Proving 2<T> = <x\frac{dV}{dX}> and Virial Theorem

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SUMMARY

The discussion focuses on proving the equation \(\frac{d}{dt} = 2 - \) and utilizing the Virial Theorem to establish that \( = \). Participants emphasize substituting \(Q\) with \(xp\) and the Hamiltonian \(H\) with \(-\frac{\hbar^2}{2m}\frac{\partial^2}{\partial x^2}+V(x)\) in the equation \(\frac{d}{dt} = \frac{i}{\hbar}<[H, Q]> + <\frac{\partial Q}{\partial t}>\). The discussion provides a clear pathway for manipulating these equations to derive the desired results.

PREREQUISITES
  • Understanding of quantum mechanics principles, particularly operators and commutation relations.
  • Familiarity with the Virial Theorem and its implications in quantum systems.
  • Knowledge of Hamiltonian mechanics and the role of the Hamiltonian operator.
  • Proficiency in calculus, specifically differentiation with respect to time.
NEXT STEPS
  • Study the derivation of the Virial Theorem in quantum mechanics.
  • Learn about the properties of commutators in quantum mechanics.
  • Explore the implications of the Hamiltonian operator in quantum systems.
  • Investigate examples of time evolution of operators in quantum mechanics.
USEFUL FOR

Students and researchers in quantum mechanics, particularly those studying operator dynamics and the Virial Theorem's applications in physics.

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Homework Statement



I must prove that:

[tex]\frac{d}{dt}<xp> = 2<T> - <x\frac{dV}{dX}>[/tex]

And use the virial theorem to prove that [tex]<T> = <V>[/tex]




Homework Equations



[tex]2<T> = <x\frac{dV}{dX}>[/tex]

[tex]\frac{d}{dt}<Q> = \frac{i}{h(bar)}<[H, Q]> + <\frac{\partial Q}{\partial t}>[/tex]

Where Q on the right side is an operator, as well as H.



The Attempt at a Solution



Do I just plug in [tex]\frac{d}{dt}<xp>[/tex] into the general equation?

Thanks.
 
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In the second equation that you posted, replace Q with xp and H with

[tex]-\frac{\hbar^2}{2m}\frac{\partial^2}{\partial x^2}+V(x)[/tex]

and expand the commutator.
 

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