Prove the Hamiltonian Operator is Hermitian

In summary, we are asked to show that the Hamiltonian operator is hermitian by proving that its kinetic energy and potential energy portions are hermitian. This can be done by finding the domains of H and H^{\dagger}, checking if they are dense everywhere in H, and ensuring that the domains are included in the domain of their adjoint. Additionally, we must verify that the ranges of the two operators are equal for all vectors in the common domain. This can be done without using Bra-Ket notation, by using partial integration in the Hilbert space L2(R).
  • #1
atay5510
10
0

Homework Statement



Show that the Hamiltonian operator ([itex]\hat{H}[/itex])=-(([itex]\hbar[/itex]/2m) d2/dx2 + V(x)) is hermitian. Assume V(x) is real

Homework Equations



A Hermitian operator [itex]\hat{O}[/itex], satisfies the equation

<[itex]\hat{O}[/itex]>=<[itex]\hat{O}[/itex]>*

or

∫[itex]\Psi[/itex]*(x,t)[itex]\hat{O}[/itex][itex]\Psi[/itex](x,t)dx = ∫[itex]\Psi[/itex](x,t)[itex]\hat{O}[/itex]*[itex]\Psi[/itex]*(x,t)dx between -∞ and +∞


The Attempt at a Solution



This is my first time using LaTex and I'm having trouble inputting what I want, but basically, I've just substituted the Hamiltonian operator for [itex]\hat{O}[/itex], into the second expression above. This is where I am stuck. I'm essentially left with two parts, one that's "telling" me to prove that the Kinetic Energy portion of H is Hermitian and another telling me to prove the Potential Energy portion is hermitian. However I can't seem to see how to do it.

Thanks

P.s. can you help with a solutio that does not use Bra-Ket notation, this question is in the section that precedes Dirac notation
 
Physics news on Phys.org
  • #3
Working in the Hilbert space L2(R) one proceeds like this:

a) finds the domain of H.
b) checks if domain is dense everywhere in H.
c) finds the domain of [itex] H^{\dagger} [/itex]
d) checks that the domain of H is included in the domain of its adjoint.
e) finally checks that the ranges of the 2 operators are equal for all vectors in the common domain (the domain of H).
 

Related to Prove the Hamiltonian Operator is Hermitian

1. What is the Hamiltonian operator?

The Hamiltonian operator is a mathematical operator used in quantum mechanics to represent the total energy of a system. It is denoted by the symbol H and is defined as the sum of the kinetic and potential energies of all particles in the system.

2. What does it mean for the Hamiltonian operator to be Hermitian?

A Hermitian operator is one that is equal to its own conjugate transpose. In other words, the operator and its conjugate transpose have the same matrix representation. This property is important in quantum mechanics as it ensures that the operator will yield real eigenvalues.

3. Why is it important to prove that the Hamiltonian operator is Hermitian?

The Hermiticity of the Hamiltonian operator is crucial in quantum mechanics as it guarantees that the energy eigenvalues of the system are real. This is essential for making accurate predictions about the behavior of quantum systems.

4. How do you prove that the Hamiltonian operator is Hermitian?

To prove that the Hamiltonian operator is Hermitian, you need to show that it is equal to its own conjugate transpose. This can be achieved by taking the conjugate transpose of the operator and comparing it to the original operator. If they are equal, then the operator is Hermitian.

5. What are the consequences if the Hamiltonian operator is not Hermitian?

If the Hamiltonian operator is not Hermitian, it means that the energy eigenvalues of the system may not be real. This can lead to incorrect predictions about the behavior of the system and can make it difficult to accurately study and understand quantum systems.

Similar threads

  • Advanced Physics Homework Help
Replies
17
Views
1K
  • Advanced Physics Homework Help
Replies
10
Views
611
  • Advanced Physics Homework Help
Replies
4
Views
2K
  • Advanced Physics Homework Help
Replies
4
Views
1K
  • Advanced Physics Homework Help
Replies
7
Views
2K
  • Advanced Physics Homework Help
Replies
4
Views
3K
Replies
22
Views
496
  • Advanced Physics Homework Help
Replies
4
Views
2K
  • Advanced Physics Homework Help
Replies
12
Views
2K
Replies
2
Views
3K
Back
Top