1,632 research outputs found
A sufficient Entanglement Criterion Based On Quantum Fisher Information and Variance
We derive criterion in the form of inequality based on quantum Fisher
information and quantum variance to detect multipartite entanglement. It can be
regarded as complementary of the well-established PPT criterion in the sense
that it can also detect bound entangled states. The inequality is motivated by
Y.Akbari-Kourbolagh [Phys. Rev A. 99, 012304 (2019)] which introduced
a multipartite entanglement criterion based on quantum Fisher information. Our
criterion is experimentally measurable for detecting any -qudit pure state
mixed with white noisy. We take several examples to illustrate that our
criterion has good performance for detecting certain entangled states.Comment: 11 pages, 1 figur
Coherence generating power of unitary transformations via probabilistic average
We study the ability of a quantum channel to generate quantum coherence when
it applies to incoherent states. Based on probabilistic averages, we define a
measure of such coherence generating power (CGP) for a generic quantum channel,
based on the average coherence generated by the quantum channel acting on a
uniform ensemble of incoherent states. Explicit analytical formula of the CGP
for any unitary channels are presented in terms of subentropy. An upper bound
for CGP of unital quantum channels has been also derived. Detailed examples are
investigated.Comment: 16 pages, 2 figures, LaTeX, accepted versio
Characterization of four-qubit states via Bell inequalities
A set of Bell inequalities classifying the quantum entanglement of four-qubit
states is presented. These inequalities involve only two measurement settings
per observer and can characterize fully separable, bi-separable and
tri-separable quantum states. In addition, a quadratic inequality of the Bell
operators for four-qubit systems is derived
Smarr Integral Formula of D-dimensional Stationary Spacetimes in Einstein-\AE ther-Maxwell Theroy
Using the Wald formalism, we investigate the thermodynamics of charged black
holes in D-dimensional stationary spacetimes with or without rotations in
Einstein-\ae ther-Maxwell theory. In particular, assuming the existence of a
scaling symmetry of the action, we obtain the Smarr integral formula, which can
be applied to both Killing and universal horizons. When restricted to
4-dimensional spherically symmetric spacetimes, previous results obtained by a
different method are re-derived.Comment: No figures and tables. Phys. Let. B782 (2018) 723-72
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