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Quantum devices comprised of elementary components with more than two stable levels - so-called qudits - enrich the accessible Hilbert space, enabling applications ranging from fault-tolerant quantum computing to simulating complex…

Quantum Physics · Physics 2026-01-21 Amir Burshtein , Shachar Fraenkel , Moshe Goldstein , Ran Finkelstein

We describe a mechanism for realizing a controlled phase gate for solid-state charge qubits. By augmenting the positionally defined qubit with an auxiliary state, and changing the charge distribution in the three-dot system, we are able to…

Quantum Physics · Physics 2009-11-10 S. G. Schirmer , D. K. L. Oi , A. D. Greentree

In this paper, we propose a new direction of research for the realization of the quantum controlled-not gate based on a technique called ``interaction-free measurement'', where qubits are two-level atoms (or ions) and information is…

Quantum Physics · Physics 2007-05-23 A. A. Methot , Kai Wicker

The ability to implement the Quantum Fourier Transform (QFT) efficiently on a quantum computer facilitates the advantages offered by a variety of fundamental quantum algorithms, such as those for integer factoring, computing discrete…

Quantum Physics · Physics 2020-04-09 Yunseong Nam , Yuan Su , Dmitri Maslov

Quantum computation provides great speedup over its classical counterpart for certain problems. One of the key challenges for quantum computation is to realize precise control of the quantum system in the presence of noise. Control of the…

Quantum Physics · Physics 2015-11-30 Xing Rong , Jianpei Geng , Fazhan Shi , Ying Liu , Kebiao Xu , Wenchao Ma , Fei Kong , Zhen Jiang , Yang Wu , Jiangfeng Du

We present a set of efficiently implementable logical multi-qubit gates in concatenated quantum error correction codes using parity qubits. In particular, we show how fault-tolerant high-weight rotation gates of arbitrary angle can be…

Quantum Physics · Physics 2025-12-16 Anette Messinger , Christophe Goeller , Wolfgang Lechner

Adiabatic geometric phase gates offer enhanced robustness against fluctuations compared to con- ventional Rydberg blockade-based phase gates that rely on dynamical phase accumulation. We theoretically demonstrate two- and multi-qubit phase…

Quantum Physics · Physics 2025-11-07 Sinchan Snigdha Rej , Bimalendu Deb

Several logical qubits and quantum gates have been proposed for semiconductor quantum dots controlled by voltages applied to top gates. The different schemes can be difficult to compare meaningfully. Here we develop a theoretical framework…

Mesoscale and Nanoscale Physics · Physics 2013-12-09 Teck Seng Koh , S. N. Coppersmith , Mark Friesen

The author analyzes quantum computation with the hybrid qubit (HQ) that is encoded using the three-electron configuration of a double quantum dot. All gate operations are controlled with electric signals, while the qubit remains at an…

Mesoscale and Nanoscale Physics · Physics 2015-07-14 Sebastian Mehl

The native gate set is fundamental to the performance of quantum devices, as it governs the accuracy of basic quantum operations and dictates the complexity of implementing quantum algorithms. Traditional approaches to extending gate sets…

It is an oft-cited fact that no quantum code can support a set of fault-tolerant logical gates that is both universal and transversal. This no-go theorem is generally responsible for the interest in alternative universality constructions…

Quantum Physics · Physics 2016-09-20 Theodore J. Yoder , Ryuji Takagi , Isaac L. Chuang

A major challenge in operating multi-qubit quantum processors is to mitigate multi-qubit coherent errors. For superconducting circuits, besides crosstalk originating from imperfect isolation of control lines, dispersive coupling between…

We demonstrate a quadratic phase gate for one-way quantum computation in the continuous-variable regime. This canonical gate, together with phase-space displacements and Fourier rotations, completes the set of universal gates for realizing…

Quantum Physics · Physics 2009-12-08 Yoshichika Miwa , Jun-ichi Yoshikawa , Peter van Loock , Akira Furusawa

In circuit-based quantum computing, the available gate set typically consists of single-qubit gates acting on each individual qubit and at least one entangling gate between pairs of qubits. In certain physical architectures, however, some…

Quantum Physics · Physics 2022-09-23 M. Pechal , G. Salis , M. Ganzhorn , D. J. Egger , M. Werninghaus , S. Filipp

Near-term quantum computers are limited by the decoherence of qubits to only being able to run low-depth quantum circuits with acceptable fidelity. This severely restricts what quantum algorithms can be compiled and implemented on such…

The physical implementation of the quantum Control-Not gate for a two-spin system is investigated numerically. The concept of a generalized quantum Control-Not gate, with arbitrary phase shift, is introduced. It is shown that a resonant…

Quantum Physics · Physics 2009-09-25 Gennady P. Berman , Gary D. Doolen , Gustavo V. López , V. I. Tsifrinovich

We propose to use a buckled plate as a qubit, where a double-well potential is mechanically produced by pushing the plate from both the sides. The right and left positions of the plate are assigned to be quantum states $|0\rangle $ and…

Quantum Physics · Physics 2023-06-27 Motohiko Ezawa , Shun Yasunaga , Akio Higo , Tetuya Iizuka , Yoshio Mita

We propose an effective set of elementary quantum gates which provide an encoded universality and demonstrate the physical feasibility of these gates for the solid-state quantum computer based on the multi-atomic systems in the QED cavity.…

Quantum Physics · Physics 2011-09-05 Farid Ablayev , Sergey Andrianov , Sergey Moiseev , Alexander Vasiliev

Physical quantum systems are commonly composed of more than two levels and offer the capacity to encode information in higher-dimensional spaces beyond the qubit, starting with the three-level qutrit. Here, we encode neutral-atom qutrits in…

Quantum Physics · Physics 2023-12-01 Joseph Lindon , Arina Tashchilina , Logan W. Cooke , Lindsay J. LeBlanc

Quantum algorithms on near-term quantum processors are typically executed using shallow quantum circuits composed of one- and two-qubit gates. However, as circuit depth and gate number increase, gate imperfections and qubit decoherence…