Engineering topics

Jianmin, Yuan

Publications and source records attributed to Jianmin, Yuan.

3 records

DOE OSTI2011

Proof-of-principle experiment of a modified photon-number-splitting attack against quantum key distribution

Any imperfections in a practical quantum key distribution (QKD) system may be exploited by an eavesdropper to collect information about the key without being discovered. We propose a modified photon-number-splitting attack scheme against QKD systems based on weak laser pulses taking advantage of possible multiphoton pulses. Proof-of-principle experiments are demonstrated. The results show that the eavesdropper can get information about the key generated between the legitimate parties without being detected. Since the equivalent attenuation introduced by the eavesdropper for pulses of different average photon numbers are different, the decoy-state method is effective in fighting against this kind of attack. This has also been proven in our experiments.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2010

Experimental study on discretely modulated continuous-variable quantum key distribution

We present a discretely modulated continuous-variable quantum key distribution system in free space by using strong coherent states. The amplitude noise in the laser source is suppressed to the shot-noise limit by using a mode cleaner combined with a frequency shift technique. Also, it is proven that the phase noise in the source has no impact on the final secret key rate. In order to increase the encoding rate, we use broadband homodyne detectors and the no-switching protocol. In a realistic model, we establish a secret key rate of 46.8 kbits/s against collective attacks at an encoding rate of 10 MHz for a 90% channel loss when the modulation variance is optimal.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2010

Detailed investigations on radiative opacity and emissivity of tin plasmas in the extreme-ultraviolet region

Radiative opacity and emissivity of tin plasmas at average ionization degree of about 10 was investigated in detail by using a fully relativistic detailed level accounting approach, in which main physical effects on the opacity were carefully taken into account. Among these physical effects, configuration interaction, in particular core-valence electron correlations, plays an important role on the determination of accurate atomic data required in the calculation of opacity. It results in a strong narrowing of lines from all transition arrays and strong absorption is located in a narrow wavelength region of 12.5-14 nm for Sn plasmas. Using a complete accurate atomic data, we investigated the opacity of Sn plasmas at a variety of physical condition. Among the respective ions of Xe{sup 6+}-Xe{sup 15+}, Xe{sup 10+} has the largest absorption cross section at 13.5 nm, while the favorable physical condition for maximal absorption at 13.5 nm do not mean that Xe{sup 10+} has the largest fraction. Comparison with other theoretical results showed that a complete set of consistent accurate atomic data, which lacks very much, is essential to predict accurate opacity. Our atomic model is useful and can be applied to interpret opacity experiments. Further benchmark experiments are urgently needed to clarify the physical effects on the opacity of Sn plasmas.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗