Numerical study of induced vortex tunneling

Induced vortex tunneling in a superconducting wire

We consider induced topological transitions in a wire made from cylindrical superconducting film. During a transition, a pulse of electric current causes transport of a virtual vortex-antivortex pair around the cylinder. We consider both the instanton approach, in which the transition is viewed as motion of vortices in the Euclidean time, and the real-time dual formulation, in which vortices are described by a fundamental quantum field. The instanton approach is convenient to discuss effects of the environment, while in the dual formulation we show that there exists a potentially useful adiaba…

Reversal of the circulation of a vortex by quantum tunneling in trapped Bose systems

We study the quantum dynamics of a model for a vortex in a Bose gas with repulsive interactions in an anisotropic, harmonic trap. By solving the Schrödinger equation numerically, we show that the circulation of the vortex can undergo periodic reversals by quantum-mechanical tunneling. With increasing interaction strength or particle number, vortices become increasingly stable, and the period for reversals increases. Tunneling between vortex and antivortex states is shown to be described to a good approximation by a superposition of vortex and antivortex states (a Schrödinger cat state), rather…

Tunneling vortex dynamics in linearly coupled Bose-Hubbard rings

The quantum dynamics of population-balanced fractional vortices and population-imbalanced vortices in an effective two-state bosonic system, made of two coupled discrete circuits with few sites, is addressed within the Bose-Hubbard model. % We show that for low on-site interaction, the tunneling of quantized vortices between the rings performs a coherent, oscillating dynamics connecting current states with chiral symmetry. The vortex-flux transfer dually follows the usual sinusoidal particle current of the Josephson effect, in good agreement with a mean-field approximation. Within such regime,…

二维$^4$He超流薄膜中涡旋的真空隧穿

Vacuum tunneling of vortices in two-dimensional $^4$He superfluid films

本文研究二维超流氦薄膜中涡旋的真空隧穿，区分边界外在过程与体内内在过程，计算隧穿速率，并类比施温格机制提出涡旋计数实验验证方案。

通用双臂共传播马约拉纳干涉仪的马约拉纳费米子与边缘涡旋隧穿输运理论

Transport theory for a generic two-arm co-propagating Majorana interferometer with Majorana fermion and edge vortex tunneling

该理论研究了共传播马约拉纳干涉仪中边缘涡旋的非阿贝尔统计，通过玻色化推广到不对称配置，发现低频有效电容携带拓扑自旋特征，且热长度决定输运可见性。

Magnetic Blockade Mechanism for Quantum Nucleation of Superconducting Vortex-Antivortex Pairs in Zero External Magnetic Field

We propose a magnetic dual of the Coulomb blockade effect for quantum nucleation of flux vortex pairs in high-Tc superconducting (HTS) films and grain boundaries in zero applied field. The magnetic blockade instability occurs at θ = π, where θ is the "vacuum" or theta angle. The θ term has recently been discussed in the context of several other systems, including charge and spin density waves, topological insulators, the quantum Hall effect, and spontaneous CP violation. Our model predicts a sharp pair creation threshold current at θ = π, analogous to the Coulomb blockade voltage of a tunnel j…