34,134 research outputs found
Coming: a Tool for Mining Change Pattern Instances from Git Commits
Software repositories such as Git have become a relevant source of
information for software engineer researcher. For instance, the detection of
Commits that fulfill a given criterion (e.g., bugfixing commits) is one of the
most frequent tasks done to understand the software evolution. However, to our
knowledge, there is not open-source tools that, given a Git repository, returns
all the instances of a given change pattern. In this paper we present Coming, a
tool that takes an input a Git repository and mines instances of change
patterns on each commit. For that, Coming computes fine-grained changes between
two consecutive revisions, analyzes those changes to detect if they correspond
to an instance of a change pattern (specified by the user using XML), and
finally, after analyzing all the commits, it presents a) the frequency of code
changes and b) the instances found on each commit. We evaluate Coming on a set
of 28 pairs of revisions from Defects4J, finding instances of change patterns
that involve If conditions on 26 of them
Particle detectors and the zero mode of a quantum field
We study the impact of the zero-mode of a quantum field on the evolution of a
particle detector. For a massless scalar field in a periodic cavity, we show
that the impact of the zero mode on the Unruh-DeWitt detector and its
derivative-coupling generalisation is necessarily nonvanishing but can be made
negligible in some limits, including those commonly occurring in
non-relativistic quantum optics. For the derivative-coupling detector this can
be accomplished by just tuning the zero mode's initial state, but the standard
Unruh-DeWitt detector requires a more subtle and careful tuning. Applications
include an inertial detector with arbitrary velocity, where we demonstrate the
regularity of the ultrarelativistic limit, and a detector with uniform
acceleration.Comment: 14 pages, 3 Figures. RevTex 4.1. v2: Added journal reference and
minor edits to match published versio
Fermionic entanglement ambiguity in non-inertial frames
We analyse an ambiguity in previous works on entanglement of fermionic fields
in non-inertial frames. This ambiguity, related to the anticommutation
properties of field operators, leads to non-unique results when computing
entanglement measures for the same state. We show that the ambiguity disappears
when we introduce detectors, which are in any case necessary as a means to
probe the field entanglement.Comment: 9 pages, 4 figures. Revtex 4.1, added Journal referenc
Redistribution of particle and anti-particle entanglement in non-inertial frames
We analyse the entanglement tradeoff between particle and anti-particle modes
of a Dirac field from the perspective of inertial and uniformly accelerated
observers. Our results show that a redistribution of entanglement between
particle and anti-particle modes plays a key role in the survival of fermionic
field entanglement in the infinite acceleration limit.Comment: 10 pages, 5 figures, revtex4. Added journal referenc
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