Is the Displacement Operator Tψ(x)=ψ(x+a) Hermitian?

In summary, the conversation discusses the definition of a Hermitian operator and whether the displacement operator Tψ(x)=ψ(x+a) satisfies this definition. The definition states that <f│Ag>=<Af│g> always if A is Hermitian, which can be translated into an integral of wave functions. The conversation also suggests finding a counterexample to determine if <Tf│g> is equal to <f│Tg>.
  • #1
Rude
3
0
Consider the displacement operator Tψ(x)=ψ(x+a). Is T Hermitian?
 
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  • #2
To get you started, what's the definition of a Hermitian operator?
 
  • #3
here is the definition: <f│Ag>=<Af│g> always if A is Hermition.
Don't know how to start.
 
  • #4
Rude said:
here is the definition: <f│Ag>=<Af│g> always if A is Hermition.

Suppose the wave function of the state |g> is ##\psi_g(x)## and the wave function of state |f> is ##\psi_f(x)##. Then what does the above definition of an operator A being Hermitian say if you translate the inner product into an integral of wave functions, using

##\langle a | b \rangle = \int dx \psi_a(x)^* \psi_b(x)##

and plug in A = T?
 
  • #5
Is this what you are suggesting?

<f│Tg>=∫dxΨ(x)*ψ(x+a)

If so I don't know how to proceed.

It does not look like this would give <Tf│g> but don't know why.
 
  • #6
Rude said:
Is this what you are suggesting?

<f│Tg>=∫dxΨ(x)*ψ(x+a)

Yup.

Rude said:
It does not look like this would give <Tf│g> but don't know why.

If you think they aren't equal, perhaps you can find an explicit counterexample?
 

FAQ: Is the Displacement Operator Tψ(x)=ψ(x+a) Hermitian?

What is the Displacement Operator?

The Displacement Operator is a mathematical operator that describes the movement of a particle or system in quantum mechanics. It is used to calculate the displacement of a particle in a given direction, and is an important tool in understanding the behavior of quantum systems.

How is the Displacement Operator different from other operators in quantum mechanics?

The Displacement Operator is unique in that it operates on the complex wavefunction of a particle, rather than the real-valued position or momentum variables. It is also known for its ability to create coherent states, which have been used in various applications such as quantum computing and quantum communication.

How is the Displacement Operator related to the Heisenberg Uncertainty Principle?

The Displacement Operator and the Heisenberg Uncertainty Principle are closely related. The principle states that it is impossible to know both the position and momentum of a particle with absolute certainty. The Displacement Operator helps to quantify this uncertainty by providing a way to calculate the average displacement of a particle in a given direction.

What are some practical applications of the Displacement Operator?

The Displacement Operator has many practical applications in quantum mechanics, such as in quantum computing, quantum cryptography, and quantum teleportation. It has also been used in experiments to manipulate and control the behavior of quantum systems, and in studying the quantum behavior of mechanical systems.

Are there any limitations or drawbacks to using the Displacement Operator?

Like any mathematical tool, the Displacement Operator has its limitations and drawbacks. It is not always easy to calculate or interpret, and may not always accurately describe the behavior of a quantum system. Additionally, it may not be applicable in certain scenarios, such as in systems with strong interactions or in the presence of external forces.

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