Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Equilibration and GGE in interacting-to-free Quantum Quenches in
  dimensions d>1   Ground states of interacting QFTs are non-gaussian states, i.e. their
connected n-point correlation functions do not vanish for n>2, in contrast to
the free QFT case. We show that when the ground state of an interacting QFT
evolves under a free massive QFT for a long time (a scenario that can be
realised by a Quantum Quench), the connected correlation functions decay and
all local physical observables equilibrate to values that are given by a
gaussian density matrix that keeps memory only of the two-point initial
correlation function. The argument hinges upon the fundamental physical
principle of cluster decomposition, which is valid for the ground state of a
general QFT. An analogous result was already known to be valid in the case of
d=1 spatial dimensions, where it is a special case of the so-called Generalised
Gibbs Ensemble (GGE) hypothesis, and we now generalise it to higher dimensions.
Moreover in the case of massless free evolution, despite the fact that the
evolution may not lead to equilibration but unbounded increase of correlations
with time instead, the GGE gives correctly the leading order asymptotic
behaviour of correlation functions in the thermodynamic and large time limit.
The demonstration is performed in the context of bosonic relativistic QFT, but
the arguments apply more generally.

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The categories of this paper are: math
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
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The categories of this paper are: comp-gas
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The categories of this paper are: cs
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The categories of this paper are: gr-qc