- #36
Tyger
- 398
- 0
Just plug "ball lightning"
into MSN or Google, you'll get a lot of stuff.
into MSN or Google, you'll get a lot of stuff.
Originally posted by Tyger
into MSN or Google, you'll get a lot of stuff.
Originally posted by Sauron
Your argument about particle labels don´t totally convince me. In fact it doesn´t convince me at all. You first begin with a 4 manifold provided with an vielbein and an spin connecton. So your departure point allows you to define spin 1/2 particles without any problem. that´s the usuall way it is done in particle physics(with the "curved" dirac matrices and all that).
Ok, later you do the ADM slicing and you pass form lagrngian to hamiltonian and get your constraints and all that. But think these. You initially have L=Lgravity + Lmatter. When you go to the hamiltonian the Lmatter would be transformed In Hmatter. That doesn´t introduce any difficoultie (constraint) for spiin 1/2 particles.
In fact even in mikownsky space i don´t understand why you claim you need to get the SU(2) covering of the SO(3) subgroup of SO(3,1) to get spin 1/2. I studied that topic in the Ramond´s book on field theory (and also i ht kaku book of field theory) and don´t remember to have seen that statement.
Originally posted by Sauron
Now you say that the lowest allowed particles are spin -1 and spin-1/2. But if spin-1/2 are fermions and your first claim was that fermions were not allowed. Now instead your problem is with the spin-0, i.e. thte hiporthethical and still unobserved Highs bosson (that tachyonic particle in the unbroken symmetry phase...). I guess that you may explain your change of opinion before i give any answer to these aspect.
Originally posted by marcus
Motl is kind of outrageous in places----like at the end in the Unsolved Questions section he raises the question "could it be that LQG does not allow for the existence of fermions?"
Originally posted by Sauron
Jeff, i understand that people eidt it´s messages, but it makes a bit confusing to follow the thread, why not just to indicate your previous mistakes in a new post?
Originally posted by Sauron And i still see a self-contradiction in the posts. You say LQG allows particles of spin not minor than 1/2, but that means fermions are allowed, and in other places ou say LQG doesn´t couple to fermionic matter. And your argument says that the absence of SU(2) is forbiding spin 1/2, so ,why are them allowed and only spin 0 particles are not allowed?.
LQG stands for Loop Quantum Gravity, which is a theoretical framework that attempts to reconcile quantum mechanics and general relativity to explain the behavior of space and time at the smallest scales.
Lubos Motl is a Czech theoretical physicist who has made contributions to string theory and quantum gravity. He is also known for his controversial and often outspoken views on various scientific topics.
Lubos Motl's clarification of LQG is a critical analysis of the theory, highlighting its limitations and weaknesses. He argues that LQG is not a viable solution to the problem of quantum gravity and suggests alternative approaches.
LQG is important because it is one of the leading theories attempting to reconcile quantum mechanics and general relativity, which are two fundamental theories in physics that have yet to be unified. If successful, LQG could provide a deeper understanding of the nature of space and time.
If LQG is proven to be a valid theory, it could have significant implications for our understanding of the universe. It could potentially lead to a better understanding of the early universe, the behavior of black holes, and the nature of gravity at the smallest scales. It could also have practical applications in fields such as quantum computing and cosmology.