time reversal

the stories of four physicists separated by the whims of fate

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always writing

October 13th, 2008 by ben

Thankfully I do not have to rush to get things done before I go off to the South Pole, but unfortunately it still seems like I am scrambling to finish all these fellowships. In fact, all I did this weekend was to write essays…and now during my time off I am writing a blog post. I guess I just wanted to let all my friends and family know that I am still alive.

I’ve managed to stay away from caffeine at home, but I now drink a lot of tea (decaffeinated), this is mostly due to my house’s drafty nature that makes the cold nights even colder. I never mentioned this about my house, but if the landlord is to be believed I am living in a house built for Ezra Cornell’s children. That’s kinda cool right?

To get back to this being a blog about our lives as physicists I wanted to mention a kind of epiphany I had the other day, it seems for the longest time that my misconceptions about gravity were in fact not misconceptions at all, a fact I would have never have realized if it weren’t for the recent talk I went to given by Raman Sundrum. As is always the case when explaining something like this I shall begin at the beginning, listing the facts and explaining how one would use those facts to get at a more meaningful deeper description of the world.

  1. Light always travels at c in vacuum regardless of the reference frame you are in.
  2. Gravity effects the course the light would take.
  3. Light takes the path of minimum time. (a simplification but ok for this argument)

In the General Relativity we learn to talk about distances being defined with respect to a metric. The metric is a tool that allows us to compute how changes in a direction a particle makes effects its total measureable distance. That might sound incredibly obtuse, but let me try to give you an example first. Say you wanted to walk from New York to Boston. While you might be use to calculating the distance you need to travel on a flat map, what if I gave you a globe instead. The method you would use to take measurements on the globe would be totally different than the method you would use to take measurements on your flat map.

In Relativity we take this analogy to heart and talk about the curvature of space. In our calculations what gives our normal flat space a curve is usually something we call mass. Mass, we say, curves the space around it and changes the normal trajectories of any objects that are moving nearby, including light! While this picture is intuitive enough when you have nice computers to make 3D diagrams for you, it was not what I originally pictured when I considered the possibility that mass effects the space around it. In fact, for years I believed that what was actually going on was that mass changed the density of space.  In my mind light bent around planets and blackholes because the path it ended up taking was the one that allowed it to go through the space with the lowest density, and therefore arrive at its destination quickest.

So brace yourself everybody but here comes the QFT, and really what Prof. Sundrum said, which makes me think I was correct all along.

Imagine that there was a field of small particles that was everywhere in our universe. Whenever you try and move through this field imagine that your motion is coupled with bouncing back and forth off of these particles. In electromagnetism we talk about the coupling as the charge you have. Here we will call it the imag-o-charge.  A body with very little imag-o-charge will be able to move through this field mostly freely and will move through it with some average speed. A body with a lot of imag-o-charge will get tosseled back and forth but will eventually get where its going, but this time at a much slower speed as it kept bouncing off the particles everywhere. Well to pull a fast one on all you, I’m going to rename imag-o-charge mass and call the all permeating field the Higgs field.

So it seems boys and girls there might be hope for particle physics yet, at least one of their ideas seems pretty intuitive…we’ll just have to wait for a year or two to find out if they are correct.

lights go off

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