Decoherence in Josephson qubits from dielectric loss
Decoherence in Josephson qubits from dielectric loss
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DOI：
10.1103/physrevlett.95.210503
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发表时间：
2005-11-18
影响因子：
8.6
通讯作者：
Yu, CC
中科院分区：
文献类型：
--
作者：
Martinis, JM;Cooper, KB;Yu, CC
在超导量子比特中，双能级态的介电损耗是主要的退相干源。根据量子位设计的不同，绝缘材料或隧道结的介电损耗会导致相干时间缩短。我们证明了各种微波和量子位测量都可以很好地由两能级缺陷的共振吸收损失来模拟。我们的研究结果表明，通过使用更好的电介质和制造小于或接近10 μ m(2)的小面积结，可以显著减少这种损失。重新设计的相位量子位采用低损耗介质，能量松弛率提高了20倍，为多量子位门和算法开辟了可能性。
Dielectric loss from two-level states is shown to be a dominant decoherence source in superconducting quantum bits. Depending on the qubit design, dielectric loss from insulating materials or the tunnel junction can lead to short coherence times. We show that a variety of microwave and qubit measurements are well modeled by loss from resonant absorption of two-level defects. Our results demonstrate that this loss can be significantly reduced by using better dielectrics and fabricating junctions of small area less than or similar to 10 mu m(2). With a redesigned phase qubit employing low-loss dielectrics, the energy relaxation rate has been improved by a factor of 20, opening up the possibility of multiqubit gates and algorithms.