Think of the universe as a painting. There’s the image made in paint, and the surface it was painted on. The canvas.
The stars, the planets, the gasses, the matter and energy and even the space between are the paint. What’s the canvas? Is there a canvas? Would the canvas follow the same rules as the paint?
How do quantum physics play with spacetime?
I’m probably not asking the right question for what I mean… For context into my own thoughts process here, I originally thought of the question when reading a science post on quantum physics vs general relativity and how they don’t mesh and wondered “could we be seeing the medium simply behaving differently than the art?”
My understanding is that quantum physics is the study of the incredibly small, and general and special relativity are the study of everything else. They don’t overlap (rules for big don’t work for small, and vice versa) and are two separate understandings. Which is why the, hopefully, next big thing will be a unifying theory that applies to everything. I believe Stephen Hawking was a well known scientist working on finding a universal theory.
Which doesn’t really answer your question, but it’s a question far surpassing my knowledge. I think quantum mechanics just doesn’t interact with spacetime, or at least not in a meaningful way (mass of an electron is so incredibly small it isn’t perceptively effected by spacetime curves).
I would be happy for someone with more knowledge to come and prove me wrong though, these are fascinating fields.
Special relativity definitely overlaps with quantum mechanics and that overlap forms the basis of the math used at collider experiments like those at the LHC. Special relativity is simple with 2 rules that let you derive all the equations: 1) no universal reference frames 2) speed of light is constant.
You’re probably thinking about general relativity which defines gravity through the curvature of space time.
If you think about quantum mechanics existing on some “canvas”, that might look like an interlocking mesh of springs (like something under a bed or cot). You could take your hand and bounces it up and down on this mesh, adding oscillations and creating standing waves in the grid. These oscillations would be different particles (electrons, protons) each with their own characteristic frequency of oscillations. If you add energy to the bed of springs, you can “pop” particles into existence. All these particles actually are are just excitations of the mesh/canvas. As of yet, there’s been no way to define or find the gravity particle on this canvas, so right now the canvas of space time and the canvas of quantum mechanics are two distinct “things”.
Well, I am pleasantly proven wrong, thanks! Yes, I was thinking of general relativity, you are correct.
Are you saying that the particles are oscillating in reaction to your hand bouncing the mesh, like a handful of marbles on a bed bouncing around? What constitutes a “hand push” in the real world? A high energy collision like at the LHC? Or day to day interactions between objects?
This is very fascinating, although I can’t help but see a similarity between the two canvases. Is that just because they are both so complex that we need simple analogies to try and wrap our heads around the concepts?
No, the analogy is more that the oscillations are themselves the particles.
The addition of energy into a system would be this hand push. The fact that the particles themselves exist means that they are oscillations in this mesh (with some energy/frequency). Interactions with other particles can add or remove energy.
Definitely these canvas metaphor are just conveniences. Also, I got it from Zee’s “Quantum Field Theory in a Nutshell” which is a standard graduate or advanced undergrad level book on QFT.
That is the key to almost everything. Quantum mechanics is neat and tidy. Space time is neat and tidy. They don’t play well with each other, though. Some scientists say that we need to figure out dark matter and dark energy to make them play together. Others say they are so incompatible that we need new science altogether to figure it out.