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A quantum Szilard engine for two-level systems coupled to a qubit

Pop, Ioan 1
1 Institut für QuantenMaterialien und Technologien (IQMT), Karlsruher Institut für Technologie (KIT)

Abstract:

The innate complexity of solid state physics exposes superconducting quantum circuits to interactions with uncontrolled degrees of freedom degrading their coherence. By using a simple stabilization sequence we show that a superconducting fluxonium qubit is coupled to a two-level system (TLS) environment of unknown origin, with a relatively long energy relaxation time exceeding \SI{50}{ms}. Implementing a quantum Szilard engine with an active feedback control loop allows us to decide whether the qubit heats or cools its TLS environment. The TLSs can be cooled down resulting in a four times lower qubit population, or they can be heated to manifest themselves as a negative temperature environment corresponding to a qubit population of $\sim\!\SI{80}{\percent}$. We show that the TLSs and the qubit are each other's dominant loss mechanism and that the qubit relaxation is independent of the TLS populations. Understanding and mitigating TLS environments is therefore not only crucial to improve qubit lifetimes but also to avoid non-Markovian qubit dynamics.


Zugehörige Institution(en) am KIT Institut für Prozessdatenverarbeitung und Elektronik (IPE)
Institut für QuantenMaterialien und Technologien (IQMT)
Publikationstyp Vortrag
Publikationsmonat/-jahr 08.2022
Sprache Englisch
Identifikator KITopen-ID: 1000149508
HGF-Programm 47.12.01 (POF IV, LK 01) Advanced Solid-State Qubits and Qubit Systems
Veranstaltung Superconducting Qubits and Algorithms Conference 2022 (2022), Helsinki, Finnland, 25.08.2022 – 28.08.2022
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