Frequency-Multiplexed Millimeter-Wave Fault-Tolerant Superconducting Qubits Enabled by an On-Chip Nonreciprocal Control Bus

• URL: http://arxiv.org/abs/2512.17588v1
• Date: Fri, 19 Dec 2025 13:57:17 GMT
• Title: Frequency-Multiplexed Millimeter-Wave Fault-Tolerant Superconducting Qubits Enabled by an On-Chip Nonreciprocal Control Bus
• Authors: Sajjad Taravati,
• Abstract summary: Scaling superconducting quantum processors is fundamentally limited by the escalating effects of microwave crosstalk and decay Purcell.<n>This paper proposes the concept of frequency-multiplexed millimeter-wave superconducting qubits.<n>It demonstrates a novel architecture that integrates an on-chip cryogenic nonreciprocal space-time-periodic superconducting frequency multiplier.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Scaling superconducting quantum processors is fundamentally limited by the escalating complexity of cryogenic wiring and the debilitating effects of microwave crosstalk and Purcell decay. This paper proposes the concept of frequency-multiplexed millimeter-wave superconducting qubits and demonstrates a novel architecture that integrates an on-chip cryogenic nonreciprocal space-time-periodic superconducting frequency multiplier as a universal control bus for a frequency-multiplexed qubit array. The bus replaces multiple high-frequency XY drive lines with a single low-frequency input tone, which the multiplier converts into a comb of high-order harmonics, each resonantly addressing a distinct qubit. Crucially, the dynamic and nonreciprocal nature of the bus provides signal gain and intrinsic isolation that simultaneously suppresses Purcell decay, enhancing T1 times across all distinct-frequency qubits, and reduces coherent crosstalk by more than two orders of magnitude. The spatiotemporal modulation enables parametric frequency multiplication and creates wave-propagation dynamics analogous to cosmological expansion, with observed redshift-like broadening and deceleration of magnetic-field wavepackets. Theoretical modeling based on a non-Markovian master equation confirms that the engineered memory kernel extends coherence while reshaping the noise spectrum. Full error-budget analysis shows that the architecture maintains gate errors below the fault-tolerance threshold for arrays exceeding 25 qubits, converting a crosstalk-dominated error budget into one limited by intrinsic material coherence. This integrated, frequency-multiplexed, and nonreciprocal control bus therefore offers a path toward unprecedented I/O simplification, noise resilience, and scalable high-coherence quantum processin

Related papers

• Flux-Activated Resonant Control of a Bosonic Quantum Memory [63.35373457838474]
  Bosonic circuit quantum electrodynamics (cQED) coherently control long-lived superconducting cavities.<n>We integrate an on-chip flux-control architecture with a long-lived bosonic memory housed in a 3D superconducting cavity.<n>We realize efficient arbitrary rotations between any pair of Fock levels in the memory.
  arXiv  Detail & Related papers  (2026-02-20T10:22:53Z)
• Active interference suppression in frequency-division-multiplexed quantum gates via off-resonant microwave tones [1.0068173369769948]
  We propose an active interference suppression method for frequency-division-multiplexed simultaneous gate operations.<n>We find that by incorporating off-resonant microwave tones, the gate decreases proportionally to the inverse square of the number of microwave tones.<n>Our approach is simple yet effective for improving the performance of frequency-division-multiplexed quantum gates.
  arXiv  Detail & Related papers  (2026-01-21T00:06:53Z)
• Crosstalk Dispersion and Spatial Scaling in Superconducting Qubit Arrays [0.5621251909851629]
  Crosstalk between qubits fundamentally limits the scalability of quantum processors.<n>We develop a theoretical and experimental framework that captures residual interactions between both adjacent and non-adjacent qubits.<n>Our framework provides design guidance for crosstalk mitigation in larger-scale quantum processors.
  arXiv  Detail & Related papers  (2025-12-20T00:08:27Z)
• Orthogonal frequency-division multiplexing for simultaneous gate operations on multiple qubits via a shared control line [1.0068173369769948]
  Scaling poses significant challenges in terms of the thermal loads, forming a major bottleneck in the realization of large-scale quantum computers.<n>We analyze simultaneous gate operations on multiple qubits using microwaves transmitted via a single cable in a frequency-division multiplexing scheme.<n>Our findings enable a scalable FDM-based microwave control scheme suitable for quantum processors with a large number of qubits.
  arXiv  Detail & Related papers  (2025-11-20T23:36:23Z)
• Microwave-activated high-fidelity three-qubit gate scheme for fixed-frequency superconducting qubits [19.88291799199791]
  We propose a microwave-activated three-qubit gate protocol for fixed-frequency transmon qubits in the large-detuning regime.<n>The protocol maintains process fidelities exceeding $98%$ under decoherence.<n>This strategy advances scalable quantum computing systems by improving coherence properties, reducing spectral congestion, and expanding the experimental toolkit for error-resilient quantum operations.
  arXiv  Detail & Related papers  (2025-04-30T06:16:16Z)
• High-fidelity parametric beamsplitting with a parity-protected converter [2.5818006849347857]
  Fast, high-fidelity operations between microwave resonators are an important tool for bosonic quantum computation and simulation. An attractive approach is to couple these resonators via a nonlinear converter and actuate parametric processes with RF drives. We show that in addition to a careful management of drive frequencies and the spectrum of environmental noise, leveraging the inbuilt symmetries of the converter Hamiltonian can suppress unwanted nonlinear interactions. We characterize this beamsplitter in the cavities' joint single-photon subspace, and show that we can detect and post-select photon loss events to achieve a beamsplitter gate
  arXiv  Detail & Related papers  (2023-03-02T04:30:01Z)
• All-microwave manipulation of superconducting qubits with a fixed-frequency transmon coupler [0.685068326729525]
  All-microwave control of superconducting quantum computing circuits is advantageous for minimizing the noise channels and wiring costs. We introduce a swap interaction between two data transmons assisted by the third-order nonlinearity of a coupler transmon under a microwave drive.
  arXiv  Detail & Related papers  (2023-02-14T09:34:20Z)
• Quantum emulation of the transient dynamics in the multistate Landau-Zener model [50.591267188664666]
  We study the transient dynamics in the multistate Landau-Zener model as a function of the Landau-Zener velocity. Our experiments pave the way for more complex simulations with qubits coupled to an engineered bosonic mode spectrum.
  arXiv  Detail & Related papers  (2022-11-26T15:04:11Z)
• Topological Josephson parametric amplifier array: A proposal for directional, broadband, and low-noise amplification [39.58317527488534]
  Low-noise microwave amplifiers are crucial for detecting weak signals in fields such as quantum technology and radio astronomy. We show that compact devices with few sites can achieve exceptional performance, with gains exceeding 20 dB over a bandwidth ranging from hundreds of MHz to GHz. The device also operates near the quantum noise limit and provides topological protection against up to 15% fabrication disorder.
  arXiv  Detail & Related papers  (2022-07-27T18:07:20Z)
• Extensible circuit-QED architecture via amplitude- and frequency-variable microwaves [52.77024349608834]
  We introduce a circuit-QED architecture combining fixed-frequency qubits and microwave-driven couplers. Drive parameters appear as tunable knobs enabling selective two-qubit coupling and coherent-error suppression.
  arXiv  Detail & Related papers  (2022-04-17T22:49:56Z)
• Frequency combs with parity-protected cross-correlations from dynamically modulated qubit arrays [117.44028458220427]
  We develop a general theoretical framework to dynamically engineer quantum correlations in the frequency-comb emission from an array of superconducting qubits in a waveguide. We demonstrate, that when the resonance of the two qubits are periodically modulated with a $pi$ phase shift, it is possible to realize simultaneous bunching and antibunching in cross-correlations of the scattered photons from different sidebands.
  arXiv  Detail & Related papers  (2022-03-01T13:12:45Z)
• Superconducting coupler with exponentially large on-off ratio [68.8204255655161]
  Tunable two-qubit couplers offer an avenue to mitigate errors in multiqubit superconducting quantum processors. Most couplers operate in a narrow frequency band and target specific couplings, such as the spurious $ZZ$ interaction. We introduce a superconducting coupler that alleviates these limitations by suppressing all two-qubit interactions with an exponentially large on-off ratio.
  arXiv  Detail & Related papers  (2021-07-21T03:03:13Z)
• Waveguide Bandgap Engineering with an Array of Superconducting Qubits [101.18253437732933]
  We experimentally study a metamaterial made of eight superconducting transmon qubits with local frequency control. We observe the formation of super- and subradiant states, as well as the emergence of a polaritonic bandgap. The circuit of this work extends experiments with one and two qubits towards a full-blown quantum metamaterial.
  arXiv  Detail & Related papers  (2020-06-05T09:27:53Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.