The consequences of coupling superconducting qubits to long livedenvironments

With increasing performance, superconducting qubits become sensitive to

the weak coupling to long lived environments. In recent years one of

these environments was discovered to be a bath of long lived

two-level-systems [1], which can be the dominant energy decay channel

for the qubit. Moreover, this decay channel deviates from the typical

Born Markov approximations for thermodynamic baths and is described by

the Solomon equations [2]. In this talk we show that the bath of long

lived TLS's reported in [1] has a significant impact on the qubit's

dynamics, beyond the expected T1 reduction.

[1] Spiecker, M. et al. Two-level system hyperpolarization using a

quantum Szilard engine. Nat. Phys. 19, 1320–1325 (2023).

[2] Spiecker, M. et al. Solomon equations for qubit and two-level

systems: Insights into non-Poissonian quantum jumps. Phys. Rev. A 109,

052218 (2024)