ALL ABOUT PARTICLE PHYSICS

the life of a physics and mathematics student, learning about the secrets of the cosmos

Hi there!


I am Rosa Posch, a physics and mathematics student at TU Graz with a strong interest in particle physics and mathematical physics. My goal is to one day work in one of these fields and contribute to a deeper understanding of how everything works.

This blog is where I share my projects, ideas and thoughts along the way. It is a space for learning, reflecting, and connecting with others who are curious about science and its many possibilities.

Whether you're a fellow student, researcher, or just interested in physics, I hope you find something here that resonates.

I tend to experience childlike excitement whenever I do physics or math and it is my deepest wish to spread this feeling around the world. I also long to lead by example that

"making mistakes is just a important component of the creative process and we have to teach younger people how to accept that." -Hugo Dominil Copin

So, if you find any wrong arguments in my work or have ideas how to improve certain components of it, I would be happy if you contacted me. If that might not be the case and you just want to talk about science, feel free to do that too!

What is the vacuum made of?

A way to define the vacuum is achived by looking at it like Dirac did. He introduced the "Dirac sea", which explains the phenomenon of antimatter. In this model, all the negative-energy states of electrons are considered to be filled in a "sea" — and when one of these states is empty (a "hole"), it behaves like a particle with positive charge: a positron (the electron's antiparticle). It's an early idea from quantum field theory — not used in modern QFT calculations anymore, but still a very cool and historically important concept.

So, according to the idea of the Dirac sea, the vacuum isn't truly empty — it's filled with negative-energy states occupied by electrons. If enough energy is pumped into the vacuum, especially beyond a certain critical field strength known as the Schwinger limit, something interesting happens: The energy is high enough to "pull" an electron out of this sea, leaving behind a hole — which we observe as a positron. This is how electron-positron pairs can be created from the vacuum.

If you continue to increase the energy density beyond that, eventually it becomes possible to create even heavier particle-antiparticle pairs — like myons, tau particles, or even hadrons — depending on how much energy you inject. In this view, the vacuum behaves like a medium full of potential particles, and extreme energy can lift them out, making them real, observable particles.

I talked about this and other phenomenons at the 38C3 in Hamburg. If you want to know more about it, you can watch the video below:

When I held this talk in Hamburg, I was only beginning to grasp the beauty of this theory. Since then I've been working on lecture notes that also explain the mathematical concepts behind those ideas. I'll upload the notes as soon as I'm done. Stay tuned!

Contact me

  • rosa@particlephysics.eu