Imaginary time propagation to find eigenfunctions

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SUMMARY

This discussion focuses on the use of imaginary time propagation to determine eigenfunctions, specifically ground and excited states. It is established that to find excited states, one must propagate two or more orthogonal functions, with the initial guess needing to be orthogonal to the ground state. Random initial guesses may not guarantee convergence to the ground state unless they are adjusted to maintain orthogonality. The importance of orthogonality in the initial conditions for accurate propagation results is emphasized.

PREREQUISITES
  • Understanding of imaginary time propagation techniques
  • Knowledge of eigenfunctions and eigenstates in quantum mechanics
  • Familiarity with orthogonality in mathematical functions
  • Basic proficiency in numerical methods for solving differential equations
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  • Research methods for ensuring orthogonality in initial guesses for eigenfunction propagation
  • Explore advanced techniques in imaginary time propagation for quantum systems
  • Study the mathematical foundations of eigenvalue problems in quantum mechanics
  • Learn about numerical algorithms for finding ground and excited states in quantum systems
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Quantum physicists, computational chemists, and researchers involved in numerical simulations of quantum systems seeking to accurately compute eigenfunctions.

semc
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Hi, I have been trying to use imaginary time propagation to get the ground state and excited states eigen function but the results I got is different from the analytical solution. I know that to get excited states, I should propagate 2 or more orthogonal functions depending on the number of excited states that you want. I just would like to check whether there is any requirement on the initial guess that you use to propagate. If I choose a random set of numbers to propagate, will it always contain my ground state?
 
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semc said:
If I choose a random set of numbers to propagate, will it always contain my ground state?
Most probably. After having found the ground state, any starting point to find the first excited state must be orthogonal to the ground state. If you start from a random guess, you need to first make it orthogonal to the ground state.
 
Hey semc.

What is your mathematical system you are solving for?
 

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