= Aleksander Stefanov
{c}
{tag=Optical physicist}
\b[Aleksander Stefanov] works across mathematical physics, mechanics and optical measurement. A 2022 Sofia University academic statement identifies his education in theoretical and mathematical physics, doctoral work on <nonlinear dynamical systems> associated with <Lie algebras>, and work in the Faculty of Mathematics and Informatics. It describes research on integrable models, walking-robot dynamics and educational physical-constant measurements.<Statement on Aleksander Stefanov's associate-professor application by Ivan Chavdarov>[pp.2–3, candidate information and research contributions]{ref}
The same document identifies <Korteweg-De Vries equation> and nonlinear Schrödinger-type models among his theoretical interests. He also coauthored the 2023 theoretical and experimental comparison of <Gouy phase> for <Bessel-Gaussian beams> with <Lyubomir Stoyanov>, <Alexander Dreischuh> and <Gerhard G. Paulus>.<Gouy phase of Bessel-Gaussian beams: theory vs. experiment by Lyubomir Stoyanov and others>[Published byline and affiliations]{ref}
An original example illustrates the quantitative idea behind a noise-based constant measurement. For ideal independent charge-transfer events, the one-sided current <shot noise> spectral density is $S_I=2eI$. With mean current $I=100\,\mu\mathrm A$, <elementary charge> $e=1.602176634\times10^{-19}$ C and a rectangular effective noise bandwidth $B=10$ kHz, the predicted root-mean-square fluctuation is
$$
\sqrt{2eIB}\approx0.566\,\mathrm{nA}.
$$
These stipulated numbers are not data from Stefanov's apparatus. They explain why estimating charge from noise requires a calibrated gain, known <bandwidth (signal processing)> and a model for other fluctuations. <Thermal noise> and detector noise must be distinguished from the charge-transfer contribution; a measured noise amplitude alone is insufficient.
The attraction of this work is the bridge between mathematical models and observable signals. The academic statement describes physical walking-robot tests as well as electronic measurements; those are different ways to test a theoretical prediction. The available sources identify this Sofia researcher, and do not justify merging him with unrelated researchers who share a surname.
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