Yu Liuqi, Matityahu Shlomi, Rosen Yaniv J, Hung Chih-Chiao, Maksymov Andrii, Burin Alexander L, Schechter Moshe, Osborn Kevin D
Laboratory for Physical Sciences, University of Maryland, College Park, MD, 20740, USA.
Department of Physics, University of Maryland, College Park, MD, 20742, USA.
Sci Rep. 2022 Oct 10;12(1):16960. doi: 10.1038/s41598-022-21256-7.
Quantum two-level systems (TLSs) intrinsic to glasses induce decoherence in many modern quantum devices, such as superconducting qubits. Although the low-temperature physics of these TLSs is usually well-explained by a phenomenological standard tunneling model of independent TLSs, the nature of these TLSs, as well as their behavior out of equilibrium and at high energies above 1 K, remain inconclusive. Here we measure the non-equilibrium dielectric loss of TLSs in amorphous silicon using a superconducting resonator, where energies of TLSs are varied in time using a swept electric field. Our results show the existence of two distinct ensembles of TLSs, interacting weakly and strongly with phonons, where the latter also possesses anomalously large electric dipole moment. These results may shed new light on the low temperature characteristics of amorphous solids, and hold implications to experiments and applications in quantum devices using time-varying electric fields.
玻璃中固有的量子二能级系统（TLSs）在许多现代量子设备中，如超导量子比特中，会引发退相干。尽管这些TLSs的低温物理通常可以通过独立TLSs的现象学标准隧穿模型得到很好的解释，但这些TLSs的本质，以及它们在非平衡状态和高于1K的高能状态下的行为，仍然没有定论。在这里，我们使用超导谐振器测量非晶硅中TLSs的非平衡介电损耗，其中通过扫描电场随时间改变TLSs的能量。我们的结果表明存在两种不同的TLSs集合，它们与声子的相互作用强弱不同，其中后者还具有异常大的电偶极矩。这些结果可能为非晶固体的低温特性提供新的见解，并对使用时变电场的量子设备中的实验和应用具有启示意义。
