554 research outputs found
Universal corner contributions to entanglement negativity
It has been realised that corners in entangling surfaces can induce new
universal contributions to the entanglement entropy and R\'enyi entropy. In
this paper we study universal corner contributions to entanglement negativity
in three- and four-dimensional CFTs using both field theory and holographic
techniques. We focus on the quantity defined by the ratio of the
universal part of the entanglement negativity over that of the entanglement
entropy, which may characterise the amount of distillable entanglement. We find
that for most of the examples takes bigger values for singular
entangling regions, which may suggest increase in distillable entanglement.
However, there also exist counterexamples where distillable entanglement
decreases for singular surfaces. We also explore the behaviour of as the
coupling varies and observe that for singular entangling surfaces, the amount
of distillable entanglement is mostly largest for free theories, while
counterexample exists for free Dirac fermion in three dimensions. For
holographic CFTs described by higher derivative gravity, may increase or
decrease, depending on the sign of the relevant parameters. Our results may
reveal a more profound connection between geometry and distillable
entanglement.Comment: 28 pages, 5 figure
Extracting energy via magnetic reconnection from Kerr-de Sitter black holes
It has been recently shown that magnetic reconnection can provide us a novel
mechanism to extract black hole rotational energy from a Kerr black holes. In
some certain values of parameters, such mechanism is found to be more efficient
than the Blandford-Znajek mechanism. In this paper, we study the energy
extraction from the Kerr-de Sitter black hole via this magnetic reconnection
process. With the increase of the cosmological constant, a slowly spinning
Kerr-de Sitter black hole can implement the energy extraction than its Kerr
counterpart. Of particular interest is that although the numerical calculation
shows that the maximum values of the power and efficiency decrease with the
cosmological constant, Kerr-de Sitter black hole still has advantages when the
black hole spin and the dominant reconnection -point is far away
from the event horizon. These results uncover the significant effects of
cosmological constant on the energy extraction via the magnetic reconnection
process.Comment: 16 pages, 11 figure
A Hybrid Quantum Encoding Algorithm of Vector Quantization for Image Compression
Many classical encoding algorithms of Vector Quantization (VQ) of image
compression that can obtain global optimal solution have computational
complexity O(N). A pure quantum VQ encoding algorithm with probability of
success near 100% has been proposed, that performs operations 45sqrt(N) times
approximately. In this paper, a hybrid quantum VQ encoding algorithm between
classical method and quantum algorithm is presented. The number of its
operations is less than sqrt(N) for most images, and it is more efficient than
the pure quantum algorithm.
Key Words: Vector Quantization, Grover's Algorithm, Image Compression,
Quantum AlgorithmComment: Modify on June 21. 10pages, 3 figure
Fabrication of multianalyte CeO2 nanograin electrolyte–insulator–semiconductor biosensors by using CF4 plasma treatment
Multianalyte CeO2 biosensors have been demonstrated to detect pH, glucose, and urine concentrations. To enhance the multianalyte sensing capability of these biosensors, CF4 plasma treatment was applied to create nanograin structures on the CeO2 membrane surface and thereby increase the contact surface area. Multiple material analyses indicated that crystallization or grainization caused by the incorporation of flourine atoms during plasma treatment might be related to the formation of the nanograins. Because of the changes in surface morphology and crystalline structures, the multianalyte sensing performance was considerably enhanced. Multianalyte CeO2 nanograin electrolyte–insulator–semiconductor biosensors exhibit potential for use in future biomedical sensing device applications
CoSDA: Continual Source-Free Domain Adaptation
Without access to the source data, source-free domain adaptation (SFDA)
transfers knowledge from a source-domain trained model to target domains.
Recently, SFDA has gained popularity due to the need to protect the data
privacy of the source domain, but it suffers from catastrophic forgetting on
the source domain due to the lack of data. To systematically investigate the
mechanism of catastrophic forgetting, we first reimplement previous SFDA
approaches within a unified framework and evaluate them on four benchmarks. We
observe that there is a trade-off between adaptation gain and forgetting loss,
which motivates us to design a consistency regularization to mitigate
forgetting. In particular, we propose a continual source-free domain adaptation
approach named CoSDA, which employs a dual-speed optimized teacher-student
model pair and is equipped with consistency learning capability. Our
experiments demonstrate that CoSDA outperforms state-of-the-art approaches in
continuous adaptation. Notably, our CoSDA can also be integrated with other
SFDA methods to alleviate forgetting.Comment: 15 pages, 6 figure
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