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Exchange-only (EO) spin qubits in silicon realise all-electrical qubit control through pairwise Heisenberg exchange interactions, making them attractive for scalable quantum computation. Their principal vulnerability is charge noise, which…

Fast and high-fidelity qubit measurement is crucial for achieving quantum error correction, a fundamental element in the development of universal quantum computing. For electron spin qubits, fast readout stands out as a major obstacle in…

Mesoscale and Nanoscale Physics · Physics 2024-01-09 Chon-Fai Kam , Xuedong Hu

Projective measurement of single electron spins, or spin readout, is among the most fundamental technologies for spin-based quantum information processing. Implementing spin readout with both high-fidelity and scalability is indispensable…

Mesoscale and Nanoscale Physics · Physics 2024-10-07 Haruki Kiyama , Danny van Hien Hien , Arne Ludwig , Andreas D. Wieck , Akira Oiwa

Initialization and readout of coupled quantum systems are essential ingredients for the implementation of quantum algorithms. If the state of a multi-qubit register can be read out in a single shot, this enables further key resources such…

We demonstrate an on-demand hole spin qubit initialization scheme meeting four key requirements of quantum information processing: fast initialization (1/e ~ 100 ps), high fidelity (F > 99%), long qubit lifetime…

We consider electron spin qubits in quantum dots and define a measurement efficiency e to characterize reliable measurements via n-shot read outs. We propose various implementations based on a double dot and quantum point contact (QPC) and…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Hans-Andreas Engel , Vitaly Golovach , Daniel Loss , L. M. K. Vandersypen , J. M. Elzerman , R. Hanson , L. P. Kouwenhoven

The gate fidelity and the coherence time of a qubit are important benchmarks for quantum computation. We construct a qubit using a single electron spin in a Si/SiGe quantum dot and control it electrically via an artificial spin-orbit field…

Spin qubits need to operate within a very precise voltage space around charge state transitions to achieve high-fidelity gates. However, the stability diagrams that allow the identification of the desired charge states are long to acquire.…

Spin-1 tunneling and splitting of energy levels as a result of tunneling are observed explicitly on IBM's quantum computer, ibmq-bogota. The spin-1 is realized with two spins-1/2. We detect oscillations of spin-1 between the states…

Quantum Physics · Physics 2022-01-25 Kh. P. Gnatenko , V. M. Tkachuk

Heavy holes confined in quantum dots are predicted to be promising candidates for the realization of spin qubits with long coherence times. Here we focus on such heavy-hole states confined in Germanium hut wires. By tuning the growth…

Mesoscale and Nanoscale Physics · Physics 2017-08-23 Lada Vukušić , Josip Kukučka , Hannes Watzinger , Georgios Katsaros

Rapid, high-fidelity single-shot readout of quantum states is a ubiquitous requirement in quantum information technologies, playing a crucial role in quantum computation, quantum error correction, and fundamental tests of non-locality.…

Efficient tuning of spin qubits remains a major bottleneck in scaling semiconductor quantum dot-based quantum processors. A key challenge is the rapid identification of gate voltage regimes suitable for qubit initialisation, control, and…

Qubits based on quantum dots have excellent prospects for scalable quantum technology due to their inherent compatibility with standard semiconductor manufacturing. While early on it was recognized that holes may offer a multitude of…

Mesoscale and Nanoscale Physics · Physics 2020-08-26 N. W. Hendrickx , W. I. L. Lawrie , L. Petit , A. Sammak , G. Scappucci , M. Veldhorst

The strong atomistic spin orbit coupling of holes makes single-shot spin readout measurements difficult because it reduces the spin lifetimes. By integrating the charge sensor into a high bandwidth radio-frequency reflectometry setup we…

Mesoscale and Nanoscale Physics · Physics 2018-12-05 Lada Vukušić , Josip Kukučka , Hannes Watzinger , Joshua M. Milem , Friedrich Schäffler , Georgios Katsaros

An outstanding hurdle for defect spin qubits in silicon carbide (SiC) is single-shot readout - a deterministic measurement of the quantum state. Here, we demonstrate single-shot readout of single defects in SiC via spin-to-charge…

The feasibility of high-fidelity single-qubit operations of a hole spin in a quantum dot molecule by electric g tensor control is demonstrated. Apart from a constant external magnetic field the proposed scheme allows for an exclusively…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 Robert Roloff , Thomas Eissfeller , Peter Vogl , Walter Pötz

We demonstrate high fidelity repetitive projective measurements of nuclear spin qubits in an array of neutral ytterbium-171 ($^{171}$Yb) atoms. We show that the qubit state can be measured with a fidelity of 0.995(4) under a condition that…

Quantum Physics · Physics 2023-09-20 William Huie , Lintao Li , Neville Chen , Xiye Hu , Zhubing Jia , Won Kyu Calvin Sun , Jacob P. Covey

The computer simulations of the process of single pulse readout from the flux-biased phase qubit is performed in the frame of one-dimensional Schroedinger equation. It has been demonstrated that the readout error can be minimized by…

Quantum Physics · Physics 2015-05-14 Andrey L. Pankratov , Andrey S. Gavrilov

We propose a scheme to read out the spin of a single electron quantum bit in a surface Paul trap using oscillating magnetic field gradients. The readout sequence is composed of cooling, driving, amplification and detection of the electron's…

Quantum Physics · Physics 2017-01-18 Pai Peng , Clemens Matthiesen , Hartmut Häffner

We report initialization, complete electrical control, and single-shot readout of an exchange-only spin qubit. Full control via the exchange interaction is fast, yielding a demonstrated 75 qubit rotations in under 2 ns. Measurement and…

Mesoscale and Nanoscale Physics · Physics 2013-09-09 J. Medford , J. Beil , J. M. Taylor , S. D. Bartlett , A. C. Doherty , E. I. Rashba , D. P. DiVincenzo , H. Lu , A. C. Gossard , C. M. Marcus