Multilayer microwave integrated quantum circuits for scalable quantum computing

Brecht, T.; Pfaff, Wolfgang; Wang, C.; Chu, Yiwen; Frunzio, Luigi; Devoret, Michel; Schoelkopf, Robert

doi:10.48550/arxiv.1509.01127

Cited by 4 publications

(5 citation statements)

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“…It seems, therefore, that even in the most optimistic scenario wherein extremely low physical error rates are achieved, a useful quantum computer will require many thousands of physical qubits, and less optimistic scenarios will require millions. This is now well understood by qubit device researchers, and there have been a number of recent proposals as to how one might architect systems that are scalable to large numbers of qubits [11,12]. Most of these proposals deal with how qubits could be integrated and interconnected in 2-dimensional arrays, using compact wafer-like configurations.…”

Section: Introductionmentioning

confidence: 99%

Flexible superconducting Nb transmission lines on thin film polyimide for quantum computing applications

Tuckerman

Hamilton

Reilly

et al. 2016

Supercond. Sci. Technol.

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We describe progress and initial results achieved towards the goal of developing integrated multi-conductor arrays of shielded controlled-impedance flexible superconducting transmission lines with ultra-miniature cross sections and wide bandwidths (dc to >10 GHz) over meter-scale lengths. Intended primarily for use in future scaled-up quantum computing systems, such flexible thin-film niobium/polyimide ribbon cables could provide a physically compact and ultra-low thermal conductance alternative to the rapidly increasing number of discrete coaxial cables that are currently used by quantum computing experimentalists to transmit signals between the several low-temperature stages (from ∼4 K down to ∼20 mK) of a dilution refrigerator. We have concluded that these structures are technically feasible to fabricate, and so far they have exhibited acceptable thermo-mechanical reliability. S-parameter results are presented for individual 2-metal layer Nb microstrip structures having 50 Ω characteristic impedance; lengths ranging from 50 to 550 mm were successfully fabricated. Solderable pads at the end terminations allowed testing using conventional rf connectors. Weakly coupled open-circuit microstrip resonators provided a sensitive measure of the overall transmission line loss as a function of frequency, temperature, and power. Two common microelectronic-grade polyimide dielectrics, one conventional and the other photo-definable (PI-2611 and HD-4100, respectively) were compared. Our most striking result, not previously reported to our knowledge, was that the dielectric loss tangents of both polyimides, over frequencies from 1 to 20 GHz, are remarkably low at deep cryogenic temperatures, typically 100× smaller than corresponding room temperature values. This enables fairly longdistance (meter-scale) transmission of microwave signals without excessive attenuation, and also permits usefully high rf power levels to be transmitted without creating excessive dielectric heating. We observed loss tangents as low as 2.2×10 −5 at 20 mK, although losses increased somewhat at very low rf power levels, similar to the well-known behavior of amorphous inorganic dielectrics such as SiO 2 . Our fabrication techniques could be extended to more complex structures such as multiconductor cables, embedded microstrip, 3-metal layer stripline or rectangular coax, and integrated attenuators and thermalization structures.

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Section: Introductionmentioning

confidence: 99%

Flexible superconducting Nb transmission lines on thin film polyimide for quantum computing applications

Tuckerman

Hamilton

Reilly

et al. 2016

Supercond. Sci. Technol.

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“…The measured frequencies and coupling energies of the multilayer device agree at the percent and ten-percent level, respectively, with design values from numerical simulations. The discrepancy can be explained by machining tolerances (25 µm) of the gap spacing and chip alignment in the sample holder, and could be improved by using micro-machined separators to support the structure [36][37][38].…”

Section: Discussionmentioning

confidence: 99%

“…This approach can be extended to provide low cross-talk inter-layer connections for devices with more than two layers, such as the architecture proposed in Ref. [38].…”

Section: Discussionmentioning

confidence: 99%

Planar Multilayer Circuit Quantum Electrodynamics

et al. 2016

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Experimental quantum information processing with superconducting circuits is rapidly advancing, driven by innovation in two classes of devices, one involving planar micro-fabricated (2D) resonators, and the other involving machined three-dimensional (3D) cavities. We demonstrate that circuit quantum electrodynamics can be implemented in a multilayer superconducting structure that combines 2D and 3D advantages. We employ standard micro-fabrication techniques to pattern each layer, and rely on a vacuum gap between the layers to store the electromagnetic energy. Planar qubits are lithographically defined as an aperture in a conducting boundary of the resonators. We demonstrate the aperture concept by implementing an integrated, two cavity-modes, one transmonqubit system.

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“…Recent work in developing air-bridge crossovers [13], vias [5] and flip-chip crossovers [2] has, however, mitigated this problem. These connections can connect medium-distance qubits and are protected from cross-talk by shielding methods [11]. Also importantly, the development of low-loss, 3D connections seem to be necessary even in double-defect codes, because of the need for off-chip control and measurement.…”

Section: Multi-simd Architecture For Planar Qecmentioning

confidence: 99%

Optimized surface code communication in superconducting quantum computers

Javadi-Abhari

Gokhale

Holmes

et al. 2017

Proceedings of the 50th Annual IEEE/ACM International Symposium on Microarchitecture

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Quantum computing (QC) is at the cusp of a revolution. Machines with 100 quantum bits (qubits) are anticipated to be operational by 2020 [30,73], and several-hundred-qubit machines are around the corner. Machines of this scale have the capacity to demonstrate quantum supremacy, the tipping point where QC is faster than the fastest classical alternative for a particular problem. Because error correction techniques will be central to QC and will be the most expensive component of quantum computation, choosing the lowest-overhead error correction scheme is critical to overall QC success. This paper evaluates two established quantum error correction codes-planar and double-defect surface codes-using a set of compilation, scheduling and network simulation tools. In considering scalable methods for optimizing both codes, we do so in the context of a full microarchitectural and compiler analysis. Contrary to previous predictions, we find that the simpler planar codes are sometimes more favorable for implementation on superconducting quantum computers, especially under conditions of high communication congestion.

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Multilayer microwave integrated quantum circuits for scalable quantum computing

Cited by 4 publications

References 0 publications

Flexible superconducting Nb transmission lines on thin film polyimide for quantum computing applications

Flexible superconducting Nb transmission lines on thin film polyimide for quantum computing applications

Planar Multilayer Circuit Quantum Electrodynamics

Optimized surface code communication in superconducting quantum computers

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