Quantum Volumes and Observables: Exploring Macroscopic States in Quantum Physics

[Spin_Network]

Marcus has Highlighted an interesting paper:http://www.arxiv.org/abs/gr-qc/0509049

But I think it should be here in the Quantum Physics thread, and it definately should have some discussion?

Quote here from the paper:

The first one is what observables (besides the volume) should be specified to actually describe a macroscopic state in a given region. Since the contribution to the volume from a given 4-valent vertex grows like j1 ·j2·j3
it is important to know whether these observables provide suppression of
the contribution from very large spins rendering final expectation value of
the volume finite. The second problem is connected with the first one and
concerns the bulk entropy: there are many sets of graphs with many different
assignments of spins on legs that give (macroscopically) the same volume. If
we specify both the volume and the other observables we are left with a
certain number of graphs. The question is, whether the logarithm of this
number is connected with the bulk entropy much as sequences of spins are
connected with the black hole surface entropy .

There is/must be a 'fix' to the authors concerns, any idea's?

 

[eljose79]

I find this paper very interesting and thought-provoking. The author raises important questions about the description of macroscopic states in a given region and the role of observables in determining the final expectation value of the volume. The issue of bulk entropy and its connection to the number of graphs with different spin assignments is also intriguing.

I agree that this paper should be discussed in the Quantum Physics thread, as it deals with fundamental concepts in quantum gravity. It would be helpful to have more context and background information on the specific model or theory being discussed in the paper.

In terms of potential solutions or "fixes" to the author's concerns, I think further research and experimentation is needed. Perhaps exploring different sets of observables or incorporating new mathematical techniques could shed light on these issues. I would also be interested in hearing other scientists' thoughts and ideas on this topic.

 

[denian]

I find this paper to be very intriguing. It raises important questions about how we define and measure macroscopic states in quantum physics. The author's discussion of observables and their role in determining the contribution of large spins to the volume is thought-provoking.

I agree that this paper should be discussed in the Quantum Physics thread, as it is relevant to the field. As for the author's concerns, I believe there are ongoing research and discussions in the field about these issues. One possible solution could be to introduce new observables that can better capture the complexity of macroscopic states and their contributions to the volume. Additionally, further studies and experiments could help shed light on the relationship between the number of graphs and the bulk entropy, potentially providing a better understanding of the underlying mechanisms at play. Overall, this paper highlights the need for continued research and exploration in this area of quantum physics.