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Multiple magnetic transitions and magnetocaloric effect of Tb_(4)Coln alloy

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Journal of Rare Earths 2023年第11期41卷 1721-1727,I0003页

作者： Remya U.D. Arun K. Swathi S. Athul S.R. Andrea Dzubinska Marian Reiffers Nagalakshmi R. intermetallics and non-linear optics laboratory Department of PhysicsNational Institute of TechnologyTiruchirappalli620015India CPM-TIP University Pavol Jozef Safarik04011KošiceSlovakia Faculty of Humanities and Natural Sciences Presov UniversityPresovSlovakia Institute of Experimental Physics SASKosiceSlovakia

We report on the magnetic,magnetocaloric,thermal,and electrical transport properties of Tb_(4)Coln alloy,which crystallizes in two phases,Tb_6Co_(2.1)In_(0.8)(space group Immm)and Tb_(2)In_(0.9)Co_(0.1)(space group P6_(3)/mmc),*** alloy reveals three successive magnetic transitions around T_(1)(163 K),T_(2)(50 K),and T_(3)(29 K),respectively,associated with paramagnetic to ferromagnetic transition and two sequential antiferromagnetic *** low-temperature transition T_(3) follows the first-order magnetic behavior and exhibits the field-induced magnetic ***,T_(2) and T_(1) are found to be second-order in nature which opens a possibility for hysteresis-free magnetocaloric *** magnetocaloric properties are determined using different magnetocaloric figures of merits such as-ΔS_(M),ΔT_(ad).RCP,and TEC(10).Additionally,the universal curve behavior in the isothermal entropy change unveils the variation in critical exponents around T_(1) and T_(2) due to the magnetic inhomogeneity in the ***,the electrical transport properties of the metallic alloy denote the maximum magnetoresistance of-10%around T_(1).

关键词： Multiple magnetic transitions Order of magnetic transition Magnetocaloric effect Magnetoresistance Universal curve behavior Rare earths

A quantum-search-based multi-classifier for image recognition

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 21-31页

作者： Lu Liu Xingyu Wu Lufan Zhang Chuan Wang School of Artificial Intelligence Beijing Normal University Applied optics Beijing Area Major laboratory Beijing Normal University

The multi-class classification of images is a pivotal challenge within the realm of image processing. As the volume of visual data continues to expand, there is a burgeoning interest in harnessing the unique capabilities of quantum computation to augment the efficiency of classification tasks. However, many existing methods for training quantum image multi-classifiers parallel classical machine learning techniques, where the requisite circuit measurements increase linearly with the volume of training data. This work introduces a novel approach for training a quantum image multi-classifier based on the quantum search algorithm. We have meticulously conducted rigorous experiments on a handwritten digit dataset, a classic benchmark in the field. The results have been meticulously compared with previous works, and the comparative analysis not only validates the efficiency of our proposed approach, requiring only O(N/b) measurements during training, but also highlights a significant quadratic speedup of the algorithm.

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The laser-intensity dependence of the photoassociation spectrum of the ultracold Cs_2(6S_(1/2) + 6P_(1/2))0_u^+ long-range molecular state

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Chinese Physics B 2013年第8期22卷 732-737页

作者：金丽冯国胜武寄洲马杰汪丽蓉肖连团贾锁堂 State Key laboratory of Quantum optics and Quantum optics Devices Laser Spectroscopy Laboratory Shanxi University

The high-resolution photoassociation spectrum of the ultracold cesium molecular 0＋ state below the 6S1/2 ＋ 6PI/2 limit is presented in this paper. The saturation of the photoassociation scattering probability is observed from the depen dence of the trap-loss probability on the photoassociation laser intensity. The corresponding resonant line width is also demonstrated to increase linearly with increasing photoassociation laser intensity. Our experimental data have good con sistency with the theoretical saturation model of Bohn and Julienne [Bohn J L and Julienne P S 1999 Phys. Rev. A 60 1].

关键词： photoassociation spectrum intensity dependence high resolution

Photon counts modulation in optical time domain reflectometry

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Chinese Physics B 2011年第6期20卷 258-262页

作者：王晓波王晶晶张国锋肖连团贾锁堂 State Key laboratory of Quantum optics and Quantum optics Devices Laser Spectroscopy Laboratory Shanxi University

The quantum fluctuation of photon counting limits the field application of optical time domain reflection. A method of photon counts modulation optics time domain reflection with single photon detection at 1.55 μm is presented. The influence of quantum fluctuation can be effectively controlled by demodulation technology since quantum fluctuation shows a uniform distribution in the frequency domain. Combined with the changing of the integration time of the lock-in amplifier, the signal to noise ratio is significantly enhanced. Accordingly the signal to noise improvement ratio reaches 31.7 dB compared with the direct photon counting measurement.

关键词： single photon detection optical time domain reflection modulation quantum fluctuation

Investigation of ultracold atoms and molecules in a dark magneto-optical trap

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Chinese Physics B 2012年第11期21卷 179-183页

作者：汪丽蓉姬中华元晋鹏杨艳赵延霆马杰肖连团贾锁堂 State Key laboratory of Quantum optics and Quantum optics Devices Laser Spectroscopy LaboratoryShanxi University

In this paper, ultracold atoms and molecules in a dark magneto-optical trap （MOT） are studied via depumping the cesium cold atoms into the dark hyperfine ground state. The collision rate is reduced to 0.45 s-1 and the density of the atoms is increased to 5.6 × 1011 cm-3 when the fractional population of the atoms in the bright hyperfine ground state is as low as 0.15. The vibrational spectra of the ultracold cesium molecules are also studied in a standard MOT and in a dark MOT separately. The experimental results are analyzed by using the perturbative quantum approach.

关键词： cold atom dark magneto-optical trap photoassociation

Single-photon modulation spectrum

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Chinese Physics B 2014年第1期23卷 30-34页

作者：刘岩于波何博张国峰肖连团贾锁堂 State Key laboratory of Quantum optics and Quantum optics Devices Laser Spectroscopy Laboratory Shanxi University

We present a robust method of single-photon modulation by directly modulating the single photons and observe its fre- quency spectrum. Compared with conventional photon counting technique, the single-photon modulation spectrum shows that the method could not only realize high-frequency modulation but also obtain higher signal-to-noise ratio. Moreover, the theoretical calculations show good agreement with the experimental results.

关键词： signal-to-noise ratio single-photon modulation spectrum

High resolution photoassociation spectra of an ultracold Cs_2 long-range 0_u^+ (6S_(1/2)+6P_(1/2) ) state

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Chinese Physics B 2013年第9期22卷 376-380页

作者：陈鹏李玉清张一驰武寄洲马杰肖连团贾锁堂 State Key laboratory of Quantum optics and Quantum optics Devices Laser Spectroscopy LaboratoryShanxi University

In this paper, ultracold cesium molecules are formed through photoassociation technology, which is carried out in a magneto-optical trap. High resolution photoassociaion spectra with the rotational progressions up to J = 7 are obtained. Three rovibrational levels of the long-range 0＋ state of Cs2 below the （6S1/2 ＋ 6P1/2） dissociation limit are specifically investigated. By fitting their binding energy intervals to the non-rigid rotational model, the rotational constant of the long- range 0u＋ state is determined. A proportional dependence of the value of the rotational constant on the vibrational quantum number is demonstrated.

关键词： ultracold molecules photoassociation trap-loss spectrum long-range molecular coefficient

Phase-locked laser coherent interference

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Chinese optics Letters 2011年第9期9卷 45-47页

作者：王晶晶王晓波何博肖连团贾锁堂 State Key laboratory of Quantum optics and Quantum optics Devices Laser Spectroscopy LaboratoryShanxi University

A method of locking the relative phase to provide stable constructive or destructive interference between the phase-modulated sidebands from a pair of phase modulators is demonstrated. It is discussed theoretically for optimal fringe visibility related to the phase noise from faulty system. After phase locking using the phase modulating and lock-in technique, the drift of the relative phase is focalized around ±0.0016 rad and the fringe visibility is restricted to 2× 10^-4.

关键词： Phase modulation

Comparison between iterative wavefront control algorithm and direct gradient wavefront control algorithm for adaptive optics system

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Chinese Physics B 2015年第8期24卷 391-397页

作者：程生毅刘文劲陈善球董理治杨平许冰 laboratory on Adaptive optics Institute of Optics and Electronics Chinese Academy of Sciences Key laboratory on Adaptive optics Chinese Academy of Sciences University of the Chinese Academy of Sciences

Among all kinds of wavefront control algorithms in adaptive optics systems, the direct gradient wavefront control algorithm is the most widespread and common method. This control algorithm obtains the actuator voltages directly from wavefront slopes through pre-measuring the relational matrix between deformable mirror actuators and Hartmann wavefront sensor with perfect real-time characteristic and stability. However, with increasing the number of sub-apertures in wavefront sensor and deformable mirror actuators of adaptive optics systems, the matrix operation in direct gradient algorithm takes too much time, which becomes a major factor influencing control effect of adaptive optics systems. In this paper we apply an iterative wavefront control algorithm to high-resolution adaptive optics systems, in which the voltages of each actuator are obtained through iteration arithmetic, which gains great advantage in calculation and storage. For AO system with thousands of actuators, the computational complexity estimate is about O(n2) ～ O(n3) in direct gradient wavefront control algorithm, while the computational complexity estimate in iterative wavefront control algorithm is about O(n) ～(O(n)3/2), in which n is the number of actuators of AO system. And the more the numbers of sub-apertures and deformable mirror actuators, the more significant advantage the iterative wavefront control algorithm exhibits.

关键词： adaptive optics iterative wavefront control algorithm direct gradient wavefront control algorithm