Quantum

Description

The quantum theory or quantum theory, affirms that radiant energy is discontinuous. The quanta are then the component “grains” this energy of value H . ν , where:

H is the Constante of Planck,
ν is the Fréquence of the wave.

Thus, one can easily determine the energy contained in a photon by multiplying his frequency (deduced its wavelength since its speed is constant) by H . It is noted that the value of H is low: 6,62.10^-34 joule*seconde. And E / v = N . H , i.e. the quotient E / v is always a multiple of H .

History

For the Greek of Antiquity, the Atome was seen like an indivisible unit. Indeed, the word comes from the Greek ατομος (“atomos”), “that one cannot divide” - “has” indicates the negation and “divides into volumes” division. One could deduce from it today that an atom is a quantum. However, this theory was put at evil by various experiments undertaken by Ernest Rutherford at the end of the XIXe century, which showed that the atom was composed of particles charged: the electron and of Proton.

John Rayleigh stated that the power radiated by a heated body is proportional to its absolute Temperature and inversely proportional to the square of the Wavelength of the considered color. However, of measurements showed that its theory was not true that for the wavelengths going from the Infrarouge to the green Starting from blue, the experiment is in contradiction with the theoretical values. Paul Ehrenfest called this error the “ultraviolet Catastrophe”.

max Planck, in 1900, proposed that the vibrations resulting from the heat of a body are distributed according to a determined law, governed by the constant H which bears its name. It, as well as the other physicists, was destabilized by his theory. It tried a long time to preserve its result by removing the quanta, for finally giving up and admitting them. The quantum theory had been born. It was the starting point of the quantum Mécanique, one of the two great physical theories of the 20th century.

The quantum mechanics, which calls in particular upon the Fonction of wave, was initiated by Bose, of Broglie, Dirac, Einstein, Fermi, Feynman, Heisenberg, Pauli and Schrödinger. of Broglie will bind the quantum to the length of Onde in the Wave mechanics , where a particle has the double quantum and undulatory characteristic. An important part of work of the end of the XIXe century and beginning of the XXe century will be devoted to the establishment of this Dualité.

Richard Feynman and Julian Schwinger developed the electrodynamic thereafter quantum relativist, theory which considers that the electromagnetic interaction between particles charged is done by the exchange of Photon S; by extension, the interaction nelle Gravitation would be done by the exchange of Graviton S and the weak interactions and strong via Boson S. to describe the interaction of the elementary particles, it were necessary to develop another theory bearing the name of Quantum theory of the fields.

Application in Electronics

In electronic, the quantum corresponds to the tension Analogique of the numerical value smallest, that is to say 1. It is thus the smallest jump of possible Tension in analogique.

$q = \ frac {V_ {EP}} {2^ {N} - 1}$ with $V_ {EP}$ the Tension Full Scale

Example

Following binary continuations on 4 bits:
0 0 0 1 = 3mV (= Q )
0 0 1 0 = 6mV (= 2q )
0 0 1 1 = 9mV (= 3q )
1 1 1 1 = TPE (= 15q )

Etymology

Quantum is a form Latin E corresponding to what indicates in Physique an indivisible quantity ( quanta in the plural);
Adjectival Quantus , meaning “how much” in the interrogative and exclamative mode ( quanta with the female singular or the plural neutral).

Let us quote some words derived from “quanta”:

quantum Quantification
(logic, theory, number, formalism, particle, probability)
to quantify
quantifier

Be-X-old: Квант

Random links: