Recent content by jarod765

To my understanding there is no proof of ADS/CFT but people seem to take it as absolute fact. What is the reason for this?

This is only true in some systems. For example, in the relativistic treatment of the hydrogen atom, this is not the case. In fact both the angular and spin angular momentum are not good quantum numbers in this system.

The full symmetry is some gauged lie group, for example SU(3)xSU(2)xU(1), *and* the Poncaire group, which is a continuous global symmetry. The intrinsic spin of particles arises because particles live in non-scalar representations of the Poncaire group. Thus, the symmetry group which is...

I had a similar question in: https://www.physicsforums.com/showthread.php?t=642283 The answer is, I think, that in high energies spin is a good quantum number because the states we are considering are asymptotically non-interacting particles. In lower energies, where spin-orbit is more...

I know this is a basic question, but why are positive frequency modes so important when expanding a field operator. Furthermore, what do they represent?

The poncaire group contains, as a subgroup, the group of 3-rotations. Thus any poncaire invariant system is also rotationally invariant. Right, the bound states belong to representations of the full symmetry group and are labeled by the groups corresponding Casimir operators. Oh! yeah that's...

I know that the generators of the Poncaire group that are associated with *orbital* angular momentum belong to an infinite dimensional representation, i.e. \begin{equation} L = \frac{\partial}{\partial \theta} \end{equation} Also the spin generators are associated with some finite...

Thanks Atyy

I have heard many talks where they mention Witten's "standard dictionary" of ADS/CFT. Where the dictionary is, to my understanding, a way to easily go between a CFT and a theory of gravity. What I want to know is where is the paper that has this dictionary?

It should be mentioned that "decay time" it is meant the decay time for a *single* event, the decay of one atom. The average decay of an ensemble of particles in universes with similar physics should come out the same.

An elementary particle is not necessarily forbidden from decay. The rule of thumb is that any process that can happen, will happen given sufficient time. For example, a muon is heavier than an electron. Thus it can decay into an electron. Energy momentum conservation however, forbids the...

Charged non-rotating black holes also have two horizons as long as the charge is sufficiently small. If the charge is sufficiently large one can obtain a naked singularity. However there is a conjecture that these cannot exist. As for the charged black hole this makes sense because a...

Don't people believe that information is not lost but preserved in the hawking cloud?

The Field tensor which is the simplest, positive definite, topologically non-trivial gauge invariant object, is defined via the commutator of of two covariant derivatives acting on an object (see Weinberg II first chapter). Thus the field tensor obeys the bianchi identity by construction...

The other two Maxwell equations, the homogenous equations, come from the Bianchi Identity that the field tensor must obey.