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quantum interference enhanced thermopower in single-molecule thiophene junctions

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Chinese Chemical Letters 2022年第1期33卷 523-526页

作者： Hang Chen Yaorong Chen Hewei Zhang Wenqiang Cao Chao Fang Yicheng Zhou Zongyuan Xiao Jia Shi Wenbo Chen Junyang Liu Wenjing Hong State Key Laboratory of Physical Chemistry of Solid Surfaces iChEMCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power Shanghai University of Electric PowerShanghai 200090China Beijing National Laboratory for Molecular Sciences Beijing 100190China

quantum interference(QI)effects,which offer unique opportunities to widely manipulate the charge transport properties in the molecular junctions,will have the potential for achieving high thermopower.Here we developed a scanning tunneling microscope break junction technique to investigate the thermopower through single-molecule thiophene junctions.We observed that the thermopower of 2,4-TPSAc with destructive quantum interference(DQI)was nearly twice of 2,5-TP-SAc without DQI,while the conductance of the 2,4-TP-SAc was two orders of magnitude lower than that of 2,5-TP-SAc.Furthermore,we found the thermopower was almost the same by altering the anchoring group or thiophene core in the control experiments,suggesting that the QI effect is responsible for the increase of thermopower.The density functional theory(DFT)calculations are in quantitative agreement with the experimental data.Our results reveal that QI effects can provide a promising platform to enhance the thermopower of molecular junctions.

关键词： quantum interference Thermopower Thermoelectric device Single-molecule electronics Single-molecule junctions

Freezing the conductance of platinum(Ⅱ)complexes by quantum interference effect

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Chinese Chemical Letters 2022年第6期33卷 3263-3266页

作者： Sai-Sai Yan Jin-Yun Wang Zi-You Pan Da-Sheng Zheng Qian-Chong Zhang Zhong-Ning Chen Fujian Normal University Fuzhou 350007China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China

Understanding the impact of substituents on the quantum interference effect at single molecule scale is of great importance for the design of molecular devices.In this work,three platinum(Ⅱ)complexes with–H,–NH_(2)and–NO_(2)groups on conductive backbones were designed and synthesized.Single-molecule conductance,which was measured using scanning tunnelling microscope break junction(STM-BJ)technique,demonstrated a conductance freeze phenomenon under the variation of substituents.Theoretical study revealed that,despite the electronic effect of the substituents shifting the energy level of molecular orbital,the quantum interference effect vanished the influence of electronic effect on the conductance and eventually leaded to the conductance freeze.

关键词： Platinum(Ⅱ)complex Electronic effect Single-molecule conductance quantum interference Magic ratio rule

Removing the Destructive quantum interference in Cross Conjugation System by Structural Restraint

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Chemical Research in Chinese Universities 2023年第2期39卷 224-227页

作者： QU Kai PAN Zi-You WANG Jin-Yun ZHANG Bochao ZENG Hao SANG Yu-Feng ZHANG Qian-Chong CHEN Zhong-Ning College of Chemistry Fuzhou UniversityFuzhou350108P.R.China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou350002P.R.China Department of Pharmacy Xiamen Medical CollegeXiamen361005P.R.China School of Physical Science and Technology ShanghaiTech UniversityShanghai201210P.R.China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou350108P.R.China University of Chinese Academy of Sciences Beijing100049P.R.China

Understanding the quantum effect in the cross-conjugated system is of fundamental significance in molecular electronics.In this study,four molecules Xa-O,Xa,BP and BP-O were synthesized to investigate the destructive quantum interference(DQI)of a carbonyl bridge.The single-molecule conductance measured by the scanning tunneling microscope break junction(STM-BJ)technique demonstrates an increase in the conductance from molecule BP-O to molecule Xa-O as the cross-conjugated system is extended.Theoretical calculations show that the explicit DQI feature is presented in BP-O but absent in Xa-O,which indicates the removal of DQI in the restrained structures and results in the conductance enhancement in Xa-O.

关键词： Single-molecule conductance Cross conjugation quantum interference Carbonyl Conductance enhancement

quantum interference with independent single-photon sources over 300 km fiber

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Advanced Photonics 2022年第6期4卷 64-70页

作者： Xiang You Ming-Yang Zheng Si Chen Run-Ze Liu Jian Qin Mo-Chi Xu Zheng-Xuan Ge Tung-Hsun Chung Yu-Kun Qiao Yang-Fan Jiang Han-Sen Zhong Ming-Cheng Chen Hui Wang Yu-Ming He Xiu-Ping Xie Hao Li Li-Xing You Christian Schneider Juan Yin Teng-Yun Chen Mohamed Benyouce Yong-Heng Huo Sven Höfling Qiang Zhang Chao-Yang Lu Jian-Wei Pan University of Science and Technology of China School of Cyberspace SecurityHefeiChina University of Science and Technology of China Hefei National Laboratory for Physical Sciences at MicroscaleDepartment of Modern PhysicsHefeiChina University of Science and Technology of China CAS Centre for Excellence in Quantum Information and Quantum PhysicsShanghaiChina Jinan Institute of quantum Technology JinanChina Chinese Academy of Sciences Shanghai Institute of Microsystem and Information Technology(SIMIT)State Key Laboratory of Functional Materials for InformaticsShanghaiChina Universitat Würzburg Technische PhysikPhysikalisches Instität and Wilhelm Conrad Röntgen-Center for Complex Material SystemsWürzburgGermany University of Oldenburg Institute of PhysicsOldenburgGermany University of Kassel Institute of Nanostructure Technologies and AnalyticsCINSaTKasselGermany NYU-ECNU Institute of Physics at NYU Shanghai ShanghaiChina

In the quest to realize a scalable quantum network,semiconductor quantum dots(QDs)offer distinct advantages,including high single-photon efficiency and indistinguishability,high repetition rate(tens of gigahertz with Purcell enhancement),interconnectivity with spin qubits,and a scalable on-chip platform.However,in the past two decades,the visibility of quantum interference between independent QDs rarely went beyond the classical limit of 50%,and the distances were limited from a few meters to kilometers.Here,we report quantum interference between two single photons from independent QDs separated by a 302 km optical fiber.The single photons are generated from resonantly driven single QDs deterministically coupled to microcavities.quantum frequency conversions are used to eliminate the QD inhomogeneity and shift the emission wavelength to the telecommunication band.The observed interference visibility is 0.670.02(0.930.04)without(with)temporal filtering.Feasible improvements can further extend the distance to∼600 km.Our work represents a key step to long-distance solid-state quantum networks.

关键词： quantum networks quantum dots solid-state single-photon sources quantum frequency conversion quantum interference

quantum interference between heralded single photon state and coherent state

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Chinese Physics B 2017年第7期26卷 111-116页

作者：杨磊马晓欣李小英 College of Precision Instrument and Opto-Electronics Engineering Tianjin UniversityKey Laboratory of Opto-Electronics Information Technology Ministry of Education High School Affiliated to Beijing Institute of Technology

Balanced homodyne detection has been introduced as a reliable technique of reconstructing the quantum state of a single photon Fock state, which is based on coupling the single photon state and a strong coherent local oscillator in a beam splitter and detecting the field quadrature at the output ports separately. The main challenge associated with a tomographic characterization of the single photon state is mode matching between the single photon state and the local oscillator. Utilizing the heralded single photon generated by the spontaneous parametric process, the multi-mode theoretical model of quantum interference between the single photon state and the coherent state in the fiber beam splitter is established.Moreover, the analytical expressions of the temporal-mode matching coefficient and interference visibility and relationship between the two parameters are shown. In the experimental scheme, the interference visibility under various temporalmode matching coefficients is demonstrated, which is almost accordant with the theoretical value. Our work explores the principle of temporal-mode matching between the single photon state and the coherent photon state, originated from a local oscillator, and could provide guidance for designing the high-performance balanced homodyne detection system.

关键词： heralded single photon state coherent state quantum interference balanced homodyne detection

quantum interference in laser-assisted photo-ionization excited by a femtosecond x-ray pulse

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Chinese Physics B 2008年第12期17卷 4492-4497页

作者：葛愉成 School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University

The photoelectron energy spectra （PESs） excited by monochromatic femtosecond x-ray pulses in the presence of a femtosecond laser are investigated. APES is composed of a set of separate peaks, showing interesting comb-like structures. These structures result from the quantum interferences between photoelectron wave packets generated at different times. The width and the localization of each peak as well as the number of peaks are determined by all the laser and x-ray parameters. Most of peak heights of the PES are higher than the classical predictions.

关键词： femtosecond x-ray pulse photo-ionization quantum interference photoelectron energy spectrum

Unconventional photon blockade in the two-photon Jaynes–Cummings model with two-frequency cavity drivings and atom driving

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Chinese Physics B 2024年第2期33卷 164-168页

作者：刘欣田梦雨崔晓宁张馨鹤 School of Physics and Technology University of JinanJinan 250022China Marketing Service Center(Center of Metrology) State Grid ShanDong Electric Power CompanyJinan 250001China

In a two-frequency cavity driving and atom driving atom-cavity system,we find the photon blockade effect.In a truncated eigenstates space,we calculate the zero-delay second-order correlation function of the cavity mode analytically and obtain an optimal condition for the photon blockade.By including three transition pathways,we find that higher excitations of the cavity mode can be further suppressed and the zero-delay second-order correlation function can be reduced additionally.Based on the master equation,we simulate the system evolution and find that the analytical solutions match well with the numerical results.Our scheme is robust with small fluctuations of parameters and may be used as a new type of single photon source.

关键词： photon blockade single photon source quantum interference

quantum interference effects on the probe amplification without and with inversion in a four-level system

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Chinese Physics B 2004年第10期13卷 1722-1727页

作者：张冰徐卫华张惠芳高锦岳 CollegeofPhysics JilinUniversityChangchun130023China KeyLaboratoryofCoherentLight AtomicandMolecularSpectroscopyEducationMinistryofChinaChina

A four-level system driven by two coherent fields is considered. It is shown that in the presence of an incoherent pump, the probe gain at a short wavelength can be achieved due to the quantum interference. Our density matrix calculation provides the conditions for probe amplification from different origins, including gain without population inversion on any state basis, gain with population inversion on the dressed-state basis, and gain with population inversion on the bare-state basis. Also, by controlling the Rabi frequency of the coupling field a total change from non-inversion to inversion can be achieved which does not depend on the intensity of the incoherent pump.

关键词： quantum interference probe gain inversion non-inversion

Spectral feature with sub-natural linewidth due to quantum interference in a four-level system

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Chinese Physics B 2008年第6期17卷 2147-2151页

作者：杨丽君张连水庄仲红郭庆林傅广生 College of Physical Science and Technology Hebei University

This paper studies the narrow spectral feature appearing in a four-level system coupled by two strong coherent fields and probed by a weak laser field. The linewidth is examined as a function of the Rabi frequencies o... 详细信息

关键词： quantum interference linewidth dressed-state