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Hideo Takezoe
Hideo Takezoe (竹添 秀男) is a Japanese liquid-crystal physicist and Professor Emeritus at Tokyo Institute of Technology, known for work on antiferroelectric and bent-core liquid crystals and liquid-crystal photonics.
Hidetoshi Katori
Hidetoshi Katori (香取秀俊, born 1964) is a Japanese physicist at the University of Tokyo who invented the optical lattice clock, accurate to one second in 30 billion years.
Hideya Matsumoto
Hideya Matsumoto is a mathematician whose 1964 note on generalized Weyl groups is the origin of Matsumoto's theorem on Coxeter groups; he earned a 1969 doctorate in Paris under François Bruhat.
Hierarchical Bayesian analysis
Hierarchical Bayesian analysis is a statistical modeling approach in which parameters have priors structured in multiple levels, partially pooling information across groups during Bayesian inference.
Hierarchical black hole merger formation
Hierarchical black hole merger formation is the process in which a black hole formed in an earlier merger pairs with another black hole and merges again.
Hierarchical Dirichlet process
The hierarchical Dirichlet process (HDP) is a Bayesian nonparametric prior introduced by Teh, Jordan, Beal, and Blei in 2006, letting related groups share mixture components.
Hierarchical equations of motion
The hierarchical equations of motion (HEOM), introduced by Yoshitaka Tanimura and Ryogo Kubo in 1989, are coupled equations that describe open quantum systems numerically exactly, without Markovian approximations.
Hierarchical structure formation
Hierarchical structure formation is the cosmological model in which small structures such as dwarf galaxies and dark matter halos form first, later merging into larger galaxies and clusters.
Hierarchical zeolites by desilication
Hierarchical zeolites by desilication are zeolite catalysts in which alkaline leaching of framework silicon creates mesopores that improve access to the catalytically active micropore sites.
Hierarchy
In mathematics, a hierarchy classifies objects by definitional complexity; in combinatorics, it is a family of subsets in which any two are disjoint or nested.
Hierarchy of evidence
The hierarchy of evidence, or levels of evidence, ranks study designs by susceptibility to bias, with systematic reviews and meta-analyses of randomized trials at the top.
Hierarchy problem
The hierarchy problem, also called the gauge hierarchy problem, is the puzzle of why the Higgs boson is so much lighter than the Planck scale.
Hieronymus Georg Zeuthen
Hieronymus Georg Zeuthen (1839–1920) was a Danish mathematician who helped found enumerative geometry, the counting of geometric figures, and later became a leading historian of Greek mathematics.
Higgs boson
The Higgs boson, also known as the God's particle, is a zero-spin elementary particle that gives mass to other particles, discovered at CERN's Large Hadron Collider in 2012.
Higgs boson pair production
Higgs boson pair production (HH, or di-Higgs production) is the simultaneous creation of two Higgs bosons in one collision, a process about 1,000 times rarer than single Higgs production and not yet observed.
Higgs bundle
A Higgs bundle is a pair consisting of a holomorphic vector bundle and a Higgs field over a Riemann surface, introduced by Nigel Hitchin in 1987.
Higgs field
The Higgs field is a fundamental quantum field with a nonzero value in empty space that gives the W and Z bosons and charged fermions their mass.
Higgs inflation
Higgs inflation is a cosmological inflation model in which the Standard Model Higgs field itself drives the early Universe's accelerated expansion, proposed by Bezrukov and Shaposhnikov in 2008.
Higgs mechanism
The Higgs mechanism, also known as the Brout-Englert-Higgs mechanism, is the particle-physics process by which elementary particles gain mass through the Higgs field filling all of space.
Higgs portal
The Higgs portal is a class of particle physics models in which dark matter interacts with ordinary particles only through couplings to the Higgs sector.
Higgsino
A higgsino is the hypothetical fermionic superpartner of the Higgs boson in supersymmetric extensions of the Standard Model; none has been observed, though LHC searches continue.
High angular resolution diffusion imaging
High angular resolution diffusion imaging (HARDI) is a diffusion MRI strategy sampling over 50 gradient directions at high b-values to resolve crossing fibers that diffusion tensor imaging cannot.
High availability
High availability (HA) is a property of a computer system that keeps a service usable through component interruptions, using redundancy, replication, and automatic failover to keep downtime small.
High Energy Photon Source
The High Energy Photon Source (HEPS; 高能同步辐射光源) is a 6 GeV fourth-generation synchrotron light source built in Beijing, the first fourth-generation synchrotron in Asia, which began user operation in 2025.
High Flux Isotope Reactor
The High Flux Isotope Reactor (HFIR) is an 85 MW research reactor at Oak Ridge National Laboratory, started in 1965, that supplies neutrons for scattering research.
High Intensity Gamma-Ray Source
The High Intensity Gamma-Ray Source (HIγS) is a Compton-backscattering gamma-ray facility at Duke University in Durham, North Carolina, producing tunable, polarized gamma-ray beams of 1–100 MeV.
High Intensity Heavy-ion Accelerator Facility
The High Intensity heavy-ion Accelerator Facility (HIAF, 强流重离子加速器装置) is a Chinese national facility in Huizhou, Guangdong, built by the Chinese Academy of Sciences for nuclear physics research.
High Resolution Model Intercomparison Project
The High Resolution Model Intercomparison Project (HighResMIP) was a CMIP6-endorsed project that applied, for the first time, a multi-model approach to studying horizontal resolution in global climate models.
High tide water
High tide water (high water, German Tidehochwasser) is the water level at a tide's highest point. Most coasts see two high tides per 24 h 50 min tidal day; spring and perigean tides raise the highest levels.
High voltage
High voltage, also called high tension, is an engineering and safety category for electrical systems exceeding 1,000 volts AC or 1,500 volts DC under IEC standards.