# Tag Info

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The information paradox is 40-45 years old. AdS/CFT is not even 20 years old, modern string theory (after D-branes) in probably 25 years old. This is to say that the information paradox doesn't need any of these, even though of course you can try to solve it in the context of string theory. In a nutshell, the information paradox is a sharp theoretical ...

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This has been open for a while so I will bite. The information paradox has two versions or iterations. The previous one is that information is demolished by black holes by the entropy of its event horizon and that Hawking radiation that is emitted is in a pure blackbody distribution. A blackbody distribution of radiation is maximally random. If you make a ...

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In a quantum world, all oscillations are quantized (if they are truly periodic, not just approximately periodic). For example, oscillations of a solid are quantized and the quanta are called phonons. That doesn't mean that the model of the solid as a lattice of (quantum) atoms is wrong, or even that it's an approximation with a limited domain of validity. On ...

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Does the discovery of a photon and development of quantum electrodynamics make Maxwellian electrodynamics redundant? Not a bit. Each physical theory has its domain of applicability. Electrodynamics successfully describes the macro phenomena of electricity and magnetism which are very much obscured when you look at them from the point of view of QED. ...

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If the graviton is detected and its cross section and other properties and interactions are measured well find out something about quantum gravity and maybe even how to unify gravity and the other forces. As @CuriousOne says we are pretty far from discovering it, nobody is looking for it, and we don't have any way of even coming within 10 orders of magnitude ...

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According to the fuzzball proposal in string theory, black hole are actually horizonless and regular solutions. For some systems in five dimensions made with bound states of intersecting branes this has been already proved directly in supergravity: there are solutions without horizons and singularities, with the same asymptotic charges (Mass, Angular ...

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At best things are pretty speculative. Cumrun Vafa has proposed that black holes have condensates of tachyons. In some sense you can understand this without much complexity. The Schwarzschild metric has a physical singularity that is a spatial surface. The Penrose conformal diagram for the Schwarzschild metric illustrates this The bosonic string has two ...

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I have communicated with both of these fellows. The mathematics is based on Donaldson's theorem that in four dimensions there exists an infinite number of atlases of charts on a manifold that are homeomorphic but not diffeomorphic. I am not able to go into the mathematics, for it is pretty deep. It centers around the moduli space of self-dual connections $SD/... 2 A spin-2 field in 4D is not five-dimensional. The standard spin-2 object transforms in the$(1,1)$-representations of the Lorentz group where the$(m,n)$-labels are half-integers labelling an equivalent representation of$\mathfrak{su}(2)\oplus\mathfrak{su}(2)$, see the Wikipedia article on representations of the Lorentz group for more information. The spin ... 1 One has to keep clearly in mind the structure of present day physics. Quantum mechanics is the theory that started as non relativistic with the Schrodinger equation for potentials, and became relativistic with the Dirac and Klein Gordon and quantized Maxwwell equations. Quantum mechanics has postulates which used with the solutions of the differential ... 0 As you said in your question, quantum field theory is very important; it takes the ideas of quantum mechanics and applies them to fields, such as the electromagnetic force (in fact, quantum electrodynamics was the beginning of quantum field theory). Quantum field theory has plenty of evidence to support it, and it is still an ongoing work. String theory, ... 2 A routine internet search for introductory material comes up with several possibilities. If you merely wish to read about the ideas in these topics you may not need any mathematics at all. eg "String Theory and Quantum Gravity for Dummies" in the "Dummies" Series. Also the more academic but briefer introduction : "Quantum Gravity for Dummies" http://arxiv.... 0 Ever after Maxwell unified electricity and magnetism, the goal of unification is a holy grail for theoretical physics, for all forces. The macroscopic forces of electricity and magnetism emerge from the underlying quantized level of nature, photons, electrons and all the elementary particles in the standard model table enter with fields in quantum field ... 0 The action for classical gravitation is the Hilbert-Palatini action $$S = \int d^4x\sqrt{-g}R$$ for$R$the Ricci scalar. The Goto or Polyakov action is of the form$\$ S = -\frac{1}{4\pi\alpha'}\int d\tau d\sigma g_{\mu\nu}\left(\frac{\partial X^\mu}{\partial\tau}\frac{\partial X^\nu}{\partial\tau}~-~\frac{\partial X^\mu}{\partial\sigma}\frac{\partial X^\...

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A good resource is M.D. Scadron, "Advanced Quantum Theory" from 1979. Gravitons in Minkowski-space have energy and momentum and couple to gravitons. Iteration (at tree level) reproduces the Einstein theory. This was first shown by Gupta 1952. Of course, there are problems in higher loop order, the gravition theory is not renormalizable.

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The following constants might vanish (e.g., place-dependent behaviors along a dimension, built-in identifiers that assign access along a string [ push-forward ], carrier-entropy) or transform--as in a qubit (a decision) flinching characteristically from dimensional memory, where the amount of the flinch is just the carriernormal length--when the initial ...

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