Archives de la catégorie: Physique

Physique a été mon premier amour. Cette catégorie contient les messages les plus proches de mon coeur. Vingt ans à partir de maintenant, si ce blog survit, cette catégorie sera probablement tenir mes idées les plus durables. Et deux cents ans, si je me souvenais de tout, ce sera pour ces idées; pas le genre de personne que je suis, l'argent que je gagne, ni rien d'autre. Only for my first and last love…

Interpretation of Special Relativity

When we looked at Quantum Mechanics, we talked about its various interpretations. The reason we have such interpretations, Je l'ai dit, is that QM deals with a reality that we have no access to, through our sensory and perceptual apparatuses. D'autre part, Special Relativity is about macro objects in motion, and we have no problem imagining such things. So why would we need to have an interpretation? The answer is a subtle one.
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Speed of Light

The speed of light being a constant sounds like a simple statement. But there is more to it, quite a bit more. Let’s look at what this constancy really means. À première vue, it says that if you are standing somewhere, and there is a ray of light going from your right to left, it has a speed c. And another ray of light going from left to right also has a speed c. So far, so good. Now let’s say you are in a rocket ship, comme représenté sur la figure ci-dessous, moving from right to left.

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Théorie de la relativité restreinte

Quand nous entendons parler d'Einstein et de la relativité restreinte (ou la théorie de la relativité, d'utiliser le nom réel), nous pensons à la célèbre E = mc^2 équation, et des choses bizarres comme le paradoxe des jumeaux. Bien que ces choses sont vraies et importantes, le problème SR tente de résoudre est un complètement différent. Il est une tentative de défendre un principe de base en physique.
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Quantum Field Theory

In this post on Quantum Mechanics (QM), we will go a bit beyond it and touch upon Quantum Field Theory – the way it is used in particle physics. In the last couple of posts, I outlined a philosophical introduction to QM, as well as its historical origin – how it came about as an ad-hoc explanation of the blackbody radiation, and a brilliant description of the photoelectric effect.
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Historical Origin of Quantum Mechanics

In this section, we will try to look at the historical origin of Quantum Mechanics, which is usually presented succinctly using scary looking mathematical formulas. The role of mathematics in physics, as Richard Feynman explains (in his lectures on QED given in Auckland, New Zealand in 1979, available on YouTube, but as poor quality recordings) is purely utilitarian.
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Mécanique quantique

Mécanique quantique (QM) is the physics of small things. How do they behave and how do they interact with each other? Conspicuously absent from this framework of QM is why. Why small things do what they do is a question QM leaves alone. Et, if you are to make any headway into this subject, your best bet is to curb your urge to ask why. Nature is what she is. Our job is to understand the rules by which she plays the game of reality, and do our best to make use of those rules to our advantage in experiments and technologies. Ours is not to reason why. Vraiment.

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Classical Physics

The main difficulty in describing particle physics to general public is the fact that it is built on modern physics. Even if you are physics aficionado and did extremely well in your high school physics, what you have learned and loved is classical physics. The difference between classical physics and modern physics is not just more physics, but a completely new way of looking at the reality around us.
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réductionnisme

Dans tous nos efforts scientifiques, nous utilisons des techniques de haut niveau similaires pour comprendre et étudier les choses. La technique la plus courante est le réductionnisme. Il est basé sur la conviction que le comportement, propriétés et la structure des grandes et complexes objets peuvent être compris en termes de leurs constituants plus simples. En d'autres termes, nous essayons de comprendre l'ensemble (l'univers, par exemple) en termes de plus petite, constituants réduits (telles que des particules).

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