Hamiltonian in an electromagnetic field

Hamiltonian..In summary, the question is about the assumption of H=H* and the use of (+iħ∇-e/c A)2 instead of (-iħ∇-e/c A)2 in an electromagnetic field. The response explains that the second equation is derived from the first equation by taking complex conjugates, and clarifies the meaning of self-adjoint in this context.
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Lucy166 said:
I have a question connected with the problem:
https://www.physicsforums.com/threads/continuity-equation-in-an-electromagnetic-field.673312/

Why don’t we assume H=H*? Isn’t hamiltonian in magnetic field a self-adjoint operator? Why? Why do we use (+iħ∇-e/c A)2 instead of (-iħ∇-e/c A)2 two times?

The second equation just mathematically follows from the first equation by taking complex conjugates. If [itex]\psi[/itex] is any complex-valued function, and [itex]\vec{A}[/itex] is any real vector-valued function, then [itex][(-i\hbar \vec{\nabla} - e \vec{A})^2 \psi]^* = (+i \hbar \vec{\nabla} - e \vec{A})^2 \psi^*[/itex]

Self-adjoint doesn't mean that [itex]H = H^*[/itex]. It means that [itex]\int \phi^*(\vec{x}) (H \psi(\vec{x})) d^3x = \int (H \phi(\vec{x}))^* \psi(\vec{x}) d^3x [/itex]
 
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Related to Hamiltonian in an electromagnetic field

1. What is the Hamiltonian in an electromagnetic field?

The Hamiltonian in an electromagnetic field is a mathematical expression that describes the total energy of a system consisting of charged particles moving in an electromagnetic field. It is a sum of the kinetic and potential energies of the particles and the energy of the electromagnetic field itself.

2. How is the Hamiltonian in an electromagnetic field related to classical mechanics?

The Hamiltonian in an electromagnetic field is a fundamental concept in classical mechanics. It is used to describe the dynamics of a system and can be used to derive equations of motion for the particles in the system.

3. What is the significance of the Hamiltonian in an electromagnetic field?

The Hamiltonian in an electromagnetic field is a powerful tool in understanding and predicting the behavior of charged particles in an electromagnetic field. It allows for the calculation of energies, forces, and trajectories of particles, which is crucial for many applications in physics and engineering.

4. How is the Hamiltonian in an electromagnetic field used in quantum mechanics?

In quantum mechanics, the Hamiltonian in an electromagnetic field is a key component in the Schrödinger equation, which describes the behavior of quantum particles. It is used to calculate the quantum states, energies, and probabilities of particles in an electromagnetic field.

5. What factors affect the Hamiltonian in an electromagnetic field?

The Hamiltonian in an electromagnetic field is affected by various factors, including the strength and direction of the electromagnetic field, the charges and masses of the particles in the system, and the distance between particles. It is also influenced by any external forces acting on the particles, such as gravitational or electric forces.

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