来自热非平衡准粒子对超导量子比特的激发。

Excitation of superconducting qubits from hot nonequilibrium quasiparticles.

作者信息

Wenner J, Yin Yi, Lucero Erik, Barends R, Chen Yu, Chiaro B, Kelly J, Lenander M, Mariantoni Matteo, Megrant A, Neill C, O'Malley P J J, Sank D, Vainsencher A, Wang H, White T C, Cleland A N, Martinis John M

机构信息

Department of Physics, University of California, Santa Barbara, California 93106, USA.

Department of Physics, University of California, Santa Barbara, California 93106, USA and California NanoSystems Institute, University of California, Santa Barbara, California 93106, USA.

出版信息

Phys Rev Lett. 2013 Apr 12;110(15):150502. doi: 10.1103/PhysRevLett.110.150502. Epub 2013 Apr 9.

DOI:10.1103/PhysRevLett.110.150502

PMID:25167235

Abstract

Superconducting qubits probe environmental defects such as nonequilibrium quasiparticles, an important source of decoherence. We show that "hot" nonequilibrium quasiparticles, with energies above the superconducting gap, affect qubits differently from quasiparticles at the gap, implying qubits can probe the dynamic quasiparticle energy distribution. For hot quasiparticles, we predict a non-negligible increase in the qubit excited state probability Pe. By injecting hot quasiparticles into a qubit, we experimentally measure an increase of Pe in semiquantitative agreement with the model and rule out the typically assumed thermal distribution.

摘要

超导量子比特可探测诸如非平衡准粒子等环境缺陷，这是退相干的一个重要来源。我们表明，能量高于超导能隙的“热”非平衡准粒子对量子比特的影响与能隙处的准粒子不同，这意味着量子比特可以探测动态准粒子能量分布。对于热准粒子，我们预测量子比特激发态概率(P_e)会有不可忽略的增加。通过向量子比特注入热准粒子，我们通过实验测量到(P_e)的增加，与模型半定量相符，并排除了通常假设的热分布。