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  • Jeremy Zang
    • Sep 3
    • 3 min read

What is Antimatter?

Nearly everything in this world is considered matter. Gazillions of particles bond together to form what we perceive as tangible and visible; however, in this world, there is also something called antimatter.


As suggested by its name, antimatter is an equivalent “ordinary” matter but consists of an opposite charge. For example, an electron with a negative charge in antimatter possesses a positive charge, and a proton with a positive charge will have a negative charge. Holding such properties, antimatter has been seen to provide revolutionary abilities in both theory and practice, with countless possible further studies to be done.


Dirac Theory - the origin


Published in 1928, physicist Paul Dirac, through extending Erwin Schrodinger’s wave equation with principles of special relativity, produced a systematic equation that was the first evidence to propose a possible positively charged electron. The publication of Dirac’s theory has provided a solid foundation for future quantum and particle research. Only 3 years later, Dirac established the existence of oppositely charged particles. The particle was first considered as anti-electron, antiproton, etc., where until the sequencing year, physicist Carl D. Anderson formerly discovered and named positively charged electrons as “positrons”. As time passed, all possible matter was considered to have a type of antimatter, along with an entire periodic table.


Here is the Dirac Wave Equation.



  • 𝛾^𝜇 are the gamma matrices

  • ψ is the wave function

  • 𝑚 is the mass of the particle

  • ℏ is the reduced Planck constant

  • 𝑐 is the speed of light


Properties


All matter is nearly identical with its corresponding antimatter, with the only exception of having opposite CPT properties (Charge, Parity and Time reversal).

 

  • Charge is rather obvious, as all antimatter has the opposite charge of its matter. 

  • Parity is related to the physical properties of particles in spatial inversion, which essentially means the coordinates of the particles traverse around. In the case of antimatter, antiparticles behave symmetrically opposite of a matter. If the spatial coordinates of a matter is (X, Y, Z), then the antimatter will be (-X, -Y, -Z), essentially mirroring the matter by an origin.

  • Time reversal is the direction a particle is moving in chronological time, where when reversed, the particle also reverses its direction. Antimatter would hold opposite directions to matter when reversed time.


When matter is met with its antimatter, it will experience destruction and produce photons, gamma rays and, in some cases, neutrinos. To put it into context, when 1 kg of both antimatter and matter meet, their interaction will approximately release energies roughly equivalent to 43 megatons worth of TNT.



Uses


Due to its annihilative properties, antimatter is hard to sustain or be kept for long periods of time, which limits their use within theory. However, antimatter still has provided revolutionary improvements in modern society. 


Notably in the medical field, the invention of PET (Positron Emission Tomography) provides a patient with an extremely minimal amount of radioactive material to visualise and measure changes in metabolic processes. The PET Scanner is able to capture a possible positron produced photon, after the radioactive material decays. The captured photons reflect a photographic image of where the position is annihilated, which indicates where metabolism occurred. Given that cancer cells are more active than normal cells, specialists would be able to determine where possible cancer can be diagnosed.


Further to the vast amount of energy produced from antimatter collisions, antimatter is theorised as a possible energy source for the future, where it, if produced, could enable possibilities for interstellar travel. Unfortunately, current technology requires further advancements to reach such levels of mobility, but the possibilities are limitless.


Works Cited



collections.lib.utah.edu. (n.d.). Positron Emission Tomography (PET) Scan | NOVEL - Andrew Lee Collection. [online] Available at: https://collections.lib.utah.edu/ark:/87278/s6qg35v8 [Accessed 15 May 2024].


Sciolla, G. (2006). The Mystery of CP Violation. [online] Available at: https://physics.mit.edu/wp-content/uploads/2021/01/physicsatmit_06_sciollafeature.pdf.


Sutton, C. (2021). Antimatter | physics. [online] Encyclopedia Britannica. Available at: https://www.britannica.com/science/antimatter.


Wikipedia. (2024). Antimatter. [online] Available at: https://en.wikipedia.org/wiki/Antimatter#Definitions [Accessed 15 May 2024].


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