A fluorescence decay fit converges with Levenberg-Marquardt to a minimum where the…

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Scientific Computing for Physicists, Ch Minimisation with guarantees, with constraints and with randomness

Problem

A fluorescence decay fit converges with Levenberg-Marquardt to a minimum where the damping parameter has been driven to μ≈0\mu\approx 0 and JTWJ=(405520)J^{\mathsf T}WJ = \begin{pmatrix}40 & 5\\ 5 & 20\end{pmatrix} with the fitted parameters made dimensionless by scaling. At the minimum, the covariance matrix of the fitted parameters is the same as it would be from an ordinary least-squares fit started close to the answer, Cov=(JTWJ)−1\mathrm{Cov} = (J^{\mathsf T}WJ)^{-1}. ((a)) Find Cov\mathrm{Cov}. ((b)) State the standard uncertainty of each parameter.

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