High cohesion and low interference in a superconducting qubit architecture

تماسك عالٍ وتداخل منخفض في بنية كيوبت فائقة التوصيل

Optical images of the lumen container and circuit. (a) Enclosure base with bore, center shaft and four cone holes for access to out-of-plane wires. (B) Cover enclosure with a central cylindrical cavity and identical cross slots for out-of-plane wires. (c) A cylindrical cavity in the cap filled with an indium sphere. (D) (Grayscale) A four-qubit circuit installed inside the base of the case. The four qubits are visible, arranged in a square grid with a distance of 2 mm. (e) helical resonator and (F) transmission qubit having electrode dimensions similar to those of the device. credit: science progress (2022). DOI: 10.1126 / sciadv.abl6698

In a new report now published in science progressdescribed by Peter A. qubit. The experimental setup comprised an inductively transformed cavity enclosure with out-of-plane non-galvanic control wires and qubits and resonators fabricated on opposite sides of the substrate. Scientists have developed a proof-of-concept device that incorporates four separate devices Send qubits, for example, a superconducting charged qubit with low sensitivity to charge noise, to show specific features that are measured via simultaneous random scaling. The integrated three-dimensional nature of control wiring allowed qubits to remain addressable as the architecture formed larger qubit networks.

Quantum engineer

Efforts to build 3D networks with many highly interconnected qubits attached are remarkable. Hardware Challenge. Researchers have previously developed superconducting circuits As a promising platform for achieving such synapses and forming a global gateway array. Typically, two sets of requirements must be met to scale these superconducting lattices, including a way to route control wires into the circuit allowing all qubits to remain routable and scalable, while preventing low frequency False modes of appearing inside the circle with increasing dimensions. The measurement process must also prevent decoherence to qubit channels and be compatible with gate resolutions that exceed the threshold of quantum error correction codes. Physicists had previously overcome the wiring limits for edge-connected circuits via integrated three-dimensional control wires as a workable solution. Alternatively, circuits can be placed in inductively transformed cavities in two dimensions with a cut-off frequency to Cavity modes. Spring et al presented experimental results relating to the latter concept on a four-qubit proof-of-principle circuit, in which the circuit architecture is characterized by three-dimensional integrated out-of-plane control wires, qubits and reading resonators fabricated on opposite sides of the substrate. The team also included a major new feature to accommodate transmission coherence times, exceeding 100 seconds, low interference errors and single-bit gate errors.

تماسك عالٍ وتداخل منخفض في بنية كيوبت فائقة التوصيل

Device schematics. (a) Out-of-plane wire design cross-section (not measurement), qubit processing is shown here. PTFE, polytetrafluoroethylene. (B) Cross-section of the bulk across the inductive shunt design (wide). Designed dimensions are shown in micrometres. (c) A schematic diagram of a circuit (not a scale). The substrate and container are partially shown, and the out-of-plane wires for Q2 are shown. Examples of Hamiltonian coupling terms and actuator voltages. credit: science progress (2022). DOI: 10.1126 / sciadv.abl6698

تماسك عالٍ وتداخل منخفض في بنية كيوبت فائقة التوصيل

Characterization of Qubit Relaxation. (a) Two hundred and fifty-one consecutive T1 measurements over a period of approximately 12 hours. (B) Histograms generated from T1. The inset shows an example of the T1 time trace for Q3, and the measurement pulse sequence. The four qubits were measured simultaneously; The data is displayed across two graphs for clarity. credit: science progress (2022). DOI: 10.1126 / sciadv.abl6698

Device architecture and characterization via talk

The researchers obtained images of the cavity and chamber container, in which the base of the enclosure retains a single central “pillar” and a lid containing a matching cylindrical cavity filled with a lid indium ball. They arranged four coaxial shunt units in a 2×2 grid with 2 mm spacing, and then implemented an out-of-plane wiring design with an inductive shunt design, and a circular layout, in which each resonator was coaxially aligned, capacitively coupled, to a qubit. The setup allowed the qubit electrodes to be “electrically floating”. The team obtained the circuit’s basic parameters and featured the device cross-talk, with the device serving as a proof-of-principle for circuit geometry with no intentional couplings, except for the qubit and resonator pairs. As a result, Spring et al identified all other couplings as unwanted interference. The team then defined cross-talk terms and summarized experimental cross-pairing and parasitic pairings in the device followed by empirical measurements of qubit control line The selectivity and selectivity of the resonator control line. They also measured the parasitic coupling of the qubit and the resonator to understand the parasitic scattering shift between the qubit and the resonator. Followed by one qubit random comparison It is performed on all four qubits separately and at the same time. The team ran each of the experiments 31 x 80, 5,000 times to build the statistics and display the resulting error for each actual gate, and also performed correlative random comparison On the basis of simultaneous experimental data. For a scale structure simulation, Spring et al . analyzed High frequency structure simulation A model of a unit cell containing the ideal dimensions of the central area of ​​the device 2 mm x 2 mm. They then set the band structure during simulations while collecting details about analytic cut-off frequency, band curvature, depth predictions and plasma skin within the setup.

  • High cohesion and low interference in a superconducting qubit architecture

    Characterization through speech. (a) The selectivity of the qubit control line experimentally measured qij = (qij/εqjj) 2 from the qubit i to the qubit control line j, expressed in dB units as 10log10 (qij). (b) The selectivity of the experimentally measured resonator control line φrij = (rij/εrj) 2 from the i resonator to the control line of the j resonator, expressed in dB units as 10log10 (φrij). (C) Frequency variance is found in Q1 of 20 repeated Ramsey experiments, with no motor on any resonator or continuous motor applied to R2, R3, or R4 at frequency ωr, j that fills it with a photon number n¯j of at least nlow , j≝ ncrit, j/10. Credit: science progress (2022). DOI: 10.1126 / sciadv.abl6698

  • High cohesion and low interference in a superconducting qubit architecture

    . Scale structure simulation. (a) HFSS model of a unit cell containing one measurable and addressable qubit (4 × 1/4) and one column transforming the enclosure inductively. The unit cell has dimensions similar to the central area of ​​2 mm x 2 mm for the device measured in this work. (b) Simulated lower band scattering of an infinite container formed from a unit cell plane tiling, with (solid) and without (dashed) the inductive shunt shaft and its associated substrate hole. It traces the wave vector k between points of symmetry Γ: (kx = 0, ky = 0), X: (kx = π/a, ky = 0), M: (kx = π/a, ky = /a). Colored curves show the expected curvature around the point with (red) and without (blue) the inductive shunt shaft and its associated substrate aperture, without using free-fit parameters. credit: science progress (2022). DOI: 10.1126 / sciadv.abl6698


In this way, Peter A. Spring and colleagues average qubit coherence times and synchronous single-qubit gate resolution in a four-qubit demonstration of a 3D superconducting circuit architecture. Before including the qubit coupling circuit, the team severely suppressed the remaining remaining talk of the setup. The visualized optimal device is applicable to study the associated errors resulting from high energy radiation In networks of highly coherent qubits and highly suppressed crosstalk. The present architecture contained an inductively transformed cavity enclosure tightly surrounding the circuit, along with integrated 3D out-of-plane control wires and backside reading resonators. The results highlighted the weak crosstalk of Experimental setup. The canister package is reusable by reshaping the indium ball into the cap cavity; However, the circuit is not attached to the chassis and cannot be removed and rearranged. The scientists highlighted several shortcomings of the presented device, including small and variable external resonator decay rates and dispersive transitions that were not ideal. qubit readings. Spring et al. He attributed the increased coherence in the preparation to the manufacturing process, which differed from previous applications from architecture.

A faster technique has been proposed to reset quantum circuits

more information:
Peter A. Spring et al, High coherence and low interference in a three-dimensional integrated switchable superconducting circuit architecture, science progress (2022). DOI: 10.1126 / sciadv.abl6698

Fowler et al., Surface symbols: towards a practical large-scale quantum computation, A . physical review (2012). DOI: 10.1103/ PhysRevA.86.032324

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