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Quantum Trinity
Quantum Trinity is a family of fixed-wing vertical take-off and landing mapping drones made by Quantum Systems, a Munich-based company, on the market since 2018.
Quantum walk
A quantum walk is the quantum-mechanical counterpart of a classical random walk, coming in discrete-time and continuous-time forms and powering quantum algorithms for search and graph problems.
Quantum well infrared photodetector
A quantum well infrared photodetector (QWIP) is a semiconductor detector that absorbs infrared photons in quantum wells, first demonstrated in GaAs/AlGaAs in 1987 and used mainly for long-wavelength infrared imaging.
Quantum-behaved particle swarm optimization
Quantum-behaved particle swarm optimization (QPSO) is a metaheuristic for continuous optimization that models particles as quantum entities in a delta potential well, introduced by Jun Sun, Bin Feng, and Wenbo Xu in 2004.
Quantum-class cruise ship
The Quantum class is a class of five cruise ships built by Meyer Werft for Royal Caribbean International from 2014, introducing firsts such as robotic bartenders and skydiving simulators.
Quantum-inspired optimization
Quantum-inspired optimization is a class of classical algorithms borrowing quantum phenomena such as superposition, tunneling, and annealing to solve optimization problems, running entirely on conventional hardware.
QuantumScape
QuantumScape is a San Jose, California battery company founded in 2010 that develops anode-free solid-state lithium-metal battery cells for electric vehicles, licensed to Volkswagen's PowerCo.
Quark
Quark is a consumer app from Alibaba that combines AI search, a browser, and an AI assistant, launched in 2016 and rebuilt in 2025 on Qwen models.
QuarkXPress
QuarkXPress is a desktop publishing and page layout application for print and digital design, first released in 1987 and dominant in professional publishing until Adobe InDesign overtook it after 1999.
Quarry
A quarry is an open-pit mine from which stone, sand, or gravel is extracted at the surface, yielding dimension stone and crushed rock for construction.
Quarter (United States coin)
The quarter, formally the quarter dollar, is the United States 25-cent coin, produced since 1796 and known for rotating commemorative reverse designs such as the 50 State Quarters of 1999 to 2008.
Quarter car model
The quarter car model is a simplified vehicle dynamics model of one wheel, its suspension, and a quarter of the body, used to study ride comfort.
Quarterstaff
A quarterstaff is a wooden staff about 6 to 9 feet long, often tipped with iron, used in England as a weapon from the late Middle Ages into the 17th century.
Quartus
Quartus, currently Quartus Prime, is the integrated development environment from Altera, the FPGA company spun out of Intel, for designing and programming its FPGAs, SoCs, and CPLDs.
Quartz accelerometer
A quartz accelerometer is a pendulous force-rebalance accelerometer machined from a single piece of fused quartz; Honeywell's Q-Flex line is the de facto industry standard for navigation-grade inertial navigation.
Quartz crisis
The quartz crisis, also called the quartz revolution, was the collapse of the Swiss watch industry in the 1970s under competition from cheap quartz watches.
Quartz Mountain (solar farm)
Quartz Mountain is the name of a solar farm with no verifiable record; the nearest namesake is the 120 MW North Fork plant near Quartz Mountain State Park in Hobart, Oklahoma.
Quasi-direct drive
Quasi-direct drive is a robot actuation approach pairing a high-torque motor with a low gear ratio for backdrivability, now the dominant architecture in commercial humanoid and quadruped robots.
Quasi-isodynamic stellarator
A quasi-isodynamic stellarator is a type of optimized stellarator, a magnetic-confinement fusion device that minimizes heat losses and produces zero bootstrap current, tested by Wendelstein 7-X and favored in recent reactor concepts like Stellaris.
Quasi-orthogonal space-time block code
A quasi-orthogonal space-time block code (QOSTBC) is a space-time block code for multiple-antenna wireless transmission in which code matrix columns are only partly orthogonal, permitting a symbol rate of one with more than two transmit antennas.
Quasi-phase-matching
Quasi-phase-matching is a nonlinear optics technique that periodically reverses a crystal's nonlinear coefficient, keeping light frequency conversion efficient despite phase mismatch, typically by periodically poled crystals like lithium niobate.
Quasi-symmetric stellarator
A quasi-symmetric stellarator is a stellarator whose magnetic field strength is approximately symmetric in one direction, reducing particle losses to tokamak-like levels; the HSX experiment first tested it.
Quasi-Z-source inverter
The quasi-Z-source inverter is a single-stage DC-to-AC converter that boosts and inverts in one stage, introduced by Anderson and Peng in 2008 for photovoltaic and fuel-cell uses.
Quasi-Zenith Satellite System (準天頂衛星システム)
The Quasi-Zenith Satellite System (準天頂衛星システム), QZSS, nicknamed Michibiki, is Japan's satellite positioning system, complementing GPS in the Asia-Oceania region; four-satellite service began in 2018, expanding toward seven satellites.
Quasi-zero-stiffness metamaterial vibration isolators
Quasi-zero-stiffness (QZS) metamaterial vibration isolators are periodic architected structures combining positive and negative stiffness elements to block low-frequency vibration while bearing heavy static loads, with tunable, programmable designs.
Quasistatic loading
Quasistatic loading is a mechanical testing method in which load is applied slowly enough that inertial forces are negligible, producing the stress-strain curves, strengths, and moduli against which higher-rate behavior is compared.
Quaternion kinematics
Quaternion kinematics is the use of unit quaternions, four-parameter numbers with one unit-length constraint, to represent rigid-body orientation in robotics, aerospace, and computer graphics, avoiding the singularities of Euler angles.
Quattro (four-wheel-drive system)
Quattro is Audi's permanent all-wheel-drive system, first shown in 1980 in the original Audi quattro, whose rally successes from 1981 made four-wheel drive the standard in top-level rallying.
Quattro robot
The Quattro robot, commercialized from the Par4 mechanism patented in 2003, is a four-arm parallel delta-type robot by Adept Technology and OMRON for high-speed packaging and food handling.
Quavers
Quavers are British cheese-flavored snacks made from potato starch and shaped into wavy curls, launched by Smiths in 1968 and produced by Walkers, a PepsiCo company.