Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Accelerating equilibrium isotope effect calculations: II. Stochastic
  implementation of direct estimators   Path integral calculations of equilibrium isotope effects and isotopic
fractionation are expensive due to the presence of path integral discretization
errors, statistical errors, and thermodynamic integration errors. Whereas the
discretization errors can be reduced by high-order factorization of the path
integral and statistical errors by using centroid virial estimators, two recent
papers proposed alternative ways to completely remove the thermodynamic
integration errors: Cheng and Ceriotti [J. Chem. Phys. 141, 244112 (2015)]
employed a variant of free-energy perturbation called "direct estimators,"
while Karandashev and Van\'{\i}\v{c}ek [J. Chem. Phys. 143, 194104 (2017)]
combined the thermodynamic integration with a stochastic change of mass and
piecewise-linear umbrella biasing potential. Here we combine the former
approach with the stochastic change of mass in order to decrease its
statistical errors when applied to larger isotope effects, and perform a
thorough comparison of different methods by computing isotope effects first on
a harmonic model, and then on methane and methanium, where we evaluate all
isotope effects of the form
$\mathrm{CH}_{\mathrm{4-x}}\mathrm{D}_{\mathrm{x}}/\mathrm{CH}_{4}$ and
$\mathrm{CH}_{\mathrm{5-x}}\mathrm{D}^{+}_{\mathrm{x}}/\mathrm{CH}^{+}_{5}$,
respectively. We discuss thoroughly the reasons for a surprising behavior of
the original method of direct estimators, which performed well for a much
larger range of isotope effects than what had been expected previously.

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The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph