Today, I wanted to expand on my previous antimatter post since I felt it was a bit short and also I attended a great lecture by Dr David Cassidy on this topic at UCL. To recap from the last post, antimatter was predicted in the 20th century through the equation E²=(mc²)²+(pc)², where, when the momentum (p) is 0, both sides were square rooted to get E=±√(mc²)². This gives us a positive and a negative value for energy and it is this negative energy that is said to be antimatter.
This was further developed in the lecture where we were told that that in quantum theory, energy or momentum is described using mathematical operators. So the classical physics equation for kinetic energy and the quantum mechanical way (the famous Schrodinger wave equation) were very different. These two separate equations were unified by Paul Dirac, another famous physics pioneer of 20th century. The solutions to Schrodinger's equation alone showed only one energy solution, which was positive but the unified equation formed by Dirac gave one positive energy solution and a negative energy solution. This was speculated to be a positron (the antimatter equivalent to the electron with a positive charge). What's more is that this equation showed that matter and antimatter have very exact symmetry in properties. They're basically like mirror images of each other. So one big mystery in the field of antimatter research is why the Big Bang produced much more matter than antimatter, if they are indeed so symmetrical.
To produce an electron, 511 keV is needed. This energy is given in the form of a gamma ray which hits a heavy nucleus. However, in order to produce a positron, since a pair is produced, 1022 keV is needed. This produces both an electron and a positron, which will then fly off in equally symmetrical trajectories away from the heavy nucleus.
An interesting feature in the study of antimatter is positronium. This is an unstable atomic system which involves a positron being bound to an electron, with a lifetime of 0.000000014 seconds. If you've read my previous post, then you'll know that after this lifetime, that the positron and electron annihilate and produce energy. However, in order to prevent this for happening for a while longer, a laser can be fired in between the two particles and this causes the positron and the electron to be locked in an orbital. If we can get Ps (positronium), to live for a long time, we could possibly find out more about this state.
Antimatter has many numerous uses in the future such as probing materials for tiny defects, watching chemicals mix together and looking into people's brains through the use of a PET scanner (positron emission tomography) so that we can detect cancers much more accurately and quickly. But, Antimatter can't be used at the moment. It must be made and we are not able to do so in large quantites at the moment. In fact, the CERN, the place where the most of it has been made, has made up to 10 nanograms of it in total, which according to E=mc² is approximately 900kJ. This is roughly 1000 times the density of normal matter energy. Another problem is storage, due to the fact that it cannot meet with normal matter, due to its annihilation.
This was further developed in the lecture where we were told that that in quantum theory, energy or momentum is described using mathematical operators. So the classical physics equation for kinetic energy and the quantum mechanical way (the famous Schrodinger wave equation) were very different. These two separate equations were unified by Paul Dirac, another famous physics pioneer of 20th century. The solutions to Schrodinger's equation alone showed only one energy solution, which was positive but the unified equation formed by Dirac gave one positive energy solution and a negative energy solution. This was speculated to be a positron (the antimatter equivalent to the electron with a positive charge). What's more is that this equation showed that matter and antimatter have very exact symmetry in properties. They're basically like mirror images of each other. So one big mystery in the field of antimatter research is why the Big Bang produced much more matter than antimatter, if they are indeed so symmetrical.
To produce an electron, 511 keV is needed. This energy is given in the form of a gamma ray which hits a heavy nucleus. However, in order to produce a positron, since a pair is produced, 1022 keV is needed. This produces both an electron and a positron, which will then fly off in equally symmetrical trajectories away from the heavy nucleus.
An interesting feature in the study of antimatter is positronium. This is an unstable atomic system which involves a positron being bound to an electron, with a lifetime of 0.000000014 seconds. If you've read my previous post, then you'll know that after this lifetime, that the positron and electron annihilate and produce energy. However, in order to prevent this for happening for a while longer, a laser can be fired in between the two particles and this causes the positron and the electron to be locked in an orbital. If we can get Ps (positronium), to live for a long time, we could possibly find out more about this state.
Antimatter has many numerous uses in the future such as probing materials for tiny defects, watching chemicals mix together and looking into people's brains through the use of a PET scanner (positron emission tomography) so that we can detect cancers much more accurately and quickly. But, Antimatter can't be used at the moment. It must be made and we are not able to do so in large quantites at the moment. In fact, the CERN, the place where the most of it has been made, has made up to 10 nanograms of it in total, which according to E=mc² is approximately 900kJ. This is roughly 1000 times the density of normal matter energy. Another problem is storage, due to the fact that it cannot meet with normal matter, due to its annihilation.
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