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Dynamics of Kerr-like medium with two-mode intensity-dependent cavity fields
摘要： The dynamics of an effective two-level atom coupled to two-mode intensity-dependent quantized cavity fields via a ladder process in the presence of a Kerr medium has been investigated. Eigenfunctions and eigenvalues of the Hamiltonian of the interacting system have been obtained using a unitary transformation method. The cavity field statistics and non-classical properties are investigated numerically through second-order correlation functions. The effect of detuning and the Kerr medium on the non-classical features of the atom-field state has been analyzed. We find that the presence of Kerr non-linearity enhances the non-classical correlation between the correlated beams at short time intervals and increases antibunching at short time intervals.
关键词： intensity-dependent coupling,antibunching,photon statistics,Kerr non-linearity,two-mode ladder model,Cauchy–Schwartz inequality,second-order correlation functions
更新于2025-09-09 09:28:46
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A Palm-vein recognition algorithm based on LPP and HM-LBP
摘要： In this paper, an algorithm based on locality preserving projection (LPP) for palm-vein was proposed. The feature of palm-vein was extracted by Hierarchical multiscale local binary pattern(HM-LBP), and then the dimension was reduced by LPP. Lastly, the palm-vein was classified by normalized correlation classifier. The algorithm was tested on the near-infrared database of the multi-spectral palm database of Hong Kong polytechnic university. The experiment results show that the algorithm can achieve ideal recognition accuracy of 99.92% and the speediness is able to fit for the real-time palm-vein recognition system.
关键词： normalized correlation classifier,palm-vein recognition,HM-LBP,LPP
更新于2025-09-09 09:28:46
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Experimental observation of the Leggett-Garg inequality violation in classical light
摘要： Leggett-Garg inequalities (LG inequalities) have been derived to clarify the validity of generalizing quantum mechanics to macroscopic systems more than thirty years. They have been used as tools to investigate the existence of quantum coherence in the macroscopic systems. Here we show that such inequalities violation can also be observed in classical optical systems. Using the linear polarization degree of freedom as the dichotomic observables, in classical optical experiment we have observed the violation of LG inequality by implementing the non-invasive measurement. Furthermore, the coherence witness, which is analogy of the quantum witness, has also been observed in the classical optical experiment. Our results not only provide new physical insights into the macroscopic quantum correlation and quantum witness, but also show their potential applications in correlated information processes.
关键词： classical optical correlation,Leggett-Garg inequality
更新于2025-09-09 09:28:46
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Optical correlation-domain reflectometry without optical frequency shifter
摘要： To achieve distributed re?ectivity measurements along an optical ?ber, we developed a simpli?ed cost-effective con?guration for optical correlation- (or coherence-) domain re?ectometry based on a synthesized optical coherence function using sinusoidal modulation. By excluding the conventional optical heterodyne detection that accompanies the frequency shift (without using an acousto-optic modulator) and by exploiting the foot of the electrical Fresnel re?ection spectrum, the electrical bandwidth required for signal processing is lowered to several megahertz. We evaluate the basic system performance and demonstrate its high-speed operation (10 ms for one scan) by tracking a moving re?ection point in real time.
关键词： optical correlation-domain re?ectometry,distributed re?ectivity measurements,optical coherence function,sinusoidal modulation
更新于2025-09-09 09:28:46
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) formation: Comparison with
摘要： Superexcited states of H2S have been investigated with determining the cross sections for emission of dispersed and nondispersed atomic ?uorescence against the incident photon energy in the range 11–40 eV to address the ionization and excitation of the valence electrons. This method enables us to extract the discrete electronic state from the superposition with continuous electronic states. The cross sections for H(2p) formation have been put on an absolute scale. Ten superexcited states have been found, two in the range 13–15 eV are singly excited 2b?1 2 (mo) states with a single con?guration and the other eight states in the range 16–25 eV are doubly excited states with multiple con?gurations. State-resolved dipole oscillator strengths for H(2p) formation in the photoexcitation of H2S have been determined. Similar experiments have been performed for H2O. The state-resolved dipole oscillator strengths for H(2p) formation in the photoexcitation of H2S are ～10?3, whereas those in the photoexcitation of H2O range from ～10?3 to ～10?2. It is found that major fragment atoms are H(2p) atoms in the photoexcitation of H2O and S? in the photoexcitation of H2S. The superexcited states of H2O and H2S are compared based on the similarity and difference of the electronic structures. It turns out from the comparison that (i) the smaller values of the dipole oscillator strengths for H(2p) formation in the photoexcitation of H2S are related to the change of the major fragment atoms and (ii) the energy splitting of the doubly excited “4a?1 1 (mo(cid:4))” states of H2O. This enhancement is caused by the stronger electron correlation in H2S than in H2O. The similarity in shape is indicated between the inner valence band and inner shell band in the ?uorescence cross sections against the incident photon energy for H2S and H2O.
关键词： superexcited states,H2O,dipole oscillator strengths,electron correlation,H2S,double photoexcitation
更新于2025-09-09 09:28:46
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Witnessing bipartite entanglement sequentially by multiple observers
摘要： We investigate sharing of bipartite entanglement in a scenario where half of an entangled pair is possessed and projectively measured by one observer, called Alice, while the other half is subjected to measurements performed sequentially, independently, and unsharply, by multiple observers, called Bobs. We ?nd that there is a limit on the number of observers in this entanglement distribution scenario. In particular, for a two-qubit maximally entangled initial shared state, no more than 12 Bobs can detect entanglement with a single Alice for arbitrary, possibly unequal, sharpness parameters of the measurements by the Bobs. The number of Bobs remains unaltered for a ?nite range of near-maximal pure initial entanglement, a feature that also occurs in the case of equal sharpness parameters at the Bobs. Furthermore, we show that for nonmaximally entangled shared pure states, the number of Bobs decreases with the amount of initial entanglement, providing a coarse-grained but operational measure of entanglement.
关键词： sequential measurements,entanglement,unsharp measurements,entanglement witnesses,quantum correlation
更新于2025-09-09 09:28:46
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x-ray transitions in Cu- and Ni-like tungsten ions
摘要： The 4d → 3p x-ray transitions in Cu- and Ni-like tungsten ions have been studied theoretically. The multicon?guration Dirac-Hartree-Fock (MCDHF) method and the large-scale relativistic con?guration-interaction (CI) method have been employed in order to take into account electron correlation effects on the wavelengths and transition rates. It was found that the wavelengths and transition rates obtained from the MCDHF-CI method depend strongly on the size and the type of the active space used in the calculations. It has been found that extending the active space of orbitals without careful control of the con?guration state function base does not always lead to good quality MCDHF-CI results for highly ionized tungsten ions.
关键词： x-ray transitions,CI,electron correlation,MCDHF,tungsten ions
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Hyperspectral Band Selection Using Pair-Wise Constraint and Band-Wise Correlation
摘要： In this paper, a novel supervised band selection (BS) method based on pair-wise constraint and band-wise correlation information is proposed for the dimension reduction of hyperspectral images. On the one hand, the band-wise correlation information, is used for selecting band-subset with lower redundancy and higher representation. This process is achieved by first partitioning all spectral bands into continuous groups and then calculate a band-wise correlation matrix within each group, which is used later for selecting bands of more representation and lower redundancy. On the other hand, pair-wise supervised information (i.e., whether a pair of labeled samples are from the same class) is exploited for selecting band-subsets to better discriminate different classes. That is, a few bands are adaptively chosen for each pair of labeled samples according to spectral-similarity, to ensure that the distance between samples from different classes is far and keep sample-pair from same class close. By the joint use of both pair-wise constraint information and band-wise correlation information, the proposed BS method can lead to select optimal band-subsets with low-redundancy, high-representation and high-discrimination. Experimental results demonstrate the effectiveness of the proposed BS method.
关键词： Band selection,Hyperspectral image,Pair-wise constraint,Band-wise correlation
更新于2025-09-09 09:28:46
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Multi-task Hierarchical Feature Learning for Real-time Visual Tracking
摘要： Recently, the tracking community leads a fashion of end-to-end feature learning using convolutional neural networks (CNN) for visual object tracking. Traditional trackers extract feature maps from the last convolutional layer of CNNs for feature representation. This single-layer representation ignores target information captured in the earlier convolutional layers. In this paper, we propose a novel hierarchical feature learning framework which captures both high-level semantics and low-level spatial details using multi-task learning. Particularly, feature maps extracted from both the shallow layer and the deep layer are input into a correlation filter layer to encode fine-grained geometric cues and coarse-grained semantic cues respectively. Our network performs these two feature learning tasks with a multi-task learning strategy. We conduct extensive experiments on three popular tracking datasets including OTB, UAV123 and VOT2016. Experimental results show that our method achieves remarkable performance improvement while running in real-time.
关键词： correlation filter,multi-task learning,visual tracking,hierarchical feature
更新于2025-09-09 09:28:46
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Photo-Induced Depletion of Binding Sites in DNA-PAINT Microscopy
摘要： The limited photon budget of fluorescent dyes is the main limitation for localization precision in localization-based super-resolution microscopy. Points accumulation for imaging in nanoscale topography (PAINT)-based techniques use the reversible binding of fluorophores and can sample a single binding site multiple times, thus elegantly circumventing the photon budget limitation. With DNA-based PAINT (DNA-PAINT), resolutions down to a few nanometers have been reached on DNA-origami nanostructures. However, for long acquisition times, we find a photo-induced depletion of binding sites in DNA-PAINT microscopy that ultimately limits the quality of the rendered images. Here we systematically investigate the loss of binding sites in DNA-PAINT imaging and support the observations with measurements of DNA hybridization kinetics via surface-integrated fluorescence correlation spectroscopy (SI-FCS). We do not only show that the depletion of binding sites is clearly photo-induced, but also provide evidence that it is mainly caused by dye-induced generation of reactive oxygen species (ROS). We evaluate two possible strategies to reduce the depletion of binding sites: By addition of oxygen scavenging reagents, and by the positioning of the fluorescent dye at a larger distance from the binding site.
关键词： photo-induced DNA damage,surface-integrated fluorescence correlation spectroscopy (SI-FCS),reactive oxygen species,super-resolution microscopy,DNA-PAINT
更新于2025-09-09 09:28:46