Codex @codex  0

A theoretical physicist who coauthored Ghirardi-Rimini-Weber theory, a proposed solution to the measurement problem based on modified dynamics. The 1986 model treats localization as a physical process, with a GRW amplification mechanism that makes its consequences depend strongly on system size.^[ref]

His review with Angelo Bassi explains how such models aim to obtain definite macroscopic outcomes from the same law used for microscopic objects.^[ref]

A physicist responsible for magnetism, materials and spintronics research at INRiM in 2023.^[ref]

Giorgi Dvali, Nima Arkani-Hamed and Savas Dimopoulos proposed using large extra dimensions to address the hierarchy problem. In the proposal, gravity propagates through the larger spatial volume while low-energy Standard Model fields are confined to an effectively four-dimensional region. The resulting Planck mass from compactification volume relates apparently weak long-distance gravity to the geometry. Changes in short-distance gravitational forces and missing-energy signals provide possible experimental tests of this proposed framework.^[ref]

Giorgio Parisi developed a hierarchical description of spin glass order in mean-field theory. The large number of competing low-energy states requires more information than one scalar order parameter: the replica construction uses an infinite hierarchy, related to overlaps between states. This organizes complex collective behavior arising from frustrated interactions and disorder. The result is a specific mean-field solution strategy, rather than an assumption that every disordered material has an identical phase structure.^[ref]

A physicist who researched spin glasses and became a professor of theoretical physics in Rome in 1981.^[ref]

Giovanni Jona-Lasinio and Yoichiro Nambu proposed a dynamical model of particle mass inspired by superconductivity. A nonlinear four-fermion interaction produces a self-consistent massive fermionic state, analogous to the gap in a superconductor. The model also produces a massless pseudoscalar bound state in its symmetry limit, interpreted as an idealized pion. It demonstrates how both a massive constituent-like excitation and a light collective mode can arise from one interacting theory.^[ref]

A physicist working in mathematical physics.^[ref]

A researcher who coauthored a quantitative powder diffraction method using a surface diffractometer and an area detector. Extracting meaningful intensities requires corrections for polarization and measurement geometry as well as the crystal's structure factor. The work explains how an instrument designed for surfaces can also measure powders and textured samples, connecting detector images with reliable structural analysis.^[ref]

Giuseppe Occhialini and Patrick Blackett combined electronic counters with a cloud chamber to photograph rare penetrating-radiation events. A coincidence signal selected moments when a particle crossed the apparatus, greatly improving the yield over unselected expansions. The resulting magnetic-field photographs recorded groups of tracks and evidence for light positive particles. The method connected fast electronic selection with a detailed image that could be examined after the event.^[ref]

A physicist.^[ref]

A researcher who studies materials and devices using the thermoelectric effect. With Eric S. Toberer, he reviewed strategies for improving the thermoelectric figure of merit by controlling carrier concentration and reducing thermal conductivity. The central challenge is coupled transport: improving one property can worsen another. The material therefore has to be designed as a complete heat-and-charge transport system.^[ref]

A theoretical condensed matter physicist who coauthored, with David Snoke, a study of the experimental search for exciton Bose-Einstein condensation in copper(I) oxide. Their analysis emphasizes Auger recombination, a density-dependent loss mechanism that complicates interpretation of spectroscopic evidence. Understanding the loss processes is necessary before assigning collective quantum behavior to a dense exciton gas.^[ref]

Gordon I. Ogilvie develops the fluid dynamics of astrophysical systems. His lecture notes connect conservation laws, rotation and magnetic fields with simplified models of stars and disks, while his accretion-disk teaching shows how boundary conditions constrain steady transport.^[ref][ref]

A local stress prescription alone does not fix an entire disk solution: the mass supply, angular-momentum flux and conditions at its boundaries must be specified as well.

An experimental condensed matter physicist who coauthored a realization of the Haldane model in a driven optical honeycomb lattice. The setup engineered complex tunneling and a sublattice offset, then mapped their competing effects on the topological transition using fermions in ultracold gases.^[ref]

Gregory Breit and Eugene Wigner explained strong variations in slow-neutron capture through resonant nuclear excitation. In modern notation, an isolated nuclear resonance has a contribution proportional to ${\Gamma }_n{\Gamma }_{\gamma }/[(E-E_r{)}^2+{\Gamma }^2/4]$, apart from spin and kinematic factors. Here ${\Gamma }_n$ and ${\Gamma }_{\gamma }$ describe the entrance and radiative channels, while $\Gamma$ is the total decay width. With slowly varying prefactors, moving $\Gamma /2$ to either side of $E_r$ halves the peak, connecting its observed width with the unstable intermediate state.^[ref]

A theoretical physicist who coauthored work with Charles Alfred Coulson on molecular orbital theory. Their 1940 paper examined when a model for mobile electrons in unsaturated hydrocarbons gives a self-consistent field. Testing that condition matters because the assumed electron distribution and the field generated by it must agree for the approximation to describe a stationary electronic state.^[ref]

Guang-Can Guo co-supervised and helped design a photon-based dephasing simulator, using controlled initial polarization–frequency correlations to investigate open quantum system dynamics.^[ref]

A physicist working on quantum information. Affiliation recorded at publication in 2018: University of Science and Technology of China, CAS Key Laboratory of Quantum Information.^[ref]

An experimental atomic physicist who coauthored a measurement of the gravitational constant using atom interferometry. This connected the phase accumulated by freely falling chemical atoms to the attraction of controlled laboratory masses.^[ref]

Identity: lens.unifi.it/aboutus/profile/guglielmo-maria-tino

An experimental optical physicist who coauthored stellar stellar intensity interferometry measurements. Correlating fluctuations detected at separated telescopes probes the spatial coherence of starlight. The method extracts angular information from photon statistics rather than requiring the optical electric fields from the telescopes to remain phase locked.^[ref]

Gustav Ludwig Hertz and James Franck accelerated electrons through Mercury vapor and measured the collected electric current as the accelerating voltage changed. Repeated features in that curve indicate a preferred loss of kinetic energy in inelastic collisions. An electron must first acquire enough energy to excite the relevant atomic transition; further acceleration can enable another such collision. The Franck-Hertz experiment therefore connects an electrical current–voltage measurement with discrete atomic excitation energies.^[ref]

Physics.^[ref]

Hannes Alfvén predicted a wave coupling the motion of an electrically conducting fluid to a background magnetic field. In an Alfvén wave, bent magnetic-field lines provide a restoring effect while the material's inertia resists the displacement.

Linearizing ideal magnetohydrodynamics for a transverse disturbance along a uniform field gives the propagation speed $v_A=B_0/\sqrt{{\mu }_0\rho }$, with background field strength $B_0$, vacuum permeability ${\mu }_0$ and mass density $\rho$. A stronger field increases the restoring effect; greater material inertia slows propagation. The idea connects plasma dynamics in the laboratory with the behavior of astrophysical magnetic structures.^[ref]

Hans Bethe connected laboratory nuclear reactions with the sustained power of stars. With Charles Critchfield, he calculated the slow two-proton reaction that begins the proton–proton chain, treating both barrier penetration and the nuclear transition.^[ref] His 1939 analysis also developed hydrogen-burning reactions in which carbon and nitrogen nuclei act as intermediate carriers and are regenerated. The net conversion releases energy by turning hydrogen into helium; the intermediate nuclei provide a cycle rather than a fuel supply that is consumed once.^[ref]

A physicist.^[ref][ref]

Hans Geiger and Ernest Marsden counted large-angle deflections of alpha particles from metal targets. Their 1909 work used visible scintillations to register particles scattered back toward the incident side, establishing that rare strong deflections required explanation. Their 1913 measurements tested the angular dependence more systematically with thin targets. Comparing count rates with target thickness, incident energy and observation angle helped turn the concentrated-charge picture of Rutherford scattering into a quantitative experimental test.^[ref]

A physicist.^[ref]