Quasiparticle decoherence in d-wave superconducting qubits.
Quasiparticle decoherence in d-wave superconducting qubits.
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d 波超导量子位中的准粒子退相干。
DOI：
10.1103/physrevlett.92.017001
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发表时间：
2003
影响因子：
8.6
通讯作者：
A. Y. Smirnov
中科院分区：
文献类型：
--
作者：
M. Amin;A. Y. Smirnov
人们通常认为，在d波超导能隙的节点处存在的无能隙准粒子激发应该会强烈地退相干d波量子比特的量子态，使得量子效应实际上是不可观测的。使用自洽的线性响应非平衡准经典形式主义，我们表明，这不一定是真的。我们发现d波晶界结的准粒子电导是强烈的相位相关。带隙中间态和节点准粒子对电导和退相干都有贡献。据估计，在包含具有适当参数的d波结的量子位中可以检测到量子行为。
It is usually argued that the presence of gapless quasiparticle excitations at the nodes of the d-wave superconducting gap should strongly decohere the quantum states of a d-wave qubit, making quantum effects practically unobservable. Using a self-consistent linear response nonequilibrium quasiclassical formalism, we show that this is not necessarily true. We find quasiparticle conductance of a d-wave grain boundary junction to be strongly phase dependent. Midgap states as well as nodal quasiparticles contribute to the conductance and therefore decoherence. Quantum behavior is estimated to be detectable in a qubit containing a d-wave junction with appropriate parameters.