Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Obstructions to Bell CMB Experiments   We present a general and systematic study of how a Bell experiment on the
cosmic microwave background could be carried out. We introduce different
classes of pseudo-spin operators and show that, if the system is placed in a
two-mode squeezed state as inflation predicts, they all lead to a violation of
the Bell inequality. However, we also discuss the obstacles that one faces in
order to realize this program in practice and show that they are probably
insurmountable. We suggest alternative methods that would reveal the quantum
origin of cosmological structures without relying on Bell experiments.

36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
35
The categories of this paper are: mtrl-th