We present transport characterizations of a fully tunable double quantum dot over the few electron number down to zero,which is defined by means of surface gates on top of a GaAs/AlGaAs heterostructure.We also perform...We present transport characterizations of a fully tunable double quantum dot over the few electron number down to zero,which is defined by means of surface gates on top of a GaAs/AlGaAs heterostructure.We also perform numerical simulations to map out the charge stability diagram,which is consistent with the measurements.The results demonstrate that the electric control in the double dot can be significantly enhanced by improving the design of the device structure,which provides potential advantages for quantum information processing.展开更多
We demonstrate how molecular states of coupled graphene quantum dots are probed in transport experiments.The applied method measures the sequential tunneling of electrons through the double dot and hence resolves the ...We demonstrate how molecular states of coupled graphene quantum dots are probed in transport experiments.The applied method measures the sequential tunneling of electrons through the double dot and hence resolves the molecular state transport channel simultaneously.The overlap of the two dots'wavefunctions,and in turn,the tunnel coupling between the two dots are controlled by the local gates.These results imply the relevance of our graphene device for implementing a quantum manipulation by adjusting the electrodes.展开更多
We propose an effective method to design the working parameters of a pulse-driven charge qubit implemented with double quantum dot.It is shown that intrinsic qubit population leakage to undesired states in the control...We propose an effective method to design the working parameters of a pulse-driven charge qubit implemented with double quantum dot.It is shown that intrinsic qubit population leakage to undesired states in the control and measurement process can be determined by the simulation of coherent dynamics of the qubit and minimized by choosing proper working parameters such as pulse shape.The result demonstrated here bodes well for future quantum gate operations and quantum computing applications.展开更多
We prepare an etched gate tunable quantum dot in single-layer graphene and present transport measurement in this system.We extract the information of the ground states and excited states of the graphene quantum dot,as...We prepare an etched gate tunable quantum dot in single-layer graphene and present transport measurement in this system.We extract the information of the ground states and excited states of the graphene quantum dot,as denoted by the presence of characteristic Coulomb blockade diamond diagrams.The results demonstrate that the quantum dot in single-layer graphene bodes well for future quantum transport study and quantum computing applications.展开更多
Background Accurate evaluation of coronary artery,aortic valve annulus diameter （AVAD）,and cardiac function in patients with aortic valve disease is of great significance for surgical strategy.In this study,we explo...Background Accurate evaluation of coronary artery,aortic valve annulus diameter （AVAD）,and cardiac function in patients with aortic valve disease is of great significance for surgical strategy.In this study,we explored the preoperative evaluation of low-dose sequence （MinDose sequence） scan of dual-source CT （DSCT） for those patients.Methods Forty patients suspected for aortic valve disease （the experimental group） underwent MinDose sequence of DSCT to observe coronary artery,AVAD,and left ventricular ejection fraction （LVEF）.Another 33 subjects suspected for coronary artery disease （the control group） underwent conventional retrospective electrocardiographically-gated sequence of DSCT.Two-dimensional transthoracic echocardiography （2D-TTE） and four-dimensional transthoracic echocardiography （4D-TTE） were applied in the experimental group to measure AVAD and LVEF and compared with MinDose-DSCT.Results There was a strong correlation between LVEFs measured by 2D-TTE and MinDose-DSCT （r=0.87,P ＜0.01）,as well as between 4D-TTE and MinDose-DSCT （r=0.90,P ＜0.01）.AVAD measured by MinDose-DSCT was in good agreement with corresponding measurements by 2D-TTE （r=0.90,P ＜0.01）.The effective dose in the experimental group was 63.54％ lower than that in the control group.Conclusions MinDose sequence of DSCT with a low radiation dose serving as a one-stop preoperative evaluation makes effective assessment of the coronary artery,AVAD,and LVEF for patients with aortic valve disease.展开更多
基金the National Basic Research Program of China under Grant No 2011CBA00200the National Natural Science Foundation of China under Grant Nos 11274294,11074243 and 10934006.
文摘We present transport characterizations of a fully tunable double quantum dot over the few electron number down to zero,which is defined by means of surface gates on top of a GaAs/AlGaAs heterostructure.We also perform numerical simulations to map out the charge stability diagram,which is consistent with the measurements.The results demonstrate that the electric control in the double dot can be significantly enhanced by improving the design of the device structure,which provides potential advantages for quantum information processing.
基金Supported by the National Basic Research Program of China under Grant No 2011CBA00200the National Natural Science Foundation of China under Grant Nos 11274294,11074243,10934006.
文摘We demonstrate how molecular states of coupled graphene quantum dots are probed in transport experiments.The applied method measures the sequential tunneling of electrons through the double dot and hence resolves the molecular state transport channel simultaneously.The overlap of the two dots'wavefunctions,and in turn,the tunnel coupling between the two dots are controlled by the local gates.These results imply the relevance of our graphene device for implementing a quantum manipulation by adjusting the electrodes.
基金Supported by the National Basic Research Program of China under Grant No 2011CBA00200the National Natural Science Foundation of China under Grant Nos 11074243 and 10934006.
文摘We propose an effective method to design the working parameters of a pulse-driven charge qubit implemented with double quantum dot.It is shown that intrinsic qubit population leakage to undesired states in the control and measurement process can be determined by the simulation of coherent dynamics of the qubit and minimized by choosing proper working parameters such as pulse shape.The result demonstrated here bodes well for future quantum gate operations and quantum computing applications.
基金by the National Basic Research Programme of China under Grant No 2011CBA00200the National Natural Science Foundation of China under Grant Nos 10934006,11074243,10804104 and 10874163.
文摘We prepare an etched gate tunable quantum dot in single-layer graphene and present transport measurement in this system.We extract the information of the ground states and excited states of the graphene quantum dot,as denoted by the presence of characteristic Coulomb blockade diamond diagrams.The results demonstrate that the quantum dot in single-layer graphene bodes well for future quantum transport study and quantum computing applications.
文摘Background Accurate evaluation of coronary artery,aortic valve annulus diameter （AVAD）,and cardiac function in patients with aortic valve disease is of great significance for surgical strategy.In this study,we explored the preoperative evaluation of low-dose sequence （MinDose sequence） scan of dual-source CT （DSCT） for those patients.Methods Forty patients suspected for aortic valve disease （the experimental group） underwent MinDose sequence of DSCT to observe coronary artery,AVAD,and left ventricular ejection fraction （LVEF）.Another 33 subjects suspected for coronary artery disease （the control group） underwent conventional retrospective electrocardiographically-gated sequence of DSCT.Two-dimensional transthoracic echocardiography （2D-TTE） and four-dimensional transthoracic echocardiography （4D-TTE） were applied in the experimental group to measure AVAD and LVEF and compared with MinDose-DSCT.Results There was a strong correlation between LVEFs measured by 2D-TTE and MinDose-DSCT （r=0.87,P ＜0.01）,as well as between 4D-TTE and MinDose-DSCT （r=0.90,P ＜0.01）.AVAD measured by MinDose-DSCT was in good agreement with corresponding measurements by 2D-TTE （r=0.90,P ＜0.01）.The effective dose in the experimental group was 63.54％ lower than that in the control group.Conclusions MinDose sequence of DSCT with a low radiation dose serving as a one-stop preoperative evaluation makes effective assessment of the coronary artery,AVAD,and LVEF for patients with aortic valve disease.
