# Arquivo da categoria: Ciência

Meus pensamentos sobre ciências não-física — como biologia evolutiva, Neurociência Cognitiva etc.

# Interpretation of Special Relativity

When we looked at Quantum Mechanics, we talked about its various interpretations. The reason we have such interpretations, I said, is that QM deals with a reality that we have no access to, through our sensory and perceptual apparatuses. Por outro lado, 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 primeira vista, 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, como se mostra na figura abaixo, moving from right to left.

Quando ouvimos falar sobre Einstein ea relatividade especial (ou a teoria da relatividade especial, para usar o nome verdadeiro), pensamos no famoso $E = mc^2$ equação, e coisas estranhas, como o paradoxo dos gêmeos. Enquanto essas coisas são todas verdadeiras e importante, o problema SR tenta resolver é um completamente diferente. É uma tentativa de defender um princípio básico na física.
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# Quantum Mechanics – Interpretations

Whenever we talk about Quantum Mechanics, one of the first questions would be, “What about the cat?” This question, realmente, is about the interpretations of Quantum Mechanics. The standard interpretation, the so-called Copenhagen interpretation, leads to the famous Schrodinger’s cat.
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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

Nesta secção, 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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# Mecânica Quântica

Mecânica Quântica (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. E, 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. Realmente.

# 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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# reducionismo

Em todos os nossos esforços científicos, usamos técnicas de alto nível semelhantes a entender e estudar coisas. A técnica mais comum é reducionismo. Ele baseia-se na crença de que o comportamento, propriedades e estrutura de objetos grandes e complexas podem ser entendidas em termos de seus constituintes mais simples. Em outras palavras, tentamos entender o todo (o universo, por exemplo) em termos de menor, constituintes reduzidos (tais como partículas).

# Partículas e Interações

Recentemente, Eu dei uma palestra sobre partículas e interações para os colegas da minha filha que estavam planejando uma viagem a Desy, Alemanha e queria ter uma idéia do que tudo estava prestes. Como a minha primeira palestra deste tipo, Eu estava um pouco nervoso porque eu não sabia o nível, e de fundo, Eu deveria atrelar a conversa no. Eu não quero fazê-lo muito básico, que eu pensei que seria um desperdício de tempo. Nem eu quero fazê-lo demasiado técnico, que também tornaria inútil de uma maneira diferente.