Recent content by Andre' Quanta

Dear Zapped Z, i have read you article but i completely don' t agree with it. "I have shown that there’s nothing to prevent anyone from knowing both the position and momentum of a particle in a single measurement that is limited only by our technology. ": you are wrong. As you know, the...

If a Lie group is not compact is it true that all its irreducibile unitary representations are infinite dimensional?

I am studying Group Theory at the moment and i am not sure about a theorem. Is it true that a Lie Group G is compact if and only if every finite complex representation of it is unitary? I know that is true the if, but what about the viceversa? Same question. Is it true that a Lie group is...

Why we require the separability of Hilbert spaces in Quantum Mechanics?

With "serious references" i was only saying "rigorous from a matematical point of view" (i am Italian and my English could lead to misunderstanding). Anyway thank you George, but unluckly i can' t find in internet the books that you linked to me, i have found only the Ballantine that linked...

During a course of QFT my teacher said that in this theory is not possible to use the operator X for the position in order to construct with the momentum P and the spin S a set of irreducible operators that charachterize particles, and that we need a different point of wiev: the irreducible...

Which are the discret subgroups of O(1,3)?

I am at the last year of specialization in theoretical physics, i have also followed in detail a course in group theory and i need a serious reference in order to study in detail the rappresentations of the Poincarè group

I need to study in detail the rappresentations of the Poincare Group, i am interessed in the idea that particles can be wieved as irriducible representations of it. Do you have some references about it?

Does exist a Lagrangian for the Euler equation describing perfect fluid? If so, what is the expression?

The weak gravitational field, the usual h mu nu, satisfies the simple D' Alemebert equation, so the lagrangian is the one of Klein-Gordon replacing the scalar field with the tensorial one in our theory: this will be valid also for the Hamiltonian so i would say the Hamiltonian that i am looking...

I was interested in the Hamiltonian operator for the theory, is it the same as the one of the free electromagnetic field?

In weak field regime i know that it is possible to quantize the gravitational field obtaining a quantum theory of free particles, called gravitons, which is very similar to the one for the electtromagnetic field. Do you know some book in wiich i can study this theory? In anycase what is the...

Suppose to have a hamiltonian with a linear potenzial like z x, where x is the variable and z a parameter. Which is the spectrum of the Hamiltonian of this sistem?

Suppose to have a killing vector that its norm is null, so at the same time is also a null geodesic. Does the metric have special propierty? What can i say about the Killing vector and its proprierties?