Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The QCD phase diagram at zero and small baryon density   I review recent developments in determining the QCD phase diagram by means of
lattice simulations. Since the invention of methods to side-step the sign
problem a few years ago, a number of additional variants have been proposed,
and progress has been made towards understanding some of the systematics
involved. All available techniques agree on the transition temperature as a
function of density in the regime \mu_q/T < 1. There are by now four
calculations with signals for a critical point, two of them at similar
parameter values and with consistent results. However, it also emerges that the
location of the critical point is exceedingly quark mass sensitive. At the same
time sizeable finite volume, cut-off and step size effects have been uncovered,
demanding additional investigations with exact algorithms on larger and finer
lattices before quantitative conclusions can be drawn. Depending on the sign of
these corrections, there is ample room for the eventual phase diagram to look
as expected or also quite different, with no critical point at all.

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The categories of this paper are: hep-th
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The categories of this paper are: atom-ph
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: math-ph
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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: plasm-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-bio
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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: patt-sol
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
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The categories of this paper are: acc-phys