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We realize a hybrid superconductor-semiconductor transmon device in which the Josephson effect is controlled by a gate-defined quantum dot in an InAs/Al nanowire. Microwave spectroscopy of the transmon's transition spectrum allows us to…

Accurate extraction of linearized quantum circuit models from electromagnetic simulations is essential for the design of superconducting circuits. We present a quantization framework based on the driving-point admittance…

Quantum Physics · Physics 2026-02-05 Mustafa Bakr , Robin Wopalenski

We show that two capacitively-coupled Josephson junctions, in the quantum limit, form a simple coupled qubit system with effective coupling controlled by the junction bias currents. We compute numerically the energy levels and wave…

Scaling up quantum computing hardware is hindered by the narrow operating margins of current quantum components. Here, we introduce a composite qubit and gate scheme that achieves wide margins by use of transistor-like nonlinearities to…

Quantum Physics · Physics 2022-02-23 Ryan J. Epstein

Using a quantum detector, a superconductor-insulator-superconductor junction, we probe separately the emission and absorption noise in the quantum regime of a superconducting resonant circuit at equilibrium. At low temperature the resonant…

Mesoscale and Nanoscale Physics · Physics 2012-01-27 Julien Basset , Hélène Bouchiat , Richard Deblock

In this article, we explore a new set of circuits, that incorporate both single-flux-quantum and quantized charge-based complementary quantum logic circuits. Circuits that convert single-flux-quantum voltage pulses to quantized charge…

Applied Physics · Physics 2019-09-04 Uday S. Goteti , Michael C. Hamilton

Superconducting flux qubits are a promising candidate for solid-state quantum computation. One of the reasons is that implementing a controlled coupling between the qubits appears to be relatively easy, if one uses tunable Josephson…

Superconductivity · Physics 2009-11-10 M. J. Storcz , F. K. Wilhelm

Robust qubit-qubit interactions mediated by bosonic modes are central to many quantum technologies. Existing proposals combining fast oscillator-mediated gates with dynamical decoupling require strong pulses or fast control over the…

Quantum Physics · Physics 2023-05-31 I. Arrazola , J. Casanova

Solid-state spin qubits have emerged as promising platforms for quantum information. Despite extensive efforts in controlling noise in spin qubit quantum applications, one important but less controlled noise source is near-field…

Quantum Physics · Physics 2024-09-18 Wenbo Sun , Sathwik Bharadwaj , Runwei Zhou , Dan Jiao , Zubin Jacob

Josephson junction arrays can be used as quantum channels to transfer quantum information between distant sites. In this work we discuss simple protocols to realize state transfer with high fidelity. The channels do not require complicate…

Quantum Physics · Physics 2009-11-10 Alessandro Romito , Rosario Fazio , C. Bruder

We propose and theoretically investigate spin superconducting qubits. Spin superconducting qubit consists of a single spin confined in a Josephson junction. We show that owing to spin-orbit interaction, superconducting difference across the…

Mesoscale and Nanoscale Physics · Physics 2012-12-07 C. Padurariu , Yu. V. Nazarov

Coherence of superconducting qubits can be improved by implementing designs that protect the parity of Cooper pairs on superconducting islands. Here, we introduce a parity-protected qubit based on voltage-controlled semiconductor nanowire…

By coupling a quantum detector, a superconductor-insulator-superconductor junction, to a Josephson junction \textit{via} a resonant circuit we probe the high frequency properties, namely the ac complex admittance and the current…

Mesoscale and Nanoscale Physics · Physics 2012-03-02 Julien Basset , Hélène Bouchiat , Richard Deblock

Low-frequency time-dependent noise is one of the main obstacles on the road towards a fully scalable quantum computer. The majority of solid-state qubit platforms, from superconducting circuits to spins in semiconductors, are greatly…

Quantum Physics · Physics 2021-10-27 Bikun Li , F. A. Calderon-Vargas , Junkai Zeng , Edwin Barnes

Stochastic switching-current distribution in a graphene-based Josephson junction exhibits a crossover from the classical to quantum regime, revealing the macroscopic quantum tunneling (MQT) of a Josephson phase particle at low temperatures.…

Mesoscale and Nanoscale Physics · Physics 2012-11-15 Gil-Ho Lee , Dongchan Jeong , Jae-Hyun Choi , Yong-Joo Doh , Hu-Jong Lee

We present a few-parameter ansatz for pulses to implement a broad set of simultaneous single-qubit rotations in frequency-crowded multilevel systems. Specifically, we consider a system of two qutrits whose working and leakage transitions…

Quantum Physics · Physics 2016-01-18 L. S. Theis , F. Motzoi , F. K. Wilhelm

High-fidelity gate operations are essential to the realization of a fault-tolerant quantum computer. In addition, the physical resources required to implement gates must scale efficiently with system size. A longstanding goal of the…

We show that a system of Josephson junctions coupled via low-resistance tunneling contacts to graphene substrate(s) may effectively operate as a current switching device. The effect is based on the dissipation-driven…

Superconductivity · Physics 2009-11-13 Roman M. Lutchyn , Victor Galitski , Gil Refael , S. Das Sarma

We investigate the driven quantum phase transition between the oscillating motion and the classical nearly free rotations of the Josephson pendulum coupled to a harmonic oscillator in the presence of dissipation. We refer to this as the…

Mesoscale and Nanoscale Physics · Physics 2019-06-25 I. Pietikäinen , J. Tuorila , D. S. Golubev , G. S. Paraoanu

Qubits on solid state devices could potentially provide the rapid control necessary for developing scalable quantum information processors. Materials innovation and design breakthroughs have increased functionality and coherence of qubits…