Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Connection-state approach to pre- and post-selected quantum measurements   We discuss the concept of connection states (or connection matrices) that
describe posterior ensembles, post-selected according to the outcomes of a
quantum measurement. Connection matrices allow one to obtain results of any
weak and some non-weak pre- and post-selected measurements, in the same manner
as density matrices allow one to predict the results of conventional quantum
measurements. Connection matrices are direct extensions of the density matrices
and are generally non-Hermitian, which we show to be a direct consequence of
quantum complementarity. This implies that the ultimate reason for unusual weak
values is quantum complementarity. We show that connection matrices can be
determined experimentally. We also show that retrodictive states are a special
case of connection states. We propose a new method of tomography of quantum
detectors.

2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio