Quantum bath suppression in a superconducting circuit by immersion cooling

Abstract

Quantum circuits interact with the environment via several temperature-dependent degrees of freedom. Yet, multiple experiments to-date have shown that most properties of superconducting devices appear to plateau out at $T\approx 50$ 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 ${}^3$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 ${}^3$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.

References in corpus (36)

• Supplementary information for "Quantum supremacy using a programmable superconducting processor"
• Observation of high coherence in Josephson junction qubits measured in a three-dimensional circuit QED architecture
• Engineering cryogenic setups for 100-qubit scale superconducting circuit systems
• Fluctuations of Energy-Relaxation Times in Superconducting Qubits
• Decoherence benchmarking of superconducting qubits
• Correlated Charge Noise and Relaxation Errors in Superconducting Qubits
• Loss and decoherence due to stray infrared light in superconducting quantum circuits
• Impact of ionizing radiation on superconducting qubit coherence
• Hot non-equilibrium quasiparticles in transmon qubits
• Correlating decoherence in transmon qubits: Low frequency noise by single fluctuators
• Thermal and Residual Excited-State Population in a 3D Transmon Qubit
• Evidence for interacting two-level systems from the 1/f noise of a superconducting resonator
• Reducing the impact of radioactivity on quantum circuits in a deep-underground facility
• Observation of classical-quantum crossover of 1/f flux noise and its paramagnetic temperature dependence
• Removing leakage-induced correlated errors in superconducting quantum error correction
• Generalized Tunneling Model for TLS in amorphous materials and its predictions for their dephasing and the noise in superconducting microresonators
• Two-level systems in superconducting quantum devices due to trapped quasiparticles
• Suppression of 1/f noise in solid state quantum devices by surface spin desorption
• Direct identification of dilute surface spins on Al${}_2$O${}_3$: Origin of flux noise in quantum circuits
• Internal loss of superconducting resonators induced by interacting two level systems
• Analysis of high quality superconducting resonators: consequences for TLS properties in amorphous oxides
• Fast tunable high Q-factor superconducting microwave resonators
• Progress in cooling nanoelectronic devices to ultra-low temperatures
• Pound-locking for characterization of superconducting microresonators
• Revealing the nonlinear response of a tunneling two-level system ensemble using coupled modes
• Low temperature 1/f noise in microwave dielectric constant of amorphous dielectrics in Josephson qubits
• Transmission-line resonators for the study of individual two-level tunneling systems
• Fragility of surface states in topological superfluid ${}^3$He
• Cooling low-dimensional electron systems into the microkelvin regime
• Probing hundreds of individual quantum defects in polycrystalline and amorphous alumina
• Integrating superfluids with superconducting qubit systems
• Measuring effective temperatures of qubits using correlations
• Fluctuation Spectroscopy of Two-Level Systems in Superconducting Resonators
• Evidence for universal relationship between the measured 1/f permittivity noise and loss tangent created by tunneling atoms
• Threefold Reduction in Thermal Conductivity of Vycor Glass Due to Adsorption of Liquid 4He
• Protocol for temperature sensing using a three-level transmon circuit

Cited by in corpus (10)

• Phonon engineering of atomic-scale defects in superconducting quantum circuits
• Quasiparticle spectroscopy, transport, and magnetic properties of Nb films used in superconducting transmon qubits
• Feasibility of the Josephson voltage and current standards on a single chip
• Loss and decoherence in superconducting circuits on silicon: Insights from electron spin resonance
• Leveraging collective effects for thermometry in waveguide quantum electrodynamics
• Theory of Two-level Tunneling Systems in Superconductors
• Logarithmic light cone, slow entanglement growth, and quantum memory
• Dissipative evolution of a two-level system through a geometry-based classical mapping
• Photonic Simulation of Localization Phenomena Using Boson Sampling
• Hydrogen crystals reduce dissipation in superconducting resonators