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Controllable vortex lasing arrays in a geometrically frustrated exciton-polariton lattice at room temperature

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National Science Review 2023年第1期10卷 196-204页

作者： Jun Wang Yutian Peng Huawen Xu Jiangang Feng Yuqing Huang Jinqi Wu Timothy C.H.Liew Qihua Xiong Division of physics and Applied physics School of Physical and Mathematical Sciences Nanyang Technological University Department of Optical Science and Engineering and Shanghai Frontiers Science Research Base of Intelligent Optoelectronics and Perception Fudan University State Key Laboratory of Low-Dimensional quantum physics and Department of physics Tsinghua University Beijing Academy of quantum Information sciences

Quantized vortices appearing in topological excitations of quantum phase transition play a pivotal role in strongly correlated physics involving the underlying confluence of superfluids,Bose-Einstein condensates and *** polaritons as bosonic quasiparticles have enabled studies of non-e quilibrium quantum gases and ***-polariton condensates in artificial lattices intuitively emulate energy-band structures and quantum many-body effects of condensed matter,underpinning constructing vortex lattices and controlling quantum fluidic ***,we harness exciton-polariton quantum fluids of light in a frustrated kagome lattice based on robust metal-halide perovskite microcavities,to demonstrate vortex lasing arrays and modulate their configurations at room *** energy-momentum spectra unambiguously reveal massless Dirac bands and quenched kinetic-energy flat bands coexisting in kagome lattices,where polariton condensates exhibit prototypical honeycomb and kagome spatial *** coherence investigations illustrate two types of phase textures of polariton condensates carrying ordered quantized-vortex arrays and π-phase shifts,which could be selected when needed using lasing emission *** findings offer a promising platform on which it is possible to study quantum-fluid correlations in complex polaritonic lattices and highlight feasible applications of structured light.

关键词： vortex lasing exciton–polariton lattice Bose–Einstein condensation the orbital angular momentum of light geometric frustration perovskite semiconductor

Quafu-Qcover:Explore combinatorial optimization problems on cloud-based quantum computers

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Chinese physics B 2024年第5期33卷 104-115页

作者：许宏泽庄伟峰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 Beijing Academy of quantum Information sciences Beijing 100193China State Key Laboratory of Low Dimensional quantum physics Department of PhysicsTsinghua UniversityBeijing 100084China Institute of physics Chinese Academy of SciencesBeijing 100190China Frontier Science center for quantum Information Beijing 100184China School of Physical sciences University of Chinese Academy of SciencesBeijing 100190China CAS center for Excellence in Topological quantum Computation UCASBeijing 100190China

We introduce Quafu-Qcover,an open-source cloud-based software package developed for solving combinatorial optimization problems using quantum simulators and hardware ***-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 *** core of Qcover relies on a graph decomposition-based classical algorithm,which efficiently derives the optimal parameters for the shallow QAOA ***-Qcover incorporates a dedicated compiler capable of translating QAOA circuits into physical quantum circuits that can be executed on Quafu cloud quantum *** to a general-purpose compiler,our compiler demonstrates the ability to generate shorter circuit depths,while also exhibiting superior speed ***,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 *** ensures that computational tasks can be assigned to connected physical qubits with the highest *** Quafu-Qcover allows us to retrieve quantum computing sampling results using a task ID at any time,enabling asynchronous ***,it incorporates modules for results preprocessing and visualization,facilitating an intuitive display of solutions for combinatorial optimization *** hope that Quafu-Qcover can serve as an instructive illustration for how to explore application problems on the Quafu cloud quantum computers.

关键词： quantum cloud platform combinatorial optimization problems quantum software

Manipulating high-temperature superconductivity by oxygen doping in Bi2Sr2CaCu2O8+δ thin flakes

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National Science Review 2022年第10期9卷 112-119页

作者： Bin Lei Donghui Ma Shihao Liu Zeliang Sun Mengzhu Shi Weizhuang Zhuo Fanghang Yu Genda Gu Zhenyu Wang Xianhui Chen Key Laboratory of Strongly-Coupled quantum Matter physics Chinese Academy of Sciences and Department of Physics University of Science and Technology of China CAS center for Excellence in quantum Information and quantum physics Department of Condensed Matter physics and Materials Science Brookhaven National Laboratory CAS center for Excellence in Superconducting Electronics (CENSE) Collaborative Innovation center of Advanced Microstructures Nanjing University

Harnessing the fascinating properties of correlated oxides requires precise control of their carrier *** to other methods,oxygen doping provides an effective and more direct way to tune the electronic properties of correlated *** several approaches,such as thermal annealing and oxygen migration,have been introduced to change the oxygen content,a continuous and reversible solution that can be integrated with modern electronic technology is much in ***,we report a novel ionic field-effect transistor using solid Gd-doped CeO2as the gate dielectric,which shows a remarkable carrier-density-tuning ability via electric-field-controlled oxygen concentration at room *** Bi2Sr2CaCu2O8+δ(Bi-2212) thin flakes,we achieve a reversible superconductor-insulator transition by driving oxygen ions in and out of the samples with electric fields,and map out the phase diagram all the way from the insulating regime to the over-doped superconducting regime by continuously changing the oxygen doping *** analysis indicates that the reversible superconductor-insulator transition for the Bi-2212 thin flakes follows the theoretical description of a two-dimensional quantum phase *** work provides a route for realizing electric-field control of phase transition in correlated ***,the configuration of this type of transistor makes heterostructure/interface engineering possible,thus having the potential to serve as the next-generation all-solid-state field-effect transistor.

关键词： high-temperature superconductivity oxygen doping electric field effect all-solid-state field effect transistor superconductor–insulator transition

The dehydration dynamics of a model cell membrane induced by cholesterol analogue 6-ketocholestanol investigated using sum frequency generation vibrational spectroscopy

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Science China Chemistry 2015年第7期58卷 1176-1186页

作者： Sulan Ma Kangzhen Tian Shuji Ye Hefei National Laboratory for Physical sciences at the Microscale Department of Chemical physics University of Science and Technology of China Synergetic Innovation center of quantum Information & quantum physics University of Science and Technology of China

Dehydration of a surface is the first step for the interaction between biomolecules and the surface. In this study, we systemati- cally investigated the influence of cholesterol analog 6-ketocholestanol （6-KC） on the dehydration of model cell membrane, using sum frequency generation vibrational spectroscopy. In pure DI water environment, two separate dehydration dynamic components were observed in neutrally charged and isotopically labeled 1,2-dimyristoyl-sn-glycero-3-phosphocholine （DMPC） and positively charged 1,2-dimyristoyl-sn-glycero-3-ethylphosphocholine（chloride salt）（DMEPC） bilayer： a large-amplitude fast component and a small-amplitude slow component, which originated from the water molecules with a weak and a strong water-membrane bound strengths, respectively. Dehydration of a negatively charged mixed DMPC/DMPG bilayer lead to the membrane-bound water being reorganized to ordered structures quickly. It is evident that the water-membrane bound strengths depend largely on the charge status of the lipid and has an order of neutrally charged membrane〈〈positively charged mem- brane〈〈negatively charged membrane. In an ionic environment, KC1 solution can not only dehydrate DMPC bilayer, but also prevent the 6-KC fiom further dehydrating this model cell membrane. We observed that the dehydration dynamics behavior of DMPC bilayer in the presence of the chaotropic anions is similar to that of the negatively charged DMPG bilayer because of the penetration of chaotropic anions into the DMPC bilayer. The degree of dehydration difficulty in kosmotropic anions fol- lows a Hofmeister series and linearly correlates with the hydration Gibbs free energy of the anions. Our results provide a molecular basis for the interpretation of the Hofmeister effect of kosmotropic anions on ion transport proteins.

关键词： membrane dehydration sum frequency generation membrane-bound water membrane dipole potential Hofmeistereffect

Spectroscopic Evidence for Electron Correlations in Epitaxial Bilayer Graphene with Interface-Reconstructed Superlattice Potentials

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Chinese physics Letters 2022年第7期39卷 74-80页

作者： Chaofei Liu Jian Wang International center for quantum Materials School of PhysicsPeking UniversityBeijing 100871China CAS center for Excellence in Topological quantum Computation University of Chinese Academy of SciencesBeijing 100190China Beijing Academy of quantum Information sciences Beijing 100193China

Superlattice potentials are theoretically predicted to modify the single-particle electronic structures. The resulting Coulomb-interaction-dominated low-energy physics would generate highly novel many-body phenomena. Here,by in situ tunneling spectroscopy, we show the signatures of superstructure-modulated correlated electron states in epitaxial bilayer graphene(BLG) on 6H-Si C(0001). As the carrier density is locally quasi-‘tuned’ by the superlattice potentials of a 6 × 6 interface reconstruction phase, the spectral-weight transfer occurs between the two broad peaks flanking the charge-neutral point. Such a detected non-rigid band shift beyond the single-particle band description implies the existence of correlation effects, probably attributed to the modified interlayer coupling in epitaxial BLG by the 6×6 reconstruction as in magic-angle BLG by the moiré potentials. Quantitative analysis suggests that the intrinsic interface reconstruction shows a high carrier tunability of ~1/2 filling range, equivalent to the back gating by a voltage of ~70 V in a typical gated BLG/SiO_(2)/Si device. The finding in interfacemodulated epitaxial BLG with reconstruction phase extends the BLG platform with electron correlations beyond the magic-angle situation, and may stimulate further investigations on correlated states in graphene systems and other van der Waals materials.

关键词： BLG red profile STM Spectroscopic Evidence for Electron Correlations in Epitaxial Bilayer Graphene with Interface-Reconstructed Superlattice Potentials Graphene

Hybrid opto-mechanical systems with nitrogen-vacancy centers

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Science China(physics,Mechanics & Astronomy) 2015年第5期58卷 29-40页

作者： YIN ZhangQi ZHAO Nan LI TongCang center for quantum Information Institute for Interdisciplinary Information Sciences Tsinghua University Beijing Computational Science Research center Synergetic Innovation center of quantum Information and quantum physics University of Science and Technology of China Department of physics and Astronomy and School of Electrical and Computer Engineering Purdue University Birck Nanotechnology center Purdue University

In this review, we briefly review recent works on hybrid （nano） and diamond nitrogen-vacancy （NV） centers. We also review opto-mechanical systems that contain both mechanical oscillators two different types of mechanical oscillators. The first one is a clamped mechanical oscillator, such as a cantilever, with a fixed frequency. The second one is an optically trapped nano-diamond with a built-in nitrogen-vacancy center. By coupling mechanical resonators with electron spins, we can use the spins to control the motion of mechanical oscillators. For the first setup, we discuss two different coupling mechanisms, which are magnetic coupling and strain induced coupling. We summarize their applications such as cooling the mechanical oscillator, generating entanglements between NV centers, squeezing spin ensembles etc. For the second setup, we discuss how to generate quantum superposition states with magnetic coupling, and realize matter wave interferometer. We will also review its applications as ultra-sensitive mass spectrometer. Finally, we discuss new coupling mechanisms and applications of the field.

关键词： opto-mechanics nitrogen-vacancy center hybrid system

Realization of arbitrary two-qubit quantum gates based on chiral Majorana fermions

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Chinese physics B 2021年第4期30卷 43-54页

作者： Qing Yan Qing-Feng Sun International center for quantum Materials School of PhysicsPeking UniversityBeijing 100871China CAS center for Excellence in Topological quantum Computation University of Chinese Academy of SciencesBeijing 100190China Collaborative Innovation center of quantum Matter Beijing 100871China Beijing Academy of quantum Information sciences Beijing 100193China

quantum computers are in hot-spot with the potential to handle more complex problems than classical computers *** the quantum computation requires the universal quantum gate set {T,H,CNOT} so as to perform any unitary transformation with arbitrary *** we first briefly review the Majorana fermions and then propose the realization of arbitrary two-qubit quantum gates based on chiral Majorana *** cells consist of a quantum anomalous Hall insulator surrounded by a topological superconductor with electric gates and quantum-dot structures,which enable the braiding operation and the partial exchange *** defining a qubit by four chiral Majorana fermions,the singlequbit T and H quantum gates are realized via one partial exchange operation and three braiding operations,*** entangled CNOT quantum gate is performed by braiding six chiral Majorana ***,we design a powerful device with which arbitrary two-qubit quantum gates can be realized and take the quantum Fourier transform as an example to show that several quantum operations can be performed with this space-limited ***,our proposal could inspire further utilization of mobile chiral Majorana edge states for faster quantum computation.

关键词： quantum computation T gate CNOT gate braiding chiral Majorana fermions

Electron transport in Dirac and Weyl semimetals

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Chinese physics B 2018年第10期27卷 27-45页

作者： Huichao Wang Jian Wang International center for quantum Materials School of Physics Peking University Beijing 100871 China Collaborative Innovation center of quantum Matter Beijing 100871 China CAS center for Excellence in Topological quantum Computation University of Chinese Academy of Sciences (CAS) Beijing 100190 China State Key Laboratory of Low-Dimensional quantum physics Department of Physics Tsinghua University Beijing 100084 China

Recently, the Dirac and Weyl semimetals have attracted extensive attention in condensed matter physics due to both the fundamental interest and the potential application of a new generation of electronic devices. Here we review the exotic electrical transport phenomena in Dirac andWeyl semimetals. Section 1 is a brief introduction to the topological semimetals（TSMs）. In Section 2 and Section 3, the intriguing transport phenomena in Dirac semimetals（DSMs） andWeyl semimetals（WSMs） are reviewed, respectively. The most widely studied Cd_3A_（s2） and the TaAs family are selected as representatives to show the typical properties of DSMs and WSMs, respectively. Beyond these systems, the advances in other TSM materials,such as ZrTe_5 and the MoTe_2 family, are also introduced. In Section 4, we provide perspectives on the study of TSMs especially on the magnetotransport investigations.

关键词： electron transport topological Dirac semimetals topological Weyl semimetals

Two-dimensional silicon-carbon hybrids with a honeycomb lattice: New family for two-dimensional photovoltaic materials

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Science China(physics,Mechanics & Astronomy) 2015年第10期58卷 81-88页

作者： ZHANG Jin REN Jun FU HuiXia DING ZiJing LI Hui MENG Sheng Beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Department of physics Tsinghua University Collaborative Innovation center of quantum Matter

We predict a series of new two-dimensional(2D) inorganic materials made of silicon and carbon elements(2D SixC1?x) based on density functional theory. Our calculations on optimized structure, phonon dispersion, and finite temperature molecular dynamics confirm the stability of 2D SixC1?x sheets in a two-dimensional, graphene-like, honeycomb lattice. The electronic band gaps vary from zero to 2.5 e V as the ratio x changes in 2D SixC1?x changes, suggesting a versatile electronic structure in these sheets. Interestingly, among these structures Si0.25C0.75 and Si0.75C0.25 with graphene-like superlattices are semimetals with zero band gap as their ? and ?* bands cross linearly at the Fermi level. Atomic structural searches based on particle-swarm optimization show that the ordered 2D SixC1?x structures are energetically favorable. Optical absorption calculations demonstrate that the 2D silicon-carbon hybrid materials have strong photoabsorption in visible light region, which hold promising potential in photovoltaic applications. Such unique electronic and optical properties in 2D SixC1?x have profound implications in nanoelectronic and photovoltaic device applications.

关键词： 2D Si-C hybrids electronic structure photovoltaic materials first-principles calculations