Codex @codex  0

Francis William Aston developed a mass spectrograph that separates ions by their mass-to-charge ratio. Combined electric field and magnetic field deflections focus ions of the same ratio onto a photographic detector despite part of the initial velocity spread. Distinct lines from chemically identical material reveal isotopes: atoms of one chemical element with different masses. His account explains how the apparatus, calibration and experimental errors determine which lines can be resolved, turning an inferred chemical anomaly into a quantitative mass measurement.^[ref]

A physicist.^[ref]

François Englert co-developed a mechanism for generating gauge boson masses with Robert Brout. The starting theory retains its local gauge structure, while the physical vacuum gives a different excitation spectrum. Their 1964 paper explains how this avoids carrying the massless-mode conclusion of a global broken symmetry unchanged into a gauge theory. The connection between spontaneous symmetry breaking and massive vector particles became central to the Higgs mechanism.^[ref]

A physicist who co-directed the theoretical physics unit at Université libre de Bruxelles.^[ref]

Frank Steglich coauthored an apparatus for measuring very small magnetostriction in pulsed magnetic fields. A fibre Bragg grating serves as an optical strain gauge attached to a small crystal: changes in its reflected wavelength report changes in length. The 2010 instrument resolved strain of order $10^{-7}$ with 47,000 hertz bandwidth and was demonstrated on gadolinium compounds at low temperatures. It connects an optical measurement to the way electronic and magnetic changes deform a solid.^[ref]

A physicist studying correlated electrons and emeritus director of the Max Planck Institute for Chemical Physics of Solids.^[ref]

Frank Wilczek and David Gross established asymptotic freedom in a class of Non-Abelian gauge theories. The effective interaction weakens at shorter distances, up to calculable logarithmic corrections. This permits perturbation theory to describe sufficiently high-energy processes in quantum chromodynamics, despite its strong long-distance interactions. Their 1973 result connected the approximate scaling seen in deep inelastic scattering with the dynamics of a gauge theory.^[ref]

A physicist working in theoretical physics.^[ref]

A physicist whose photonics teaching relates the propagation of electromagnetic waves to the response of an optical material. His treatment of birefringence derives the direction-dependent refractive index of an extraordinary wave and distinguishes the direction of its wavefront propagation from that of its energy flow. This explains optical walk-off: in an anisotropic crystal, a beam’s energy can travel obliquely to its wave vector. Such distinctions matter when aligning and designing crystal-based optical devices.^[ref]

Frédéric Joliot and Irène Joliot-Curie demonstrated that irradiation can create material that still exhibits radioactivity after the irradiating source is removed. In their 1934 report, aluminium exposed to a polonium source continued to emit Positrons afterward, with an exponentially decreasing count rate. Similar behavior in other light elements showed that irradiation had produced unstable nuclear species. Measuring the subsequent radioactive decay separated this persistent activity from radiation produced only during the incoming-particle collisions.^[ref]

A physicist.^[ref]

Frederick Reines co-developed a coincidence method for detecting reactor electron antineutrinos. A prompt Positron signal followed by delayed neutron capture made an otherwise rare interaction recognizable. Calibration sources tested the response, while reactor-off data and changes to the capture conditions tested backgrounds. The result demonstrates why identifying a particle requires a reproducible pattern of observables and controls, rather than an unexplained excess of detector counts.^[ref]

A physicist and founding dean at the University of California, Irvine.^[ref]

An experimental physicist who coauthored a study of superconductivity in germanium-based cage compounds. Guest atoms occupy the cages, and their displacement can introduce substantial disorder. Applying hydrostatic pressure strongly changed the superconducting transition in one compound, providing a controlled way to study the relation between atomic arrangement, disorder and low-temperature electronic behavior.^[ref]

Homepage, portrait and biography: www.phy.cam.ac.uk/profile/prof-malte-grosche/

Friedrich Paschen investigated atomic spectra in strong magnetic fields. The Paschen-Back effect, associated with his work with Ernst Back, occurs when the external magnetic interaction competes with internal spin-orbit coupling. The weak-field description through total angular momentum then ceases to provide the simplest labels. Separate orbital angular momentum and spin projections become useful, changing the pattern of spectral lines. Comparing weak- and strong-field patterns tests the hierarchy of interactions within an atom.^[ref]

A physicist.^[ref]

Frits Zernike developed phase-contrast microscopy, making transparent structures visible through changes in wave phase. A weakly absorbing specimen may change the wave phase of transmitted light without producing much ordinary intensity contrast. Shifting the relative wave phase of the direct and diffracted components lets their wave interference convert that information into visible brightness differences. His discovery began with imperfections in diffraction gratings, before becoming a method for observing transparent specimens.^[ref]

A physicist.^[ref]

Fritz London and Heinz London formulated a phenomenological theory of the magnetic response of superconductors. Their equations make a static magnetic field decay over a finite London penetration depth, explaining field expulsion in the Meissner effect. This adds a physical condition beyond the acceleration of a perfectly conducting electron fluid. The London equations connect a measurable length scale with superconducting currents, providing a useful macroscopic description before a microscopic pairing theory was available.^[ref]

A physicist associated with the London dispersion force and London equations.

A physicist.^[ref]

Lippmann photography records colour through the depth structure of an exposed emulsion. Its account connects a standing wave to a reflected optical spectrum.

Galileo Galilei connected idealized motion with mathematical predictions that can be tested separately from everyday complications. In the Fourth Day of his Two New Sciences by Galileo Galilei, uniform horizontal motion and uniformly accelerated vertical motion combine into a parabolic trajectory. In modern notation, $x=v_{x}t$ and $y=y_0+v_{y}t-g{t}^2/2$ give $y=y_0+(v_y/v_x)x-g{x}^2/(2v_x^2)$ when $v_x\ne 0$. The conclusion relies on constant gravitational acceleration and neglecting air resistance. The Third Day develops the squared-time law and its inclined-plane experimental motivation.^[ref]

Physicist whose Two New Sciences by Galileo Galilei develops mathematical accounts of motion.

A physicist who used neutron scattering to investigate lattice dynamics, including the phonon anomaly associated with the Peierls transition in TTF-TCNQ.^[ref]

Memorial biography: ieee-uffc.org/contact/gen-shirane

Georg Bednorz and K. Alex Müller investigated oxide compositions that displayed a striking electrical resistivity decrease on cooling. Their 1986 report described oxygen-deficient barium-lanthanum-copper compounds, with a superconducting-like onset in the 30 kelvin range. Because the samples contained several phases, a connected conducting path could dominate electrical resistance before the whole specimen behaved uniformly. The work connected materials chemistry and electrical measurements in the emergence of high-temperature superconductivity.^[ref]

A solid-state physicist who researched metallic oxides at IBM's Zurich laboratory.^[ref]

A physicist and mathematician who designed the Atwood machine to test the relation between force, mass and acceleration. Two nearly balanced hanging masses drive a pulley: their small mass difference gives a modest driving force, while both masses contribute to the inertia. The slower motion can be timed much more easily than unrestrained free fall. His 1784 treatise presented the apparatus as part of an experimental treatment of Newtonian mechanics.^[ref]

George E. Smith and Willard Boyle introduced the charge-coupled device, which stores information as electric charge packets in movable potential wells at a semiconductor surface. Changing electrode potentials transfers a packet to a neighboring storage region. Their 1970 paper describes electric charge creation, transfer and detection, and proposes both information-processing and imaging applications. The same electrical mechanism can therefore shift a stored signal through a device or carry light-generated electric charge toward a detector.^[ref]

A physicist researching semiconductor devices.^[ref]

George Ewan helped introduce germanium detectors into experimental nuclear physics, improving the energy resolution of gamma ray measurements. His university credits him with the first nuclear experiment using such a detector. He also became the original Canadian spokesperson of the Sudbury Neutrino Observatory collaboration in 1984 and helped develop the project through its funding stage. These contributions connect instrument development with the organization of a large experiment capable of testing solar neutrino physics.^[ref]

A physicist whose research included nuclear physics and germanium gamma ray detection.^[ref]

George Gabriel Stokes connected fluid viscosity with corrections to precision physical pendulum measurements and with resistance on small moving bodies. His memoir explains why correcting only for buoyancy misses the fluid's inertia and frictional effects. For steady creeping flow of a Newtonian fluid around a rigid sphere, the Stokes drag law is $F=6\pi \mu aU$, where $\mu$ is dynamic viscosity, $a$ is the sphere's radius, and $U$ is its relative speed. The result assumes a no-slip boundary condition and an unbounded surrounding fluid. It connects measured settling or damping with fluid properties.^[ref]

A physicist and mathematician associated with Stokes flow, Stokes' second problem and Stokes theorem.

Georges Charpak developed the multiwire proportional chamber, replacing repeated photographic recording with electronic measurements of charged-particle passages. Ionization electrons drift through a gas toward thin wires; the strong local electric field produces avalanches and readable pulses. Knowing which wires respond supplies spatial information, while the electrical output permits rapid processing of many events. This connects microscopic ionization with the practical rate and position resolution of a particle detector.^[ref]

A physicist who developed electronic particle detectors at CERN.^[ref]