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We present an example of quantum process tomography performed on a single solid state qubit. The qubit used is two energy levels of the triplet state in the Nitrogen-Vacancy defect in Diamond. Quantum process tomography is applied to a…

Quantum Physics · Physics 2007-05-23 M. Howard , J. Twamley , C. Wittmann , T. Gaebel , F. Jelezko , J. Wrachtrup

In this paper, we proposed a design of integrated programmable controlled-phase (CPHASE) gate to be used in quantum information processing applications. This gate is capable of introducing arbitrary phase difference to target qubit in the…

Quantum Physics · Physics 2022-01-25 Yalın Başay , Serdar Kocaman

High-fidelity multi-qubit gates are a critical resource for near-term quantum computing, as they underpin the execution of both quantum algorithms and fault-tolerant protocols. The Toffoli gate (CCNOT), in particular, plays a central role…

Quantum Physics · Physics 2025-09-09 M. AbuGhanem

High fidelity generation of two-qubit gates is important for quantum computation, since such gates are components of popular universal sets of gates. Here we consider the problem of high fidelity generation of two-qubit C-NOT and C-PHASE…

Quantum Physics · Physics 2024-05-24 Alexander N. Pechen , Vadim N. Petruhanov , Oleg V. Morzhin , Boris O. Volkov

The similarities between gated quantum dots and the transistors in modern microelectronics - in fabrication methods, physical structure, and voltage scales for manipulation - have led to great interest in the development of quantum bits…

We propose and experimentally demonstrate a scheme for implementation of a maximally entangling quantum controlled-Z gate between two weakly interacting systems. We conditionally enhance the interqubit coupling by quantum interference. Both…

Quantum Physics · Physics 2015-09-23 M. Micuda , R. Starek , I. Straka , M. Mikova , M. Dusek , M. Jezek , R. Filip , J. Fiurasek

In recent years, the tunable coupling scheme has become the mainstream scheme for designing superconducting quan tum circuits. By working in the dispersive regime, the ZZ coupling and high-energy level leakage can be effectively suppressed…

Quantum Physics · Physics 2024-04-15 Tao Zhang , Chaoying Zhao

Recently, significant progress has been made in the demonstration of single qutrit and coupled qutrit gates with superconducting circuits. Coupled qutrit gates have significantly lower fidelity than single qutrit gates, owing to long…

Quantum Physics · Physics 2024-04-05 Mahadevan Subramanian , Adrian Lupascu

As systems for quantum computing keep growing in size and number of qubits, challenges in scaling the control capabilities are becoming increasingly relevant. Efficient schemes to simultaneously mediate coherent interactions between…

Fast robust two-qubit gate operation with low susceptibility to crosstalk are the key to scalable quantum information processing. Parametrically driven gate is inherently insensitive to crosstalk while superadiabatic control can speed up…

Cat-state qubits (qubits encoded with cat states) have recently drawn intensive attention due to their enhanced life times with quantum error correction. We here propose a method to implement a universal controlled-phase gate of two…

Quantum Physics · Physics 2017-11-22 Yu Zhang , Xiong Zhao , Li Yu , Qi-Ping Su , Chui-Ping Yang

A scheme for implementing 2-qubit quantum controlled phase gate (QCPG) is proposed with two superconducting quantum interference devices (SQUIDs) in a cavity. The gate operations are realized within the two lower flux states of the SQUIDs…

Quantum Physics · Physics 2011-11-09 Zheng-Yuan Xue , Gang Zhang , Ping Dong , You-Min Yi , Zhuo-Liang Cao

We investigate an approach to universal quantum computation based on the modulation of longitudinal qubit-oscillator coupling. We show how to realize a controlled-phase gate by simultaneously modulating the longitudinal coupling of two…

Quantum Physics · Physics 2017-05-15 Baptiste Royer , Arne L. Grimsmo , Nicolas Didier , Alexandre Blais

Quantum algorithms often benefit from the ability to execute multi-qubit (>2) gates. To date such multi-qubit gates are typically decomposed into single- and two-qubit gates, particularly in superconducting qubit architectures. The ability…

Quantum dot hybrid qubits exploit an extended charge-noise sweet spot that suppresses dephasing and has enabled the experimental achievement of high-fidelity single-qubit gates. However, current proposals for two-qubit gates require tuning…

Quantum Physics · Physics 2020-01-28 Yuan-Chi Yang , S. N. Coppersmith , Mark Friesen

Single-qubit operations on singlet-triplet qubits in GaAs double quantum dots have not yet reached the fidelities required for fault-tolerant quantum information processing. Considering experimentally important constraints and using…

Quantum Physics · Physics 2021-01-25 Pascal Cerfontaine , Tim Botzem , David P. DiVincenzo , Hendrik Bluhm

Fault-tolerant quantum computers which can solve hard problems rely on quantum error correction. One of the most promising error correction codes is the surface code, which requires universal gate fidelities exceeding the error correction…

The two-qubit controlled-not (C-NOT) gate is an essential component for gate-based quantum circuits. In fact, its operation, combined with single qubit rotations allows to realise any quantum circuit. Several strategies have been adopted in…

Quantum Physics · Physics 2026-04-28 Federico Pegoraro , Philip Held , Jonas Lammers , Benjamin Brecht , Christine Silberhorn

We present a scheme for implementing a high-fidelity non-linear phase shift on a photonic state. The scheme is based on repeated scattering off a two-level quantum emitter embedded in a chiral or one-sided waveguide. The waveguide is…

Quantum Physics · Physics 2026-03-12 Love A. Pettersson , Victor R. Christiansen , Klaus Mølmer , Anders S. Sørensen

For the quantum error correction (QEC) and noisy intermediate-scale quantum (NISQ) algorithms to function with high efficiency, the raw fidelity of quantum logic gates on physical qubits needs to satisfy strict requirement. The neutral atom…

Quantum Physics · Physics 2025-06-02 Yuan Sun