Quantum dissociation of a vortex-antivortex pair in a long Josephson junction
Quantum dissociation of a vortex-antivortex pair in a long Josephson junction
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DOI：
10.1103/physrevlett.91.257004
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发表时间：
2003-12-19
影响因子：
8.6
通讯作者：
Ustinov, AV
中科院分区：
文献类型：
--
作者：
Fistul, MV;Wallraff, A;Ustinov, AV
对环形约瑟夫森结中单个涡旋-反涡旋（VAV）对的热解离和量子解离进行了实验观察和理论分析。在我们的实验中，VAV 对被限制在由外部磁场和偏置电流控制的钉扎电位中。钉扎 VAV 对的解离表现为约瑟夫森结从超导状态切换到电阻状态。观察到的开关电流分布的温度和场依赖性与分析一致。从热解离到宏观量子隧道机制的交叉发生在大约 100 mK 的温度下。我们还预测了固定 VAV 态振荡能级的特定磁场依赖性。
The thermal and the quantum dissociation of a single vortex-antivortex (VAV) pair in an annular Josephson junction is experimentally observed and theoretically analyzed. In our experiments, the VAV pair is confined in a pinning potential controlled by external magnetic field and bias current. The dissociation of the pinned VAV pair manifests itself in a switching of the Josephson junction from the superconducting to the resistive state. The observed temperature and field dependence of the switching current distribution is in agreement with the analysis. The crossover from the thermal to the macroscopic quantum tunneling mechanism of dissociation occurs at a temperature of about 100 mK. We also predict the specific magnetic field dependence of the oscillatory energy levels of the pinned VAV state.