Fr.: gravité quantique
A theory of gravity, yet to be developed, that would properly include quantum mechanics. Because of the tensor nature of general relativity, it is not renormalizable as a field theory in perturbation from flat space. So far various attempts to quantize general relativity have been unsuccessful.
Fr.: information quantique
The science concerned with the transmission, storage, and processing of information using quantum mechanical systems. It exploits the notion of → quantum entanglement between systems and joins several fields of knowledge, mainly quantum physics, information, computation, and probability.
Fr.: saut quantique
The transition of a quantum system from one stationary state to another, accompanied by absorption or emission of energy.
quantum mechanical system
râžmân-e kuântom mekâniki
Fr.: système mécanique quantique
kuântom mekânik, mekânik-e kuântomi
Fr.: mécanique quantique
A development of Newtonian mechanics based on the discrete character of energy (Planck 1900) and the wave motion of material particles (de Broglie 1924). It is relies on the consideration that energy state of a quantum mechanical system can be derived at a given instant by a function whose square of the modulus gives the probability distribution of the coordinates of the system. Quantum mechanics is essential for the treatment of all atomic processes. It holds also for ordinary large scale processes although in this case the deviations from Newtonian mechanics are negligible.
Fr.: bruit quantique
A random variation of signal due to fluctuations in the average rate of incidence of quanta on a detector. Quantum noise is described by the → Poisson distribution. Same as → photon noise and → shot effect.
adad-e kuântomi (#)
Fr.: nombre quantique
A number used in quantum mechanics, specifying the state of an electron bound in an atomic system. The quantum numbers are integers or half integers and specify the number of units of energy, momentum, spin, etc. possessed by an electron.
quantum of action
Fr.: quantum d'action
quantum phase transition (QPT)
gozareš-e fâz-e kuântomi
Fr.: transition de phase quantique
A phase transitions that occurs at zero temperature as a function of a non-thermal parameter like → pressure, → magnetic field, or → chemical composition. In contrast to ordinary → phase transitions, which are associated with passage through a critical temperature, quantum phase transitions are associated with → quantum fluctuations, a consequence of → Heisenberg's uncertainty principle. For example, see → Bose-Einstein condensation.
Fr.: état quantique
negare-ye kuântomi (#)
Fr.: théorie quantique
The theoretical basis of modern physics which describes the behavior and interactions of elementary particles or energy states based on the assumptions that energy is subdivided into discrete amounts and that matter possesses wave properties. → quantum mechanics; → quantum field theory.
Fr.: marche quantique
A generalization of the classical concept of → random walk using quantum mechanical laws such as the → superposition principle and → interference of quantum amplitudes. In the classical version the particle moves in the position space with a certain probability. In contrast, in the quantum counterpart the particle moves by exploring multiple possible paths simultaneously with the amplitudes corresponding to the influence of different paths. The concept of quantum walk is studied in two standard forms: → continuous-time quantum walk and → discrete-time quantum walk. Quantum walk was first introduced by Aharonov et al. (1993, Phys. Rev. A, 48, 1687).
Fr.: rendement quantique
In photochemistry, the number of defined events which occur per photon absorbed by the system.
âpârgar-e mekânik-e kuântomi
Fr.: opérateur en mécanique quantique
A linear → Hermitian operator associated with a physical quantity.
A faint object (magnitude 18.5), probably a dwarf planet, orbiting the Sun beyond Neptune in the Kuiper belt. Discovered in 2002, Quaoar is estimated to have a diameter of 1260 km and an orbital period of 287 years.
Quaoar the name of a creation deity of the Native American Tongva, located in the Los Angeles area, where the discovery was made.
Any of the hypothetical particles with spin 1/2, baryon number 1/3, and electric charge 1/3 or -2/3 that, together with their antiparticles, are believed to constitute all the elementary particles classed as baryons and mesons. Quarks are distinguished by their flavors, designated as up (u), down (d), strange (s), charm (c), bottom or beauty (b), and top or truth (t), and their colors, red, green, and blue.
Quark, coined in 1963 by the American physicist Murray Gell-Mann (1929-), who took it from a nonsense word in James Joyce's novel Finnegans Wake (1939): Three quarks for Muster Mark! // Sure he has not got much of a bark // And sure any he has it's all beside the mark.
Fr.: confinement des quarks
Fr.: étoile de quarks
A hypothetical star so dense that it is composed of degenerate quarks, a matter denser than that of a neutron star.
quark-hadron phase transition
gozareš-e fâz-e kuârk-hâdron
Fr.: transition de phase quark-hadron
A phase transition, predicted by cosmological models, to have occurred at approximately 10-5 seconds after the Big Bang to convert a plasma of free quarks and gluons into hadron.
from O.Fr. quartier, from L. quartarius "fourth part," from quartus "fourth," related to quattuor "four," cognate with Pers. câr, cahâr, as below.
Cârak "quarter," literally "fourth, a fourth part of one," from câr, contraction of cahâr, → four, + -ak, contraction of yak, yek "one." Yek "one, alone," from Mid.Pers. êwak (Proto-Iranian *aiua-ka-); O.Pers. aiva- "one, alone;" Av. aēuua- "one, alone;" cf. Skt. éka- "one, alone, single;" Gk. oios "alone, lonely;" L. unus "one;" E. one.