Co-reporter:Ying Liu;Fei Kong;Fazhan Shi
Science Bulletin 2016 Volume 61( Issue 14) pp:1132-1137
Publication Date(Web):2016 July
DOI:10.1007/s11434-016-1122-y
Detection of a.c. magnetic field is consequential for many developments in physical and biological sciences, and various designs of magnetometer have been proposed recently. However, the large size of sensor and the extreme measurement conditions required strongly limit their application. It remains a challenge to reconstruct the vector of a.c. field with nanoscale spatial resolution using a single spin under ambient conditions. In this work, we choose the radio-frequency (RF) field as a typical case and realize the measurement of RF field based on a nitrogen-vacancy (NV) center in diamond. We build a solid sensor through measuring the effect of RF field on NV electron spin energy levels and the transition between them. Both of the phase and amplitude (including the transverse and longitudinal components) are measured by this new approach.射频场的探测对于物理学、电子学与生命科学等很多领域的发展有着重要的意义。近年来,一些关于射频场探测的方案被提出。但是由于有的探针尺寸过大,有的探针需要极端探测条件(比如低温),它们的应用受到了限制。本文展示了如何在室温下用金刚石氮-空穴色心(NV色心)体系的单个电子自旋来探测射频场。通过射频场对NV色心电子自旋拉比振荡的影响,我们实现了对射频场的横向幅度、纵向幅度与相位的探测。
Co-reporter:PengFei Wang;ChenYong Ju;FaZhan Shi
Science Bulletin 2013 Volume 58( Issue 24) pp:2920-2923
Publication Date(Web):2013 August
DOI:10.1007/s11434-013-5967-z
The measurement of the weak magnetic field in nanoscale resolution and at room temperature is always a significant topic in biological, physical, and material science. Such detection can be used to decide the characterization of the samples, such as cells, materials, and so on. Nitrogen-vacancy (NV) center in diamond has been proved to be able to detect a magnetic field with nano Tesla sensitivity and nanometer resolution at room temperature. Here we experimentally demonstrate an optimized NV center based single electron magnetometer in a commercial diamond and under a home-built optically detected magnetic resonance (ODMR) microscope. With current technology, we change the optically detected time window to get a better signal to noise ratio, and use dynamical decoupling to increase the slope of magnetic field amplitude versus fluorescence signal. By employing the 8-pulse XY-4 dynamical decoupling sequence we achieve a sensitivity of 18.9 nT/\(\sqrt {Hz} \), which is 1.7 times better than spin echo. We also propose a NV center based scanning diamond microscope for electron and nuclear spins detection as well as nanoscale magnetic resonance imaging. If it is realized, the NV center based magnetometry will have wide application in the future.
Co-reporter:Dawei Lu, Boruo Xu, Nanyang Xu, Zhaokai Li, Hongwei Chen, Xinhua Peng, Ruixue Xu and Jiangfeng Du
Physical Chemistry Chemical Physics 2012 vol. 14(Issue 26) pp:9411-9420
Publication Date(Web):31 May 2012
DOI:10.1039/C2CP23700H
It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations.
Co-reporter:Li Zhang, Ji-Hu Su, Sujing Wang, Changfeng Wan, Zhenggen Zha, Jiangfeng Du and Zhiyong Wang
Chemical Communications 2011 vol. 47(Issue 19) pp:5488-5490
Publication Date(Web):11 Apr 2011
DOI:10.1039/C1CC10871A
Direct electrochemical synthesis of sulfonyl amidines from aliphatic amines and sulfonyl azides was realized with good to excellent yields. Traditional tertiary amine substrates were broadened to secondary and primary amines. The reaction intermediates were observed and a reaction mechanism was proposed and discussed.
Co-reporter:Dr. Sujing Wang;Dr. Shunshun Xiong; Zhiyong Wang; Jiangfeng Du
Chemistry - A European Journal 2011 Volume 17( Issue 31) pp:8630-8642
Publication Date(Web):
DOI:10.1002/chem.201100226
Abstract
A family of ZnII-based metal–organic coordination polymers (MOCPs) [Zn(L)(imid)2] (1), [Zn(L)(2,2′-bpy)] (2), [Zn2(L)2(Py)3] (3), [Zn(L)(DPP)]⋅DMF (4), [Zn(L)(DPEA)] (5), [Zn2(L)2(4,4′-bpy)] (6), [Zn(L)(3,4′-DPEE)]⋅DMF (7), and [Zn3(L)3(3,4′-DPEE)2]⋅DMF (8) (L=dithieno[3,2-b:2′,3′-e]benzene-2,6-dicarboxylic acid, imid=imidazole, bpy=bipyridine, Py=pyridine, DPP=1,3-di(pyridin-4-yl)propane, DPEA=1,2-di(pyridin-4-yl)ethane, and DPEE=(E)-3,4′-(ethene-1,2-diyl)dipyridine) have been rationally designed and generated in the solvothermal reaction systems of the new conjugated thiophene derivative L, Zn(ClO4)2⋅6 H2O, and seven different aromatic N-donor co-ligands separately. These N-donor compounds were carefully selected and employed in the crystal preparation of the eight MOCPs as structure-directing co-ligands owing to their structural specialties and habitual coordination fashions. Among these MOCPs, compounds 1–3 are 1D polymers with different chain structures. Compounds 4, 7, and 8 are 2D structures, in which 4 has two sets of twofold interpenetrating layers, whereas 7 and 8 are both built from three independent sheets. Compounds 5 and 6 are 3D frameworks, in which 5 exhibits a fivefold interpenetrating diamondoid network, whereas 6 shows a typical twofold interpenetrating pillared layer structure with nanoscale channels. The photoluminescent properties of these MOCPs, including excitation, emission, and radiactive lifetime, have also been investigated to help us tentatively understand their structure–property relationships.
Co-reporter:Xing Rong;Ya Wang;JiaHui Yang;JinXian Zhu;WanJie Xu
Science Bulletin 2011 Volume 56( Issue 7) pp:591-597
Publication Date(Web):2011 March
DOI:10.1007/s11434-010-4321-y
Quantum coherence is an important enabling feature underpinning quantum computation. However, because of couplings with its noisy surrounding environment, qubits suffer from the decoherence effects. The dynamical decoupling (DD) technique uses pulse-induced qubit flips to effectively mitigate couplings between qubits and environment. Optimal DD eliminates dephasing up to a given order with the minimum number of pulses. In this paper, we first introduce our recent work on prolonging electron spin coherence in γ-irradiated malonic acid crystals and analyze different decoherence mechanisms in this solid system. Then we focus on electron spin relaxation properties in another system, phosphorous-doped silicon (Si:P) crystals. These properties have been investigated by pulse electron paramagnetic resonance (EPR). We also investigate the performance of the dynamical decoupling technique on this system. Using 8-pulse periodic DD, the coherence time can be extended to 296 μs compared with 112 μs with one-pulse control.
Co-reporter:Jiangfeng Du,
Xing Rong,
Nan Zhao,
Ya Wang,
Jiahui Yang
&
R. B. Liu
Nature 2009 461(7268) pp:1265
Publication Date(Web):2009-10-29
DOI:10.1038/nature08470
For the quantum coherence of electron spins in solid materials to be exploited in future technologies such as quantum computing, the problem of spin decoherence due to electron spins coupling to the noisy environment must first be solved. Here, pulsed electron paramagnetic resonance is used to demonstrate experimentally optimal dynamical decoupling for preserving electron spin coherence in irradiated malonic acid crystals at temperatures from 50 K to room temperature.
Co-reporter:Ying Liu, Fei Kong, Fazhan Shi, Jiangfeng Du
Science Bulletin (July 2016) Volume 61(Issue 14) pp:1132-1137
Publication Date(Web):1 July 2016
DOI:10.1007/s11434-016-1122-y
Detection of a.c. magnetic field is consequential for many developments in physical and biological sciences, and various designs of magnetometer have been proposed recently. However, the large size of sensor and the extreme measurement conditions required strongly limit their application. It remains a challenge to reconstruct the vector of a.c. field with nanoscale spatial resolution using a single spin under ambient conditions. In this work, we choose the radio-frequency (RF) field as a typical case and realize the measurement of RF field based on a nitrogen-vacancy (NV) center in diamond. We build a solid sensor through measuring the effect of RF field on NV electron spin energy levels and the transition between them. Both of the phase and amplitude (including the transverse and longitudinal components) are measured by this new approach.
Co-reporter:Li Zhang, Ji-Hu Su, Sujing Wang, Changfeng Wan, Zhenggen Zha, Jiangfeng Du and Zhiyong Wang
Chemical Communications 2011 - vol. 47(Issue 19) pp:NaN5490-5490
Publication Date(Web):2011/04/11
DOI:10.1039/C1CC10871A
Direct electrochemical synthesis of sulfonyl amidines from aliphatic amines and sulfonyl azides was realized with good to excellent yields. Traditional tertiary amine substrates were broadened to secondary and primary amines. The reaction intermediates were observed and a reaction mechanism was proposed and discussed.
Co-reporter:Dawei Lu, Boruo Xu, Nanyang Xu, Zhaokai Li, Hongwei Chen, Xinhua Peng, Ruixue Xu and Jiangfeng Du
Physical Chemistry Chemical Physics 2012 - vol. 14(Issue 26) pp:NaN9420-9420
Publication Date(Web):2012/05/31
DOI:10.1039/C2CP23700H
It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations.
