Difference between Hamiltonian operator and Total energy operator?

In summary, the Hamiltonian operator and Total energy operator are often used interchangeably, but they are actually two different sides of the same equation (Hamiltonian = H and total energy = E). The Hamiltonian operator is used in the time-independent Schrodinger equation, while the Total energy operator is used in the time-dependent equation. Additionally, they have different meanings in other "pictures" of quantum mechanics.
  • #1
annms
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What is the difference between the Hamiltonian operator and the Total energy operator? If both is used when working with total energy, why are there two different operators?
 
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  • #2
They are both sides to the same equation. Hamiltonian = H and total energy = E.
H \psi = E \psi
 
  • #3
annms said:
What is the difference between the Hamiltonian operator and the Total energy operator? If both is used when working with total energy, why are there two different operators?

As far as I am aware, they are one and the same. What was the context that led you to think they might be different?
 
  • #4
Thank you for the responses guys. Forgive me for asking such a stupid question, I am a newbie to quantum mechanics. I was just reading my textbook and it first listed the total energy operator, then a few pages later it listed the Hamiltonian operator. It just looked very different than the total energy operator to me so I guess I was confused. Thanks again for the responses.
 
  • #5
In the time-dependent Schrodinger Equation (ih ∂/∂t) ψ = H ψ, people sometimes mistakenly refer to the left hand side ih ∂/∂t as the energy operator. It is not, of course, it merely describes how ψ(x, t) evolves with time. It does not appear in the time-independent Schrodinger equation H ψ = E ψ, and it appears but has a different meaning in other "pictures", e.g. the Heisenberg picture in which (ih ∂/∂t) ψ = 0 and the time evolution is cast onto the operators themselves, or the interaction picture in which (ih ∂/∂t) ψ = Hint ψ where Hint is the interaction Hamiltonian.
 

1. What is the difference between the Hamiltonian operator and Total energy operator?

The Hamiltonian operator is a mathematical representation of the total energy of a system in quantum mechanics, while the Total energy operator is a physical observable that represents the total energy of a system in classical mechanics.

2. How are the Hamiltonian operator and Total energy operator related?

The Hamiltonian operator is derived from the Total energy operator and includes all the terms necessary to fully describe the system's energy, such as kinetic energy and potential energy.

3. Can the Hamiltonian operator and Total energy operator be used interchangeably?

No, they cannot be used interchangeably. While they both represent the total energy of a system, they are used in different contexts and have different mathematical formulations.

4. Which operator is more commonly used in quantum mechanics?

The Hamiltonian operator is more commonly used in quantum mechanics as it is a fundamental concept in this field and is used to describe the dynamics of a system.

5. Are there any similarities between the Hamiltonian operator and Total energy operator?

Yes, both the Hamiltonian operator and Total energy operator are linear operators and are represented by matrices in matrix mechanics. They also both have corresponding eigenvalues and eigenstates.

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