55 research outputs found
Engineering asymmetric steady-state Einstein-Podolsky-Rosen steering in macroscopic hybrid systems
Generation of quantum correlations between separate objects is of
significance both in fundamental physics and in quantum networks. One important
challenge is to create the directional "spooky action-at-a-distanc" effects
that Schr\"{o}dinger called "steering" between two macroscopic and massive
objects. Here, we analyze a generic scheme for generating steering correlations
in cascaded hybrid systems in which two distant oscillators with effective
masses of opposite signs are coupled to a unidirectional light field, a setup
which is known to build up quantum correlations by means of quantum back-action
evasion. The unidirectional coupling of the first to the second oscillator via
the light field can be engineered to enhance steering in both directions and
provides an active method for controlling the asymmetry of steering. We show
that the resulting scheme can efficiently generate unconditional steady-state
Einstein-Podolsky-Rosen steering between the two subsystems, even in the
presence of thermal noise and optical losses. As a scenario of particular
technological interest in quantum networks, we use our scheme to engineer
enhanced steering from an untrusted node with limited tunability (in terms of
interaction strength and type with the light field) to a trusted, highly
tunable node, hence offering a path to implementing one-sided
device-independent quantum tasks.Comment: 11 pages, 8 figure
Unconditional steady-state entanglement in macroscopic hybrid systems by coherent noise cancellation
The generation of entanglement between disparate physical objects is a key
ingredient in the field of quantum technologies, since they can have different
functionalities in a quantum network. Here we propose and analyze a generic
approach to steady-state entanglement generation between two oscillators with
different temperatures and decoherence properties coupled in cascade to a
common unidirectional light field. The scheme is based on a combination of
coherent noise cancellation and dynamical cooling techniques for two
oscillators with effective masses of opposite signs, such as quasi-spin and
motional degrees of freedom, respectively. The interference effect provided by
the cascaded setup can be tuned to implement additional noise cancellation
leading to improved entanglement even in the presence of a hot thermal
environment. The unconditional entanglement generation is advantageous since it
provides a ready-to-use quantum resource. Remarkably, by comparing to the
conditional entanglement achievable in the dynamically stable regime, we find
our unconditional scheme to deliver a virtually identical performance when
operated optimally.Comment: Final version; 6 pages, 3 figures + Supplemental Materia
MVA2023 Small Object Detection Challenge for Spotting Birds: Dataset, Methods, and Results
Small Object Detection (SOD) is an important machine vision topic because (i)
a variety of real-world applications require object detection for distant
objects and (ii) SOD is a challenging task due to the noisy, blurred, and
less-informative image appearances of small objects. This paper proposes a new
SOD dataset consisting of 39,070 images including 137,121 bird instances, which
is called the Small Object Detection for Spotting Birds (SOD4SB) dataset. The
detail of the challenge with the SOD4SB dataset is introduced in this paper. In
total, 223 participants joined this challenge. This paper briefly introduces
the award-winning methods. The dataset, the baseline code, and the website for
evaluation on the public testset are publicly available.Comment: This paper is included in the proceedings of the 18th International
Conference on Machine Vision Applications (MVA2023). It will be officially
published at a later date. Project page :
https://www.mva-org.jp/mva2023/challeng
Theoretical Insights into the Regiodivergence in Ni-Catalyzed [2+2+2] Cycloaddition of Unsymmetric Diynes and CO<sub>2</sub>
To achieve the peak of carbon dioxide emission and carbon neutrality, utilizing it as a renewable carbon unit in organic synthesis presents an effective chemical solution for sustainable development. In this study, we report a theoretical investigation into the reaction mechanism and the regiodivergence of the Ni-catalyzed [2+2+2] cycloaddition of unsymmetric diynes and CO2 by using DFT calculations. The reaction mechanisms can be classified into two types: one is related to the oxidative coupling of the C≡C moiety with CO2, and the other is related to the oxidative coupling of the two C≡C moieties of diyne. In each type, two possible paths were proposed depending upon the positions of the substituents (H and silyl). Our calculation results indicate that the oxidative coupling of the C≡C moiety and CO2 favors the positions of H-substituent, while the oxidative coupling of the two C≡C moieties is beneficial for inserting CO2 at the positions of silyl-substituent. The regiodivergence is controlled by substrate chain-length and ligand in the different reaction mechanisms
Background-Quenched Aggregation-Induced Emission through Electrostatic Interactions for the Detection of Poly(ADP-ribose) Polymerase-1 Activity
Poly(ADP-ribose) polymerase-1 (PARP1) is a potential biomarker and therapeutic target for cancers that can catalyze the poly-ADP-ribosylation of nicotinamide adenine dinucleotide (NAD+) onto the acceptor proteins to form long poly(ADP-ribose) (PAR) polymers. Through integration with aggregation-induced emission (AIE), a background-quenched strategy for the detection of PARP1 activity was designed. In the absence of PARP1, the background signal caused by the electrostatic interactions between quencher-labeled PARP1-specitic DNA and tetraphenylethene-substituted pyridinium salt (TPE-Py, a positively charged AIE fluorogen) was low due to the fluorescence resonance energy transfer effect. After poly-ADP-ribosylation, the TPE-Py fluorogens were recruited by the negatively charged PAR polymers to form larger aggregates through electrostatic interactions, thus enhancing the emission. The detection limit of this method for PARP1 detection was found to be 0.006 U with a linear range of 0.01~2 U. The strategy was used to evaluate the inhibition efficiency of inhibitors and the activity of PARP1 in breast cancer cells with satisfactory results, thus showing great potential for clinical diagnostic and therapeutic monitoring
- …