# rlx_scalar.m

Scalar relaxation superoperator using Redfield theory.

## Syntax

    R=rlx_scalar(spin_system,H0,H1,tau_c)


## Description

Computes Redfield superoperator in situations when the system has a static background Hamiltonian and a perturbation with a scalar stochastic function in front of it. Scalar hyperfine relaxation is a common example. This function is called by Spinach relaxation theory module, but may also be invoked directly.

## Arguments

    H0 - background Hamiltonian

H1 - the stochastically modulated interaction operator
multiplied by its root mean square modulation depth

tau_c - the correlation time of the stochastic modulation


## Outputs

    R  - relaxation superoperator as a negative definite matrix


## Notes

If H1(t) has a non-zero average value, it must be subtracted out and put into H0.