Prove the operator d/dx is hermitian

  • Thread starter Thread starter baldywaldy
  • Start date Start date
  • Tags Tags
    Hermitian Operator
AI Thread Summary
The discussion centers around proving that the operator d/dx is not Hermitian. Participants clarify that an operator is Hermitian if it satisfies the equation <m|Ω|n> = <n|Ω|m>*. The user attempts to apply integration by parts to show the relationship between the integrals involving the operator and the functions, but struggles with the application. It is emphasized that the proof requires demonstrating that the integrals of the products of the functions and their derivatives do not satisfy the Hermitian condition. The conversation highlights the need for a clearer understanding of integration by parts in this context.
baldywaldy
Messages
19
Reaction score
0
Hiya :) the title is meant to be prove it isn't hermitian

Homework Statement


Prove the operator d/dx is hermitian


Homework Equations


I know that an operator is hermitian if it satisfies the equation : <m|Ω|n> = <n|Ω|m>*


The Attempt at a Solution


Forgive the lack of latex , I have know idea how to use it and find it baffling.

the intergral of (fm* d/dx fn) dx = the intergral of fm* d fn
={fm* fn - the intergral of fn d fm*} between the limits x=infinity and - infinity.

This is where i get stuck. I just don't know where to go from here, like i said sorry for the lack of latex usage :(.

Thanks for the help :D
 
Physics news on Phys.org
Think of integration by parts.

ehild
 
I know intergration by parts but i just don't understand how to apply in this situation because there are two functions and an operator
 
d/dx f means that you differentiate f with respect to x. d/dx f = df/dx = f'

You have to show that \int{f_n f&#039;_mdx}\neq (\int{f&#039;_n f_mdx})^*

ehild
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...

Similar threads

Replies
10
Views
14K
Replies
17
Views
2K
Replies
4
Views
7K
Replies
3
Views
2K
Back
Top