## Introduction: THE GRAND-UNIFICATION

Hi universe

(*all images are created by me)

My self Garvit chouhan a 10th standard part-time thinker

It just not an instructable rather it's a advance approach of physics

It's TheGrand-Unification or The theory of everything #string theory

I will try my best to explain the secret of universe in the simplest language without too much math but it s not possible to understand the universe without pure math. It's a irony you are thinking me to

Now let begin's the quest of finding The Grand-Unification or T.G.U

## Step 1: THE CURRENT PICTURE OF UNIVERSE

First of all what is physics , it's all started when Newton formulated the equation of motions and gravitation

Over the past few centuries, two theoretical frameworks have been developed that, as a whole, most closely resemble a TGU(The Grand-Unification). These two theories upon which all modern physics rests are general relativity (GR) and quantum field theory (QFT). GR is a theoretical framework that only focuses on gravity for understanding the universe in regions of both large-scale and high-mass: stars, galaxies, clusters of galaxies, etc. On the other hand, QFT is a theoretical framework that only focuses on three non-gravitational forces for understanding the universe in regions of both small scale and low mass: sub-atomic particles, atoms, molecules, etc.

So, why do we need a single theory or TGU ( The Grand-Unification) it's basically because

We are having 4 fundamental forces

◆gravitational forces

◆electromegnatism

◆strong nuclear forces

◆weak nuclear forces

Except gravitation all remaining forces are governed by the laws of quantum mechanics and gravitation is explained by general theory of relativity . This theories works perfectly on their own domains without interrupting rivals domain . But there are certain parts of space which need both General relativity and quantum field theory to explain ; For example, the sigularity of a black hole requires both General Relativity for the black hole's massive gravitational field and Quantum Mechanics for the infinitesimal space in which it occupies. When these two theories are brought together, they go haywire and yield non-sense answers such as infinity. The theories break down, as you correctly pointed out.

## Step 2: General Theory of Relativity

From our elementary class we are visualizing gravitation as Newtonian force given by the inverse square law

Given by F=G*m1*m2/r2

Where F= force of attraction , G= gravitational constant, m(1,2)= masses of objects , r= distance between objects

But in my 9th standard a disturbing elements comes out in my mind during my physics lecture that did Newton could explain how gravitational attraction is created. As sudden as question arise in my mind I was flashed in front of my physics teacher(one of the best in our school), this instance was humours

I asked why do we study Newtonian physics? & I got an confusing answer = """WHAT""

That was a big blunder in my mind but now i could answer that blunder , Newton only know quantitative approach of gravity not derivative.

So a young physicist of her time sir Albert Einstein developed General theory of relativity

'General theory says that gravitation is not an actual force but an effect of spacetime curvature'

Do you notice I didn't give space between space and time in above sentence

That's not a mistake that's reality at cosmological level space and time are not two different aspects but they are united and form 4 dimensional space time geometry, it's 4d we can't illustrate it so we assume spacetime as 2d for the beneficial understanding of concepts in 2d it seems like fabric . And if any massive object is projected in space it curve the space like a rubber sheet. And that curvature' causes gravitation. How? let's watch a video

https://youtu.be/MTY1Kje0yLg

## Step 3: EINSTEIN FIELD EQUATIONS

The Einstein field equations (EFE; also known asEinstein's equations) is the set of 10 equations in Albert Einstein's general theory of relativity that describes the fundamental interaction of gravitation as a result of spacetime being curved by mass and energy.

But as I have to explain this incredible 10 equation in simplest form I can

I abbreviated and summarized into a single equation( given above in the picture)

where Rμν is the Ricci curvature tensor, R is thescalar curvature, gμν is the metric tensor, Λ is thecosmological constant, G is Newton's gravitational constant, c is the speed of light in vacuum, and Tμν is the stress–energy tensor.

The EFE is a tensor equation relating a set ofsymmetric 4 × 4 tensors. Each tensor has 10 independent components

Hence Rμν is a tensor about curvature of spacetime and Tμν is tensor about energy or mass (what is tensor we will go in couple of minutes)

Thereby in accordance to equation it comes out that the curvature or magnitude of gravitation (in Newtonian physics) depends upon the energy and mass of object ( as mass and energy are same by E=MC^2)

And adding to this we can say gravitation both as force or effect of curvature it's like dual nature of light.

## Step 4: TENSOR???

https://youtu.be/f5liqUk0ZTw

The best way to understand tensor is by geometry first watch the video and then read the abstract

In mathematics, tensors are geometric objects that describe linear relations between geometric vectors,scalars, and other tensors. Elementary examples of such relations include the dot product, the cross product, and linear maps. Geometric vectors, often used in physics and engineering applications, and scalars themselves are also tensors

## Step 5: ELECTROMEGNATISM

From earlie physics electricity and magnetism were to far concept

This view changed, however, with the publication of James Clerk Maxwell's 1873 A Treatise on Electricity and Magnetism in which the interactions of positive and negative charges were shown to be mediated by one force. There are four main effects resulting from these interactions, all of which have been clearly demonstrated by experiments:

Electric charges attract or repel one another with a force inversely proportional to the square of the distance between them: unlike charges attract, like ones repel.Magnetic poles (or states of polarization at individual points) attract or repel one another in a manner similar to positive and negative charges and always exist as pairs: every north pole is yoked to a south pole.An electric current inside a wire creates a corresponding circumferential magnetic field outside the wire. Its direction (clockwise or counter-clockwise) depends on the direction of the current in the wire.A current is induced in a loop of wire when it is moved toward or away from a magnetic field, or a magnet is moved towards or away from it; the direction of current depends on that of the movement.

Till there E.M forces where united but how ? This reasoning was possible because of special relativity of Einstein

Not going to mathematically I will explain a law of relativity ie:; "Moving bodies shrink"

Now explaining first watch the picture above now we start; if an electric current is flowing in a wire electrons are moving and protons are stable and if we bring a positive particle parallel to the flow of electrons till there the charge has no affect but when we start moving the charge , we will see a repulsive force from the wire to which we called magnetism but it's with our reference frame thus with the respect frame of that moving charge we will see that charge will feel he and electrons are stationary( it's like two car moving with same velocities) and protons appear moving as accordance of relativity moving bodies shrink protons appears coming closer this create higher density of proton in wire and creating net positive charge hence opposite charges repel that positive particle appears repelling. Ultimately electricity and magnetism are different side's of same coin , with only difference of frame of reference.

## Step 6: STRONG AND WEAK NUCLEAR FORCES

The weak interaction or weak nuclear force is responsible for some nuclear phenomena such asbeta decay. Electromagnetism and the weak force are now understood to be two aspects of a unifiedelectroweak interaction — this discovery was the first step toward the unified theory known as the Standard Model.

The strong interaction, or strong nuclear force, is the most complicated interaction, mainly because of the way it varies with distance. At distances greater than 10 femtometers, the strong force is practically unobservable. Moreover, it holds only inside theatomic nucleus.

After the nucleus was discovered in 1908, it was clear that a new force, today known as the nuclear force, was needed to overcome the electrostaticrepulsion, a manifestation of electromagnetism, of the positively charged protons. Otherwise, the nucleus could not exist. Moreover, the force had to be strong enough to squeeze the protons into a volume that is about 10−15 m, much smaller than that of the entire atom.

## Step 7: MOVING TOWARDS UNIFICATION

As till this topic we have explore to much about fundamental interaction as you might have noticed

The fundamental forces are arising from two concepts only General relativity(GR) and Quantum mechanics(QM), more presisly space-time and atom or sub atomic particle

So the final quest is to unifying GR & QM or space-time and sub -atomic particle

Now let's go to atomic lvl to unifying things

Firstly I reached the atom then electrons- protons-neutrons and then ???

Conventionally In particle physics smallest particle where quark's , anti quark's

When I reached there I found particle physics was broken into chains

Million of vibrating energy strrangs have replaced quark's?? Still confused if not you are not thinking

We will explore this strings in upcoming steps.

## Step 8: STRING THEORY

In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings. It describes how these strings propagate through space and interact with each other.

But why this strings are too interesting¿(accordance of official STRING THEORY site)

Relativistic quantum field theory has worked very well to describe the observed behaviors and properties of elementary particles. But the theory itself only works well when gravity is so weak that it can be neglected. Particle theory only works when we pretend gravity doesn't exist.

General relativity has yielded a wealth of insight into the Universe, the orbits of planets, the evolution of stars and galaxies, the Big Bang and recently observed black holes and gravitational lenses. However, the theory itself only works when we pretend that the Universe is purely classical and that quantum mechanics is not needed in our description of Nature. String theory is believed to close this gap. Originally, string theory was proposed as an explanation for the observed relationship between mass and spin for certain particles called hadrons, which include the proton and neutron. Things didn't work out, though, and Quantum Chromodynamicseventually proved a better theory for hadrons. But particles in string theory arise as excitations of the string, and included in the excitations of a string in string theory is a particle with zero mass and two units of spin. If there were a good quantum theory of gravity, then the particle that would carry the gravitational force would have zero mass and two units of spin. This has been known by theoretical physicists for a long time. This theorized particle is called the graviton. This led early string theorists to propose that string theory be applied not as a theory of hadronic particles, but as a theory ofquantum gravity, the unfulfilled fantasy of theoretical physics in the particle and gravity communities for decades. But it wasn't enough that there be a graviton predicted by string theory. One can add a graviton to quantum field theory by hand, but the calculations that are supposed to describe Nature become useless. This is because, as illustrated in the diagram above, particle interactions occur at a single point of spacetime, at zero distance between the interacting particles. For gravitons, the mathematics behaves so badly at zero distance that the answers just don't make sense. In string theory, the strings collide over a small but finite distance, and the answers do make sense.

This doesn't mean that string theory is not without its deficiencies. But the zero distance behavior is such that we can combine quantum mechanics and gravity, and we can talk sensibly about a string excitation that carries the gravitational force. This was a very great hurdle that was overcome for late 20th century physics, which is why so many young people are willing to learn the grueling complex and abstract mathematics that is necessary to study a quantum theory of interacting strings.

## Step 9: EXTRA DIMENSIONS OF STRING THEORY

string theory is all about strings and dimensions

For visualizing extra dimensions just imagine a cable wire you from far distance will observe wire as 1 dimensions but when we go to that wire at very small size ie:; of an ant. The wire appears 3d from where does these extra 2dimensions come?

From no where they already exists there but we can't see them.

We observe universe as 3 dimensional but when strings come in role we can se universe is 10 dimensional and 1 dimension of time

Strings are also alike that wires .

This extra dimensions give us opportunity to form space time fabric in different dimensions#next topic

I prefer to watch the video given in this step

https://youtu.be/0t4aKJuKP0Q

## Step 10: THE GRAND-UNIFICATION

As gravitation is caused by curvature of spacetime in 4 dimensions , my hypothetical theory propose that

"""The spacetime curvature in higher dimensions causes different forces of nature" ~Garvit chouhan

If this comes out true , the number of fundamental forces might be increased as we are have 10 dimensions in string theory it might possible we have 10 fundamental forces 6 new forces could govern the laws of black hole , worm hole ,singularity or the force acting between multi- universes (bubbles in string theory)

How could forgot the most powerful dimension "TIME"

Bending of time as dimension may yields fruitfull results such as force led to big bang or before the universe started how does time exist

Strings are of two types open and close

It might be possible that a particle form with open string having no mass and spin 2 formally known as graviton (graviton in my hypothetical theory) is omnipresent in universe in matrix 11 dimensional grids and that have influence on closed strings and the matrix is expanding which is expanding matter in universe or the bubble of universe is might made up of open strings which is expanding , and when two bubbles of universe collides the open strings might realise enormous energy and causes big bang like events.

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