# Category Archives: Physics

Physics was my first love. This category contains the posts closest to my heart. Twenty years from now, if this blog survives, this category will probably hold my most enduring insights. And two hundred years from now, if I am remembered at all, it will be for these insights; not for the kind of person I am, the money I make, nor anything else. Only for my first and last love

# Recap of Modern Physics

Since the post series on Particles and Interactions became a bit longer than I wanted, I thought I would break it up. Let’s start with a recap of modern physics that will you will need to understand the structure of matter.

# 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. On the other hand, 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.

# Speed of Light

빛의 속도가 일정하다는 것은 단순한 진술처럼 들립니다.,,en,그러나 그것에 더 많은 것이 있습니다,,en,꽤 많이,,en,이 불변성이 실제로 무엇을 의미하는지 살펴 보겠습니다.,,en,어딘가에 서 있다면,,en,그리고 오른쪽에서 왼쪽으로가는 광선이 있습니다.,,en,속도가있다,,en,씨,,en,그리고 왼쪽에서 오른쪽으로가는 또 다른 광선도 속도가 있습니다.,,en,지금까지,,en,너무 좋아,,en,이제 당신이 로켓 선에 있다고 가정 해 봅시다.,,en,오른쪽에서 왼쪽으로 이동,,en,특수 상대성 이론,,en,아인슈타인과 특수 상대성 이론을들을 때,,en,또는 특수 상대성 이론,,en,실명 사용,,en,우리는 유명한 것을 생각한다,,en,E = mc ^ 2,,en,방정식,,en,그리고 쌍둥이 역설 같은 이상한 것들,,en,그 모든 것이 사실이고 중요하지만,,en,SR이 해결하려는 문제는 완전히 다른 문제입니다.,,en. But there is more to it, quite a bit more. Let’s look at what this constancy really means. At first glance, 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, as shown in the figure below, moving from right to left.

# Special Theory of Relativity

When we hear about Einstein and the special relativity (or the special theory of relativity, to use the real name), we think of the famous $E = mc^2$ equation, and weird things like the twin paradox. While those things are all true and important, the problem SR tries to solve is a completely different one. 물리학의 기본 원리를 지키려는 시도,,en,주제 아카이브,,en.

# Quantum Mechanics – Interpretations

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

# 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.

# 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.