论文标题
量动量的连续体中的绑定状态
Bound states in the continuum in a fluxonium qutrit
论文作者
论文摘要
当与任何其他系统耦合时，零外部通量的重量磁通具有长寿命。我们通过将所有Fluxonium相关的操作员投影到QUTRIT子空间中来分析它，因为这种长期寿命的配置对应于第二个激发的磁通量水平。当耦合发生到支持连续模式的扩展系统时，该状态成为连续体（BIC）中的界限。在没有噪音的情况下，当Fluxonium耦合到超导波导时，我们发现BIC寿命可能大于秒$ t_1 \ gg {\ rm s} $，而典型的设备频率为$ {\ rm ghz} $。我们已经在现实的实验中对不同的破坏来源进行了详细的研究，并获得了由波导中有限温度引起的向上过渡，并衰减$ 1/f $ -Flux噪声是最危险的。即使在他们面前，BICS衰减时间也可能达到$ {T_1 \ sim \ rm 10^{ - 1} MS}的范围，而准备时间为$ 10^{2} $ ns。
The heavy fluxonium at zero external flux has a long-lived state when coupled capacitively to any other system. We analyze it by projecting all the fluxonium relevant operators into the qutrit subspace, as this long-lived configuration corresponds to the second excited fluxonium level. This state becomes a bound-state in the continuum (BIC) when the coupling occurs to an extended system supporting a continuum of modes. In the case without noise, we find BIC lifetimes that can be much larger than seconds $T_1\gg {\rm s}$ when the fluxonium is coupled to a superconducting waveguide, while typical device frequencies are in the order of ${\rm GHz}$. We have performed a detailed study of the different sources of decoherence in a realistic experiment, obtaining that upward transitions caused by a finite temperature in the waveguide and decay induced by $1/f$-flux noise are the most dangerous ones. Even in their presence, BICs decay times could reach the range of ${T_1\sim \rm 10^{-1} ms},$ while preparation times are of the order of $10^{2}$ns.
