Loop Quantum Gravity
Why Physics Stack Exchange recommends it
Physics Stack Exchange users link it as a short, accessible reference when discussing whether space is quantized or made of discrete units in loop quantum gravity.
Recommended by 0 people across 0 different months, 2020 to 2022.
What it is
A 9-minute Fermilab explainer in which Dr. Don Lincoln introduces loop quantum gravity as one of the few promising routes to a theory of quantum gravity. It covers quantized space, spin networks, and how mass and energy distort the shape of space's tiny volumes to recover general relativity.
What people said
Cites PG1995 · 2020-08 · Physics Stack Exchange · on “Volume of fundamental unit of discrete space and expansion of space”
In this [this video] video, the following is said between 06:07 to 06:38: Now one of the interesting questions is how do you get from the quantum of space and time to Einstein’s theory of general relativity? It’s because when you add mass and energy, you can distort the shape of the little volumes. Now that seems like it wouldn’t make sense because I said that there were quanta of lengths, areas, and volumes, but you need to remember that you are bending space and time and that has the property that you can distort the local definition of space in such a way that the volumes are unchanged . So these ideas of quantum spacetime are all good and all, but are they real? Suppose that space is made up
Cites foolishmuse · 2021-09 · Physics Stack Exchange · on “Can we think of space as any kind of aether in any way?”
It sounds to me that you are asking about the theory of Loop Quantum Gravity [LINK] . This is the theory that space itself is particulate, made up of extremely small particles or loops. This theory is based on relativity, but it does not imply an aether. Rather, space is described as the stage on which other things occur, like the waves that you are describing. I'll note that LQG is considered as an alternative to string theory. Physicist Carlo Rovelli, (in his book Covariant Loop Quantum Gravity) described them shaped as tetrahedra (a 3 dimensional triangle), noted, “The physics of quantum gravity is the physics of the quantum fields that build up spacetime… A region of space can be describ
Cites mmesser314 · 2021-12 · Physics Stack Exchange · on “Is space build of smaller space-particles?”
Let me answer this in parts. It is too much of a leap to say matter is stretchy and bendable. Matter is made of atoms. Space is stretchy and bendable. Space must be made of atoms too. There could be other ways of being stretchy and bendable. Space can curve, but it is a different thing from the stretchiness of matter. We don't know what space is like on the tiniest scales. We can't say if space has a granular structure or not. Part of the reason that matter is stretchy comes from it being made of atoms. The atoms are connected together with atomic bonds, and the bonds are stretchy and bendable to a degree. But that isn't the only way to imagine the cause of an object being stretchable. Peopl
Cites foolishmuse · 2022-06 · Physics Stack Exchange · on “Is the space-part of a four-vector temporally connected to the time-part and vice-versa?”
I offer up a different view that does tie space and time together as you are thinking, based on Loop Quantum Gravity. LQG is an alternative theory of space (alternative to string theory) that is currently being championed by Physicist Carlo Rovelli [LINK] and others myself included with this speculative theory [LINK] . In LQG, space is quantum (or as I like to call it "particulate"), with each particle being extremely small, on the order of 10^-35 metres. Dr. Don Lincoln from Fermilab made the statement When you add mass and energy, you can distort the shape of the little volumes of quantum space... [this video] And Arvin Ash noted When mass and energy are added to the spin foam the shape of the