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So far, superconducting quantum computers have certain constraints on qubit connectivity, such as nearest-neighbor couplings. To overcome this limitation, we propose a scalable architecture to simultaneously connect several pairs of distant…

Quantum Physics · Physics 2020-09-02 Roberto Stassi , Mauro Cirio , Franco Nori

We propose a novel architecture for superconducting circuits to improve the efficiency of a quantum annealing system. To increase the capability of a circuit, it is desirable for a qubit to be coupled not only with adjacent qubits but also…

Quantum Physics · Physics 2019-04-22 Hiroto Mukai , Akiyoshi Tomonaga , Jaw-Shen Tsai

Constructing a fault-tolerant quantum computer is a daunting task. Given any design, it is possible to determine the maximum error rate of each type of component that can be tolerated while still permitting arbitrarily large-scale quantum…

We present a flip-chip architecture for an array of coupled superconducting qubits, in which circuit components reside inside individual microwave enclosures. In contrast to other flip-chip approaches, the qubit chips in our architecture…

We propose a qubit-qubit coupling scheme for superconducting flux quantum bits (qubits), where a quantized Josephson junction resonator and microwave irradiation are utilized. The junction is used as a tunable inductance controlled by…

Superconductivity · Physics 2009-11-13 H. Nakano , K. Kakuyanagi , M. Ueda , K. Semba

Understanding how and to what magnitude solid-state qubits couple to metallic wires is crucial to the design of quantum systems such as quantum computers. Here, we investigate the coupling between a multi-level system, or qudit, and a…

Mesoscale and Nanoscale Physics · Physics 2023-12-07 Rusko Ruskov , Charles Tahan

To reduce circuit depth when executing Quantum algorithms, it is necessary to maximize qubit connectivity on a near-term quantum processor. While addressing this, we also need to ensure high gate fidelity, suppression of unwanted ZZ…

Quantum Physics · Physics 2026-02-09 Uday Sannigrahi , Amlan Chakrabarti , Swapnil Saha , Shrinjita Biswas

Semiconductor qubits rely on the control of charge and spin degrees of freedom of electrons or holes confined in quantum dots (QDs). They constitute a promising approach to quantum information processing [1, 2], complementary to…

In contrast to the commonly used qubit resonator transverse coupling via the $\sigma_{xy}$-degree of freedom, longitudinal coupling through $\sigma_z$ presents a tantalizing alternative: it does not hybridize the modes, eliminating Purcell…

Quantum Physics · Physics 2025-10-03 S. Günzler , D. Rieger , M. Spiecker , T. Koch , G. A. Timco , R. E. P. Winpenny , I. M. Pop , W. Wernsdorfer

Spin qubits and superconducting qubits are among the promising candidates for a solid state quantum computer. For the implementation of a hybrid architecture which can profit from the advantages of either world, a coherent long-distance…

We have proposed and experimentally verified a tunable inter-qubit coupling scheme for large-scale integration of superconducting qubits. The key feature of the scheme is the insertion of connecting pads between qubit and tunable coupling…

We analyze a coupling scheme for qubits in different cavities of circuit-QED architecture. In contrast to the usual scheme where the cavities are coupled by an interface capacitance we employ a bridge qubit connecting cavities to mediate…

Quantum Physics · Physics 2016-01-27 Mun Dae Kim , Jaewan Kim

Superconducting quantum computing emerges as one of leading candidates for achieving quantum advantage. However, a prevailing challenge is the coding overhead due to limited quantum connectivity, constrained by nearest-neighbor coupling…

We study a circuit QED setup where multiple superconducting qubits are ultrastrongly coupled to a single radio-frequency resonator. In this extreme parameter regime of cavity QED the dynamics of the electromagnetic mode is very slow…

Quantum Physics · Physics 2020-02-28 T. Jaako , J. J. Garcia-Ripoll , P. Rabl

Hybrid circuit quantum electrodynamics (QED) involves the study of coherent quantum physics in solid state systems via their interactions with superconducting microwave circuits. Here we present an implementation of a hybrid superconducting…

Qubit coherence and gate fidelity are typically considered the two most important metrics for characterizing a quantum processor. An equally important metric is inter-qubit connectivity as it minimizes gate count and allows implementing…

Superconducting quantum circuits typically use capacitive charge-based linear coupling schemes to control interactions between elements such as qubits. While simple and effective, this coupling scheme makes it difficult to satisfy competing…

Quantum Physics · Physics 2026-02-04 Gihwan Kim , Andreas Butler , Oskar Painter

We propose a scheme for scalable and robust quantum computing on two-dimensional arrays of qubits with fixed longitudinal coupling. This opens the possibility for bypassing the device complexity associated with tunable couplers required in…

Quantum Physics · Physics 2023-03-08 Nguyen H. Le , Max Cykiert , Eran Ginossar

Quantum coherence in solid-state systems has been demonstrated in superconducting circuits and in semiconductor quantum dots. This has paved the way to investigate solid-state systems for quantum information processing with the potential…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 T. Frey , P. J. Leek , M. Beck , A. Blais , T. Ihn , K. Ensslin , A. Wallraff

Quantum error correction codes with non-local connections such as quantum low-density parity-check (qLDPC) incur lower overhead and outperform surface codes on large-scale devices. These codes are not applicable on current superconducting…