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While all quantum algorithms can be expressed in terms of single-qubit and two-qubit gates, more expressive gate sets can help reduce the algorithmic depth. This is important in the presence of gate errors, especially those due to…

Quantum error correcting codes have been developed to protect a quantum computer from decoherence due to a noisy environment. In this paper, we present two methods for optimizing the physical implementation of such error correction schemes.…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Guido Burkard , Daniel Loss , David P. DiVincenzo , John A. Smolin

We consider a class of multi-qubit dephasing models that combine classical noise sources and linear coupling to a bosonic environment, and are controlled by arbitrary sequences of dynamical decoupling pulses. Building on a general transfer…

Quantum Physics · Physics 2016-08-03 Gerardo A. Paz-Silva , Seung-Woo Lee , Todd J. Green , Lorenza Viola

We give an arbitrary single-qubit gate compilation scheme on superconducting processors that takes advantage of tuning the phase shift of microwave pulses to obtain a continuous gate set. This scheme is compatible with any two-qubit gate,…

Quantum Physics · Physics 2025-08-05 Jianxin Chen , Dawei Ding , Cupjin Huang , Qi Ye

Dynamical decoupling pulse sequences have been used to extend coherence times in quantum systems ever since the discovery of the spin-echo effect. Here we introduce a method of recursively concatenated dynamical decoupling pulses, designed…

Quantum Physics · Physics 2007-05-23 K. Khodjasteh , D. A. Lidar

We propose a method to design pulses in a resonant three-level system to enhance the robustness of non-adiabatic geometric gate operations. By optimizing the shape of the pulse envelope, we show that the gate operations are more robust…

Quantum Physics · Physics 2019-03-27 Ying Yan , Jie Lu , Lin Wan , Joel Moser

We derive an integral expression for the filter-transfer function of an arbitrary one-qubit gate through the use of dynamical invariant theory and Hamiltonian reverse engineering. We use this result to define a cost function which can be…

Quantum Physics · Physics 2022-09-19 R. K. L. Colmenar , J. P. Kestner

Scaling of quantum gates remains a central challenge in quantum information science. Ultrafast gates based on spin-dependent kicks provide a promising approach for trapped-ion systems. However, these gates require laser pulses with both…

Quantum Physics · Physics 2025-11-10 En-Teng An , Hao-Qing Zhang , Yun-Feng Huang , Chuan-Feng Li , Jin-Ming Cui

Superconducting quantum devices are a leading technology for quantum computation, but they suffer from several challenges. Gate errors, coherence errors and a lack of connectivity all contribute to low fidelity results. In particular,…

High-fidelity two-qubit gates in quantum computers are often hampered by fluctuating experimental parameters. The effects of time-varying parameter fluctuations lead to coherent noise on the qubits, which can be suppressed by designing…

Quantum Physics · Physics 2023-01-06 Mingyu Kang , Ye Wang , Chao Fang , Bichen Zhang , Omid Khosravani , Jungsang Kim , Kenneth R. Brown

While the accuracy of qubit operations has been greatly improved in the last decade, further development is demanded to achieve the ultimate goal: a fault-tolerant quantum computer that can solve real-world problems more efficiently than…

Quantum Physics · Physics 2024-08-29 Kiyoto Nakamura , Joachim Ankerhold

We propose an optimal set of quantum gates for a singlet-triplet qubit in a double quantum dot with two electrons utilizing the $S$-$T_-$ subspace. Qubit rotations are driven by the applied magnetic field and an orthogonal field gradient…

Mesoscale and Nanoscale Physics · Physics 2015-07-20 Clement H. Wong , M. A. Eriksson , S. N. Coppersmith , Mark Friesen

Quantum computers are poised to radically outperform their classical counterparts by manipulating coherent quantum systems. A realistic quantum computer will experience errors due to the environment and imperfect control. When these errors…

Quantum Physics · Physics 2016-11-21 Joel J. Wallman , Joseph Emerson

We present rigorous performance bounds for the optimal dynamical decoupling pulse sequence protecting a quantum bit (qubit) against pure dephasing. Our bounds apply under the assumption of instantaneous pulses and of bounded perturbing…

Quantum Physics · Physics 2010-07-08 Götz S. Uhrig , Daniel A. Lidar

In the burgeoning field of quantum computing, the precise design and optimization of quantum pulses are essential for enhancing qubit operation fidelity. This study focuses on refining the pulse engineering techniques for superconducting…

Quantum Physics · Physics 2024-09-13 Annika S. Wiening , Joern Bergendahl , Vicente Leyton-Ortega , Peter Nalbach

We show how "single" quantum dots, each hosting a singlet-triplet qubit, can be placed in arrays to build a spin quantum cellular automaton. A fast ($\sim 10$ ns) deterministic coherent singlet-triplet filtering, as opposed to current…

Quantum Physics · Physics 2015-09-10 Abolfazl Bayat , Charles E. Creffield , John H. Jefferson , Michael Pepper , Sougato Bose

We propose a method for exact circuit synthesis using a discrete gate set, as required for fault-tolerant quantum computing. Our approach translates the problem of synthesizing a gate specified by its unitary matrix into a boolean…

Quantum Physics · Physics 2025-03-20 Élie Gouzien , Nicolas Sangouard

Near-term applications of quantum information processors will rely on optimized circuit implementations to minimize gate depth and therefore mitigate the impact of gate errors in noisy intermediate-scale quantum (NISQ) computers. More…

Quantum Physics · Physics 2020-12-21 Deanna M. Abrams , Nicolas Didier , Blake R. Johnson , Marcus P. da Silva , Colm A. Ryan

Two qubit gates constitute fundamental building blocks in the realization of large-scale quantum devices. Using superconducting circuits, two-qubit gates have previously been implemented in different ways with each method aiming to maximize…

One of the greatest challenges for current quantum computing hardware is how to obtain reliable results from noisy devices. A recent paper [A. Kandala et al., Nature 567, 491 (2019)] described a method for injecting noise by stretching gate…

Quantum Physics · Physics 2022-07-22 Sam Tomkins , Rogério de Sousa