We don't know the answer, but I've been thinking about it a little bit because it's a question that I'm curious about as well.
So, here are my personal thoughts:
Let's start with the following equation:
A = A
Before the universe was birthed, the concept of A did not even exist. This A is an concept created by intellectual creature called humanity, 13.8 billion years after the creation of the universe. Also, mathematical terms, including =, are concepts created by humans born after the birth of the universe.
If we move A from the left side to the right side,
0 = A - A = 0
To make the idea clearer, let's express this a little differently.
0 = (+A) + (-A) = 0
This equation can be conceptually decomposed as "0", "0=(+A)+(-A)", "(+A)+(-A)=0", "0=0".
1)"0" : Something did not exist. Nothing state.
2)"0 = (+A) + (-A)" : +A and -A were born from "nothing". Or "Nothing" changed to +A and -A. Because +A and -A exist, it is a Something state.
3)"(+A) + (-A) = 0" : The sum of +A and -A is still zero. From one perspective it's "Something", from another perspective it's still “Nothing”.
4)"0 = 0" At the beginning and end of the process, the state of “Nothing” is maintained.
5) "B = 0 = (+A) + (-A) = 0" : The intelligent life form called humanity defines the "first nothing" as B. B may be total A, which is the sum of all A, or it may be a new notion.
In other words, “nothing” can create something +A and something -A and still remain “nothing” state. And, the newly created +A and -A create new physical quantities and new changes. For example, in order for the newly created +A and -A to be preserved in space, a new relational equation must be created.
∂ρ/∂t +
∇·j=0
Is there such a case in the nature or the universe? Yes!
1)
Let's look at how pair production (electron and positron) occurs from photon (light).
B = 0 = (+Q) + (-Q) = 0
The charge of a photon is zero. When photon do pair production (electron and positron), photon do not conserve charge by creating beings with zero charge, but by creating +Q and -Q to preserve zero. That is, in all cases, in all circumstances, in order to satisfy or maintain “nothing”, this equation of the form (+Q) + (-Q) = 0 must hold. This may be because "0" is not representative of all situations and is only a subset of (+Q) + (-Q) = 0.
At the beginning and end of the process, the total charge is conserved, but in the middle process +Q and -Q are created. Due to the electric charge generated at this time, new concepts including electromagnetic fields and electromagnetic forces are needed.
According to Emmy Noether's theorem, if a system has a certain symmetry, there is a corresponding conserved physical quantity. Therefore, symmetry and conservation laws are closely related.
Conservation of spin, conservation of particle number, conservation of energy, conservation of momentum, conservation of angular momentum, conservation of flux... etc.. New concepts may be born from conservation laws like these.
2)
Let’s look at the birth process of energy. (This is not a proven fact and is still a hypothesis. Edward Tryon, Alan Guth, Stephen Hawking, and others have advocated such a model.)
https://icarus2.quora.com/The-Birth...erse-from-Nothing-and-New-Inflation-Mechanism
E_T = 0 = (+E) + (-E) = Σmc^2 + Σ(-Gmm/r) = 0
“E_T = 0” represents “Nothing” state.
Mass appears in “Σ(+mc^2)” stage, which suggests the state of “Something”.
In other words, “Nothing” produces a negative energy of the same size as that of a positive mass energy and can produce “Something” while keeping the state of “Nothing” in the entire process (“E_T = 0” is kept both in the beginning of and in the end of the process).
*I don't think the total energy of the universe is currently 0. I just think there must have been a moment when the energy was zero when the universe started.
Another example is the case of gauge transformation for scalar potential Φ and vector potential A in electromagnetic fields.
Φ --> Φ - ∂Λ/∂t
A -->
A +
∇Λ
Maxwell equations of electromagnetism hold them in the same form for gauge transformation. After all, the existence of some symmetry or the invariance that the shape of a certain physical law must not change requires a gauge transformation, and this leads to the existence of new physical quantities (Λ, ∂Λ/∂t,
∇Λ) that did not exist in the beginning (Φ,
A).
This can be interpreted as requiring the birth of a new thing in order for the conserved physical quantity to be conserved and not change. The condition or state that should not change is what makes change.
Why was the universe born? Why is there something rather than nothing? Why did the change happen?
Everything in the world can be classified into the following two categories:
Those that have a "changing nature"
Those that have a "non-changing nature"
"Nothing” or “something” that has the property of changing create change.
However, as we've seen above, we can see that “Nothing” or “something” with unchanging property can also create change.
B = 0 = (+Q) + (-Q) = 0
E_T = 0 =(+E) + (-E) = Σmc^2 + Σ-Gmm/r = 0
∂ρ/∂t +
∇·j=0
Φ --> Φ - ∂Λ/∂t
A -->
A +
∇Λ
It changes, but does not change!
It changes in order not to change!
What does not change (B = 0) also creates changes in order not to change in various situations (Local, Global, phase transformation, translation, time translation, rotation transformation ...). This is because only the self (B) that does not want to change needs to be preserved.
The change of the universe seems to have created a change by the nature of not changing. The universe created Something (space-time, quantum fluctuation, energy, mass, charge, spin, force, field, potential, conservation laws, continuity equation...) to preserve Nothing. By the way, as this something was born, another something was born, and the birth of something chained like this may still preserve the first "nothing", and in some cases, the first "nothing" itself may also have changed.
Charge and energy are the basic physical quantities of matter or existence. If such a basic physical quantity can come out of a 0, we must think about the possibility that other things can also come out of a 0.
The Birth Mechanism of the Universe from Nothing and New Inflation Mechanism