Based on a one dimensional quantum wave guide theory, we investigate the ballistic conductance through an Aharonov Bohm ring with a quantum gate. The analytical expression of the conductance is exactly obtained as t...Based on a one dimensional quantum wave guide theory, we investigate the ballistic conductance through an Aharonov Bohm ring with a quantum gate. The analytical expression of the conductance is exactly obtained as the function of magnetic flux penetrating the ring and Fermi energy of indcident electrons. When Fermi energy equals that of bound states in the isolated stub, the conductance is fixed at a constant value which is only determined by the geometric structure of the ring system. We have found that there are a new kind of conductance oscillations for some special mesoscopic ring systems. As Fermi energy of incident electrons crosses that of bound state in the isolated stub, the conductance oscillations have no abrupt change of phase by π and are in phase. This striking feature is not in ageement with that of previous experiments and theories. The mechanism causing this new feature is discussed.展开更多
真随机数发生器(True Random Number Generator,TRNG)在密码学、统计学、信息技术等领域发挥着不可替代的作用。以环形振荡器(Ring Oscillator,RO)为基础的TRNG,由于需要累积足够的抖动,才能使异或处理后的输出信号被抖动区域覆盖,因此...真随机数发生器(True Random Number Generator,TRNG)在密码学、统计学、信息技术等领域发挥着不可替代的作用。以环形振荡器(Ring Oscillator,RO)为基础的TRNG,由于需要累积足够的抖动,才能使异或处理后的输出信号被抖动区域覆盖,因此会消耗大量时间。提出了一种在现场可编程门列阵(Field Programmable Gate Array,FPGA)上产生真随机数的新方法,以RO产生的抖动为熵源。区别于直接采样其输出,通过异或门链提取2个RO的相位差,量化为脉冲信号,利用逻辑化的短脉冲抑制效应对脉冲信号精度计数,从而提高采样精度。同时,对输出进行异或处理,减少了输出值偏差,提高了随机性。提出的TRNG设计在Xilinx Virtex-7和Artix-7 FPGA上实现。生成的随机序列通过了NIST SP800-22测试和NIST SP800-90B测试。所提出的TRNG还在不同的电压和温度变化下进行测试,显示出良好的鲁棒性。展开更多
文摘Based on a one dimensional quantum wave guide theory, we investigate the ballistic conductance through an Aharonov Bohm ring with a quantum gate. The analytical expression of the conductance is exactly obtained as the function of magnetic flux penetrating the ring and Fermi energy of indcident electrons. When Fermi energy equals that of bound states in the isolated stub, the conductance is fixed at a constant value which is only determined by the geometric structure of the ring system. We have found that there are a new kind of conductance oscillations for some special mesoscopic ring systems. As Fermi energy of incident electrons crosses that of bound state in the isolated stub, the conductance oscillations have no abrupt change of phase by π and are in phase. This striking feature is not in ageement with that of previous experiments and theories. The mechanism causing this new feature is discussed.
