Solve Equation of Continuity Using Schrodinger Equation

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SUMMARY

The discussion focuses on using the Schrödinger Equation to demonstrate the continuity equation in quantum mechanics, specifically showing that the time derivative of the probability density, \(\frac{\partial}{\partial t}(\Psi^{*} \Psi)\), is equal to the negative divergence of the probability current density, \(-\underline{\nabla} \cdot \underline{j}\). The probability current density is defined as \(\underline{j} = \frac{-i}{2m} \left[\Psi^{*}(\nabla \Psi) - (\nabla \Psi^{*})\Psi\right]\). Participants emphasize the need to connect time and space derivatives through the Schrödinger equation and its complex conjugate to derive the continuity equation.

PREREQUISITES
  • Understanding of the Schrödinger Equation in quantum mechanics
  • Familiarity with complex functions and their conjugates
  • Knowledge of vector calculus, specifically divergence
  • Basic concepts of probability density in quantum mechanics
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  • Study the derivation of the Schrödinger Equation and its implications in quantum mechanics
  • Learn about the continuity equation and its significance in quantum theory
  • Explore vector calculus techniques, particularly divergence and gradient operations
  • Investigate the role of probability density and current density in quantum mechanics
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This discussion is beneficial for physics students, quantum mechanics researchers, and anyone interested in the mathematical foundations of quantum theory and the continuity equation.

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Homework Statement



Use the Schrödinger Equation to show that

\frac{\partial}{\partial t}(\Psi^{*} \Psi) = - \underline{\nabla}. \underline{j}

Homework Equations



\underline{j} = \frac{-i}{2m} \left[\Psi^{*}(\nabla \Psi) - (\nabla \Psi^{*})\Psi]\right

\frac{\partial}{\partial t}n(x,t) = -\underline{\nabla}. \underline{j}(x,t)

n(x,t) = \Psi^{*}(x,t)\Psi (x,t)

I'm not sure how the Schrödinger equation comes into play here... can anyone offer any suggestions?
 
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On the left hand side I see a time derivative, while on the right hand side there is a space derivative (gradient). The Schrödinger equation contains both, so you could use it to go from one to the other (and you might also want to use the complex conjugate of it)
 

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