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A semiconductor-based charge qubit, confined in double quantum dots, can be a platform to implement quantum computing. However, it suffers severely from charge noises. Here, we provide a theoretical framework to implement universal…

Quantum Physics · Physics 2021-06-28 Chengxian Zhang , Tao Chen , Xin Wang , Zheng-Yuan Xue

Two-qubit gates in trapped-ion quantum computers are generated by applying spin-dependent forces that temporarily entangle the internal state of the ion with its motion. Laser pulses are carefully designed to generate a maximally entangling…

Quantum Physics · Physics 2021-12-21 Mingyu Kang , Qiyao Liang , Bichen Zhang , Shilin Huang , Ye Wang , Chao Fang , Jungsang Kim , Kenneth R. Brown

We demonstrate laser-driven two-qubit and single-qubit logic gates with fidelities 99.9(1)% and 99.9934(3)% respectively, significantly above the approximately 99% minimum threshold level required for fault-tolerant quantum computation,…

Quantum Physics · Physics 2016-08-08 C. J. Ballance , T. P. Harty , N. M. Linke , M. A. Sepiol , D. M. Lucas

We present a general theory for laser-free entangling gates with trapped-ion hyperfine qubits, using either static or oscillating magnetic-field gradients combined with a pair of uniform microwave fields symmetrically detuned about the…

We introduce a new entangling gate between two fixed-frequency qubits statically coupled via a microwave resonator bus which combines the following desirable qualities: all-microwave control, appreciable qubit separation for reduction of…

Quantum Physics · Physics 2013-12-03 Jerry M. Chow , Jay M. Gambetta , Andrew W. Cross , Seth T. Merkel , Chad Rigetti , M. Steffen

Recent work on Ising-coupled double-quantum-dot spin qubits in GaAs with voltage-controlled exchange interaction has shown improved two-qubit gate fidelities from the application of oscillating exchange along with a strong magnetic field…

Mesoscale and Nanoscale Physics · Physics 2019-02-06 R. K. L. Colmenar , J. P. Kestner

We present the experimental implementation of a two-qubit phase gate, using a radio frequency (RF) controlled trapped-ion quantum processor. The RF-driven gate is generated by a pulsed dynamical decoupling sequence applied to the ions'…

With superconducting transmon qubits --- a promising platform for quantum information processing --- two-qubit gates can be performed using AC signals to modulate a tunable transmon's frequency via magnetic flux through its SQUID loop.…

Noise resilience of quantum information processing is a crucial precondition to reach the fault-tolerance threshold. While resilience to many types of noise can be achieved through suitable control schemes, resilience to amplitude noise…

We propose a new protocol to implement ultra-fast two-qubit phase gates with trapped ions using spin-dependent kicks induced by resonant transitions. By only optimizing the allocation of the arrival times in a pulse train sequence the gate…

Quantum Physics · Physics 2020-10-28 E. Torrontegui , D. Heinrich , M. I. Hussain , R. Blatt , J. J. García-Ripoll

All-microwave control of fixed-frequency superconducting quantum systems offers the potential to reduce control circuit complexity and increase system coherence. Nevertheless, due to the limited control flexibility in qubit parameters, one…

Quantum Physics · Physics 2024-10-11 Ling Jiang , Peng Xu , Shengjun Wu , Jian-An Sun , Fu-Quan Dou

We propose a $\sigma_z\otimes \sigma_z$ laser-free entangling gate which uses the intrinsic J-coupling of ions in a static magnetic gradient. Dephasing of the interaction is suppressed by means of continuous dynamical decoupling using pairs…

Quantum Physics · Physics 2021-11-17 C. H. Valahu , A. M. Lawrence , S. Weidt , W. K. Hensinger

We construct a detailed microscopic noise model for multi-qubit (MQ) gate operations in the context of trapped ion architecture with all-to-all connectivity. We find that phonon heating and motional dephasing are well captured by effective…

Quantum Physics · Physics 2026-05-28 Ori Grossman , Yotam Kadish , Snir Gazit , Amit Ben-Kish , Roee Ozeri , Yotam Shapira

Isolated spins in semiconductors provide a promising platform to explore quantum mechanical coherence and develop engineered quantum systems. Silicon has attracted great interest as a host material for developing spin qubits because of its…

Mesoscale and Nanoscale Physics · Physics 2015-10-29 Dohun Kim , D. R. Ward , C. B. Simmons , D. E. Savage , M. G. Lagally , Mark Friesen , S. N. Coppersmith , Mark A. Eriksson

A novel two-qubit entangling gate for trapped-ion quantum processors is proposed theoretically and demonstrated experimentally. During the gate, double-dressed quantum states are created by applying a phase-modulated continuous driving…

We propose and study ways speeding up of the entangling operations in the trapped ions system with high fidelity. First, we find a scheme to increase the speed of a two-qubit gate without the limitation of trap frequency, which was…

Quantum Physics · Physics 2023-03-31 Kaizhao Wang , Jing-Fan Yu , Pengfei Wang , Chunyang Luan , Jing-Ning Zhang , Kihwan Kim

A central challenge in developing practical quantum processors is maintaining low control complexity while scaling to large numbers of qubits. Trapped-ion systems excel in small-scale operations and support rapid qubit scaling via…

Quantum Physics · Physics 2025-06-25 Xueying Mai , Liyun Zhang , Qinyang Yu , Junhua Zhang , Yao Lu

We present an efficient approach to optimising pulse sequences for implementing fast entangling two-qubit gates on trapped ion quantum information processors. We employ a two-phase procedure for optimising gate fidelity, which we…

We demonstrate a controlled-Z gate between capacitively coupled fluxonium qubits with transition frequencies $72.3~\textrm{MHz}$ and $136.3~\textrm{MHz}$. The gate is activated by a $61.6~\textrm{ns}$ long pulse at the frequency between…

We present a method of sensing AC magnetic fields. The method is based on the construction of a robust qubit by the application of continuous driving fields. Specifically, magnetic noise and power fluctuations of the driving fields do not…

Quantum Physics · Physics 2017-07-13 N. Aharon , M. Drewsen , A. Retzker