ABSTRACT
When considered as orthogonal bases in distinct vector spaces, the unit vectors of polarization directions and the Laguerre-Gaussian modes of polarization amplitude are inseparable, constituting a so-called classical entangled light beam. Equating this classical entanglement to quantum entanglement necessary for computing purpose, we show that the parallelism featured in Shor's factoring algorithm is equivalent to the concurrent light-path propagation of an entangled beam or pulse train. A gedanken experiment is proposed for executing the key algorithmic steps of modular exponentiation and Fourier transform on a target integer N using only classical manipulations on the amplitudes and polarization directions. The multiplicative order associated with the sought-after integer factors is identified through a four-hole diffraction interference from sources obtained from the entangled beam profile. The unique mapping from the fringe patterns to the computed order is demonstrated through simulations for the case [Formula: see text].
ABSTRACT
Broadband 5G communication requires the operation of nonreciprocal devices in the Ku band. A wideband photonic crystal circulator is implemented by introducing two partial-height triangular Ni-Zn ferrites into the Al2O3 ceramic rod-arrays. The asymmetric sizes of the two equilateral triangles paired with self-matching effectively extend the bandwidth of the circulator eight times over that of the symmetric scheme. Numerical simulations demonstrate that the photonic crystal circulator can obtain a bandwidth of 1.00 GHz with an isolation 25.75 dB and an insertion loss 0.381 dB through optimized matched triangle size ratio, suitable for applications in future communication systems.
ABSTRACT
Immunosensors are molecular recognition-based solid-state biosensing devices, in which the immunochemical reactions are coupled with transducers. As biologic or biochemical substances produced by tumor cells, tumor marker plays an important role in clinical diagnosis and treatment of cancer because its concentration is related to tumor size, clinical stage, and predicting prognosis. Voltammetric immunosensors based on the electrochemical analysis technique provide a sensitive electroanalytical approach for quantitatively detecting tumor markers by measuring the current as a function of the potential. To satisfy the need for accurate monitoring of tumor markers in low-concentration and their slight changes in concentration, the primary aim of developing a novel voltammetric immunosensor is to improve its sensitivity and limit of detection. Compared with traditional immunoassay, the advanced sensitivity-amplified immunosensors have applied appropriate amplification strategies to convert the bio-signal of antigen-antibody recognition events to the high electrochemical signal of redox species. Building on the significant concepts, sensitivity and limit of detection, we describe how the performance of voltammetric immunosensors can be improved by various sensitivity amplification mechanisms: (1) construction of labels with a high loading of signal species; (2) introduction of interfacial reaction initiated by functionalized nanomaterials; (3) building a synergistic connection between labels and substrate. The review ends with a summary of the shortage of current sensitivity amplified immunosensors and the perspective of enhancement strategies for more simple, efficient, and reliable voltammetric immunosensors.
Subject(s)
Biosensing Techniques , Nanostructures , Biomarkers, Tumor , Electrochemical Techniques , ImmunoassayABSTRACT
Some nonlinear radiations such as superfluorescence can be understood as cooperative effects between atoms. We regard cooperative radiations as a manifested effect secondary to the intrinsic synchronization among the two-level atoms and propose the entanglement measure, concurrence, as a time-resolved measure of synchronization. Modeled on two cavity-coupled qubits, the evolved concurrence monotonically increases to a saturated level. The finite duration required for the rising to saturation coincides with the time delay characteristic to the initiation of superfluorescence, showing the role of synchronization in establishing the cooperation among the qubits. We verify concurrence to be a good measure of synchronization by comparing it with asynchronicity computed from the difference between the density matrices of the qubits. We find that the feature of time delay agrees in both measures and is determined by the coupling regimes of the cavity-qubit interaction. Specifically, synchronization is impossible in the weak coupling regime.
ABSTRACT
It is generally believed that the perpendicular magnetic anisotropy (PMA) plays an important role in stabilizing skyrmion lattices (SkL) in two-dimensional (2D) magnetic systems in which both Heisenberg exchange and Dzyaloshinskii-Moriya interactions co-exist, and the skyrmion sizes in SkLs are mainly determined by the strengths of these two intrinsic interactions. To investigate the details, we employ here a quantum computational approach we develop in recent years to simulate the Néel-type skyrmion lattices formed on a 2D PdFe/Ir(1 1 1)-like film. From our simulated results, we find that: within an external magnetic field applied normal to the film plane, the PMA is indeed able to help induce Néel-type SkLs in a wider field range; however, to stabilize the SkLs, the PMA cannot be too strong, the strengths of the external magnetic field and the maximal PMA must satisfy a sum rule since the effective perpendicular magnetic field generated by these two interactions cannot exceed a largest value. We also notice that the periodical boundary condition imposed on the FM system in simulations is able to facilitate SkL formations, and it can also modify the skyrmion size in a certain extend.
ABSTRACT
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.
ABSTRACT
We study the absorption spectrum of a probe field by a Λ-type three-level system, which is coupled to a quantized control field through the two upper energy levels. The probe field is applied to the ground and the second excited states. When the quantized control field is in vacuum, we derive a threshold condition to discern vacuum induced transparency (VIT) and vacuum induced Autler-Townes splitting (ATS). We also find that the parameter changing from VIT to vacuum induced ATS is very similar to that from broken PT symmetry to PT symmetry. Moreover, we find the photon number resolved spectrum in the parameter regime of vacuum induced ATS when the mean photon number of the quantized control field is changed from zero (vacuum) to a finite number. However, there is no photon number resolved spectrum in the parameter regime of VIT even that the quantized control field contains the finite number of photons. Finally, we further discuss possible experimental realization.
ABSTRACT
In recent years, quantum image processing is one of the most active fields in quantum computation and quantum information. Image scaling as a kind of image geometric transformation has been widely studied and applied in the classical image processing, however, the quantum version of which does not exist. This paper is concerned with the feasibility of the classical bilinear interpolation based on novel enhanced quantum image representation (NEQR). Firstly, the feasibility of the bilinear interpolation for NEQR is proven. Then the concrete quantum circuits of the bilinear interpolation including scaling up and scaling down for NEQR are given by using the multiply Control-Not operation, special adding one operation, the reverse parallel adder, parallel subtractor, multiplier and division operations. Finally, the complexity analysis of the quantum network circuit based on the basic quantum gates is deduced. Simulation result shows that the scaled-up image using bilinear interpolation is clearer and less distorted than nearest interpolation.
