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Questions tagged [unified-theories]

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3answers
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Unification of gravity and electromagnetism

Have there been any attempts at unifying gravity and electromagnetism at least at classical level since Hermann Weyl's idea of gauge principle (1918)? We now have Standard Model which is very ...
2
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1answer
197 views

How does physics research work? [closed]

I am going to try and be as short and as concise as possible. I was thinking these last few days about how we're still trying to discover a unified Theory of Everything. The question is: how is this ...
0
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1answer
88 views

What if quantum mechanics and general relativity are not connected? [duplicate]

The main objective in modern physics research is to find a way to unify quantum mechanics and general relativity thorugh a series of theoretical approaches called "quantum gravity theories" But what ...
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2answers
80 views

What is the motivation for developing a “theory of everything”?

What is the reason physicists are working so hard looking for a "theory of everything" and trying to unify gravity with quantum mechanics? Historically, new theories were always developed to explain ...
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1answer
64 views

Is there a unified field? [closed]

Does the same force that holds the electron in orbit around the proton hold the Earth in orbit around the sun.
0
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1answer
128 views

Why Einstein's unified field theory is believed not to work?

In his later life, Albert Einstein was trying to extend his general theory of relativity to incorporate electromagnetism and other fundamental forces with it, something he himself called "The theory ...
3
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1answer
64 views

Is Gravity still considered to be part of the “Superforce” which existed at the instant of the “Big Bang”

My limited understanding of the Big Bang is that all the Fundemental Forces (Electromagnetic, Weak Nuclear, Strong Nuclear and Gravity) were originally part of a "Superforce." As the universe cooled ...
1
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1answer
55 views

Faraday's Law and the Law of Inertia

Faraday's Law can be stated qualitatively as : Any loop (of wire) opposes/resists the change of magnetic flux through it. The Law of Inertia states that any physical object resists its change in ...
12
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5answers
2k views

Why do we say there are four fundamental forces in the Standard Model (if gravity is included)? [duplicate]

In my physics textbook (and in popular science culture) it is stated that there are four fundamental forces: electromagnetism, strong, weak, and gravity. But Wikipedia tells me that there is a ...
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0answers
41 views

Classification of $E_6$ symmetry breaking

Is there a good reference which details the various ways of breaking $E_6$ into smaller groups using Wilson lines? I'm looking for a list of discrete (Abelian) symmetries, e.g. $\mathbb{Z}_5$, and the ...
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1answer
79 views

Relation between electroweak force and gravity? [closed]

I'm really stuck on the following idea. For gravity to in any way be 'unified' with the electroweak interaction wouldn't it need to include a model whereby the electron somehow tunnels to within the ...
5
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1answer
85 views

Why did physicists in the 1950s and 1960s suspect the weak and EM interactions were at some level the same interaction?

Around the 1950s and 1960s there was a lot of work in particle physics motivated by two issues - finding a workable quantum field model for the weak interaction, and finding a model that unified the ...
2
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1answer
145 views

Mathematical challenge for unification of gravity and electromagnetism in classical theory?

I am trying to better understand the mathematical foundations of a possible reconciliation between quantum field theory and gravity in general relativity. However, before the application of the ...
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0answers
71 views

Attempt to understand the Kaluza-Klein theory

I'm currently doing an internship on Kaluza-Klein theory. by reading some articles, I don't understand some things that seem easy to authors for example : In this article https://arxiv.org/abs/gr-qc/...
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0answers
102 views

Einstein's last attempt

Are there any good sources on Einstein's attempt to unify general relativity with electrodynamics, a unified field theory, before he died?
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0answers
34 views

Can we say the concept of wave and particle unifies in quantum mechanics?

I read this concept of unification in Physics like the unification of electromagnetism and weak interaction, unification of magnetic field and electric field by Maxwell. In this light of knowledge I ...
0
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1answer
41 views

Attributing direction as well as metrical structure to space - What did Einstein mean?

In notes from a lecture on The Concept of Space delivered by Einstein - 6 June, 1930 - it was reported: … he himself had faith that the idea of attributing direction as well as metrical structure ...
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1answer
132 views

Is String Theory the end of (currently known) physics? [closed]

Assuming that String Theory were true, does it explain all the currently known physics? Or are there anything that is known to exist and that even String Theory would not be able to explain?
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1answer
91 views

Who are the present 'superstars' pursuing significant breakthroughs toward a Theory of Everything (TOE)? [closed]

What are the main problems remaining to create a Theory of Everything (TOE) and who are some of the main contemporaries pursuing the TOE?
0
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2answers
195 views

Einstein's attempts at a unified field theory

Does anyone know where to find an English translation of Einstein's papers re his attempts to unify electromagnetism and gravity? Einheitliche Feldtheorie von Gravitation und Elektrizität and ...
2
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1answer
68 views

Why can increasing energy, the weak force and the EM-force become a similar force?

When the heat of the universe was much higher it seems that the weak force and the EM-force was combined into the electro weak force. For a layman the EM-force and the weak force look quite different,...
6
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3answers
365 views

Why to unify gravity with the other forces if gravity isn't really a force?

As I understand, the Theory of General Relativity says that the force of gravity doesn't exist. The planets move in elliptical orbits because the spacetime is curved by the mass of the sun, not ...
5
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4answers
3k views

Why is there a need to unify quantum mechanics and general relativity and what is meant by such a unification?

If general relativity (GR) describes gravity as a fictitious force, then shouldn't it be easy to quantize gravity in the sense that the spacetime distortion of a body changes in discrete values as a ...
2
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1answer
115 views

Why did Kaluza need to invent a new theory to unify general relativity and electromagnetism?

Wikipedia (and many other sources) say that by extending the number of spacetime dimensions from four to five, Kaluza–Klein theory unifies general relativity and electromagnetism into a single theory. ...
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1answer
68 views

Splitting the Fundamental Forces

So one interesting idea in physics is that at higher energy levels, fundamental forces fuse together (ex: Electricity and Magnetism into Electromagnetism) and (Eletromagnetism + Weak Force -> ...
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0answers
94 views

Is it true the Michio Kaku has completed a unified field theory started by Einstein by making use of string theory? [duplicate]

This professor has a few documentaries available explaining science to the layman like myself and he showed an equation no longer then a sentence that he says unifies all the know forces and particles ...
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0answers
47 views

What is the minimum set of hypotheses which the present physics is based on? [duplicate]

Based on nowadays human understanding, what are the most fundamental hypotheses or principles in present physics which could deduce all other formula/theorem/details/applications?
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1answer
510 views

How did Einstein plan to Unify Electromagnetism and Gravity?

I'm asking the question on this site because I'm more concerned with the physics and philosophy of unification than historical details I know that Einsteins description of gravity includes curvature ...
5
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4answers
201 views

Does any unifying theory explain why nature is Chiral?

I'm currently studying particle physics and find the experimental fact that massless particles are always left-handed quite surprising.In fact, the need to add projectors in the lagrangian seems not ...
3
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3answers
2k views

How does string theory try to Unite Quantum mechanics with General relativity?

I've always thought that the reason we had trouble unifying Quantum mechanics and General relativity is: Quantum mechanics is defined "on" space time and time doesn't vary because of energy. Time is ...
5
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4answers
202 views

Reformulating QFT to exclude space-time basis

This is, I guess, a pretty loose or general question and so I hope it's ok to post in this forum. But I suppose this is what science is all about: asking and seeing what happens. It is just personal ...
3
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1answer
264 views

Why does the Standard Model not unify $SU(3)$ and $SU(2)\times U(1)$?

I am struggling with the definition of a unification. I read this question and i am wondering why the standard model is not unifying strong and weak force according to the given definition of a ...
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2answers
693 views

Are the fundamental forces unified in a black hole?

Regarding the question of unification of the forces it is usually presented the following diagram: So it seems the matter of whether the forces are unified or not relates to how high the energy is. ...
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2answers
219 views

Massless particles in a universe with compact extra-dimensions

One common idea behind many extensions to the Standard Model (such as String Theory or Kaluza-Klein Theory) are small or hidden "Extra-Dimensions", that are compactified. According to my ...
3
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0answers
150 views

Modifying Heisenberg's Unified field theory with gravity

How would Heisenberg's unified field equations (as presented in "Introduction to Unified Field Theory of Elementary Particles" by Heisenberg) be represented if gravity is incorporated? Would it result ...
2
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2answers
163 views

Is it possible that there is a 5th force or is it proven that there is no other force?

I heard about in high energy the 4 fundamental forces can combine. They were not separated until $10^{-11}$ seconds after the big bang and as the univers gets cold, they begun to seperate. Is it ...
32
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1answer
2k views

What does it mean to say that “the fundamental forces of nature were unified”?

It is said that immediately after the Big Bang, the fundamental forces of nature were unified. It is also said that later they decoupled, becoming separate forces. Indeed, if we look at the list of ...
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1answer
253 views

Geometric interpretation of mass [closed]

I have a question about the definition of mass. In general relativity mass is closely related the curvature of spacetime, which indicates that mass might be interpreted as a geometric concept (maybe ...
5
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1answer
171 views

Is there a path to go from GR, to Gravitational Waves, to Gravitational Particles (Gravitons), to Quantum Gravity?

The articles on the subject often say : a part of the mass of the 2 celestial bodies became energy for gravitational waves after merging : E(gravitational waves) = (M1 + M2 - M_merged).c^2 ...
5
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4answers
158 views

Is there a theory where there are (recursively) infinitely smaller particles?

So I read that electrons are just points, with no mass, and furthermore, protons look like they have some "size" but that's really 3 "point-like" quarks. We first thought atoms were the smallest ...
6
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2answers
720 views

Should 4 fundamental forces really be 3 because of electroweak unification?

I read @ http://www.particleadventure.org/ Physicists concluded that, in fact, the weak and electromagnetic forces have essentially equal strengths. This is because the strength of the interaction ...
1
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1answer
331 views

How do physicists develop theories? [closed]

I'm wondering about the way physicists develop "unified theories" and models about the universe, like string theory, or quantum mechanics. People (on this forum for example) often say things like "at ...
0
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1answer
100 views

Unification: what does it mean for the forces to become equal?

The Coulomb force constant $k_c$ has si-units of $Nm^2C^{-2}$. The gravitational force constant $G$ has si-units of $Nm^2kg^{-2}$. What does it mean that at very high energies these forces become ...
5
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2answers
217 views

What is it exactly that conflicts when trying to unify all 4 fundamental forces? [duplicate]

Everyone knows that there are 4 fundamental forces: Gravity Electromagnetic Weak Strong At school and university you're taught that no one has been able to unify these 4 fources. However, not a ...
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1answer
91 views

Is it possible that there is more than one entirely correct unified field theory? [closed]

As we approach a more and more solid limit to the data we can get in physics, we find that there are multiple possible explanations (although they are not whole). Is it possible that instead of a ...
1
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1answer
245 views

Why didn't we have inflation when the theory of everything and GUTS broke symmetry?

I asked this in astronomy and they suggested I ask it here. Inflation seems to have occurred when the symmetry breaking of the electroweak occurred. But do we know of any reason why we did not have ...
2
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1answer
80 views

Can anyone explain to a novice physicist whether there is a gravitational-electromagnetic symmetry?

I am trying to understand how the four fundamental forces relate to one another and to a theory of everything. As I understand it the unified force that is thought to exist at very high energies gets ...
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0answers
534 views

Are there any good books about Grand Unified Theories?

I'm starting to get a little desperate, because I can't find any introductory treatments of Grand Unified Theories (GUT). So far the only books I found are Mohapatra Unification and Supersymmetry ...
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0answers
160 views

Evaluation of the anomalous dimensions of fields in SUSY $SU(5)$

The general formula for the anomalous dimension can be found in Martin΄s review article (hep-ph/9709356), on page 62 relation (6.5.4). In the case of $SU(5)$ and especially in the paper of Kobayashi, ...
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2answers
241 views

A model that unifies the strong, EM, weak and gravity forces?

Does there exist such a model that explains the force clusters (their origin, relations between them): the strong, EM, weak and gravity forces?