Tagged Questions

0
votes
0answers
81 views

How can it be seen that ST unifies GR and QM as the quantum gravity scale is not directly accessible

I am a newbie to superstring theories, but I came into this question: so superstring theories purport to unify general relativity and quantum theory. However, there is yet no definitive way to test ...
1
vote
2answers
147 views

Where does quantum mechanics come from? [closed]

Where does quantum mechanics come from? If string theory is proved to be the correct quantum theory of gravity but it failed to explain where quantum mechanics came from can we still consider it a ...
2
votes
0answers
50 views

Standard Quantum Mechanics representation as a constrained 2 + 1 space-time (membrane) theory?

Could a particular Standard Quantum Mechanics representation be a constrained 2 + 1 space-time theory (membrane theory) ? (i) This question is motivated by a possible (approximative) analogy with ...
5
votes
0answers
238 views

Can the laws of quantum mechanics be derived from a more fundamental theory? [closed]

String theory takes quantum mechanics for granted and tries to make it compatible with gravity but if it turns out to be a theory of everything then shouldn't it in principle explain why our world is ...
-5
votes
0answers
60 views

Consequences of Third Postulate of Special Relativity [closed]

Consequences of SR arise from two postulates. know as this abstract states: "relativistic action is limited to planck's constant", and maybe we've to consider it as the possible third postulate of ...
0
votes
1answer
110 views

Strings and QFT: particles moving backward in time?

New question: In string theory and QFT, do particles travel back in time? Not related to antimatter: Do they travel back and forth in time in reality or are these just interpretations of mathematical ...
3
votes
2answers
168 views

Can string theory be used to solve basic quantum problems?

When I studied physics I was shown that special relativity would become Newton's laws at low speeds. Similarly, quantum mechanics could also be shown to be Newtonian at large quantum numbers. My ...
2
votes
3answers
272 views

Could all strings be one single string which weaves the fabric of the universe?

This question popped out of another discussion, about if the photon needs a receiver to exist. Can a photon get emitted without a receiver? A universe containing only one electron was hypothetically ...
1
vote
1answer
195 views

Quantization of Nambu–Goto action in multiples of Planck's constant?

Isn't it possible? Quantization of Nambu–Goto action $$\mathcal{S} ~=~ -\frac{1}{2\pi\alpha'} \int \mathrm{d}^2 \Sigma \sqrt{{\dot{X}} ^2 - {X'}^2}~=~nh\qquad n \in\mathbb{Z}.$$
0
votes
0answers
398 views

Are there any list of String Theory Equations? [closed]

I Google it but did not find anything. here is a list of QM Formuals and a list of relativistic equations Are there any list of String Theory Equations?
3
votes
0answers
308 views

Isn't a single Quantum one single string? [duplicate]

In physics, a quantum (plural: quanta) is the minimum amount of any physical entity involved in an interaction. In Quantum Mechanics There is no difference between one Quantum to another one. ...
3
votes
1answer
97 views

Is matrix picture of quantum mechnics further used in QFT and superstring theories?

Just curious: is matrix picture of quantum mechnaics further used in QFT and superstring theories? It seems like not....
0
votes
1answer
132 views

uncertainty principle of spin in (super)string theory

In quantum mechanics, uncertainty principle states that we can only measure the quantity of spin in one axis but not others. Then what about in superstring theory? As quantum mechanics is basically ...
4
votes
2answers
298 views

Does String theory say that spacetime is not fundamental but should be considered an emergent phenomenon?

Does String theory say that spacetime is not fundamental but should be considered an emergent phenomenon? If so, can quantum mechanics describe the universe at high energies where there is no ...
22
votes
10answers
5k views

Discreteness and Determinism in Superstrings?

So Gerard 't Hooft has a brand new paper (thanks to Mitchell Porter for making me aware of it) so this is somewhat of a expansion to the question I posed on this site a month or so ago regarding 't ...
1
vote
1answer
878 views

What's next after Higgs Boson discovery? [duplicate]

Possible Duplicate: Practical matter of the Higgs-Mechanism As everybody knows that the Higgs Boson was discovered on July 4th,2012, I am so curious about it. What are the possible ...
5
votes
4answers
413 views

Is String Theory a Field Theory?

Is String Theory a Field or Quantum Mechanical Theory of the String rather than a Particle? I should know this having studied this for a term, but we jumped into the deep end, without really ...
6
votes
1answer
86 views

random matrix ensembles from BMN model

My friends working on Thermalization of Black Holes explained solutions to their matrix-valued differential equations (from numerical implementation of the Berenstein-Maldacena-Nastase matrix model) ...
1
vote
3answers
199 views

Quantum of Time

I am not a String Theorist, but I just want to ask if there is anything which specifies a quantum of time, as per M-theory? Can a quantity such as $$ t_p = \left(\frac{\ell_p}{c}\right),$$ where ...
1
vote
0answers
80 views

Giving some intuition of particle physics, quantum physics,classical mechanics etc etc to a layman [closed]

I am a software engineer by profession and sometimes get curious on some physics terms I hear about and expect myself to have some at least basic intuition of what it is all about. I keep hearing of ...
13
votes
1answer
428 views

How come random matrices can predict energy spectra of heavy atoms?

Some of the applications of random matrices is to find the spectra of heavy atoms in nuclear physics which are usually difficult to find otherwise. How can starting from randomness of some kind, ...
3
votes
1answer
218 views

Can we have non continuous models of reality? Why don't we have them?

This question is about Godel's theorem, continuity of reality and the Luvenheim-Skolem theorem. I know that all leading physical theories assume reality is continuous. These are my questions: 1) Is ...
0
votes
1answer
179 views

Is the quantum state or information of a particle is all that differentiates it from another particle?

So I have learned in my QM classes that you can't tell one electron from another electron. They are indistinguishable. I also learned that the wavefunction of a particle includes the spacial part and ...
6
votes
3answers
257 views

References on the non-compositeness of the known elementary particles

What paper(s) or theory(s) describe or prove that the elementary particles that we have determined today cannot be made up of smaller more fundamental particles?
4
votes
1answer
236 views

What are the current (popular(ish)) approaches to modelling the quantum nature of spacetime at the Planck scale?

My guess at a list of them would be: spin foams, casual sets, non-commutative geometry, Machian theories, twistor theory or strings and membranes existing in some higher-dimensional geometry... ...
5
votes
2answers
187 views

Superselection sectors and $p+1$ form potentials in String Theory

we often come across the phrase superselection sector. I have couple of questions from that. First of all, I learned from some references about it (as a overview) and how is it related to ...
0
votes
3answers
3k views

Total number of subatomic particles in the universe. Are they finite ? assuming any of GR or QM or even ST

Total number of subatomic particles in the universe. Are they finite ? assuming any of GR or QM or even ST.