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Probabilistic Controlled Teleportation of a Triplet W State
JIANG Wei-Xing, FANG Jian-Xing, ZHU Shi-Qun, SHA Jin-Qiao
Chin. Phys. Lett. 2007, 24 (5):
1144-1146
.
A scheme for probabilistic controlled teleportation of a triplet W state from the sender Alice to the distant receiver Bob is proposed. In this scheme, an m-qubit GHZ state serves as the control parameter. The m control qubits are shared by m(s1,s2... sm) spatially-separated supervisors. With the aid of local operations and individual measurements, including Bell-state measurement, Von Neumann measurement, and mutual classical communication, etc., Bob can faithfully reconstruct the original state by performing relevant unitary transformations. However, even if one participant does not cooperate during the process, the receiver Bob cannot fully recover the original state. This protocol can be extended to probabilistic controlled teleportation of an arbitrary N-qubit state and some other N-qubit entangled states.
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Differential System's Nonlinear Behaviour of Real Nonlinear Dynamical Systems
YANG Zheng-Ling, WANG Wei-Wei, YIN Zhen-Xing, ZHANG Jun, CHEN Xi
Chin. Phys. Lett. 2007, 24 (5):
1170-1172
.
Chaos attractor behaviour is usually preserved if the four basic arithmetic perations, i.e. addition, subtraction, multiplication, division, or their compound, are applied. First-order differential systems of one-dimensional real discrete dynamical systems and nonautonomous real continuous-time dynamical systems are also dynamical systems and their Lyapunov exponents are kept, if they are twice differentiable. These two conclusions are shown here by the definitions of dynamical system and Lyapunov exponent. Numerical simulations support our analytical results. The conclusions can apply to higher order differential systems if their corresponding order differentials exist.
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Identification of a New Band and Its Signature Inversion in 174Re
ZHANG Yu-Hu, GUO Song, ZHOU Xiao-Hong, MA Long, GUO Wen-Tao, Oshima M., Toh Y., Koizumi M., Osa A., Kimura A., Hatsukawa Y., Sugawara M., Kusakari H.
Chin. Phys. Lett. 2007, 24 (5):
1203-1206
.
High spin states in 174Re are investigated via the 152Sm(27Al,5nγ)174Re reaction and γ-γ coincidence relationships are analysed carefully. A new band is identified due to its spectroscopic connection with the known π1/2-[541]⊕ν1/2-[521] band. This band is proposed to be the ground-state band built on the π 1/2- [541]⊕ν5/2- [512] configuration in view of the low-lying intrinsic states in the neighbouring odd-mass nuclei. It is of particular interesting that the new band exhibits a phenomenon of low-spin signature inversion, providing a new situation for theoretical investigations.
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Theoretical Study of Relativistic Retardation Effects: the Abnormal Fine Structure of OII
CHEN Shao-Hao, HAN Xiao-Ying, WANG Xiao-Lu, LI Jia-Ming,
Chin. Phys. Lett. 2007, 24 (5):
1214-1216
.
Using multi-configuration Dirac--Fock and relativistic configuration interaction methods with high-order corrections, we report our precise calculation results of the fine-structure energy levels of the ground-state configuration of OII (1s22s22p3). Our calculated fine-structure splittings of 2D 3/2,5/2 and 2P 1/2,3/2 are abnormal. We elucidate that the transverse (Breit) interaction, i.e. relativistic retardation effect, plays an important role for the abnormal fine-structure splittings. Our calculation results are in good agreement with experimental measurements.
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Experimental Improvement of Signal of a Single Laser-Cooled Trapped 40Ca+ Ion
SHU Hua-Lin, , GUO Bin, , GUAN Hua, , LIU Qu, , HUANG Xue-Ren, GAO Ke-Lin,
Chin. Phys. Lett. 2007, 24 (5):
1217-1219
.
A single 40Ca+ ion is loaded in a miniature Paul trap and the probability of directly loading a single ion is above 50%. The signal-to-noise ratio and the storage time for a single ion have been improved by minimizing the ion micromotion and locking a 397nm cooling laser to a Fabry--Perot interferometer and optogalvanic signal. From the fluorescence spectrum, the ion temperature is estimated to be about 5mK.
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A Theoretical Study of Super-Excited States of F2
ZHANG Wei-Hua, HE Chun-long, HAO Yu-Song, MO Yu-Xiang, LI Jia-Ming,
Chin. Phys. Lett. 2007, 24 (5):
1220-1223
.
In the framework of quantum defect theory, we study super-excited states of F2 molecules which can dissociate into F+(3P 2,1,0) and F-(1S0) ion-pair. Based on our calculation, we present a vibrational resolved assignment of the high precision photofragment yield spectra for F- from the F2 ion-pair production.
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Electrostatic Surface Trap for Cold Polar Molecules with a Charged Circular Wire
MA Hui, ZHOU Bei, LIAO Bin, YIN Jian-Ping
Chin. Phys. Lett. 2007, 24 (5):
1228-1230
.
We propose a novel scheme to trap cold polar molecules on the surface of an insulating substrate (i.e. a chip) by using an inhomogeneous electrostatic field, which is generated by the combination of a circular charged wire (a ring electrode) and a grounded metal plate. The spatial distributions of the electrostatic field from the above charged wire layout and its Stark potentials for CO molecules are calculated. Our study shows that when the voltage applied to the wire is U=15kV, a ring radius is R=5mm, the thickness of the insulating substrate is b=5mm, and a wire radius is r=1mm, the maximum efficient trapping potential (i.e., as equivalent temperature) for CO molecules is greater than 141.7mK, which is high enough to trap cold polar molecules with a temperature of 50mK in the low-field-seeking states.
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Multiple-Pulse Operation in Passively Mode-Locked Fibre Laser with Positive Dispersion Cavity
GAO Wei-Qing, ZHENG Huan, XU Li-Xin, WANG An-Ting, MING Hai, ANQi, HE Hu-Cheng, WANG Yun-Cai
Chin. Phys. Lett. 2007, 24 (5):
1267-1269
.
We report the observation of rectangular shape spectrum in passively mode-locked fibre laser with positive dispersion cavity. The spectrum is broad and flat, and 3dB bandwidth can be up to 17.61nm. Multiple-pulse operation is observed in our laser system. The spectrum width, pulse energy, pulse width and peak power of the mode-locked laser output change with the appearance of multiple-pulse operation.
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A Bidirectional, Diode-Pumped, Passively Mode-Locked Nd:YVO4 Ring Laser with a Low-Temperature-Grown Semiconductor Saturable Absorber Mirror
CAI Zhi-Qiang, YAO Jian-Quan, WANG Peng, WANG Yong-Gang, ZHANG Zhi-Gang
Chin. Phys. Lett. 2007, 24 (5):
1270-1272
.
We report the operation of a bidirectional picosecond pulsed ring Nd:YVO4 laser based on a low-temperature-grown semiconductor saturable absorber mirror. Except for the laser crystal, the six-mirror ring laser cavity has no intra-cavity elements such as focusing lens or mirror. The bidirectional mode locked pluses are obtained at the repetition rate of 117.5MHz, pulse duration of 81ps, power of 2×200mW.
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Highly Birefringent Honeycomb Photonic Bandgap Fibre
FANG Hong, LOU Shu-Qin, GUO Tie-Ying, JIAN Shui-Sheng
Chin. Phys. Lett. 2007, 24 (5):
1294-1297
.
A new structure of highly birefringent honeycomb photonic bandgap fibres (PBGFs), including an elliptical air hole in its solid core, is proposed and analysed by using full vectorial plane wave expansion method. From the numerical results it is confirmed that the proposed PBGF has birefringence of the order of 10-3. Moreover, there are two single-polarization single-mode ranges at varying normalized wavelength, in one of which only the slow-axis mode exists, and in the other only the fast-axis mode exists, which has not been achieved in index-guiding photonic crystal fibres so far.
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Photovoltaic and Electroluminescence Characters in Hybrid ZnO and Conjugated Polymer Bulk Heterojunction Devices
LIU Jun-Peng, QU Sheng-Chun, XU Ying, CHEN Yong-Hai, ZENG Xiang-Bo, WANG Zhi-Jie, ZHOU Hui-Ying, WANG Zhan-Guo
Chin. Phys. Lett. 2007, 24 (5):
1350-1353
.
We report electroluminescence in hybrid ZnO and conjugated polymer poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) bulk heterojunction photovoltaic cells. Photoluminescence quenching experimental results indicate that the ultrafast photoinduced electron transfer occurs from MDMO-PPV to ZnO under illumination. The ultrafast photoinduced electron transfer effect is induced because ZnO has an electron affinity about 1.2eV greater than that of MDMO-PPV. Electron `back transfer' can occur if the interfacial barrier between ZnO and MDMO-PPV can be overcome by applying a substantial electric field. Therefore, electroluminescence action due to the fact that the back transfer effect can be observed in the ZnO:MDMO-PPV devices since a forward bias is applied. The photovoltaic and electroluminescence actions in the same ZnO:MDMO-PPV device can be induced by different injection ways: photoinjection and electrical injection. The devices are expected to provide an opportunity for dual functionality devices with photovoltaic effect and electroluminescence character.
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Strain Effect on Photoluminescences from InGaN MQWs with Different Barriers Grown by MOCVD
YU Tong-Jun, KANG Xiang-Ning, PAN Yao-Bo, QIN Zhi-Xin, CHEN Zhi-Zhong, YANG Zhi-Jian, ZHANG Guo-Yi
Chin. Phys. Lett. 2007, 24 (5):
1365-1367
.
InGaN/GaN MQWs, InGaN/AlGaN MQWs and InGaN/AlInGaN MQWs are grown on (0001) sapphire substrates by MOCVD. Membrane samples are fabricated by laser lift-off technology. The photoluminescence spectra of membranes show a blue shift of peak positions in InGaN/GaN MQWs, a red shift of peak positions in InGaN/AlGaN MQWs and no shift of peak positions in InGaN/AlInGaN MQWs from those of samples with substrates. Different changes in Raman scattering spectra and HR-XRD (0002) profile of InGaN/AlInGaN MQWs, from those of InGaN/GaN MQWs and InGaN/AlGaN MQWs, are observed. The fact that the strain changes differently among InGaN MQWs with different barriers is confirmed. The AlInGaN barrier could adjust the residual stress for the least strain-induced electric field in InGaN/AlInGaN quantum wells.
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Organic Light Emitting Diodes with an Organic Acceptor/Donor Interface Involved in Hole Injection
CAO Guo-Hua, QIN Da-Shan, GUAN Min, CAO Jun-Song, ZENG Yi-Ping, LIJin-Min
Chin. Phys. Lett. 2007, 24 (5):
1380-1382
.
Organic light emitting diodes with an interface of organic acceptor 3-, 4-, 9-, 10-perylenetetracarboxylic dianhydride (PTCDA) and donor copper phthalocyanine (CuPc) involved in hole injection are fabricated. As compared to the conventional device using a 5nm CuPc hole injection layer, the device using an interface of 10nm PTCDA and 5nm CuPc layers shows much lower operating voltage with an increase of about 46% in the maximum power efficiency. The enhanced device performance is attributed to the efficient hole generation at the PTCDA/CuPc interface. This study provides a new way of designing hole injection.
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Enhanced Green Electrophosphorescence from Oxadiazole-Functionalized Iridium Complex-Doped Devices Using Poly(9,9-Dioctylfluorene) Instead of Poly(N-Vinylcarbazole) as a Host Matrix
LUO Cui-Ping, ZHOU Ji, WANG Lei, Deng Ji-Yong, QIN Zhi-Jun, ZHU Mei-Xiang, ZHU Wei-Guo,
Chin. Phys. Lett. 2007, 24 (5):
1386-1389
.
Optoelectronic properties of the oxadiazole-functionalized iridium complex-doped polymer light-emitting devices (PLEDs) are demonstrated with two different polymeric host matrices at the dopant concentrations 1--8%. The devices using a blend of poly(9,9-dioctylfluorene)(PFO) and 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) as a host matrix exhibited a maximum luminance efficiency of 11.3cd/A at 17.6mA/cm2. In contrast, the devices using a blend of poly(N-vinylcarbazole) (PVK) and PBD as a host matrix reveal only a peak luminance efficiency of 6.5cd/A at 4.1mA/cm2. The significantly enhanced electrophosphorescent emissions are observed in the devices with the PFO-PBD blend as a host matrix. This indicates that choice of polymers in the host matrices is crucial to achieve highly efficient phosphorescent dye-doped PLEDs.
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Effect of Reactor Pressure on Qualities of GaN Layers Grown by Hydride Vapour Phase Epitaxy
QIU Kai, YIN Zhi-Jun, LI Xin-Hua, ZHONG Fei, JI Chang-Jian, HAN Qi-Feng, CAO Xian-Cun, CHEN Jia-Rong, LUO Xiang-Dong, WANG Yu-Qi
Chin. Phys. Lett. 2007, 24 (5):
1390-1392
.
The influence of reactor pressure on GaN layers grown by hydride vapour phase epitaxy (HVPE) is investigated. By decreasing the reactor pressure from 0.7 to 0.5atm, the GaN layer growth mode changes from the island-like one to the step flow. The improvements in structural and optical properties and surface morphology of GaN layers are observed in the step flow growth mode. The results clearly indicate that the reactor pressure, similarly to the growth temperature, is one of the important parameters to influence the qualities of GaN epilayers grown by HVPE, due to the change of growth mode.
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MOCVD Growth and Characterization of Epitaxial AlxGa1-x N Films
LI Liang, ZHANG Rong, XIE Zi-Li, ZHANG Yu, XIU Xiang-Qian, LIU Bin, CHEN Lin, YU Hui-Qiang, HAN Ping, GONG Hai-Mei, ZHENG You-Dou
Chin. Phys. Lett. 2007, 24 (5):
1393-1396
.
We study the growth of AlxGa1-x N epilayers on (0001) sapphire by low-pressure MOCVD, using a low-temperature AlN buffer. By varying the input flow rates of trimethylgallium (TMGa), we obtain crack-free AlGaN films in the whole range of composition. A linear relationship between gas and solid Al content is observed. The structural properties of the layers (x = 0-1) are investigated by x-ray diffraction, atomic force microscopy (AFM) and scanning electron microscopy (SEM). It is found that a two-direction growth appears along the c-axis and the (10\11) directions for x≥0.45. From the results of Raman spectroscopy, we suggest that the compressive stain and the lack of mobility of Al adatoms can induce the formation of (10\11) grains.
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Detection Wavelength of Strained InxGa1-x As/GaAs Very-Long-Wavelength Quantum Well Infrared Photodetectors
XIONG Da-Yuan, LI Ning, LI Zhi-Feng, ZHEN Hong-Lou, LU Wei
Chin. Phys. Lett. 2007, 24 (5):
1403-1406
.
Detection wavelength is one of the key performance indices of infrared photodetectors. We study the character of detection wavelength of the strained InxGa1-x As/GaAs very-long-wavelength (>12μm) quantum well infrared photodetectors (VLW-QWIPs) characterized by the photoluminescence (PL) and photocurrent (PC) measurements. Based on the theoretical calculation and experimental data, we have built a practical model for the InxGa1-x As/GaAs strained VLW-QWIPs, from which the interband transitions, intersubband transition and peak detection wavelength can be determined. Afterwards, the dependences of detection wavelength and device operation mode on the In mole fraction and InxGa 1-x As well width are presented, which will be helpful for device design and optimization.
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Neutron-Capture Elements in the Double-Enhanced Star HE 1305-0007: a New s- and r-Process Paradigm
CUI Wen-Yuan, , CUI Dong-Nuan, DU Yun-Shuang, ZHANG Bo,
Chin. Phys. Lett. 2007, 24 (5):
1417-1420
.
The star HE 1305-0007 is a metal-poor double-enhanced star with metallicity [Fe/H] =-2.0, which is just at the upper limit of the metallicity for the observed double-enhanced stars. Using a parametric model, we find that almost all s-elements were made in a single neutron exposure. This star should be a member of a post-common-envelope binary. After the s-process material has experienced only one neutron exposure in the nucleosynthesis region and is dredged-up to its envelope, the AGB evolution is terminated by the onset of common-envelope evolution. Based on the high radial-velocity of HE 1305-0007, we speculate that the star could be a runaway star from a binary system, in which the AIC event has occurred and produced the r-process elements.
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83 articles
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