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Performing parallel gate operations while retaining low crosstalk is an essential step in transforming neutral atom arrays into powerful quantum computers and simulators. Tightly focusing control beams in small areas for crosstalk…

Quantum Physics · Physics 2023-10-31 Guoqing Wang , Wenchao Xu , Changhao Li , Vladan Vuletić , Paola Cappellaro

Since the first demonstration of coherent control of a quantum state of a superconducting charge qubit a variety of Josephson-junction-based qubits have been implemented with remarkable progress in coherence time and read-out schemes.…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 T. Yamamoto , Yu. A. Pashkin , O. Astafiev , Y. Nakamura , J. S. Tsai

We introduce a scheme for realizing arbitrary controlled-unitary operations in a two qubit system. If the 2 \times 2 unitary matrix is special unitary (has unit determinant), the controlled-unitary gate operation can be realized in a single…

Quantum Physics · Physics 2015-06-04 Preethika Kumar , Steven R. Skinner

We describe the construction of a conditional quantum control-not (CNOT) gate from linear optical elements following the program of Knill, Laflamme and Milburn [Nature {\bf 409}, 46 (2001)]. We show that the basic operation of this gate can…

Quantum Physics · Physics 2009-11-07 T. C. Ralph , A. G. White , W. J. Munro , G. J. Milburn

Semiconductor spin qubits offer a unique opportunity for scalable quantum computation by leveraging classical transistor technology. Hole spin qubits benefit from fast all-electrical qubit control and sweet spots to counteract charge and…

It has previously been shown that probabilistic quantum logic operations can be performed using linear optical elements, additional photons (ancilla), and post-selection based on the output of single-photon detectors. Here we describe the…

Quantum Physics · Physics 2009-11-07 T. B. Pittman , B. C. Jacobs , J. D. Franson

Using electrostatic gates to control the electron positions, we present a new controlled-NOT gate based on quantum dots. The qubit states are chosen to be the spin states of an excess conductor electron in the quantum dot; and the main…

Quantum Physics · Physics 2007-05-23 Cyrus C. Y. Lin , Chopin Soo , Yin-Zhong Wu , Wei-Min Zhang

We introduce a novel scheme that combines phonon-mediated quantum logic gates in trapped ions with the benefits of continuous dynamical decoupling. We demonstrate theoretically that a strong driving of the qubit decouples it from external…

Quantum Physics · Physics 2012-04-11 A. Bermudez , P. O. Schmidt , M. B. Plenio , A. Retzker

We present a universal set of quantum gate operations based on exchange-only spin qubits in a double quantum dot, where each qubit is obtained by three electrons in the (2,1) filling. Gate operations are addressed by modulating…

Quantum Physics · Physics 2018-09-05 Marco De Michielis , Elena Ferraro , Marco Fanciulli , Enrico Prati

We investigate to what extent two trapped ions can be manipulated coherently when their coupling is mediated by a dipole-dipole interaction. We will show how the resulting level shift induced by this interaction can be used to create…

Quantum Physics · Physics 2015-06-26 A. Beige , S. F. Huelga , P. L. Knight , M. B. Plenio , R. C. Thompson

We theoretically propose a set of universal quantum gates acting on a hybrid qubit formed by coupling a quantum dot spin qubit and Majorana fermion qubit. First, we consider a quantum dot tunnel-coupled to two topological superconductors.…

Mesoscale and Nanoscale Physics · Physics 2016-08-03 Silas Hoffman , Constantin Schrade , Jelena Klinovaja , Daniel Loss

Any single-qubit unitary operation or quantum gate can be considered a rotation. Typical experimental implementations of single-qubit gates involve two or three fixed rotation axes, and up to three rotation steps. Here we show that, if the…

Mesoscale and Nanoscale Physics · Physics 2013-03-05 Yun-Pil Shim , Jianjia Fei , Sangchul Oh , Xuedong Hu , Mark Friesen

Qudit-based quantum gates in high-dimensional Hilbert space can provide a viable route towards effectively accelerating the speed of quantum computing and performing complex quantum logic operations. In the paper, we propose a 2-qudit…

Quantum Physics · Physics 2024-09-19 Gang Fan , Fang-Fang Du

Coherent errors constitute a significant barrier to successful large-scale quantum computation. One such error mechanism is crosstalk, which violates spatial locality or the independence of operations. We present a description of crosstalk…

Quantum Physics · Physics 2025-02-11 Jan Balewski , Adam Winick , Yilun Xu , Neel Vora , Gang Huang , David Santiago , Joseph Emerson , Irfan Siddiqi

In this work we present a model qubit whose basis states are eigenstates of a multi-layered quantum dot. We show that the proper design of the quantum dot results in qubit states that have excellent dynamical properties when a…

Quantum Physics · Physics 2013-05-13 Alejandro Ferrón , Pablo Serra , Omar Osenda

We propose a single-step implementation of a muti-target-qubit controlled phase gate with one cat-state qubit (\textit{cqubit}) simultaneously controlling $n-1$ target \textit{cqubits}. The two logic states of a \textit{cqubit} are…

Quantum Physics · Physics 2019-10-24 You-Ji Fan , Zhen-Fei Zheng , Yu Zhang , Dao-Ming Lu , Chui-Ping Yang

We have analyzed the electronic spectrum and wave function characteristics of a strongly correlated two-electron quantum ring with model parameters close to those observed in experiments. The analysis is based on an exact diagonalization of…

Mesoscale and Nanoscale Physics · Physics 2010-04-26 Erik Waltersson , Eva Lindroth , Ingjald Pilskog , J. P. Hansen

Usually, the hyperparallel quantum computation can speed up quantum computing, reduce the quantum resource consumed largely, resist to noise, and simplify the storage of quantum information. Here, we present the first scheme for the…

Quantum Physics · Physics 2018-09-05 Guan-Yu Wang , Tao Li , Qing Ai , Fu-Guo Deng

Couplings between qubits, while essential for generating multi-qubit entanglement, can induce crosstalk errors that significantly degrade single-qubit gate fidelity. In this paper, we present a novel non-perturbative analytical framework…

Quantum Physics · Physics 2025-03-18 Junkai Zeng , Lin Chen , Xiu-Hao Deng

We investigate the nonstationary electronic transport in noninteracting nanostructures driven by a finite bias and time-dependent signals applied at their contacts to the leads. The systems are modelled by a tight-binding Hamiltonian and…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Valeriu Moldoveanu , Vidar Gudmundsson , Andrei Manolescu