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Nov 16
2009
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A combination of quantum mechanics and relativity allows us to examine subatomic processes in a new light. Symmetry is very important to physical theories. Thus, the existence of a type of `opposite' matter was hypothesized soon after the development of quantum physics. `Opposite' matter is called antimatter. Particles of antimatter has the same mass and characteristics of regular matter, but opposite in charge. When matter and antimatter come in contact they are both instantaneously converted into pure energy, in the form of  photons.
Antimatter is produced all the time by the collision of high energy photons, a process called pair production, where an electron and its antimatter twin (the positron) are created from energy (E=mc2). A typical spacetime diagram of pair production looks like the following:
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Positrons only survive for a short time since they are attracted to other electrons and disintegrate. Since quantum mechanics states that energy, time and space can be violated, another way of looking at pair production is to state that the positron does not exist, but rather it is an electron traveling backwards in time. Since it is going backwards in time, its charge would be reversed and its spacetime diagram would look like the following:
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In this interpretation, the collision of an electron and two photons causes the electron to go backward in time till it meets another pair of photons, then reverses itself again. The world of quantum physics allows for many such strange views of subatomic interactions. |
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