the potential energy of a nucleon within the nucleus approximated by 3D harmonic oscillator potential? Is the 3D harmonic oscillator potential approximately equal to the yukawa potential experienced by the nucleon as a result of all the other nuclei(ie collectively) ?

What is the nature of magnetic dipole radiation? Does a rotating bar magnet give rise to electromagnetic radiation(magnetic dipole radiation to be more specific)??
26. ### Storing Lightning Energy

But don't you agree with my comment regarding storing of electromagnetic energy?
27. ### Storing Lightning Energy

Btw i have never learned fluid dynamics. Im no expert,i do have a flair for the obvious though.
28. ### Storing Lightning Energy

Yes div(v)=0 is assumed. Its obvious since water gushes out of a pipe faster when you partially cover the opening. Its because whatever volume flowing into pipe per unit time=water flowing out of pipe per unit time.
29. ### Storing Lightning Energy

No,Stokes and green theorems can be derived mathematically
30. ### Storing Lightning Energy

I don't quite have a clue how it could be done practically
31. ### Storing Lightning Energy

Theoretically speaking it would be possible to store light since the ponting vector has a non zero divergence.Which means that whatever power in form of electromagnetic fields flows into a closed surface,the same amount of power may not necessarily flow out of the surface.So there can be a net...
32. ### Why i don't believe in ghosts as potrayed in popular culture?

Cats are very cute and smart hence people do get attached to them. My full sympathies are with the families which have lost their cats. I know how it feels to loose one.
33. ### Why i don't believe in ghosts as potrayed in popular culture?

The cats were probably eaten by foxes or wolves, or may have been swallowed by a python.(if there are pythons in england) As i said earlier 5-6 of my cats have disappeared without any trace. I hope Gareth is not trying to imply that they were abducted by aliens or metamorphed into a witch :-))
34. ### Huygens principle and single slit diffraction

How can empty space act as individual point sources as in sinle slit diffraction?
35. ### Why i don't believe in ghosts as potrayed in popular culture?

Plz don't get me wrong. i never said that i don't believe in the existence of the soul or disembodied conciousness. Yes its a matter of faith albeit not a blind one. What I am trying to say that conciousness cannot be visible to the eye,or be heard,move objects or increase E.M.F activity or...
36. ### Why i don't believe in ghosts as potrayed in popular culture?

BTW I live in an ancestral home that's 200-250 years old. So many of my ancestors have probably died in this home. But tell you what i have never experienced anything supernatural in these 23 years of my existence. And i have also stayed awake till 3:00 in the morning alone in my veranda,not...
37. ### Why i don't believe in ghosts as potrayed in popular culture?

Cats are surely one of the coolest creatures. I had around 8-9 cats(one after the other)however all of them just disappeared suddenly without trace.Only two died of natural causes. My neighbour recently brought me a kitten after the last one died after 20 days of being sick.This kitten is so...
38. ### Commutator in QM vs. Lie brackets in DG

the above link does not exist. Anyways thanks for the explanation
39. ### Why i don't believe in ghosts as potrayed in popular culture?

If ghosts could be seen then its obvious that they are emitting visible light,and light is nothing both electromagnetic fields. which would imply that they are made of physical matter,as everbody knows that electromagnetic fields couple to accelerating charges. What is even more...
40. ### Commutator in QM vs. Lie brackets in DG

Sir, But is it not a fallacy to equate operators on one side ,to real valued functions(classical observables) on the other? Plz Give me the link to the derivation in case i have got the entire concept wrong By the way I am absolutely sure that both PB and commutators define a Lie algebra...
41. ### Poisson brackets, HELP!

{x,p} = 1 therefore (dx/dx)(dp/dp) - (dx/dp)(dp/dx)=i
42. ### Commutator in QM vs. Lie brackets in DG

The Algebra of The Poisson brackets studied in classical physics is the same as that of the commutator. ie[a,b]=ab-ba generates the same algebra as the poisson bracket of two classical observables a(p,q),b(p,q)
43. ### Higgs field

Well i meant whatever i asked and Mr Belchmann has answered my question well. However since i have not learned about weak interactions i am not familiar with weak isospin. However its clear to me now why the electromagnetic field does not interact with the higgs field,since th em field only...
44. ### Higgs field

But is there no underlying reason? are you implying that the photon lacks a kind of charge which prevents it from coupling to the Higgs field? What is this charge called as by the physics community? eg, electric charge,weak charge,colour charge etccc
45. ### Higgs field

Why don't the photon and the neutrinos couple to the higgs field? Is there any associated charge which determines which particles couple to the Higgs field?
46. ### Is the lagrangian always K.E-PE?

Is the lagrangian always K.E-PE? I don't think so? so WHAT REALLY is the physical significance of the lagrangian? Superficially it appears to be KE-PE,but the lagrangian for a charged particle in a vector potential is 1/2MV.V +qV.A-qW. where V=velocity A=vector potential...
47. ### Why do particles annhillate with their particles?

why do particles annhillate with their particles? Why is an electron-positron bound state so short lived? In other words why does an electron readily anhillate its corresponding antiparticle(positron)?
48. ### How is the electromagnetic field different from aether?

How is the electromagnetic field different from aether? if there is an em field why is it not considered to be at absolute rest
49. ### Energy momentum tensor

How to visualize thhe components of the energy tensor? I mean to say that what it means to say that "the amount of x component of momentum flowing in the z direction per unit time"?? how can x compononent of momentum flow in some other direction how to visulaize this geometricallty?
50. ### Black holes and particles

i wasnt speaking of stellar collapse on chandrashekar limit. what i meant to say that any point like mass should have a swarzchild radius in the case of electrons it should be infinitely infinitely small