Encyclopaedia Britannica Online Shop

0-9

quantum ... qubit

quantum: in physics, discrete natural unit, or packet, of energy, charge, angular momentum, or other physical property. Light, for example, appearing in some respects as a continuous electromagnetic wave, on the ... [24 Related Articles]
quantum chromodynamics: in physics, the theory that describes the action of the strong force. QCD was constructed in analogy to quantum electrodynamics (QED), the quantum field theory of the electromagnetic force. In ... [16 Related Articles]
quantum computer: device that employs properties described by quantum mechanics to enhance computations. [2 Related Articles]
quantum cryptography: (from the article "Glauber, Roy J.") Practical applications of Glauber's work included the development of highly secure codes in the field known as quantum cryptography. His research also had a central role in efforts to develop ...
quantum dot: (from the article "Physical Sciences") ...possible for two qubit devices to interact instantaneously. There were many candidates for quantum-mechanical systems upon which such devices could be based, including atoms, trapped ions, or "quantum dots" (tiny ...
quantum electrodynamics: quantum field theory of the interactions of charged particles with the electromagnetic field. It describes mathematically not only all interactions of light with matter but also those of charged particles ... [22 Related Articles]
quantum encryption: (from the article "quantum computer") ...computer is built, it will break current encryption schemes based on multiplying two large primes; in compensation, quantum mechanical effects offer a new method of secure communication known as quantum ...
quantum entanglement: (from the article "Physical Sciences") ...transfer of information from one place to another. It circumvents the restriction on exceeding the speed of light (a restriction imposed by relativity theory) by making use of the phenomenon ...
quantum field theory: body of physical principles combining the elements of quantum mechanics with those of relativity to explain the behaviour of subatomic particles and their interactions via a variety of force fields. ... [7 Related Articles]
quantum logic: (from the article "mathematics, foundations of") ...many-valued, or multivalued, logics, which admit a finite number of truth-values; fuzzy logic, with an imprecise membership relationship (though, paradoxically, a precise equality relation); and quantum logic, where conjunction may ...
quantum mechanics: science dealing with the behaviour of matter and light on the atomic and subatomic scale. It attempts to describe and account for the properties of molecules and atoms and their ... [48 Related Articles]
quantum number: any of several quantities of integral or half-integral value that identify the state of a physical system such as an atom, a nucleus, or a subatomic particle. Quantum numbers refer ... [4 Related Articles]
quantum optics: (from the article "light") Quantum optics, the study and application of the quantum interactions of light with matter, is an active and expanding field of experiment and theory. Progress in the development of light ...
quantum oscillation frequency: (from the article "quantum mechanics") ...intensity of the light varies with direction after passing through the slits (Figure 5B). The intensity oscillates because of interference between the light waves emerging from the two slits, the ...
quantum speciation: (from the article "evolution") In some modes of speciation the first stage is achieved in a short period of time. These modes are known by a variety of names, such as quantum, rapid, and ...
quantum statistical mechanics: (from the article "physics") Quantum statistical mechanics plays a major role in many other modern fields of science, as, for example, in plasma physics (the study of fully ionized gases), in solid-state physics, and ...
quantum well: (from the article "nanotechnology") VCSELs have nanoscale layers of compound semiconductors epitaxially grown into their structure-alternating dielectric layers as mirrors and quantum wells. Quantum wells allow the charge carriers to be confined in well-defined ...
quantum yield: (from the article "radiation measurement") 4. A fraction of the emerging light photons are converted to charge in a light sensor normally mounted in optical contact with the exit window. This fraction is known as ...
quantum-mechanical exchange effect: (from the article "physical science") The key to the nature of the chemical bond was found to be the quantum-mechanical exchange effect, first described by Heisenberg in 1926-27. Resonance is related to the requirement that ...
Quantz, Johann Joachim: German composer and flute virtuoso who left an important treatise on the flute and who made mechanical improvements in the instrument.
Quanzhou: port and city, eastern coastal Fujian sheng (province), China. It is situated on the north bank of the Jin River, at the head of the river's estuary, ... [1 Related Articles]
Quapaw: North American Indian people of the Dhegiha branch of the Siouan language stock. With the other members of this subgroup (including the Osage, Ponca, Kansa, and Omaha), the Quapaw migrated ... [1 Related Articles]
Quaranta, Gianni: (from the article "1986: Other Winners") ...Allen for Hannah and Her SistersAdapted Screenplay: Ruth Prawer Jhabvala for A Room with a ViewCinematography: Chris Menges for The MissionArt Direction: Brian Ackland-Snow and Gianni Quaranta for A Room ...
quarantine: the detention or restraint of humans or other creatures that may have come into contact with communicable disease until it is deemed certain that they have escaped infection. In the ... [5 Related Articles]
Quaratesi Polyptych: (from the article "Gentile da Fabriano") ...artists throughout the century and presented a counterattraction to the austere realism introduced by Masaccio. Gentile also produced a number of Madonnas, such as the altarpiece known as the Quaratesi ...
Quare, Daniel: celebrated English clock maker, who invented a repeating watch mechanism (1680) that sounded the nearest hour and quarter hour when the owner pushed a pin protruding from the case. He ...
Quarenghi, Giacomo Antonio Domenico: Italian Neoclassical architect and painter, best known as the builder of numerous works in Russia during and immediately after the reign of Catherine II the Great. He was named "Grand ... [3 Related Articles]
quark: any member of a group of elementary subatomic particles that interact by means of the strong force and are believed to be among the fundamental ... [32 Related Articles]
quark-gluon plasma: (from the article "particle accelerator") ...Ion Collider (RHIC) came into operation in 2000. This has two rings of magnets that cross to accelerate beams of gold ions to 50 GeV and then bring them into ...
Quarles, Francis: religious poet remembered for his Emblemes, the most notable emblem book in English.
quarry: place where dimension stone or aggregate (sand, gravel, crushed rock) is mined. The products of dimension stone quarries are prismatic blocks of rock such as marble, granite, limestone, sandstone, and ... [5 Related Articles]
quarry tile: (from the article "brick and tile") Structural clay-facing tile is often glazed for use as an exposed finish. Wall and floor tile is a thin material of fireclay with a natural or glazed finish. Quarry tile ...
Quarry, Jerry: American boxer (b. May 15, 1945, Los Angeles, Calif.-d. Jan. 3, 1999, Templeton, Calif.), became a championship heavyweight contender but never a champion; he posted a professional record of 53-9-4 ...
quart: unit of capacity in the British Imperial and U.S. Customary systems of measurement. For both liquid and dry measure, the British system uses one standard quart, which is equal to ... [1 Related Articles]
quartan malaria: (from the article "malaria") ...drops back to normal. Between attacks the temperature may be normal or below normal. The classic attack cycles, recurring at intervals of 48 hours (in so-called tertian malaria) or 72 ...
quartarus: (from the article "measurement system") ...sextarius, modius, and amphora for dry products and the quartarus, sextarius, congius, ...
quarter: (from the article "heraldry") ...orles set closely together. The small shield used as a charge is an inescutcheon and often is used to bear the arms of an heraldic heiress (a daughter of a ...
quarter sessions: formerly, in England and Wales, sessions of a court held four times a year by a justice of the peace to hear criminal charges as well as civil and criminal ... [1 Related Articles]
quarter tone: (from the article "Haba, Alois") Quarter tones had been used as early as 1849 by the French composer Fromental Halevy, but Haba drew his inspiration from Moravian folk tunes and rhythms, music abounding in microtones. ...
quarter-horse racing: in the United States, the racing of horses at great speed for short distances on a straightaway course, originally a quarter of a mile, hence the name. Quarter-horse racing was ... [1 Related Articles]
quarter-wave plate: (from the article "radiation") ...is so selected that the path difference for the ordinary and the extraordinary rays is one-quarter the wavelength of the single-wavelength, or monochromatic, light used. Such a crystal is called ...
quarterback: (from the article "football, gridiron") ...the 1930s, but college football remained fundamentally a power running game into the 1980s. College coaches' most distinctive innovations in the 1970s and '80s came in offenses that featured running ...
quarterdeck: (from the article "castle") ...for the area around the foremast in 19th-century men-of-war, although the deck was flush from bow to stern. Many cargo vessels have a forecastle (deck). The aftercastle was superseded by ...
quartering: (from the article "heraldry") In the quarterings and the marshaling (arrangement of more than one coat of arms on the same shield), the position of heiresses must be considered first. The children of an ...
quartering: (from the article "logistics") The provision of military facilities, as distinct from fortification, did not become a large and complex sphere of logistic activity until the transformation of warfare in the industrial era. In ...
Quartering Act: (1765), in American colonial history, the British parliamentary provision (actually an amendment to the annual Mutiny Act) requiring colonial authorities to provide food, drink, quarters, fuel, and transportation to British ...
quartermaster: officer who superintends arrangements for the quartering and movement of troops. In Europe the office dates back at least to the 15th century. During the late 17th century, when the ...
quarterstaff: a staff of wood from 6 to 9 feet (about 2 to 3 m) long, used for attack and defense. It is probably the cudgel or sapling with which many ...
quartet: a musical composition for four instruments or voices; also, the group of four performers. Although any music in four parts can be performed by four individuals, the term has come ...
quartet: (from the article "chemical compound") ...pattern of the absorption peaks. In the bromoethane example, the CH₃ peak is split into three distinct peaks, called a triplet. The CH₂ peak is split into four peaks, called ...
quartic equation: (from the article "mathematics") Another subject that was transformed in the 19th century was the theory of equations. Ever since Tartaglia and Ferrari in the 16th century had found rules giving the solutions of ...
quartile: (from the article "statistics") ...below the pth percentile, and roughly 100 − p percent of the data values are above the pth percentile. Percentiles are reported, for example, on most standardized tests. Quartiles divide ...
Quartodecimanism: (from the article "calendar") ...to sunset. The question arose of how the evening of the 14th day should be calculated, and some-the Quintodecimans-claimed that it meant one particular evening, but others-the Quartodecimans-claimed that it ...
quartz: widely distributed mineral of many varieties that consists primarily of silica, or silicon dioxide (SiO₂). Minor impurities such as lithium, sodium, potassium, and titanium may be present. Quartz has attracted ... [16 Related Articles]
quartz arenite: (from the article "quartz arenite") variety of the rock quartzite (q.v.) formed by deposition of silica in subterranean sandstone.conversion to quartzitequartzite...instead of a rough and ...
quartz cat's-eye: (from the article "cat's-eye") ...Precious, or oriental, cat's-eye, the rarest and most highly prized, is a greenish chatoyant variety of chrysoberyl called cymophane; the chatoyant effect is due to minute parallel cavities. Quartz cat's-eye, ...
quartz microbalance: (from the article "balance") Small quartz microbalances with capacities of less than a gram have been constructed with a reliability much greater than is ordinarily found with small assay-type balances having a metal beam ...
quartz monzonite: intrusive igneous rock (solidified from a liquid state) that contains plagioclase feldspar, orthoclase feldspar, and quartz. It is abundant in the large batholiths (great masses of igneous rocks mostly deep ...
quartz-crystal clock: (from the article "clock") The timekeeping element of a quartz clock consists of a ring of quartz about 2.5 inches (63.5 mm) in diameter, suspended by threads and enclosed in a heat-insulated chamber. Electrodes ...
quartzarenite: (from the article "sedimentary rock") Quartz arenites are usually white, but they may be any other colour; cementation by hematite, for example, makes them red. They are usually well sorted and well rounded (supermature) and ...
quartzite: sandstone that has been converted into a solid quartz rock. Unlike sandstones, quartzites are free from pores and have a smooth fracture; when struck, they break through, not around, the ... [4 Related Articles]
quasar: any of a class of rare cosmic objects of high luminosity that often have strong radio emission that is observed at great distances. These objects are also called QSOs, which ... [12 Related Articles]
quasi extra territorium: (from the article "diplomatic immunity") ...residences, and their goods as though they were located outside the host country-to justify diplomatic exemption from both criminal and civil law. The doctrine of quasi extra ...
quasi in rem: (from the article "judgment") ...no personal liability on anyone but adjudicates the interests of all persons in a specific thing or property in the custody of the court or otherwise subject to its jurisdiction. ...
quasi-biennial oscillation: layer of winds that encircle the Earth in the lower stratosphere, at altitudes from 20 to 40 kilometres (about 12 to 25 miles), between latitudes 15° N and 15° S. ... [2 Related Articles]
quasi-contract: (from the article "Roman law") Quasi-contract embraced obligations that had no common feature save that they did not properly fall under contract, because there was no agreement, or under delict, because there was no wrongful ...
quasi-delict: (from the article "Roman law") Quasi-delict covered four types of harm, grouped together by no clearly ascertainable principle. They included the action against an occupier for harm done by things thrown or poured from his ...
quasi-olfaction: (from the article "cetacean") ...to the standard four qualities of taste: sweet, salty, sour, and bitter. It has been established that the bottlenose dolphin (Tursiops truncatus) has a highly effective sense, called quasi-olfaction, operating ...
quasi-reflexive relation: (from the article "formal logic") ...even themselves. But this relation is reflexive in the weaker sense that whenever an object is of the same length as anything it is of the same length as itself. ...
quasi-rent: (from the article "rent") ...like land, it is a "free gift of nature." A particularly effective machine also, though its supply can be increased in time by productive effort, may for a period also ...
quasi-steady wave: (from the article "ship") In a long-favoured application of beam theory to the design of a ship's hull, the ship is assumed to be supported by a quasi-steady wave (i.e., not moving with respect ...
quasicrystal: matter formed atomically in a manner somewhere between the amorphous solids of glasses (special forms of metals and other minerals, as well as common glass) and the precise pattern of ... [1 Related Articles]
Quasimodo, Salvatore: Italian poet, critic, and translator. Originally a leader of the Hermetic poets, he became, after World War II, a powerful poet commenting on modern social issues. He received the Nobel ... [5 Related Articles]
quasiparticle: in physics, a disturbance, in a medium, that behaves as a particle and that may conveniently be regarded as one. A rudimentary analogy is that of a bubble in a ...
quasiperiodicity: (from the article "quasicrystal") ...Steinhardt, physicists at the University of Pennsylvania, proposed a resolution of this apparent conflict. They suggested that the translational order of atoms in quasicrystalline alloys might be quasiperiodic rather than ...
quassia: (from the article "Simaroubaceae") ...the male flowers release a disagreeable odour. Several varieties have colourful, twisted fruits and coloured leafstalks. Bark of species of the genera Quassia and Picrasma yields quassia, a bitter substance ...
Quassia: (from the article "Sapindales") Simaroubaceae, or the quassia family, consists of 19 genera and 95 species of trees and shrubs that are mostly tropical in distribution. Quassia, with 40 species in the rainforests of ...
quassia wood: (from the article "Simaroubaceae") ...Female plants are preferred because the male flowers release a disagreeable odour. Several varieties have colourful, twisted fruits and coloured leafstalks. Bark of species of the genera Quassia and Picrasma ...
Quasthoff, Thomas: Bass-baritone Thomas Quasthoff made his opera debut in April 2003, singing the role of Don Fernando in a production of Beethoven's Fidelio with Sir Simon Rattle and the Berlin Philharmonic ...
Quaternary: in the geologic history of Earth, a unit of time within the Cenozoic Era, beginning approximately 2.6 million years ago and continuing to the present day. The Quaternary has been ... [8 Related Articles]
quaternary ammonium compound: (from the article "amine") ...have been replaced by organic groups. In chemical notation these three classes are represented as RNH₂, R₂NH, and R₃N, respectively. A fourth category consists of quaternary ammonium compounds, which are ...
quaternary system: (from the article "olivine") ...tends to develop at lower temperatures than monticellite as the process of decarbonation in the contact zone progresses. Fayalitic olivines develop within metamorphosed iron-rich sediments. In the quaternary (i.e., four-component) ...
quaternion: (from the article "Clifford, William Kingdon") Clifford developed the theory of biquaternions (a generalization of the Irish mathematician Sir William Rowan Hamilton's theory of quaternions) and then linked them with more general associative algebras. He used ...
quatrain: (from the article "Ghassaniy, Muyaka bin Haji al-") Ghassaniy is known particularly as an outstanding composer of quatrains (the most popular Swahili verse form for both philosophical and topical themes). Although he experimented little with prosody, his work ...
Quatre Bornes: town ("township") on the island of Mauritius, in the western Indian Ocean. It lies in the western highlands region of the country, about 9 miles (14 km) south of Port ...
Quatre Gats: (from the article "Nonell y Monturiol, Isidro") ...people. In 1899 these works were exhibited in Barcelona as well as in Paris by the influential dealer Ambroise Vollard. In Barcelona, Nonell was the leader of a group of ...
Quatre-Bras, Battle of: (from the article "Waterloo, Battle of") ...Dutch, Belgian, and German units) and about 45,000 Prussians, the main force of Gebhard Leberecht von Blucher's command. After defeating the Prussians at Ligny and holding Wellington at Quatre-Bras in ...
quatre-vingts: (from the article "numerals and numeral systems") ...the gross measure by twelves. In English the base 20 occurs chiefly in the score ("Four score and seven years ago&elipsis;"); in French it survives in the word
Quattrocchi, Fabrizio: (from the article "Italy") Three other hostages from Italy, snatched in separate kidnappings, were executed by their captors. Fabrizio Quattrocchi was among four private bodyguards working for a U.S.-based security firm seized in April ...
Quattrocento: the totality of cultural and artistic events and movements that occurred in Italy during the 15th century, the major period of the Early Renaissance. Designations such as Quattrocento (1400s) and ... [1 Related Articles]
Quattrone, Frank: (from the article "Computers and Information Systems") Frank Quattrone, a former investment banker who made tens of millions of dollars during the Internet-stock boom, was sentenced to 18 months in prison and two years' probation and fined ...
Quauhteca: (from the article "pre-Columbian civilizations") Two categories of dead persons went up to the heavens as companions of the sun: the Quauhteca ("Eagle People"), who comprised the warriors who died on the battlefield or on ...
quay wall: (from the article "dock") ...the normal course of traffic and cargo transfer. The latter function was later rendered by another group of structures especially designed for that purpose and given different designations such as ...
Quay, Matthew S.: (from the article "Penrose, Boies") ...with law partner Edward P. Allinson, which advocated certain municipal reforms. The politics of reform did not long hold his interest, however, as he became associated with state party boss ...
Quay, Stephen: (from the article "animation") ...Alice (1988), Faust (1994), and Conspirators of Pleasure (1996). Svankmajer's most dedicated disciples are the Quay brothers, Stephen and Timothy, identical twins born in ...
Quay, Timothy: (from the article "animation") ...(1988), Faust (1994), and Conspirators of Pleasure (1996). Svankmajer's most dedicated disciples are the Quay brothers, Stephen and Timothy, identical twins born in Philadelphia ...
Quayle, Dan: 44th vice president of the United States (1989-93) in the Republican administration of President George Bush.
Quayle, Sir Anthony: British actor and director who was well known for his roles in classic plays on the stage as well as for his motion-picture career.
Quba: city in northeastern Azerbaijan. It is situated on the eastern slopes of the Greater Caucasus, on the right bank of the Kudial River. In the 18th century a khanate was ...
Quba-Xacmaz: (from the article "Azerbaijan") The Quba-Xacmaz region lies to the north of Abseron. Its coastal lowlands specialize in grain and vegetable production, while vast orchards surround the towns of Quba and Qusar. The mountain ...
qubit: (from the article "Physical Sciences") The next development in computing might well involve quantum computing-the storage and transport of qubits, quantum-system states that can be used to represent bits of data. A great advantage of ...