Difference between revisions of "Ngce.m"

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{{DISPLAYTITLE:ngce.m}}
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{{DISPLAYTITLE:ngce.m}} __NOTOC__
 
Numerical integral route to the Redfield relaxation superoperator.
 
Numerical integral route to the Redfield relaxation superoperator.
  
 
==Syntax==
 
==Syntax==
  
     R=ngce(spin_system,H,dt)
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     R=ngce(spin_system,H0,H1,dt,tau_est,reg)
  
 
==Arguments==
 
==Arguments==
  
 
   H0 - static laboratory frame Hamiltonian commutation su-
 
   H0 - static laboratory frame Hamiltonian commutation su-
       peroperator acting in the background
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       peroperator acting in the background, a matrix
 
   
 
   
   H1 - stochastic part of the laboratory frame Hamiltonian
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   H1 - stochastic part (zero mean) of the laboratory frame
       commutation superoperator with a zero average, as a
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       Hamiltonian commutation superoperator, a cell array
       K by N cell array with the following topology:
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       of matrices for each point in the MD trajectory.
 
   
 
   
        {H(0) H(dt) H(2dt) ... H(Ndt);  % MD trajectory 1
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  dt - time step of the MD trajectory, seconds
        H(0) H(dt) H(2dt) ... H(Ndt);  % MD trajectory 2
 
        ............................
 
        H(0) H(dt) H(2dt) ... H(Ndt)}; % MD trajectory K
 
 
   
 
   
      i.e. the rows are made of individual MD trajectories.
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  tau_est - correlation tiume estimate for internal safety
 +
            control, seconds
 
   
 
   
   dt - time step of the MD trajectory, seconds
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   reg - optional overall relaxation rate, this is added to
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        every eigenvalue of the resulting matrix to prevent
 +
        very small relaxation rates (e.g. singlets) from
 +
        jumping into positive due to integration accuracy
 +
        limits and then causing problems
  
 
==Outputs==
 
==Outputs==
  
      R   - laboratory frame relaxation superoperator
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  R - laboratory frame relaxation superoperator
  
 
==Examples==
 
==Examples==
A test against the analytical relaxation superoperator is provided in examples/relaxation_theory/ngce_test.m file.
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See our recent paper with Jim Prestegard: https://doi.org/10.1016/j.jmr.2020.106891
  
 
==Notes==
 
==Notes==
Enough trajectory points must be present to converge each integral, and enough trajectories must be present to converge the average.
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Enough trajectory points must be present to converge the ensemble averages and Redfield's integral.
  
 
==See also==
 
==See also==
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''Version 2.5, authors: [[Ilya Kuprov]], [[Jim Prestegard]]''
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''Version 2.6, authors: [[Ilya Kuprov]], [[Jim Prestegard]]''

Revision as of 13:34, 1 July 2021

Numerical integral route to the Redfield relaxation superoperator.

Syntax

    R=ngce(spin_system,H0,H1,dt,tau_est,reg)

Arguments

 H0 - static laboratory frame Hamiltonian commutation su-
      peroperator acting in the background, a matrix

 H1 - stochastic part (zero mean) of the laboratory frame
      Hamiltonian commutation superoperator, a cell array
      of matrices for each point in the MD trajectory.

 dt - time step of the MD trajectory, seconds

 tau_est - correlation tiume estimate for internal safety
           control, seconds

 reg - optional overall relaxation rate, this is added to 
       every eigenvalue of the resulting matrix to prevent
       very small relaxation rates (e.g. singlets) from 
       jumping into positive due to integration accuracy
       limits and then causing problems

Outputs

 R  - laboratory frame relaxation superoperator

Examples

See our recent paper with Jim Prestegard: https://doi.org/10.1016/j.jmr.2020.106891

Notes

Enough trajectory points must be present to converge the ensemble averages and Redfield's integral.

See also

relaxation.m, lindbladian.m, magpump.m


Version 2.6, authors: Ilya Kuprov, Jim Prestegard