556 research outputs found
Transformations among Pure Multipartite Entangled States via Local Operations Are Almost Never Possible
Local operations assisted by classical communication (LOCC) constitute the
free operations in entanglement theory. Hence, the determination of LOCC
transformations is crucial for the understanding of entanglement. We
characterize here almost all LOCC transformations among pure multipartite
multilevel states. Combined with the analogous results for qubit states shown
by Gour \emph{et al.} [J. Math. Phys. 58, 092204 (2017)], this gives a
characterization of almost all local transformations among multipartite pure
states. We show that nontrivial LOCC transformations among generic, fully
entangled, pure states are almost never possible. Thus, almost all multipartite
states are isolated. They can neither be deterministically obtained from
local-unitary-inequivalent (LU-inequivalent) states via local operations, nor
can they be deterministically transformed to pure, fully entangled
LU-inequivalent states. In order to derive this result, we prove a more general
statement, namely, that, generically, a state possesses no nontrivial local
symmetry. We discuss further consequences of this result for the
characterization of optimal, probabilistic single copy and probabilistic
multi-copy LOCC transformations and the characterization of LU-equivalence
classes of multipartite pure states.Comment: 13 pages main text + 10 pages appendix, 1 figure; close to published
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Least squares approximations of measures via geometric condition numbers
For a probability measure on a real separable Hilbert space, we are
interested in "volume-based" approximations of the d-dimensional least squares
error of it, i.e., least squares error with respect to a best fit d-dimensional
affine subspace. Such approximations are given by averaging real-valued
multivariate functions which are typically scalings of squared (d+1)-volumes of
(d+1)-simplices. Specifically, we show that such averages are comparable to the
square of the d-dimensional least squares error of that measure, where the
comparison depends on a simple quantitative geometric property of it. This
result is a higher dimensional generalization of the elementary fact that the
double integral of the squared distances between points is proportional to the
variance of measure. We relate our work to two recent algorithms, one for
clustering affine subspaces and the other for Monte-Carlo SVD based on volume
sampling
Gender Moderation in Gamification: Does One Size Fit All?
Organizations actively seek methods for increasing employee engagement by incorporating game elements in core systems and processes, in an effort to increase their perceived playfulness. However, little is known about the actual impact of these elements on perceived playfulness. This study includes results from three repeated experiments performed during a gamified academic course. The relationships between enjoyment of specific game elements, the way they increase perceived playfulness, and gender moderations of these relations were examined. All three experiments show that badges had a positive relation with perceived playfulness and were more enjoyable to women. Surprisingly, the results showed that when men were the majority of subjects in the group, the relations between the game elements and perceived playfulness were different from when men were a minority. These results provide important insight into what possibly influences perceived playfulness in gamified solutions
Three-Prong Distribution of Massive Narrow QCD Jets
We study the planar-flow distributions of narrow, highly boosted, massive QCD
jets. Using the factorization properties of QCD in the collinear limit, we
compute the planar-flow jet function from the one-to-three splitting function
at tree-level. We derive the leading-log behavior of the jet function
analytically. We also compare our semi-analytic jet function with parton-shower
predictions using various generators.Comment: 59 pages, 9 figure
PreFair: Privately Generating Justifiably Fair Synthetic Data
When a database is protected by Differential Privacy (DP), its usability is
limited in scope. In this scenario, generating a synthetic version of the data
that mimics the properties of the private data allows users to perform any
operation on the synthetic data, while maintaining the privacy of the original
data. Therefore, multiple works have been devoted to devising systems for DP
synthetic data generation. However, such systems may preserve or even magnify
properties of the data that make it unfair, endering the synthetic data unfit
for use. In this work, we present PreFair, a system that allows for DP fair
synthetic data generation. PreFair extends the state-of-the-art DP data
generation mechanisms by incorporating a causal fairness criterion that ensures
fair synthetic data. We adapt the notion of justifiable fairness to fit the
synthetic data generation scenario. We further study the problem of generating
DP fair synthetic data, showing its intractability and designing algorithms
that are optimal under certain assumptions. We also provide an extensive
experimental evaluation, showing that PreFair generates synthetic data that is
significantly fairer than the data generated by leading DP data generation
mechanisms, while remaining faithful to the private data.Comment: 15 pages, 11 figure
Deterministic Entanglement of Assistance and Monogamy Constraints
Certain quantum information tasks require entanglement of assistance, namely
a reduction of a tripartite entangled state to a bipartite entangled state via
local measurements. We establish that 'concurrence of assistance' (CoA)
identifies capabilities and limitations to producing pure bipartite entangled
states from pure tripartite entangled states and prove that CoA is an
entanglement monotone for -dimensional pure states.
Moreover, if the CoA for the pure tripartite state is at least as large as the
concurrence of the desired pure bipartite state, then the former may be
transformed to the latter via local operations and classical communication, and
we calculate the maximum probability for this transformation when this
condition is not met.Comment: 5 pages, no figure
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