Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Heuristic Approach to the Quantum Measurement Problem: How to
  Distinguish Particle Detectors from Ordinary Objects   Elementary particle detectors fall broadly into only two classes:
phase-transformation devices, such as the bubble chamber, and charge-transfer
devices like the Geiger-Mueller tube. Quantum measurements are seen to involve
transitions from a long-lived metastable state (e. g., superheated liquid or a
gas of atoms between charged capacitor plates) to a thermodinamically stable
condition. A detector is then a specially prepared object undergoing a
metastable-to-stable transformation that is significantly enhanced by the
presence of the measured particle, which behaves, in some sense, as the seed of
a process of heterogeneous nucleation. Based on this understanding of the
operation of a conventional detector, and using results of
orthogonality-catastrophe theory, we argue that, in the thermodynamic limit,
the pre-measurement Hamiltonian is not the same as that describing the detector
during or after the interaction with a particle and, thus, that superpositions
of pointer states (Schroedinger cats) are unphysical because their time
evolution is ill defined. Examples of particle-induced changes in the
Hamiltonian are also given for ordinary systems whose macroscopic parameters
are susceptible to radiation damage, but are not modified by the interaction
with a single particle.

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The categories of this paper are: eess
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
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The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph