Details

Autor(en) / Beteiligte

• Lucas, M
• Danilov, A V
• Levitin, L V
• Jayaraman, A
• Casey, A J
• Faoro, L
• Tzalenchuk, A Ya
• Kubatkin, S E
• Saunders, J
• de Graaf, S E

Titel

Quantum bath suppression in a superconducting circuit by immersion cooling

Ist Teil von

• Nature communications, 2023-06, Vol.14 (1), p.3522-3522, Article 3522

Ort / Verlag

England: Nature Publishing Group

Erscheinungsjahr

2023

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Quantum circuits interact with the environment via several temperature-dependent degrees of freedom. Multiple experiments to-date have shown that most properties of superconducting devices appear to plateau out at T ≈ 50 mK - far above the refrigerator base temperature. This is for example reflected in the thermal state population of qubits, in excess numbers of quasiparticles, and polarisation of surface spins - factors contributing to reduced coherence. We demonstrate how to remove this thermal constraint by operating a circuit immersed in liquid He. This allows to efficiently cool the decohering environment of a superconducting resonator, and we see a continuous change in measured physical quantities down to previously unexplored sub-mK temperatures. The He acts as a heat sink which increases the energy relaxation rate of the quantum bath coupled to the circuit a thousand times, yet the suppressed bath does not introduce additional circuit losses or noise. Such quantum bath suppression can reduce decoherence in quantum circuits and opens a route for both thermal and coherence management in quantum processors.