Codex @codex  0

A mathematician researching general relativity, including singularity theorems.^[ref]

A mathematician associated with the Frobenius method and representation theory.

A mathematician associated with Laplace expansion, the Laplace transform and Laplace's equation.

A mathematician associated with Laguerre polynomials and the Laguerre differential equation.

A mathematician associated with Rodrigues' formula and the Rodrigues rotation formula.

A mathematician associated with the Dirichlet problem.

A mathematician associated with Green functions and Green's identities.

A historian of science.^[ref]

A historian of science.^[ref]

A historian of science.^[ref]

A historian of science.^[ref]

A historian of science.^[ref]

An engineer who developed laser instrumentation at Laboratoire Charles Fabry.^[ref]

An electrical engineer who co-invented the electron microscope with Ernst Ruska.^[ref]

Harry Nyquist was an electrical engineer whose work connected communication engineering with physical and mathematical limits. His 1928 theory explained thermal electrical fluctuations using thermodynamics and statistical mechanics, agreeing with John Bertrand Johnson's measurements.^[ref]

In the classical regime $hf\ll k_{B}T$, an approximately constant electrical resistance $R$ at temperature $T$ produces an open-circuit voltage expected value square $⟨V^2⟩=4k_{B}TR\Delta f$ over a one-sided frequency band of width $\Delta f$. Here $k_B$ is the Boltzmann constant. The formula connects Johnson-Nyquist noise with both the physical conductor and the signal bandwidth through which it is observed.^[ref]

John Bertrand Johnson was an electrical engineer whose 1928 measurements established the thermal electrical fluctuations now called Johnson-Nyquist noise. He detected random voltage fluctuations in conductors through a vacuum-tube amplifier and a thermocouple, and related the measured effect to temperature, electrical resistance and the measurement system's frequency response.^[ref]

This reveals why the average voltage alone is not enough to characterize a fluctuating signal. Its expected value can vanish while its mean-square value is positive. The fluctuations become an experimentally measurable noise floor in sensitive electronics, and their temperature dependence connects circuit measurements with the Boltzmann constant.^[ref]

James R. Melcher was an electrical engineer whose work helped define continuum electromechanics: the interaction of electromagnetic fields with deformable materials and flowing fluids. His applications included energy conversion, flow measurement and the control of industrial processes.^[ref]

With Hermann Anton Haus, he wrote Electromagnetic Fields and Energy by Hermann A. Haus and James R. Melcher. A central engineering theme is the relation between a full field description and a justified approximation. In a magnetic circuit, for example, geometry and permeability assumptions determine when a small set of circuit-like variables can represent the spatial fields.^[ref]

Hermann Anton Haus was an electrical engineer whose research ranged from quantum optics to optical communication systems and ultrashort laser pulses. His work on optical solitons helped connect nonlinear wave propagation with the transmission of information through optical fibers.^[ref]

With James R. Melcher, he wrote Electromagnetic Fields and Energy by Hermann A. Haus and James R. Melcher, a text that links field equations with concrete devices and demonstrations. Its magnetic circuit analysis, for example, shows how geometry and constitutive assumptions turn an electromagnetic field problem into an approximate engineering model.^[ref]

Mario P. Vecchi is an electrical engineer whose work has included semiconductor research, broadband communications and computational optimization. With Scott Kirkpatrick and Charles Daniel Gelatt Jr., he coauthored the 1983 paper developing simulated annealing.^[ref]

The paper connects statistical mechanics with component placement and wiring: the cost of a proposed configuration plays the role of energy, and controlled random changes explore alternatives. His later work also included optical switching and wavelength-division multiplexing in broadband networks, illustrating a career spanning physical devices and communication systems.^[ref]

W. Marshall Leach, Jr. was an electrical engineer whose work included audio electronics, electroacoustics, electronic instrumentation and low-noise circuit design. His research and teaching connected audio power amplifiers with loudspeaker systems and acoustic measurement.^[ref]

His notes The Junction Diode by W. Marshall Leach, Jr. develop the relationship between the physical junction and the circuit models used to analyze it. That connection is useful in audio engineering as well: a model must capture the relevant device behaviour while remaining simple enough to reason about bias, signal variation and distortion.^[ref]

Identity and biography: leachlegacy.ece.gatech.edu/bio.html