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Quafu-Qcover:Explore combinatorial optimization problems on cloud-based quantum computers
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作者 许宏泽 庄伟峰 +29 位作者 王正安 黄凯旋 时运豪 马卫国 李天铭 陈驰通 许凯 冯玉龙 刘培 陈墨 李尚书 杨智鹏 钱辰 靳羽欣 马运恒 肖骁 钱鹏 顾炎武 柴绪丹 普亚南 张翼鹏 魏世杰 增进峰 李行 龙桂鲁 金贻荣 于海峰 范桁 刘东 胡孟军 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期104-115,共12页
We introduce Quafu-Qcover,an open-source cloud-based software package developed for solving combinatorial optimization problems using quantum simulators and hardware backends.Quafu-Qcover provides a standardized and c... We introduce Quafu-Qcover,an open-source cloud-based software package developed for solving combinatorial optimization problems using quantum simulators and hardware backends.Quafu-Qcover provides a standardized and comprehensive workflow that utilizes the quantum approximate optimization algorithm(QAOA).It facilitates the automatic conversion of the original problem into a quadratic unconstrained binary optimization(QUBO)model and its corresponding Ising model,which can be subsequently transformed into a weight graph.The core of Qcover relies on a graph decomposition-based classical algorithm,which efficiently derives the optimal parameters for the shallow QAOA circuit.Quafu-Qcover incorporates a dedicated compiler capable of translating QAOA circuits into physical quantum circuits that can be executed on Quafu cloud quantum computers.Compared to a general-purpose compiler,our compiler demonstrates the ability to generate shorter circuit depths,while also exhibiting superior speed performance.Additionally,the Qcover compiler has the capability to dynamically create a library of qubits coupling substructures in real-time,utilizing the most recent calibration data from the superconducting quantum devices.This ensures that computational tasks can be assigned to connected physical qubits with the highest fidelity.The Quafu-Qcover allows us to retrieve quantum computing sampling results using a task ID at any time,enabling asynchronous processing.Moreover,it incorporates modules for results preprocessing and visualization,facilitating an intuitive display of solutions for combinatorial optimization problems.We hope that Quafu-Qcover can serve as an instructive illustration for how to explore application problems on the Quafu cloud quantum computers. 展开更多
关键词 quantum cloud platform combinatorial optimization problems quantum software
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Delayed-measurement one-way quantum computing on cloud quantum computer
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作者 Zhi-Peng Yang Yu-Ran Zhang +1 位作者 Fu-Li Li heng fan 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期125-131,共7页
One-way quantum computation focuses on initially generating an entangled cluster state followed by a sequence of measurements with classical communication of their individual outcomes.Recently,a delayed-measurement ap... One-way quantum computation focuses on initially generating an entangled cluster state followed by a sequence of measurements with classical communication of their individual outcomes.Recently,a delayed-measurement approach has been applied to replace classical communication of individual measurement outcomes.In this work,by considering the delayed-measurement approach,we demonstrate a modified one-way CNOT gate using the on-cloud superconducting quantum computing platform:Quafu.The modified protocol for one-way quantum computing requires only three qubits rather than the four used in the standard protocol.Since this modified cluster state decreases the number of physical qubits required to implement one-way computation,both the scalability and complexity of the computing process are improved.Compared to previous work,this modified one-way CNOT gate is superior to the standard one in both fidelity and resource requirements.We have also numerically compared the behavior of standard and modified methods in large-scale one-way quantum computing.Our results suggest that in a noisy intermediate-scale quantum(NISQ)era,the modified method shows a significant advantage for one-way quantum computation. 展开更多
关键词 measurement-based quantum computing quantum entanglement quantum gates
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Quafu-RL:The cloud quantum computers based quantum reinforcement learning
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作者 靳羽欣 许宏泽 +29 位作者 王正安 庄伟峰 黄凯旋 时运豪 马卫国 李天铭 陈驰通 许凯 冯玉龙 刘培 陈墨 李尚书 杨智鹏 钱辰 马运恒 肖骁 钱鹏 顾炎武 柴绪丹 普亚南 张翼鹏 魏世杰 曾进峰 李行 龙桂鲁 金贻荣 于海峰 范桁 刘东 胡孟军 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期29-34,共6页
With the rapid advancement of quantum computing,hybrid quantum–classical machine learning has shown numerous potential applications at the current stage,with expectations of being achievable in the noisy intermediate... With the rapid advancement of quantum computing,hybrid quantum–classical machine learning has shown numerous potential applications at the current stage,with expectations of being achievable in the noisy intermediate-scale quantum(NISQ)era.Quantum reinforcement learning,as an indispensable study,has recently demonstrated its ability to solve standard benchmark environments with formally provable theoretical advantages over classical counterparts.However,despite the progress of quantum processors and the emergence of quantum computing clouds,implementing quantum reinforcement learning algorithms utilizing parameterized quantum circuits(PQCs)on NISQ devices remains infrequent.In this work,we take the first step towards executing benchmark quantum reinforcement problems on real devices equipped with at most 136 qubits on the BAQIS Quafu quantum computing cloud.The experimental results demonstrate that the policy agents can successfully accomplish objectives under modified conditions in both the training and inference phases.Moreover,we design hardware-efficient PQC architectures in the quantum model using a multi-objective evolutionary algorithm and develop a learning algorithm that is adaptable to quantum devices.We hope that the Quafu-RL can be a guiding example to show how to realize machine learning tasks by taking advantage of quantum computers on the quantum cloud platform. 展开更多
关键词 quantum cloud platform quantum reinforcement learning evolutionary quantum architecture search
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Construction of the underlying circRNA-miRNA-mRNA regulatory network and a new diagnostic model in ulcerative colitis by bioinformatics analysis
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作者 Yu-Yi Yuan Hui Wu +2 位作者 Qian-Yun Chen heng fan Bo Shuai 《World Journal of Clinical Cases》 SCIE 2024年第9期1606-1621,共16页
BACKGROUND Circular RNAs(circRNAs)are involved in the pathogenesis of many diseases through competing endogenous RNA(ceRNA)regulatory mechanisms.AIM To investigate a circRNA-related ceRNA regulatory network and a new ... BACKGROUND Circular RNAs(circRNAs)are involved in the pathogenesis of many diseases through competing endogenous RNA(ceRNA)regulatory mechanisms.AIM To investigate a circRNA-related ceRNA regulatory network and a new predictive model by circRNA to understand the diagnostic mechanism of circRNAs in ulcerative colitis(UC).METHODS We obtained gene expression profiles of circRNAs,miRNAs,and mRNAs in UC from the Gene Expression Omnibus dataset.The circRNA-miRNA-mRNA network was constructed based on circRNA-miRNA and miRNA-mRNA interactions.Functional enrichment analysis was performed to identify the biological mechanisms involved in circRNAs.We identified the most relevant differential circRNAs for diagnosing UC and constructed a new predictive nomogram,whose efficacy was tested with the C-index,receiver operating characteristic curve(ROC),and decision curve analysis(DCA).RESULTS A circRNA-miRNA-mRNA regulatory network was obtained,containing 12 circRNAs,three miRNAs,and 38 mRNAs.Two optimal prognostic-related differentially expressed circRNAs,hsa_circ_0085323 and hsa_circ_0036906,were included to construct a predictive nomogram.The model showed good discrimination,with a C-index of 1(>0.9,high accuracy).ROC and DCA suggested that the nomogram had a beneficial diagnostic ability.CONCLUSION This novel predictive nomogram incorporating hsa_circ_0085323 and hsa_circ_0036906 can be conveniently used to predict the risk of UC.The circRNa-miRNA-mRNA network in UC could be more clinically significant. 展开更多
关键词 Circular RNAs RNA regulatory network Ulcerative colitis New predictive model BIOINFORMATICS DIAGNOSE
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Calibration and cancellation of microwave crosstalk in superconducting circuits
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作者 严海生 赵寿宽 +8 位作者 相忠诚 王子婷 杨钊华 许凯 田野 于海峰 郑东宁 范桁 赵士平 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第9期267-273,共7页
The precise control and manipulation of the qubit state are vital for quantum simulation and quantum computation.In superconducting circuits,one notorious error comes from the crosstalk of microwave signals applied to... The precise control and manipulation of the qubit state are vital for quantum simulation and quantum computation.In superconducting circuits,one notorious error comes from the crosstalk of microwave signals applied to different qubit control lines.In this work,we present a method for the calibration and cancellation of the microwave crosstalk and experimentally demonstrate its effectiveness in a superconducting 10-qubit chain.The method is convenient and efficient especially for calibrating the microwave crosstalk with large amplitudes and variations,which can be performed successively to reduce the microwave crosstalk by two to three orders.The qubit chain with microwave driving is governed by one-dimensional(1D)Bose-Hubbard model in transverse field,which is nonintegrable and shows thermalization behaviour during the time evolution from certain initial states.Such thermalization process is observed with excellent agreement between experiment and theory further confirming the effective global cancellation of the microwave crosstalk. 展开更多
关键词 superconducting qubit microwave crosstalk Rabi oscillation
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miR-155在炎症性肠病中的免疫作用机制研究进展 被引量:3
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作者 朱凤 范恒 刘星星 《世界华人消化杂志》 CAS 2019年第17期1070-1075,共6页
炎症性肠病(inflammatory bowel disease,IBD)是一种原因未明的肠道非特异性炎症性疾病,其发病率逐年升高,对IBD的发病机制研究有待进一步深入,找到合适的治疗方法亟待解决.近期研究表明miR-155在IBD中的作用不可小觑,可通过Jarid2/not... 炎症性肠病(inflammatory bowel disease,IBD)是一种原因未明的肠道非特异性炎症性疾病,其发病率逐年升高,对IBD的发病机制研究有待进一步深入,找到合适的治疗方法亟待解决.近期研究表明miR-155在IBD中的作用不可小觑,可通过Jarid2/notch1信号通路及促进2型巨噬细胞分化来调节TH17分化,并通过抑制细胞毒T淋巴细胞相关抗原4调节Treg、通过细胞信号传导的抑制因子1调节肠成纤维细胞和肌成纤维细胞以及通过调节DNA双链断裂沉积来影响肠道炎症,本文就miR-155在IBD中的免疫作用机制作一综述. 展开更多
关键词 炎症性肠病 溃疡性结肠炎 克罗恩病 MIR-155 Jarid2
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ECR微波等离子体对单晶金刚石表面的碳纳米墙修饰 被引量:1
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作者 衡凡 廖学红 +4 位作者 曹为 付秋明 许传波 赵洪阳 马志斌 《金刚石与磨料磨具工程》 CAS 北大核心 2020年第1期34-38,共5页
利用电子回旋共振(ECR)微波等离子体,在CH4/H2体系下,对高温高压单晶金刚石表面进行了碳纳米墙修饰。通过等离子体发射光谱研究ECR等离子体内基团的谱线强度在不同工作气压、CH4浓度下的变化规律,结合扫描电子显微镜对单晶金刚石表面的... 利用电子回旋共振(ECR)微波等离子体,在CH4/H2体系下,对高温高压单晶金刚石表面进行了碳纳米墙修饰。通过等离子体发射光谱研究ECR等离子体内基团的谱线强度在不同工作气压、CH4浓度下的变化规律,结合扫描电子显微镜对单晶金刚石表面的微观形貌进行分析,进一步研究了工作气压和CH4浓度对碳纳米墙修饰结果的影响。结果表明:碳纳米墙的取向性受工作气压影响大,低气压(0.07 Pa)条件下生长的碳纳米墙垂直取向明显,金刚石表面也出现垂直刻蚀形貌;在高气压(5 Pa)条件下生长的碳纳米墙取向性较差。同时,碳纳米墙生长的临界CH4浓度也与工作气压有关:低气压条件下碳纳米墙生长的临界CH4浓度高,工作气压为0.07 Pa时,碳纳米墙生长的临界CH4浓度为3%;工作气压升至5 Pa时,碳纳米墙生长的临界CH4浓度降为1%,碳纳米墙密度随CH4浓度升高而增大。 展开更多
关键词 ECR微波等离子体 单晶金刚石 碳纳米墙修饰
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MPCVD法中氮气对单晶金刚石生长机理影响的探究 被引量:3
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作者 夏禹豪 耿传文 +2 位作者 衡凡 李方辉 马志斌 《真空科学与技术学报》 EI CAS CSCD 北大核心 2018年第8期684-688,共5页
在微波等离子体化学气相沉积法同质外延生长单晶金刚石的过程中添加不同浓度的氮气,利用发射光谱、拉曼光谱等测试手段探究不同浓度氮气对等离子体以及单晶金刚石生长质量和速率的影响,通过分析等离子体内部基团强度的变化探究添加氮气... 在微波等离子体化学气相沉积法同质外延生长单晶金刚石的过程中添加不同浓度的氮气,利用发射光谱、拉曼光谱等测试手段探究不同浓度氮气对等离子体以及单晶金刚石生长质量和速率的影响,通过分析等离子体内部基团强度的变化探究添加氮气对单晶金刚石生长机理的影响。探究发现:氮气的添加对于等离子体内基团的种类并没有明显改变,但随着氮气浓度的升高,CN基团的基团强度具有明显升高的趋势,C2基团的基团强度不断降低,单晶金刚石的生长速率不断提高。氮气并不是通过提高甲烷的离解度来产生更多的C2基团从而促进单晶金刚石的生长,而是作为一种催化剂加快单了晶金刚石表面的化学反应。当氮气浓度低于0.5%时,单晶金刚石的生长速率提高幅度较大且生长质量良好。但当氮气浓度超过0.8%时,单晶金刚石的生长速率逐渐趋近于饱和,且非金刚石相不断增多,生长质量不断降低,因而通入氮气的最佳浓度应该低于0.5%。 展开更多
关键词 微波等离子体化学气相沉积 氮气 等离子体基团 单晶金刚石生长机理
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MicroRNA-146a生物学作用的研究进展 被引量:1
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作者 吴慧 范恒 刘星星 《世界华人消化杂志》 CAS 2019年第18期1155-1160,共6页
MicroRNA是一种内源性单链非编码小分子RNA,通过与靶mRNA的特异性结合,以降解mRNA或阻碍其翻译从而在转录后水平调节靶mRNA的表达.MicroRNA-146a参与机体的多种生物学过程,具有多种生物学功能.本文将从其控制炎症反应,调节免疫,介导髓... MicroRNA是一种内源性单链非编码小分子RNA,通过与靶mRNA的特异性结合,以降解mRNA或阻碍其翻译从而在转录后水平调节靶mRNA的表达.MicroRNA-146a参与机体的多种生物学过程,具有多种生物学功能.本文将从其控制炎症反应,调节免疫,介导髓样细胞增殖以及肿瘤发生发展等几个方面进行综述. 展开更多
关键词 MicroRNA-146a 生物学作用 综述
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Effects of four regulating-intestine prescriptions on pathology and ultrastructure of colon tissue in rats with ulcerative colitis 被引量:19
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作者 heng fan Ming-Yi Qiu +3 位作者 Jia-Jun Mei Guan-Xin Shen Song-Lin Liu Rui Chen 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第31期4800-4806,共7页
AIM: To observe different histomorphologic changes of ulcerative colitis (UC) rats that were treated with four regulating-intestine prescriptions (FRIP), to investigate the curative effects of FRIP and to analyze thei... AIM: To observe different histomorphologic changes of ulcerative colitis (UC) rats that were treated with four regulating-intestine prescriptions (FRIP), to investigate the curative effects of FRIP and to analyze their treatment mechanism.METHODS: The UC rat model was made by the method of 2,4-dinitro chloro benzene (DNCB) immunity and acetic acid local enema. Ninety-eight SD rats were randomly divided into seven groups, namely, the normal control group, model group, salicylazosulfapyridine (SASP) group,Wumeiwan (WMW) group, Baitouwengtang (BTWT) group,Senglingbaishusan (SLBSS) group, and Tongxieyaofang (TXYF) group. Each group had 14 rats (with equal ratio of male and female). The six animal model groups of UC-SASP, TXYF, WMW, BTWT, SLBSS, TXYF-were treated by distilled water except the normal control group. Changes of the rat's general conditions after treatment were respectively observed, the colon tissue damage scores were given out, the pathology of colonic mucosa and changes of ultrastructure were analyzed.RESULTS: Different pathological changes on histology were shown after treatment by FRIP. The colon tissue damage score in model group was higher than that of FRIP groups and SASP group (q = 4.59, 4.77, P<0.05 or q = 5.48,6.25, 5.97, P<0.01). The scores of WMW group, BTWT group and SLBSS group were lower than that of SASP (q = 4.13, P<0.05 or q = 5.31, 5.12, P<0.01). There was no remarkable difference between the damage score of TXYF group and SASP group (q = 3.75, P>0.05). In addition, some apoptosis cells were found in the pathologic control group.CONCLUSION: The model made with DNCB and acetic acid was successful, and FRIP had better curative effect and WMW was the best curative effect, BTW, SLBSS and TXYF were similar to SASP, and we discovered that apoptosis was possibly related to UC. 展开更多
关键词 Ulcerative colitis TCM therapy Experimentalresearch PATHOLOGY ULTRASTRUCTURE Apoptosis
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促进大肠癌血管新生相关因素研究进展 被引量:1
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作者 李明月 范恒 胡德胜 《世界华人消化杂志》 CAS 2020年第11期435-442,共8页
大肠癌(colorectal cancer,CRC)是胃肠道常见的恶性肿瘤,占全球男性和女性恶性肿瘤约10%和9.4%,每年因大肠癌死亡的患者可达70万人,每年新增患者数约为140万人,呈逐年增加趋势.血管新生参与多种生理病理过程,是很多疾病(肿瘤、局部缺血... 大肠癌(colorectal cancer,CRC)是胃肠道常见的恶性肿瘤,占全球男性和女性恶性肿瘤约10%和9.4%,每年因大肠癌死亡的患者可达70万人,每年新增患者数约为140万人,呈逐年增加趋势.血管新生参与多种生理病理过程,是很多疾病(肿瘤、局部缺血、动脉粥样硬化、炎症性疾病等)以及创口愈合、组织再生的重要病理学标志.血管新生在CRC的发生、发展与转移中发挥重要作用.对于促进大肠癌血管新生相关因素的研究有利于寻找或者研发更有效的抑制CRC血管新生的药物,从而达到抗肿瘤的效果.本文就肿瘤相关血管新生、促CRC血管新生因素、结论三个方面进行综述,为我们更好地认识血管新生在CRC发病过程中的作用提供理论依据. 展开更多
关键词 大肠癌 血管新生 血管新生促进因素
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COVID-19 infection with keratitis as the first clinical manifestation 被引量:3
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作者 Dong-Mei Zuo Lin-Ping Xue +5 位作者 heng fan Sheng-Li Yang Liang-Chang Li Ji-Hong Luo Shuo Zang Jun Xiao 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2022年第9期1544-1548,共5页
·AIM:To report a case which keratitis is the first clinical manifestation of COVID-19 that occurred 3 d earlier than the common COVID-19 symptoms.·METHODS:Regular slit lamp examination,corneal scraping test,... ·AIM:To report a case which keratitis is the first clinical manifestation of COVID-19 that occurred 3 d earlier than the common COVID-19 symptoms.·METHODS:Regular slit lamp examination,corneal scraping test,and chest computed tomography(CT)were performed for patients with COVID-19 infection.The ophthalmologic treatment included ganciclovir eye drop(50 mglmL,6 times/d).The treatment for diarrhea included Guifu Lizhong pills(TID).The antiviral therapy consisted of oseltamivir(75 mg capsule Q12 H);therapy preventing bacterial infection consisted of azithromycin(250 mg tablet QD)and moxifloxacin(0.4 g tablet Q12 H);and therapy for cough relief and fever prevention consisted of Chinese herbal decoction.·RESULTS:A 35-year-old male suddenly suffered pain,photophobia,and tears in his right eye for one day without systemic COVID-19 symptoms.Patient was diagnosed with keratitis,which was seemingly different from common keratitis.Ganciclovir eye drop was initiated.The corneal scraping test for COVID-19 was positive.The chest CT images were abnormal confirming the diagnosis of COVID-19 infection.The antiviral and antibacterial therapies were initiated.Chinese herbal therapy was used for cough relief and fever prevention.After roughly two weeks,patient recovered from COVID-19.·CONCLUSION:A new type of keratitis,atypical keratitis,is a clinical manifestation of COVID-19,and this clinical manifestation could appear 3 d earlier than fever and cough.The earlier a COVID-19 clinical manifestation is identified,the earlier can a patient be directed to stay at home,and significantly fewer people would be infected. 展开更多
关键词 KERATITIS first clinical manifestation COVID-19 atypical keratitis
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Nonlocal advantage of quantum coherence in a dephasing channel with memory 被引量:1
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作者 Ming-Liang Hu Yu-Han Zhang heng fan 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第3期68-73,共6页
We investigate nonlocal advantage of quantum coherence(NAQC)in a correlated dephasing channel modeled by themultimode bosonic reservoir.We obtain analytically the dephasing and memory factors of this channel for the r... We investigate nonlocal advantage of quantum coherence(NAQC)in a correlated dephasing channel modeled by themultimode bosonic reservoir.We obtain analytically the dephasing and memory factors of this channel for the reservoirhaving a Lorentzian spectral density,and analyze how they affect the NAQC defined by the l1 norm and relative entropy.It is shown that the memory effects of this channel on NAQC are state-dependent,and they suppress noticeably the rapiddecay of NAQC for the family of input Bell-like states with one excitation.For the given transmission time of each qubit,we also obtain the regions of the dephasing and memory factors during which there is NAQC in the output states. 展开更多
关键词 quantum coherence correlated quantum channel memory effects
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Construction of Complete Orthogonal Genuine Multipartite Entanglement State
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作者 Feng-Lin Wu Si-Yuan Liu +1 位作者 Wen-Li Yang heng fan 《Chinese Physics Letters》 SCIE CAS CSCD 2019年第6期1-5,共5页
With the development of quantum information processing, multipartite entanglement measures are needed in many cases. However, there are still no complete orthogonal genuine multipartite entanglement(GME) bases availab... With the development of quantum information processing, multipartite entanglement measures are needed in many cases. However, there are still no complete orthogonal genuine multipartite entanglement(GME) bases available as Bell states to bipartite systems. To achieve this goal, we find a method to construct complete orthogonal GME states, and we exclude many equivalent states by leveraging the group theory. We also provide the case of a 3-order 3-dimensional Hilbert space as an example and study the application of general results in the dense coding scheme as an application. Moreover, we discuss some open questions and believe that this work will enlighten extensive studies in this field. 展开更多
关键词 GENUINE MULTIPARTITE entanglement(GME) QUANTUM information processing MULTIPARTITE ENTANGLEMENT measures
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Quantum simulation and quantum computation of noisy-intermediate scale
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作者 Kai Xu heng fan 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第10期1-7,共7页
In the past years, great progresses have been made on quantum computation and quantum simulation. Increasing the number of qubits in the quantum processors is expected to be one of the main motivations in the next yea... In the past years, great progresses have been made on quantum computation and quantum simulation. Increasing the number of qubits in the quantum processors is expected to be one of the main motivations in the next years, while noises in manipulation of quantum states may still be inevitable even the precision will improve. For research in this direction, it is necessary to review the available results about noisy multiqubit quantum computation and quantum simulation. The review focuses on multiqubit state generations, quantum computational advantage, and simulating physics of quantum many-body systems. Perspectives of near term noisy intermediate-quantum processors will be discussed. 展开更多
关键词 quantum computation quantum simulation many-body physics quantum supremacy noisy intermediate-scale quantum technologies
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Beating standard quantum limit via two-axis magnetic susceptibility measurement
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作者 Zheng-An Wang Yi Peng +1 位作者 Dapeng Yu heng fan 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第4期170-174,共5页
We report a metrology scheme which measures the magnetic susceptibility of an atomic spin ensemble along the x and z directions and produces parameter estimation with precision beating the standard quantum limit.The a... We report a metrology scheme which measures the magnetic susceptibility of an atomic spin ensemble along the x and z directions and produces parameter estimation with precision beating the standard quantum limit.The atomic ensemble is initialized via one-axis spin squeezing with optimized squeezing time and parameterΦ(to be estimated)assumed as uniformly distributed between 0 and 2πwhile fixed in each estimation.One estimation ofΦcan be produced with every two magnetic susceptibility data measured along the two axes respectively,which has an imprecision scaling(1.43±0.02)/N^(0.687±0.003)with respect to the number N of the atomic spins.The measurement scheme is easy to implement and is robust against the measurement fluctuation caused by environment noise and measurement defects. 展开更多
关键词 quantum metrology spin-squeezing standard quantum limit FLUCTUATION
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Measuring Loschmidt echo via Floquet engineering in superconducting circuits
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作者 Shou-Kuan Zhao Zi-Yong Ge +16 位作者 Zhong-Cheng Xiang Guang-Ming Xue Hai-Sheng Yan Zi-Ting Wang Zhan Wang Hui-Kai Xu Fei-fan Su Zhao-Hua Yang He Zhang Yu-Ran Zhang Xue-Yi Guo Kai Xu Ye Tian Hai-Feng Yu Dong-Ning Zheng heng fan Shi-Ping Zhao 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第3期117-121,共5页
The Loschmidt echo is a useful diagnostic for the perfection of quantum time-reversal process and the sensitivity of quantum evolution to small perturbations. The main challenge for measuring the Loschmidt echo is the... The Loschmidt echo is a useful diagnostic for the perfection of quantum time-reversal process and the sensitivity of quantum evolution to small perturbations. The main challenge for measuring the Loschmidt echo is the time reversal of a quantum evolution. In this work, we demonstrate the measurement of the Loschmidt echo in a superconducting 10-qubit system using Floquet engineering and discuss the imperfection of an initial Bell-state recovery arising from the next-nearestneighbor(NNN) coupling present in the qubit device. Our results show that the Loschmidt echo is very sensitive to small perturbations during quantum-state evolution, in contrast to the quantities like qubit population that is often considered in the time-reversal experiment. These properties may be employed for the investigation of multiqubit system concerning many-body decoherence and entanglement, etc., especially when devices with reduced or vanishing NNN coupling are used. 展开更多
关键词 superconducting qubit quantum simulation Loschmidt echo Floquet engineering
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Strong Superadditive Deficit of Coherence and Quantum Correlations Distribution
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作者 Si-Yuan Liu Feng-Lin Wu +1 位作者 Yao-Zhong Zhang heng fan 《Chinese Physics Letters》 SCIE CAS CSCD 2019年第8期14-18,共5页
The definitions of strong superadditive deficit for relative entropy coherence and monogamy deficit of measurement-dependent global quantum discord are proposed.The equivalence between them is proved,which provides a ... The definitions of strong superadditive deficit for relative entropy coherence and monogamy deficit of measurement-dependent global quantum discord are proposed.The equivalence between them is proved,which provides a useful criterion for the validity of the strong superadditive inequality of relative entropy coherence.In addition,the strong superadditive deficit of rela.tive entropy coherence is proved to be greater than or equal to zero under the condition that bipartite measurement-dependent global quantum discord(GQD)does not increase under the discarding of subsystems.Using the Monte Carlo method,it is shown that both the strong superadditive inequality of relative entropy coherence and the monogamy inequality of measurement-dependent GQD are established under general circumstances.The bipartite measurement-dependent GQD does not increase under the discarding of subsystems.The multipartite situation is also discussed in detail. 展开更多
关键词 DEFICIT COHERENCE QUANTUM
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Quantum simulation of lattice gauge theories on superconducting circuits:Quantum phase transition and quench dynamics
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作者 Zi-Yong Ge Rui-Zhen Huang +1 位作者 Zi-Yang Meng heng fan 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第2期217-222,共6页
Recently,quantum simulation of low-dimensional lattice gauge theories(LGTs)has attracted many interests,which may improve our understanding of strongly correlated quantum many-body systems.Here,we propose an implement... Recently,quantum simulation of low-dimensional lattice gauge theories(LGTs)has attracted many interests,which may improve our understanding of strongly correlated quantum many-body systems.Here,we propose an implementation to approximate Z;LGT on superconducting quantum circuits,where the effective theory is a mixture of a LGT and a gauge-broken term.By using matrix product state based methods,both the ground state properties and quench dynamics are systematically investigated.With an increase of the transverse(electric)field,the system displays a quantum phase transition from a disordered phase to a translational symmetry breaking phase.In the ordered phase,an approximate Gauss law of the Z;LGT emerges in the ground state.Moreover,to shed light on the experiments,we also study the quench dynamics,where there is a dynamical signature of the spontaneous translational symmetry breaking.The spreading of the single particle of matter degree is diffusive under the weak transverse field,while it is ballistic with small velocity for the strong field.Furthermore,due to the emergent Gauss law under the strong transverse field,the matter degree can also exhibit confinement dynamics which leads to a strong suppression of the nearest-neighbor hopping.Our results pave the way for simulating the LGT on superconducting circuits,including the quantum phase transition and quench dynamics. 展开更多
关键词 quantum simulation superconducting circuits lattice gauge theories
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Nonlocal advantage of quantum coherence and entanglement of two spins under intrinsic decoherence
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作者 Bao-Min Li Ming-Liang Hu heng fan 《Chinese Physics B》 SCIE EI CAS CSCD 2021年第7期33-38,共6页
We investigate the nonlocal advantage of quantum coherence(NAQC)and entanglement for two spins coupled via the Heisenberg interaction and under the intrinsic decoherence.Solutions of this decoherence model for the ini... We investigate the nonlocal advantage of quantum coherence(NAQC)and entanglement for two spins coupled via the Heisenberg interaction and under the intrinsic decoherence.Solutions of this decoherence model for the initial spin-1/2 and spin-1 maximally entangled states are obtained,based on which we calculate the NAQC and entanglement.In the weak region of magnetic field,the NAQC behaves as a damped oscillation with the time evolves,while the entanglement decays exponentially(behaves as a damped oscillation)for the spin-1/2(spin-1)case.Moreover,the decay of both the NAQC and entanglement can be suppressed significantly by tuning the magnetic field and anisotropy of the spin interaction to some decoherence-rate-determined optimal values. 展开更多
关键词 quantum coherence quantum entanglement intrinsic decoherence
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