Questions tagged [unified-theories]

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Can we find a unified theory of physics? [duplicate]

We now have two overarching theories to explain just about every physical phenomenon: Einstein’s theory of gravity (general relativity) and quantum mechanics. The former is good at explaining the ...
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2answers
51 views

Uncertainty of the past

If the future today can be described as a complex set of probabilistic wave functions which collapse to form our reality, is it possible that the past history of the universe could also be ...
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4answers
140 views

Why do we believe in symmetry being a unifying principle in elementary particle physics?

As far as I can see, symmetry is something that is preferred at lower temperature. For example a crystal lattice has discrete translational symmetries at $T=0$, but at $T>0$ this symmetry is not ...
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46 views

Assumed form for beta function

In a classical paper on Hierarchy of Interactions in Unified Gauge Theories, Georgi et al define the renormalization group equation $$ \mu \frac{\partial g(\mu)}{\partial \mu } =\beta(g(\mu)). $$ He ...
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2answers
104 views

Particle fields and field theory

All particles have their own fields. More precisely, I've learned that an electron is just a bundle-up packet of energy from an 'electron field'. So as in this sense, all particles (from the standard ...
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0answers
60 views

What did Einstein's unified theory look like, quantitatively?

I'm writing an essay on the history of physics from a mathematical point of view. It's divided into a handful of impactful persons/ideas, one of the largest being the works of Einstein. Immediately ...
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1answer
54 views

Meaning of “unification of interactions”

What do we exactly mean when we speak about "unification of two interactions" or say "the electromagnetic and weak interactions are unified"? Wikipedia states that: the ...
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1answer
102 views

What is the mechanism that causes forces to get unified at high energies?

There are a lot of questions and answers on this site about the unification of forces, and all of them univocally say that at high energy levels, all the forces get unified. But none of them answer my ...
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1answer
60 views

Why did Kaluza-Klein need an additional dimension? [closed]

Why did Kaluza-Klein need an additional dimension and not just treat the fourth dimension as a description of both time and space? Assume that you can exchange the time dimension to a space dimension ...
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48 views

What is a simple QFT calculation that could show that some theory of Quantum Gravity might be correct? [closed]

Imagine that we could do QFT calculations with a Hamiltonian that takes GR into account. What is a relatively simple calculation that could show that this theory is more accurate than a "normal&...
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1answer
54 views

Is the fundamental relationship between electromagnetism & gravity unknown?

Richard Feynman made the following statement: the relationship between the gravity forces and electrical forces remains unknown in the interview linked here. In context, he made this statement ...
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0answers
104 views

Does Mark Hadley's Theory make Sense? [closed]

I just recently discovered this theory. It claims to derive quantum mechanics from general relativity. I found this interesting and perhaps promising, but I'm afraid I don't have enough expertise to ...
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2answers
70 views

Combining gravity with other forces [duplicate]

We all know we have 4 fundamental forces, and among them we can combine 3 forces but not gravity as in Standard model and some other. But force is something we can measure, as Einstein told us in ...
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0answers
30 views

Why is a unified field theory necessary? [duplicate]

I have read almost everywhere that the biggest questions in physics is to unify all the fundamental forces but I simply do not understand why do the forces have to follow a same set of rules or why is ...
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0answers
22 views

Unifying quantum mechanics and general relativity [duplicate]

I am very new to physics and I want to pursue Unified Field theory now when I read about how to unify quantum mechanics with relativity as they are essentially the same thing and a relation must be ...
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0answers
30 views

Unification of Forces

I was reading that unification of Forces is the most important task in the entirety of Physics. My question is why do the forces have to Unified. Why can't they be different forces what makes us think ...
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29 views

Book Recommendation for Unified Field theory

What are the best books to study a unified field theory. Is it simply studying both quantum mechanics and relativity?
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2answers
798 views

Can a theory of everything solve the oldest problem of turbulence? [closed]

Can a theory of everything solve the oldest problem of turbulence? Can we have unified theory of universe without solving the problem of turbulence?
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1answer
71 views

Unified field theory [closed]

I had a physics thought that i'd like some clarification on. My background in math and physics isn't super sophisticated so I'd like some feedback from those who've done more research in the fields. ...
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0answers
117 views

Why is gravity the only force not quantizable only at high energies?

There are a lot of questions on this site about the quantization of gravity. Now what I do understand is, that we can quantize gravity, but only at low energies, and this is really different from all ...
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3answers
308 views

Are standard QFT and general relativity contradictory?

My professors say it's only a matter of finding the right mathematical formalism to unite GR and QFT, and that new physics can only possibly be found on extremely high energies and small scales. they ...
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1answer
58 views

Can fundamental quantities be “unified”?

( Probably a stupid question. But the thought crossed my mind. I'm not a physicist; I'm a mathematician) Is there any way that the fundamental quantities (like length, time ) be "unified" in some ...
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1answer
101 views

Why is there a possibility for unification of GR and quantum mechanics when they are fundamentally in contradiction?

To me it's quite obvious that these theories are mutually exclusive simply by fundamental logic. QM at its very core is dependent on flat spacetime background and its implied conservation laws (...
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2answers
124 views

Can classical theories exhibit quantum-like effects?

For quite a while in the first half of the 20th century, many physicists tried to concoct some manner of unified theory to explain all known phenomenon, a lot of them using geometric theories (ie ...
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1answer
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What is the justification for Dirac's large numbers hypothesis?

Dirac stated that "Any two of the very large dimensionless numbers occuring in Nature are connected by a simple mathematical relation, in which the coefficients are of the order of magnitude unity." ...
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1answer
60 views

Earliest existence of particles and forces

I'm trying to understand the relation between particles and forces during the very early universe--the Planck epoch and subsequent stages as the fundamental forces separated. At what point did the ...
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2answers
117 views

Formal name for the “pianology” objection towards contemporary particle physics direction of research?

In a popular science book, an interesting objection towards the current direction of particle physics was stated. I tried to search for more on this, but got nowhere. Since I assume this is not an ...
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39 views

As anyone attempted to show that QM and GR cannot be unified? [duplicate]

Sometimes it possible to make very general statement about functional form of things and show, for example, that QM cannot be described by the use of hidden variable (I'm not a physicist in any sense, ...
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17 views

Interaction range of fundamental forces at a unification energies

At low energies, all fundamental forces have different coupling constants as well as an interaction ranges. As one know, at a some high energy (GUT energy $10^{14}$ GeV), all the coupling constants ...
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86 views

Spacetime as an independent yet interacting frame of reference for QM. Looking.for papers [duplicate]

We know that GR and QM are both valid and verified and yet for some reason they just don't want to go together. We say QM describes the microscopic while GR describes the macroscopic. I was thinking ...
4
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3answers
647 views

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 ...
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1answer
427 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 ...
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1answer
155 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
150 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
84 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.
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1answer
230 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 ...
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1answer
124 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 ...
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1answer
161 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 ...
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5answers
3k 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
46 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
149 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
122 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 ...
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1answer
185 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
112 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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137 views

Einstein's last attempt of a unified field theory

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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1answer
60 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
185 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
101 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?
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2answers
280 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 ...
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1answer
90 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,...