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A method for synthesizing quantum gates is presented based on interpolation methods applied to operators in Hilbert space. Starting from the diagonal forms of specific generating seed operators with non-degenerate eigenvalue spectrum one…

Quantum Physics · Physics 2018-02-14 Zeno Toffano , François Dubois

Complex control protocols and sensitivity to experimental imperfections have limited the practical implementation of quantum gate operations. Here, we present an analytical framework for universal single-qubit gates using rotational states…

Quantum Physics · Physics 2026-05-06 Qi Chen , Hao-Xuan Luo , Jin-Kang Guo , Qian-Qian Hong , Li-Bao Fan , Chuan-Cun Shu

Accurate, nontrivial quantum operations on many qubits are experimentally challenging. As opposed to the standard approach of compiling larger unitaries into sequences of 2-qubit gates, we propose a protocol on Hamiltonian control fields…

Quantum Physics · Physics 2019-12-02 Koen Groenland , Kareljan Schoutens

We characterize the set of optimal protocols for two-qubit entangling gates through a mechanism analysis based on quantum pathways, which allows us to compare and rank the different solutions. As an example of a flexible platform with a…

Quantum Physics · Physics 2023-04-28 Ignacio R. Sola , Seokmin Shin , Bo Y. Chang

Quantum computing is currently limited by the cost of two-qubit entangling operations. In order to scale up quantum processors and achieve a quantum advantage, it is crucial to economize on the power requirement of two-qubit gates, make…

We propose and validate on real quantum computing hardware a new method for extended two-qubit gate set design, replacing iterative, fine calibration with fast characterization of a small number of gate parameters which are then tracked and…

Implementation of logical entangling gates is an important step towards realizing a quantum computer. We use a gradient-based optimization approach to find single-qubit rotations which can be interleaved between applications of a noisy…

Quantum Physics · Physics 2018-06-28 Arman A. Setser , Michael H. Goerz , Jason P. Kestner

We report the quantum process tomography of a M$\o$lmer-S$\o$rensen entangling gate. The tomographic protocol relies on a single discriminatory transition, exploiting excess micromotion in the trap to realize all operations required to…

Quantum Physics · Physics 2015-06-17 Nir Navon , Nitzan Akerman , Shlomi Kotler , Yinnon Glickman , Roee Ozeri

We propose a scalable qudit-based quantum processor using rotational states of polar molecules. Previously, molecular internal states were used to enlarge Hilbert space, whereas our approach uses optical tweezer arrays to achieve scalable…

Singlet-triplet qubits in lateral quantum dots in semiconductor heterostructures exhibit high-fidelity single-qubit gates via exchange interactions and magnetic field gradients. High-fidelity two-qubit entangling gates are challenging to…

Mesoscale and Nanoscale Physics · Physics 2017-12-06 M. A. Wolfe , F. A. Calderon-Vargas , J. P. Kestner

An arbitrary lossless transformation in high-dimensional quantum space can be decomposed into elementary operations which are easy to implement, and an effective decomposition algorithm is important for constructing high-dimensional…

Quantum Physics · Physics 2022-12-07 Dong-Xu Chen , Junliang Jia , Pei Zhang , Chui-Ping Yang

Digital-analog quantum computing with two-level systems is a computational paradigm that combines an analog Hamiltonian with single-qubit gates to achieve universality. We extend this framework to $d$-level systems by conjugating an analog…

Quantum Physics · Physics 2026-03-19 Alatz Alvarez-Ahedo , Mikel Garcia de Andoin , Mikel Sanz

A qubit, or quantum bit, is conventionally defined as "a physical system for storing information that is capable of existing in either of two quantum states or in a superposition of both". In this paper, we examine the simple question of…

Quantum Physics · Physics 2026-03-19 Zhuoran Bao , Daniel F. V. James

The quantum Fourier transform (QFT) is a crucial subroutine in many quantum algorithms. In this paper, we study the exact lower bound problem of CNOT gate complexity for fault-tolerant QFT. First, we consider approximating the ancilla-free…

Quantum Physics · Physics 2024-09-05 Qiqing Xia , Huiqin Xie , Li Yang

A new method for simulation of a binary homogeneous Markov process using a quantum computer was proposed. This new method allows using the distinguished properties of the quantum mechanical systems -- superposition, entanglement and…

Quantum Physics · Physics 2021-03-12 Petar Nikolov

The prospect of computational hardware with quantum advantage relies critically on the quality of quantum gate operations. Imperfect two-qubit gates is a major bottleneck for achieving scalable quantum information processors. Here, we…

We propose an iterative algorithm to simulate the dynamics generated by any $n$-qubit Hamiltonian. The simulation entails decomposing the unitary time evolution operator $U$ (unitary) into a product of different time-step unitaries. The…

Quantum Physics · Physics 2012-04-09 Ashok Ajoy , Rama Koteswara Rao , Anil Kumar , Pranaw Rungta

A new method for compiling quantum algorithms is proposed and tested for a three qubit system. The proposed method is to decompose a a unitary matrix U, into a product of simpler U j via a neural network. These U j can then be decomposed…

Quantum Physics · Physics 2017-10-11 Michael Swaddle , Lyle Noakes , Liam Salter , Harry Smallbone , Jingbo Wang

We demonstrate the applicability of a universal gate set in the parity encoding, which is a dual to the standard gate model, by exploring several quantum gate algorithms such as the quantum Fourier transform and quantum addition. Embedding…

Quantum Physics · Physics 2022-11-03 Michael Fellner , Anette Messinger , Kilian Ender , Wolfgang Lechner

Quantum information carriers, just like most physical systems, naturally occupy high-dimensional Hilbert spaces. Instead of restricting them to a two-level subspace, these high-dimensional (qudit) quantum systems are emerging as a powerful…