{"id":3092,"date":"2026-09-13T08:49:45","date_gmt":"2026-09-13T07:49:45","guid":{"rendered":"https:\/\/www.laurensoff.com\/wordpress\/?p=3092"},"modified":"2026-09-13T08:50:46","modified_gmt":"2026-09-13T07:50:46","slug":"comment-fonctionne-la-physique-quantique","status":"publish","type":"post","link":"https:\/\/www.laurensoff.com\/wordpress\/comment-fonctionne-la-physique-quantique\/","title":{"rendered":"Comment fonctionne la physique quantique ?"},"content":{"rendered":"<p data-path-to-node=\"0\">La <b data-path-to-node=\"0\" data-index-in-node=\"3\">physique quantique<\/b> est la branche de la science qui d\u00e9crit le comportement de la mati\u00e8re et de la lumi\u00e8re \u00e0 l&#8217;\u00e9chelle de l&#8217;infiniment petit (atomes, \u00e9lectrons, photons).<\/p>\n<p data-path-to-node=\"1\">\u00c0 notre \u00e9chelle, les objets suivent la physique classique : une balle est soit \u00e0 gauche, soit \u00e0 droite. Mais dans le monde quantique, les r\u00e8gles changent radicalement :<\/p>\n<ul data-path-to-node=\"2\">\n<li>\n<p data-path-to-node=\"2,0,0\"><b data-path-to-node=\"2,0,0\" data-index-in-node=\"0\">La superposition :<\/b> Une particule peut \u00eatre dans plusieurs \u00e9tats ou endroits en m\u00eame temps, tant qu&#8217;on ne la mesure pas.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"2,1,0\"><b data-path-to-node=\"2,1,0\" data-index-in-node=\"0\">La dualit\u00e9 onde-corpuscule :<\/b> La lumi\u00e8re ou un \u00e9lectron se comportent parfois comme un grain de mati\u00e8re (une bille), parfois comme une onde (une vague).<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"2,2,0\"><b data-path-to-node=\"2,2,0\" data-index-in-node=\"0\">L&#8217;intrication quantique :<\/b> Deux particules peuvent \u00eatre li\u00e9es de sorte que modifier l&#8217;une modifie l&#8217;autre instantan\u00e9ment, peu importe la distance qui les s\u00e9pare.<\/p>\n<\/li>\n<\/ul>\n<p data-path-to-node=\"3\">L&#8217;exp\u00e9rience des fentes de Young illustre ce comportement : quand on envoie de la lumi\u00e8re ou des \u00e9lectrons \u00e0 travers deux fentes, ils cr\u00e9ent une figure d&#8217;interf\u00e9rence (des bandes) comme des vagues d&#8217;eau qui se croisent, prouvant qu&#8217;une seule particule peut passer par les deux fentes \u00e0 la fois.<\/p>\n<h3 data-path-to-node=\"5\">Qu&#8217;est-ce qu&#8217;on peut fabriquer avec ?<\/h3>\n<p data-path-to-node=\"6\">Nous utilisons d\u00e9j\u00e0 la physique quantique au quotidien. Elle est \u00e0 la base de la premi\u00e8re r\u00e9volution industrielle num\u00e9rique :<\/p>\n<ul data-path-to-node=\"7\">\n<li>\n<p data-path-to-node=\"7,0,0\"><b data-path-to-node=\"7,0,0\" data-index-in-node=\"0\">Les puces \u00e9lectroniques et smartphones :<\/b> Les transistors fonctionnent gr\u00e2ce aux propri\u00e9t\u00e9s quantiques des semi-conducteurs (comme le silicium).<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"7,1,0\"><b data-path-to-node=\"7,1,0\" data-index-in-node=\"0\">Les lasers :<\/b> La lecture de codes-barres, la chirurgie de l&#8217;\u0153il et la fibre optique reposent sur l&#8217;\u00e9mission stimul\u00e9e de photons.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"7,2,0\"><b data-path-to-node=\"7,2,0\" data-index-in-node=\"0\">L&#8217;imagerie m\u00e9dicale (IRM) :<\/b> Elle exploite le magn\u00e9tisme des noyaux atomiques.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"7,3,0\"><b data-path-to-node=\"7,3,0\" data-index-in-node=\"0\">Les ordinateurs quantiques :<\/b> En cours de d\u00e9veloppement, ils utilisent des \u00ab qubits \u00bb (superpos\u00e9s) au lieu de bits classiques (0 ou 1) pour calculer des millions de fois plus vite certains algorithmes.<\/p>\n<\/li>\n<\/ul>\n<div class=\"attachment-container search-images\"><\/div>\n<h3 data-path-to-node=\"10\">Qu&#8217;est-ce qu&#8217;on peut comprendre et modifier ?<\/h3>\n<table data-path-to-node=\"11\">\n<thead>\n<tr>\n<td><strong>Ce qu&#8217;on peut comprendre<\/strong><\/td>\n<td><strong>Ce qu&#8217;on peut modifier \/ manipuler<\/strong><\/td>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><span data-path-to-node=\"11,1,0,0\"><b data-path-to-node=\"11,1,0,0\" data-index-in-node=\"0\">La chimie et les mol\u00e9cules :<\/b> Pourquoi les atomes s&#8217;assemblent et comment r\u00e9agissent les prot\u00e9ines ou les m\u00e9dicaments.<\/span><\/td>\n<td><span data-path-to-node=\"11,1,1,0\"><b data-path-to-node=\"11,1,1,0\" data-index-in-node=\"0\">Les propri\u00e9t\u00e9s des mat\u00e9riaux :<\/b> Cr\u00e9er des supraconducteurs (qui conduisent l&#8217;\u00e9lectricit\u00e9 sans aucune perte).<\/span><\/td>\n<\/tr>\n<tr>\n<td><span data-path-to-node=\"11,2,0,0\"><b data-path-to-node=\"11,2,0,0\" data-index-in-node=\"0\">La structure des \u00e9toiles :<\/b> Comment le Soleil produit sa lumi\u00e8re gr\u00e2ce \u00e0 la fusion nucl\u00e9aire.<\/span><\/td>\n<td><span data-path-to-node=\"11,2,1,0\"><b data-path-to-node=\"11,2,1,0\" data-index-in-node=\"0\">L&#8217;information et le chiffrement :<\/b> Concevoir des r\u00e9seaux de communication quantiques impossibles \u00e0 pirater.<\/span><\/td>\n<\/tr>\n<tr>\n<td><span data-path-to-node=\"11,3,0,0\"><b data-path-to-node=\"11,3,0,0\" data-index-in-node=\"0\">La couleur des objets :<\/b> Pourquoi certains \u00e9l\u00e9ments absorbent certaines longueurs d&#8217;onde lumineuses.<\/span><\/td>\n<td><span data-path-to-node=\"11,3,1,0\"><b data-path-to-node=\"11,3,1,0\" data-index-in-node=\"0\">La pr\u00e9cision des mesures :<\/b> Fabriquer des horloges atomiques d\u00e9rivant de moins d&#8217;une seconde en plusieurs milliards d&#8217;ann\u00e9es.<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3 data-path-to-node=\"13\">\u00c7a ressemble \u00e0 quoi dans la r\u00e9alit\u00e9 ?<\/h3>\n<p data-path-to-node=\"14\">La physique quantique elle-m\u00eame est une th\u00e9orie invisible \u00e0 nos yeux. Cependant, les machines qui l&#8217;exploitent ont un aspect tr\u00e8s concret :<\/p>\n<ul data-path-to-node=\"15\">\n<li>\n<p data-path-to-node=\"15,0,0\">Un <b data-path-to-node=\"15,0,0\" data-index-in-node=\"3\">ordinateur quantique<\/b> ressemble \u00e0 un grand chandelier en cuivre et en or (un cryostat) refroidi proche du z\u00e9ro absolu (-273 \u00b0C) pour figer les atomes.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"15,1,0\">Un <b data-path-to-node=\"15,1,0\" data-index-in-node=\"3\">laser quantique<\/b> est un petit composant \u00e9lectronique ou un tube de verre \u00e9mettant un faisceau lumineux d&#8217;une seule couleur ultra-pure.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"15,2,0\">\u00c0 l&#8217;\u00e9chelle atomique, un atome ne ressemble pas \u00e0 un petit syst\u00e8me solaire, mais plut\u00f4t \u00e0 un <b data-path-to-node=\"15,2,0\" data-index-in-node=\"93\">nuage de probabilit\u00e9s<\/b> (une zone floue o\u00f9 l&#8217;\u00e9lectron a de fortes chances de se trouver)<\/p>\n<div class=\"user-query-container\">\n<div id=\"user-query-content-1\" class=\"query-content ng-star-inserted\" data-hveid=\"0\" data-ved=\"0CAAQ3ucQahcKEwjYienLh-uWAxUAAAAAHQAAAAAQQg\">\n<div class=\"query-text gds-body-l\" dir=\"ltr\">\n<p class=\"query-text-line ng-star-inserted\">Comment fonctionne un qubit par rapport \u00e0 un bit classique dans un ordinateur quantique ?<\/p>\n<\/div>\n<\/div>\n<\/div>\n<div>\n<div class=\"response-container response-container-with-gpi ng-tns-c653086746-17 no-background response-container-has-multiple-responses\" data-hveid=\"1\">\n<div class=\"response-container-header ng-tns-c653086746-17 ng-star-inserted\">\n<div class=\"response-container-header-controls ng-tns-c653086746-17\"><\/div>\n<div class=\"response-container-header-status ng-tns-c653086746-17\">\n<div class=\"response-container-header-processing-state ng-tns-c653086746-17\"><\/div>\n<\/div>\n<\/div>\n<div class=\"presented-response-container ng-tns-c653086746-17\" data-hveid=\"2\">\n<div class=\"response-container-content ng-tns-c653086746-17\">\n<div class=\"response-content ng-tns-c653086746-17\">\n<div class=\"model-response-label-announcer\" aria-busy=\"false\" aria-live=\"polite\"><\/div>\n<div class=\"container\">\n<div id=\"model-response-message-contentr_04c6f705a0f5be93\" class=\"markdown markdown-main-panel md-content enable-luminous-fast-follows enable-updated-hr-color stronger\" dir=\"ltr\" aria-busy=\"false\" aria-live=\"polite\">\n<p data-path-to-node=\"0\">Un <b data-path-to-node=\"0\" data-index-in-node=\"3\">bit classique<\/b> est l&#8217;unit\u00e9 de base d&#8217;un ordinateur traditionnel. Il fonctionne comme un interrupteur : il est soit \u00e9teint (<b data-path-to-node=\"0\" data-index-in-node=\"125\">0<\/b>), soit allum\u00e9 (<b data-path-to-node=\"0\" data-index-in-node=\"142\">1<\/b>). Un <b data-path-to-node=\"0\" data-index-in-node=\"149\">qubit<\/b> (bit quantique) est l&#8217;\u00e9quivalent dans un ordinateur quantique, mais il repose sur les lois de la m\u00e9canique quantique.<\/p>\n<h3 data-path-to-node=\"2\">La diff\u00e9rence fondamentale : Interrupteur vs Sph\u00e8re<\/h3>\n<ul data-path-to-node=\"3\">\n<li>\n<p data-path-to-node=\"3,0,0\"><b data-path-to-node=\"3,0,0\" data-index-in-node=\"0\">Bit classique :<\/b> Imaginons une pi\u00e8ce de monnaie pos\u00e9e \u00e0 plat sur une table. Elle montre soit pile (0), soit face (1). Elle ne peut \u00eatre que dans l&#8217;un de ces deux \u00e9tats \u00e0 la fois.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"3,1,0\"><b data-path-to-node=\"3,1,0\" data-index-in-node=\"0\">Qubit :<\/b> Imaginons cette m\u00eame pi\u00e8ce en train de tourner rapidement sur elle-m\u00eame. Tant qu&#8217;elle tourne, elle est dans une <b data-path-to-node=\"3,1,0\" data-index-in-node=\"120\">superposition<\/b> de pile et de face simultan\u00e9ment.<\/p>\n<\/li>\n<\/ul>\n<div class=\"attachment-container search-images\">\n<div class=\"image-container spark-licensed-center hide-from-message-actions ng-star-inserted\" data-full-size-image-uri=\"https:\/\/encrypted-tbn0.gstatic.com\/licensed-image?q=tbn:ANd9GcQBTYBKR_Dw_zSkX7aEuU4TUuWYW_vKvJa6SGL1eD2YhW7QFy5Q3ZbGcjy4M2POlvcFfx5y8-C2g-s1NMA\">\n<div class=\"overlay-container hero-overlay-container ng-star-inserted\">\n<div class=\"hero-caption-row ng-star-inserted\">\n<div class=\"caption gds-extended-caption hero-caption ng-star-inserted\" aria-hidden=\"true\"><\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<p data-path-to-node=\"5\">En physique, cette possibilit\u00e9 s&#8217;exprime sous la forme d&#8217;une sph\u00e8re (la <i data-path-to-node=\"5\" data-index-in-node=\"72\">sph\u00e8re de Bloch<\/i>) :<\/p>\n<ul data-path-to-node=\"6\">\n<li>\n<p data-path-to-node=\"6,0,0\">Le p\u00f4le Nord repr\u00e9sente le <b data-path-to-node=\"6,0,0\" data-index-in-node=\"27\">0<\/b>.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"6,1,0\">Le p\u00f4le Sud repr\u00e9sente le <b data-path-to-node=\"6,1,0\" data-index-in-node=\"26\">1<\/b>.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"6,2,0\">Le qubit peut pointer vers <b data-path-to-node=\"6,2,0\" data-index-in-node=\"27\">n&#8217;importe quel endroit sur la surface de la sph\u00e8re<\/b>, combinant une proportion de 0 et de 1 en m\u00eame temps.<\/p>\n<\/li>\n<\/ul>\n<h3 data-path-to-node=\"8\">Pourquoi cela change tout pour les calculs ?<\/h3>\n<p data-path-to-node=\"9\">La puissance th\u00e9orique ne vient pas seulement d&#8217;un qubit isol\u00e9, mais de la fa\u00e7on dont plusieurs qubits fonctionnent ensemble gr\u00e2ce \u00e0 la superposition et \u00e0 l&#8217;intrication quantique.<\/p>\n<div class=\"horizontal-scroll-wrapper\">\n<div class=\"table-block-component\">\n<div class=\"table-block has-export-button new-table-style is-at-scroll-start is-at-scroll-end\">\n<div class=\"table-content md-content\" data-hveid=\"0\" data-ved=\"0CAAQ3ecQahcKEwjYienLh-uWAxUAAAAAHQAAAAAQTQ\">\n<table data-path-to-node=\"10\">\n<thead>\n<tr>\n<th><span data-path-to-node=\"10,0,0,0\">Nombre d&#8217;unit\u00e9s<\/span><\/th>\n<th><span data-path-to-node=\"10,0,1,0\">Ordinateur classique (Bits)<\/span><\/th>\n<th><span data-path-to-node=\"10,0,2,0\">Ordinateur quantique (Qubits)<\/span><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><span data-path-to-node=\"10,1,0,0\"><b data-path-to-node=\"10,1,0,0\" data-index-in-node=\"0\">2 unit\u00e9s<\/b><\/span><\/td>\n<td><span data-path-to-node=\"10,1,1,0\">Traite <b data-path-to-node=\"10,1,1,0\" data-index-in-node=\"7\">1<\/b> valeur parmi 4 (00, 01, 10 ou 11) \u00e0 un instant <span class=\"math-inline\" data-math=\"t\" data-index-in-node=\"56\"><span class=\"katex\"><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord mathnormal\">t<\/span><\/span><\/span><\/span><\/span>.<\/span><\/td>\n<td><span data-path-to-node=\"10,1,2,0\">Contient les <b data-path-to-node=\"10,1,2,0\" data-index-in-node=\"13\">4<\/b> valeurs simultan\u00e9ment (<span class=\"math-inline\" data-math=\"2^2\" data-index-in-node=\"38\"><span class=\"katex\"><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord\">2<span class=\"msupsub\"><span class=\"vlist-t\"><span class=\"vlist-r\"><span class=\"vlist\"><span class=\"\"><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\">2<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>).<\/span><\/td>\n<\/tr>\n<tr>\n<td><span data-path-to-node=\"10,2,0,0\"><b data-path-to-node=\"10,2,0,0\" data-index-in-node=\"0\">3 unit\u00e9s<\/b><\/span><\/td>\n<td><span data-path-to-node=\"10,2,1,0\">Traite <b data-path-to-node=\"10,2,1,0\" data-index-in-node=\"7\">1<\/b> valeur parmi 8 \u00e0 la fois.<\/span><\/td>\n<td><span data-path-to-node=\"10,2,2,0\">Contient <b data-path-to-node=\"10,2,2,0\" data-index-in-node=\"9\">8<\/b> valeurs simultan\u00e9ment (<span class=\"math-inline\" data-math=\"2^3\" data-index-in-node=\"34\"><span class=\"katex\"><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord\">2<span class=\"msupsub\"><span class=\"vlist-t\"><span class=\"vlist-r\"><span class=\"vlist\"><span class=\"\"><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mtight\">3<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span>).<\/span><\/td>\n<\/tr>\n<tr>\n<td><span data-path-to-node=\"10,3,0,0\"><b data-path-to-node=\"10,3,0,0\" data-index-in-node=\"0\">N unit\u00e9s<\/b><\/span><\/td>\n<td><span data-path-to-node=\"10,3,1,0\">\u00c9value les combinaisons <b data-path-to-node=\"10,3,1,0\" data-index-in-node=\"24\">les unes apr\u00e8s les autres<\/b>.<\/span><\/td>\n<td><span data-path-to-node=\"10,3,2,0\">\u00c9value <span class=\"math-inline\" data-math=\"2^N\" data-index-in-node=\"7\"><span class=\"katex\"><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord\">2<span class=\"msupsub\"><span class=\"vlist-t\"><span class=\"vlist-r\"><span class=\"vlist\"><span class=\"\"><span class=\"sizing reset-size6 size3 mtight\"><span class=\"mord mathnormal mtight\">N<\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span><\/span> combinaisons <b data-path-to-node=\"10,3,2,0\" data-index-in-node=\"24\">en m\u00eame temps<\/b>.<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div class=\"table-footer hide-on-print hide-from-message-actions\"><\/div>\n<\/div>\n<\/div>\n<\/div>\n<p data-path-to-node=\"11\">Pour <span class=\"math-inline\" data-math=\"N = 300\" data-index-in-node=\"5\"><span class=\"katex\"><span class=\"katex-html\" aria-hidden=\"true\"><span class=\"base\"><span class=\"mord mathnormal\">N<\/span><span class=\"mrel\">=<\/span><\/span><span class=\"base\"><span class=\"mord\">300<\/span><\/span><\/span><\/span><\/span> qubits, le nombre d&#8217;\u00e9tats superpos\u00e9s simultan\u00e9s d\u00e9passe le nombre total d&#8217;atomes pr\u00e9sents dans l&#8217;univers observable.<\/p>\n<h3 data-path-to-node=\"13\">La contrainte : La mesure d\u00e9truit l&#8217;\u00e9tat quantique<\/h3>\n<p data-path-to-node=\"14\">Un qubit conserve sa superposition tant qu&#8217;il reste isol\u00e9 de son environnement. D\u00e8s qu&#8217;un instrument effectue une <b data-path-to-node=\"14\" data-index-in-node=\"114\">mesure<\/b> pour lire le r\u00e9sultat :<\/p>\n<ol start=\"1\" data-path-to-node=\"15\">\n<li>\n<p data-path-to-node=\"15,0,0\">La superposition &#8220;s&#8217;effondre&#8221; instantan\u00e9ment.<\/p>\n<\/li>\n<li>\n<p data-path-to-node=\"15,1,0\">Le qubit redevient une valeur classique : soit un <b data-path-to-node=\"15,1,0\" data-index-in-node=\"50\">0<\/b>, soit un <b data-path-to-node=\"15,1,0\" data-index-in-node=\"61\">1<\/b> (avec une probabilit\u00e9 qui d\u00e9pendait de sa position sur la sph\u00e8re avant la mesure).<\/p>\n<\/li>\n<\/ol>\n<p data-path-to-node=\"16\">Les algorithmes quantiques sont donc con\u00e7us pour faire interf\u00e9rer les probabilit\u00e9s entre elles pendant le calcul afin que la r\u00e9ponse correcte soit celle qui \u00e9merge au moment de la lecture finale.<\/p>\n<p data-path-to-node=\"0\">La physique quantique repose sur <b data-path-to-node=\"0\" data-index-in-node=\"33\">cinq principes fondamentaux<\/b> qui d\u00e9crivent le comportement de l&#8217;\u00e9nergie et de la mati\u00e8re \u00e0 l&#8217;\u00e9chelle microscopique :<\/p>\n<h3 data-path-to-node=\"2\">1. La quantification des niveaux d&#8217;\u00e9nergie<\/h3>\n<p data-path-to-node=\"3\">Dans le monde classique, l&#8217;\u00e9nergie varie de fa\u00e7on continue (comme une rampe). Dans le monde quantique, l&#8217;\u00e9nergie est <b data-path-to-node=\"3\" data-index-in-node=\"117\">quantifi\u00e9e<\/b> : elle ne s&#8217;\u00e9change que par paquets indivisibles appel\u00e9s <b data-path-to-node=\"3\" data-index-in-node=\"185\">quanta<\/b> (comme les marches d&#8217;un escalier). Un \u00e9lectron ne peut pas se trouver entre deux niveaux d&#8217;\u00e9nergie d&#8217;un atome ; il saute instantan\u00e9ment d&#8217;un niveau \u00e0 l&#8217;autre en absorbant ou en \u00e9mettant un photon.<\/p>\n<h3 data-path-to-node=\"5\">2. La dualit\u00e9 onde-corpuscule<\/h3>\n<p data-path-to-node=\"6\">Toute particule microscopique (\u00e9lectron, photon, atome) poss\u00e8de simultan\u00e9ment des propri\u00e9t\u00e9s de <b data-path-to-node=\"6\" data-index-in-node=\"96\">particule<\/b> (mati\u00e8re localis\u00e9e) et d&#8217;<b data-path-to-node=\"6\" data-index-in-node=\"131\">onde<\/b> (vague r\u00e9partie dans l&#8217;espace).<\/p>\n<div class=\"attachment-container search-images\"><\/div>\n<p data-path-to-node=\"8\">Dans l&#8217;exp\u00e9rience des fentes de Young, m\u00eame si l&#8217;on envoie des \u00e9lectrons un par un, ils forment \u00e0 la fin une figure d&#8217;interf\u00e9rence sur l&#8217;\u00e9cran. Chaque particule passe par les deux fentes \u00e0 la fois sous forme d&#8217;onde avant d&#8217;impacter l&#8217;\u00e9cran sous forme de point.<\/p>\n<h3 data-path-to-node=\"10\">3. La fonction d&#8217;onde et le probabilisme<\/h3>\n<p data-path-to-node=\"11\">En physique classique, la position d&#8217;un objet est connue avec certitude. En physique quantique, une particule est d\u00e9crite par une <b data-path-to-node=\"11\" data-index-in-node=\"130\">fonction d&#8217;onde<\/b> (souvent not\u00e9e <span class=\"math-inline\" data-math=\"\\Psi\" data-index-in-node=\"161\">$\\Psi$<\/span>).<\/p>\n<p data-path-to-node=\"12\">Cette \u00e9quation math\u00e9matique ne donne pas la position exacte de la particule, mais la <b data-path-to-node=\"12\" data-index-in-node=\"85\">probabilit\u00e9 de la trouver \u00e0 un endroit donn\u00e9<\/b> lors d&#8217;une mesure. Avant la mesure, la particule est r\u00e9partie dans un \u00ab nuage de probabilit\u00e9s \u00bb.<\/p>\n<h3 data-path-to-node=\"14\">4. Le principe d&#8217;incertitude d&#8217;Heisenberg<\/h3>\n<p data-path-to-node=\"15\">\u00c9nonc\u00e9 par Werner Heisenberg, ce principe \u00e9tablit qu&#8217;il est physiquement impossible de conna\u00eetre simultan\u00e9ment avec une pr\u00e9cision infinie la <b data-path-to-node=\"15\" data-index-in-node=\"141\">position<\/b> (<span class=\"math-inline\" data-math=\"x\" data-index-in-node=\"151\">$x$<\/span>) et la <b data-path-to-node=\"15\" data-index-in-node=\"160\">quantit\u00e9 de mouvement<\/b> (<span class=\"math-inline\" data-math=\"p\" data-index-in-node=\"183\">$p$<\/span>) d&#8217;une particule :<\/p>\n<div data-path-to-node=\"16\">\n<div class=\"math-block\" data-math=\"\\Delta x \\cdot \\Delta p \\ge \\frac{\\hbar}{2}\">$$\\Delta x \\cdot \\Delta p \\ge \\frac{\\hbar}{2}$$<\/div>\n<\/div>\n<p data-path-to-node=\"17\">Plus on mesure pr\u00e9cis\u00e9ment o\u00f9 se trouve une particule, moins on peut savoir \u00e0 quelle vitesse et dans quelle direction elle se d\u00e9place, et inversement. Ce n&#8217;est pas un d\u00e9faut d&#8217;instrument de mesure, mais une propri\u00e9t\u00e9 intrins\u00e8que de la nature.<\/p>\n<h3 data-path-to-node=\"19\">5. L&#8217;effet tunnel<\/h3>\n<p data-path-to-node=\"20\">Puisqu&#8217;une particule est d\u00e9crite par une onde de probabilit\u00e9, cette onde peut traverser une barri\u00e8re d&#8217;\u00e9nergie th\u00e9oriquement franchissable uniquement avec une \u00e9nergie sup\u00e9rieure.<\/p>\n<p data-path-to-node=\"21\">M\u00eame si la particule n&#8217;a pas assez d&#8217;\u00e9nergie classique pour franchir l&#8217;obstacle, il existe une probabilit\u00e9 non nulle qu&#8217;elle apparaisse de l&#8217;autre c\u00f4t\u00e9. C&#8217;est cet effet tunnel qui permet au Soleil de r\u00e9aliser la fusion nucl\u00e9aire en son c\u0153ur.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>La physique quantique est la branche de la science qui d\u00e9crit le comportement de la&#8230;<\/p>\n","protected":false},"author":1,"featured_media":3093,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[5091,5092],"tags":[5129,5226,5190,5222,5223,5215,5225,5224,5227,5160,5146,5099,4640,5093,5191,2604,5214,5213,5212,5104,5165,5187,5098,5139,5157,4649,5158,5229,5221,5231,5134,5218,5169,5196,5166,5111,5164,5140,5199,5141,4654,5159,5119,5150,5200,5233,5135,5175,5217,5156,4659,5210,5122,5138,5137,5188,5185,5181,5228,5106,5105,5177,5126,5143,5133,5113,5109,5102,4661,5130,5144,5168,5167,5131,5151,5174,5097,5100,5123,5155,5154,5206,5208,5207,5209,5108,5145,252,5115,5118,5172,5197,5198,5096,5220,5192,5103,4677,5127,5095,5163,5142,5153,5203,5202,5147,5189,4682,2506,5116,5152,5219,5201,5120,5176,5184,5094,1365,5132,5101,5179,4686,5183,5182,5204,5149,4688,5180,5162,5170,5107,5114,5194,5193,5195,5148,5230,5178,5186,5110,5173,5171,5211,5121,1363,5216,5136,5232,5125,2958,5205,5112,5128,4703,5161,5117,5124,4705],"class_list":["post-3092","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-la-physique-quantique","category-physique-chimie","tag-acceleration","tag-acide-carboxylique","tag-acidite","tag-alcane","tag-alcene","tag-alchimie","tag-alcool","tag-alcynoide","tag-amine","tag-ampere","tag-amplitude","tag-anion","tag-astrophysique","tag-atome","tag-basicite","tag-biochimie","tag-bloc-d","tag-bloc-p","tag-bloc-s","tag-boson","tag-capacite","tag-catalyseur","tag-cation","tag-chaleur","tag-champ-electrique","tag-champ-magnetique","tag-charge-electrique","tag-chimie-inorganique","tag-chimie-organique","tag-chromatographie","tag-cinematique","tag-cinetique-chimique","tag-circuit","tag-concentration","tag-condensateur","tag-condensation","tag-conductance","tag-conduction","tag-constante-davogadro","tag-convection","tag-cosmologie","tag-courant-electrique","tag-densite","tag-diffraction","tag-dissolution","tag-distillation","tag-dynamique","tag-effet-tunnel","tag-electrochimie","tag-electromagnetisme","tag-electron","tag-electronegativite","tag-energie","tag-enthalpie","tag-entropie","tag-enzyme","tag-equation-chimique","tag-espace-temps","tag-ester","tag-etat-de-la-matiere","tag-fermion","tag-fonction-donde","tag-force","tag-frequence","tag-frottement","tag-fusion","tag-gaz","tag-gluon","tag-gravitation","tag-gravite","tag-hertz","tag-impedance","tag-induction","tag-inertie","tag-interference","tag-intrication","tag-ion","tag-isotope","tag-joule","tag-laser","tag-lentille","tag-liaison-covalente","tag-liaison-hydrogene","tag-liaison-ionique","tag-liaison-metallique","tag-liquide","tag-longueur-donde","tag-lumiere","tag-masse","tag-masse-volumique","tag-mecanique-quantique","tag-molarite","tag-mole","tag-molecule","tag-monomere","tag-neutre","tag-neutrino","tag-neutron","tag-newton","tag-noyau","tag-ohm","tag-onde","tag-optique","tag-oxydant","tag-oxydoreduction","tag-periode","tag-ph","tag-photon","tag-plasma","tag-poids","tag-polarisation","tag-polymere","tag-precipitation","tag-pression","tag-principe-dincertitude","tag-produit","tag-proton","tag-puissance","tag-quantite-de-mouvement","tag-quark","tag-qubit","tag-rayonnement","tag-reactif","tag-reaction-chimique","tag-reducteur","tag-reflexion","tag-refraction","tag-relativite","tag-resistance","tag-semi-conducteur","tag-solide","tag-solidification","tag-solute","tag-solution","tag-solvant","tag-spectre","tag-spectrometrie","tag-spin","tag-stoechiometrie","tag-sublimation","tag-superposition","tag-supraconductivite","tag-tableau-periodique","tag-temperature","tag-tension","tag-thermochimie","tag-thermodynamique","tag-titrage","tag-travail","tag-trou-noir","tag-valence","tag-vaporisation","tag-vitesse","tag-vitesse-de-la-lumiere","tag-volt","tag-volume","tag-watt","tag-zero-absolu"],"jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/www.laurensoff.com\/wordpress\/wp-content\/uploads\/2026\/09\/licensed-image-2-e1789285560561.jpg","_links":{"self":[{"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/posts\/3092","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/comments?post=3092"}],"version-history":[{"count":2,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/posts\/3092\/revisions"}],"predecessor-version":[{"id":3095,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/posts\/3092\/revisions\/3095"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/media\/3093"}],"wp:attachment":[{"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/media?parent=3092"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/categories?post=3092"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laurensoff.com\/wordpress\/wp-json\/wp\/v2\/tags?post=3092"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}