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Polar meron
A polar meron is a half-skyrmion topological texture of electric polarization in ferroelectric materials, first observed in strained ultrathin oxide films in 2020 and pursued for high-density information storage.
Polar metal
A polar metal is a crystalline material in which a dipole-carrying polar structure coexists with metallic conductivity, long thought impossible and first uncontested in LiOsO3 in 2013.
Polar night
Polar night is the winter period north of the Arctic Circle and south of the Antarctic Circle when the Sun does not rise for more than 24 hours.
Polar night jet
The polar night jet is a strong westerly wind current in the stratosphere, encircling the winter polar vortex in each hemisphere and acting as a barrier that isolates cold polar air.
Polar plot
A polar plot is a graph of a curve on a polar coordinate system, plotting points at a radius and angle, often circles, cardioids, roses, and spirals.
Polar skyrmion
A polar skyrmion is a nanoscale swirling texture of electric polarization in a ferroelectric, the electrical analog of the magnetic skyrmion, first observed at room temperature in PbTiO3/SrTiO3 superlattices.
Polar skyrmions
Polar skyrmions are nanoscale topological textures of electric polarization in ferroelectric materials, where polarization winds around a core like a particle, discovered in PbTiO3/SrTiO3 superlattices.
Polar skyrmions in ferroelectric superlattices
Polar skyrmions in ferroelectric superlattices are nanoscale, topologically stable textures in which electric polarization swirls in three dimensions, first observed at room temperature in lead titanate/strontium titanate layers in 2019.
Polar space
A polar space is a point-line incidence geometry satisfying the one-or-all axiom, introduced by F. D. Veldkamp in 1959 and tied to the classical groups of Lie type.
Polar stratospheric cloud
The polar stratospheric cloud, also called a nacreous or mother-of-pearl cloud, forms in the winter stratosphere at 15 to 30 km and drives Antarctic ozone depletion.
Polar vortex
The polar vortex, also called a polar cyclone, is a band of westerly winds encircling each pole in the stratosphere, forming each winter and breaking down in spring.
Polar vortices in ferroelectric superlattices
Polar vortices in ferroelectric superlattices are nanoscale, smoothly rotating arrangements of electric dipoles in the ferroelectric layers of stacked perovskite oxides, first observed in 2016 in lead titanate and strontium titanate superlattices.
Polar WRF
Polar WRF (PWRF) is a polar-optimized version of the Weather Research and Forecasting model, developed at Ohio State University in 2008 for Arctic and Antarctic simulations.
POLARBEAR
POLARBEAR (Polarization of the Background Radiation) is a ground-based cosmic microwave background polarization experiment at the Huan Tran Telescope in Chile's Atacama Desert, known for its 2014 lensing detection.
PolarClean
PolarClean (Rhodiasolv PolarClean) is the commercial name for methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate, a low-toxicity polar aprotic solvent made by Solvay from a Nylon-66 byproduct, used mainly for membrane fabrication and battery cathode slurries.
Polarimeter
A polarimeter is an instrument that measures the amount and direction of rotation of plane-polarized light by chiral substances, used to identify compounds, assess purity, and quantify sugar solutions.
Polarimetric imaging
Polarimetric imaging is an imaging technique that measures the polarization state of light from every point in a scene, adding contrast where conventional cameras show little.
Polarimetry
Polarimetry is the measurement of the polarization state of light, performed by an instrument called a polarimeter; scattering, reflection, and optically active matter alter polarization, making it useful in chemistry, remote sensing, astronomy, and biomedical imaging.
Polaris
Polaris, also known as Alpha Ursae Minoris and Stella Polaris, is a yellow supergiant and the nearest classical Cepheid variable, about 520 light-years away in the northern sky.
Polarite
Polarite is a rare palladium bismuthide mineral with the formula Pd(Bi,Pb), first described in 1969 from copper-nickel sulfide ores at the Talnakh deposit, Norilsk, Russia.
Polariton
A polariton is a quasiparticle formed when a photon couples strongly to a matter excitation, such as an exciton, plasmon, or optical phonon, hybridizing into mixed states.
Polariton blockade
Polariton blockade is a quantum-optical effect in which one polariton, a hybrid light–matter quasiparticle, blocks a second from occupying the same optical mode, by analogy with the Coulomb blockade of electrons.
Polariton condensates
A polariton condensate is a macroscopic quantum state formed when exciton-polaritons, quasiparticles of strongly coupled excitons and photons in a semiconductor microcavity, occupy one quantum state above a threshold density, first demonstrated in 2006.
Polariton Josephson junction
A polariton Josephson junction is a weak link joining two exciton-polariton condensates in a semiconductor microcavity, reproducing Josephson physics, first seen in superconductors, in a light-matter platform.
Polariton laser
A polariton laser is a coherent light source that emits through a Bose-Einstein condensate of exciton-polaritons in a semiconductor microcavity, promising coherent light at far lower energy than conventional lasers.
Polariton superfluidity
Polariton superfluidity is the frictionless flow of exciton-polaritons, hybrid light-matter quasiparticles formed when cavity photons couple to excitons in semiconductor microcavities, demonstrated in 2009 and at room temperature by 2017.
Polariton transport
Polariton transport is the propagation of polaritons, hybrid quasiparticles formed when photons couple strongly to excitons, plasmons, or phonons, through a solid, reaching distances far beyond bare excitons.
Polaritonic Mott transition
The polaritonic Mott transition is a phase transition of polaritons, hybrid light-matter quasiparticles in coupled cavities, between a localized Mott-insulator state and a delocalized superfluid.
Polarity-reversal catalysis
Polarity-reversal catalysis (PRC) is a strategy in radical chemistry, introduced by Vikram Paul and Brian P. Roberts in 1987, in which a catalyst converts a slow, polarity-mismatched hydrogen-atom abstraction into two fast, polarity-matched steps.
Polarizability
Polarizability, also called molecular polarizability, measures how easily an electric field induces a dipole moment in an atom or molecule, underlieing dielectric behavior and refractive index.