Tagged Questions

-2
votes
0answers
54 views

How can superstring theories unify general relativity and quantum theory when no prediction can be made?

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 ...
5
votes
0answers
237 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 ...
3
votes
1answer
208 views

How do I quantize a classical field theory

I have not been able to find any information about this on the Internet. I am a middle-schooler, 14, who self-studies physics, and I know up to and including ODEs, and some of the calculus of ...
5
votes
2answers
321 views

The Uncertainty Principle and Black Holes

What are the consequences of applying the uncertainty principle to black holes? Does the uncertainty principle need to be modified in the context of a black hole and if so what are the implications ...
2
votes
3answers
270 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 ...
6
votes
0answers
138 views

Does local physics depend on global topology?

Motivating Example In standard treatments of AdS/CFT (MAGOO for example), one defines $\mathrm{AdS}_{p+2}$ as a particular embedded submanifold of $\mathbb R^{2,p+1}$ which gives it topology ...
7
votes
3answers
306 views

An electron falling into a black hole

If an electron falls into a black hole. How can the Heisenberg uncertainty principle hold? The electron has fallen into the singularity now so it has a well defined position which means that it ...
0
votes
0answers
139 views

Newton Gravitational constant $G$, Plank constant $\hbar$ , Speed of Light $c$ : The Dream Team of moderators?

The 3 great constants of Nature are well known : The Speed of light $c$ (special relativity) The Plank constant $\hbar$ (quantum mechanics) The Newton ...
16
votes
3answers
529 views

Is there a thought experiment which brings to light the contradiction between General Relativity and Quantum Mechanics?

I've been told that GR and QM are not compatible, is there an intuitive reason/thought experiment which demonstrates the issue? (Or one of the issues?)
4
votes
0answers
128 views

How is the 'cluster decomposition principle' implemented in holographic theories?

Since holographic theories are non-local by definition, how is this principle implemented? Naively, it seems to me it is not, at least, in some sense. I would appreciate an explanation as simple ...
2
votes
2answers
177 views

Was Planck's constant $h$ the same when the Big Bang happened as it is today?

Was Planck's constant $h$ the same when the Big Bang happened as it is today? Planck's constant : $$h= 6.626068 × 10^{-34}\, m^2 kg / s,$$ $$E=n.h.\nu,$$ $$\epsilon=h.\nu$$
4
votes
2answers
150 views

Motivation for “discretized quantum state spaces”

I know that the title of the question is rather vague, so let me clarify what I mean. For a quantum system, the set of states has infinitely (even continuously) many extreme points, i.e. there are ...
3
votes
1answer
248 views

Set theory, category theory, realism and the recent “reality of the wavefunction” papers

I will add a better phrased question here. Do we need to consider quantum foundations to form a quantum theory of gravity? The kind of foundational question I am thinking of is expressed in the ...
-2
votes
1answer
202 views

A quanta of time

A question of Quantum Time: Does a minimum interval of time cause wave-like behavior? If we think about the uncertainty principle, could it derive from a quanta of time? Does plank’s constant somehow ...
7
votes
1answer
303 views

Physical interpretation of Wheeler - Dewitt equation

What is the mainstream ( if there is one ) interpretation of the Wheeler - Dewitt equation $\hat{H}\Psi =0$ ?
0
votes
2answers
271 views

Momentum Energy and Higgs

So, as an object accelerates it gains energy. And energy is mass. So an object becomes more massive as it approaches the speed of light. But, if mass is ONLY due to an object's interaction with the ...
2
votes
2answers
164 views

Can the implications of dark energy be used to bridge the gap between Quantum Mechanics and General Relativity?

Can the findings of the Physics Nobel Laureates of 2011, namely the overpowering existence of dark energy (vacuum energy) have any implications in the quest the combine Quantum Mechanics and General ...
6
votes
1answer
81 views

Quantum mechanical gravitational bound states

The quantum mechanics of Coloumb-force bound states of atomic nuclei and electrons lead to the extremely rich theory of molecules. In particular, I think the richness of the theory is related to the ...
2
votes
0answers
63 views

Complementarity between the laws of physics? [closed]

Is this following proposal plausible, worth considering, or dismissable as lunatic fringe science? What if the universe isn't really what we think it is but some universal quantum computer where we ...
0
votes
1answer
153 views

Sun-Earth Virtual Gravitons?

How many virtual gravitons do the sun and earth exchange in one year? What are their wavelengths?
7
votes
1answer
189 views

Scale set by cosmological constant

Following on Jim Graber's answer to: Can "big rip" rip apart an atomic nucleus? If the cosmological constant is large enough, even the ground state of a hydrogen atom can be affected. So ...
2
votes
4answers
197 views

What are the conditions to be satisfied by a theory in order to be a quantum theory?

This is in continuation to my previous question. It is not a duplicate of the previous one. This question arises because of the answers and discussions in that question. Can we call a theory, quantum ...
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... ...
11
votes
6answers
1k views

Is the Planck length Lorentz invariant?

The planck length is defined as $l_P = \sqrt{\frac{\hbar G}{c^3}}$. So it is a combination of the constants $c, h, G$ which I believe are all Lorentz invariants. So I think the Planck length should ...
-4
votes
2answers
2k views

What are the main differences between these quantum theories?

What are the main differences between these quantum theories? Quantum Mechanics Quantum Field theory Quantum Gravity EDIT: I ask this question because when I asked a question before people talk ...
11
votes
4answers
1k views

Is there a maximum possible acceleration?

I'm thinking equivalence principle, possibilities of unbounded space-time curvature, quantum gravity ...
-7
votes
7answers
2k views

Does Quantum Physics really suggests this universe as a computer simulation? [closed]

I was reading about interesting article here which suggests that our universe is a big computer simulation and the proof of it is a Quantum Physics. I know quantum physics tries to provide some ...
22
votes
5answers
2k views

A list of inconveniences between quantum mechanics and relativity?

It is well known that quantum mechanics and (special and/or general) relativity do not fit well. I am wondering whether it is possible to make a list of contradictions or problems between them? E.g. ...