We have observed the macroscopic resonant tunneling of magnetic flux between macroscopically distinct quantum states in a superconducting flux qubit. The dependences of the macroscopic resonant tunneling on the barrier height of the potential well, the flux bias and the initial state are investigated. Detailed measurements of the tunneling rate as a function of the flux bias reveal the feature of the quantum noise in the superconducting flux qubit.
Terahertz(THz) time-domain spectroscopy(TDS) has been applied to investigate liquid's optical property in recent years.However,comprehensive discussion of how to compute liquids' complex refractive indices and absorption rates are seldom reported.So,in this work,we try to find a way to compute liquids' optical property accurately and conveniently.
ZHOU Lei,XU WeiWei,JIN BiaoBing,CHEN Jian,KANG Lin & WU PeiHeng Research Institute of Superconductor Electronics(RISE),Nanjing University,Nanjing 210093,China
Using YBa2Cu3O7-δ/MgO bicrystal Josephson junction,we have developed a setup for spectrum analyses of terahertz signals,up to 2.5 THz,with a frequency resolution of 3 GHz.The junction works at liquid nitrogen temperature when the signal frequencies are low while for signals at 1.6 THz and 2.5 THz the junction is cooled to 6 K.Digital signal processing(DSP) chips are made use of to build a data acquisition and processing system so that it can be compact,fast,and intelligent.With the completion of the relevant hardwares and softwares,the measurements are now automated.
XU WeiWei,CHEN Jian,KANG Lin & WU PeiHeng Department of Electronic Science & Engineering,Nanjing University,Nanjing 210093,China
The absorption and dispersion of several non-polar organic solvents from 0.2 to 2.5 THz are measured with the method of time-domain spectroscopy.Based on the result,we believe that liquid paraffin might be a proper choice for liquid dielectric waveguide.Transmitting performance of THz liquid dielectric waveguide at 98 GHz is tested.
ZHOU Lei,XU WeiWei,HUA Tao,LU XueHui,CHEN Jian,JIN BiaoBing,KANG Lin & WU PeiHeng Research Institute of Superconductor Electronics (RISE),Nanjing University,Nanjing 210093,China
