We propose a protocol for directly measuring the concurrence of a two-qubit electronic pure entangled state. To complete this task, we first design a parity-check measurement（PCM） which is constructed by two polariz...We propose a protocol for directly measuring the concurrence of a two-qubit electronic pure entangled state. To complete this task, we first design a parity-check measurement（PCM） which is constructed by two polarization beam splitters（PBSs） and a charge detector. By using the PCM for three rounds, we can achieve the concurrence by calculating the total probability of picking up the odd parity states from the initial states. Since the conduction electron may be a good candidate for the realization of quantum computation, this protocol may be useful in future solid quantum computation.展开更多
Sagnac effect enhancement can improve optical gyro precision. For a certain input intensity, we suggest that the other input port of beam splitter（BS） should be fed with some quantum light to break through shot nois...Sagnac effect enhancement can improve optical gyro precision. For a certain input intensity, we suggest that the other input port of beam splitter（BS） should be fed with some quantum light to break through shot noise limit（SNL） to improve Sagnac effect without increasing radiation-pressure noise（NRP）. We design a Sagnac effect quantum enhancement criterion（SQEC） to judge whether some quantum light can enhance Sagnac effect and present a Sagnac effect enhancement scheme that utilizing Fock state light and parity measurement technique to extract the output phase. The results of the theoretical analysis show that the maximum sensitivity can be reached at θ = 0, and the phase precision can break through SNL and even achieve Heisenberg limit（HL）. When the Fock state average photon number n is far less than coherent state, the minimum measurable angular rate is improved with √2n＋1 times, which can deduce shot noise and increase NRP little.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474168 and 61401222)the Qing Lan Project in Jiangsu Province,Chinathe Priority Academic Development Program of Jiangsu Higher Education Institutions,China
文摘We propose a protocol for directly measuring the concurrence of a two-qubit electronic pure entangled state. To complete this task, we first design a parity-check measurement（PCM） which is constructed by two polarization beam splitters（PBSs） and a charge detector. By using the PCM for three rounds, we can achieve the concurrence by calculating the total probability of picking up the odd parity states from the initial states. Since the conduction electron may be a good candidate for the realization of quantum computation, this protocol may be useful in future solid quantum computation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61573372 and 61603413)
文摘Sagnac effect enhancement can improve optical gyro precision. For a certain input intensity, we suggest that the other input port of beam splitter（BS） should be fed with some quantum light to break through shot noise limit（SNL） to improve Sagnac effect without increasing radiation-pressure noise（NRP）. We design a Sagnac effect quantum enhancement criterion（SQEC） to judge whether some quantum light can enhance Sagnac effect and present a Sagnac effect enhancement scheme that utilizing Fock state light and parity measurement technique to extract the output phase. The results of the theoretical analysis show that the maximum sensitivity can be reached at θ = 0, and the phase precision can break through SNL and even achieve Heisenberg limit（HL）. When the Fock state average photon number n is far less than coherent state, the minimum measurable angular rate is improved with √2n＋1 times, which can deduce shot noise and increase NRP little.
