Realizing high-fidelity n-qubit quantum controlled-not gates is of critical significance. Applying quantum-dot (QD) spins as qubits, an (n - 1)-qubit control 1-qubit not gate and a 1-qubit control (n - 1)-qubit not gate is constructed. By utilizing the balanced condition, even under the condition of weak coupling, the circuit including the wave-form correctors and the balanced reflection condition of the cavity may effectively reduce the noise resulting from the unequal reflectance, so that the fidelity of each quantum gate operation can be increased to unity in theory. The operational complexity is further reduced, considering that low-Q cavities are used. In addition, the control gate of m-qubit control (n - m)-qubit can also be performed with a similar device diagram, only by changing the numbers of the control qubits and target qubits. These n-qubit controlled-not gates can help construct simpler quantum computing circuits that can be widely applied in quantum information processing.
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http://dx.doi.org/10.1364/OE.536828 | DOI Listing |
Sci Rep
January 2025
Key Laboratory of Micro/nano Devices and Systems, Ministry of Education, North University of China, Taiyuan, 030051, China.
As the hyperentanglement of photon systems holds lots of remarkable applications for enhancing channel capacity with less quantum resource, the interconversion of various hyperentangled states warrants in-depth investigation and becomes a vital work for quantum information technologies. Here we realize completely mutual conversions between spatial-polarization hyperentangled Knill-Laflamme-Milburn state and hyperentangled W state for three-photon systems, resorting to hyperparallel quantum control gates and the practical nonlinear interaction of nitrogen-vacancy centers coupled with whispering-gallery-mode microresonators. The hyperparallel quantum gates, i.
View Article and Find Full Text PDFEntropy (Basel)
November 2024
School of Physics, Engineering and Technology, University of York, York YO10 5DD, UK.
We explore the use of fractional controlled-not gates in quantum thermodynamics. The Nth-root gate allows for a paced application of two-qubit operations. We apply it in quantum thermodynamic protocols for charging a quantum battery.
View Article and Find Full Text PDFJ Chem Phys
July 2024
Changping Laboratory, Beijing 102206, China.
We propose a scheme for achieving basic quantum gates using ultracold polar molecules in pendular states. The qubits are encoded in the YbF molecules trapped in an electric field with a certain gradient and coupled by the dipole-dipole interaction. The time-dependent control sequences consisting of multiple pulses are considered to interact with the pendular qubits.
View Article and Find Full Text PDFNat Commun
July 2024
Qubit Pharmaceuticals, Advanced Research Department, Paris, France.
Controlled operations are fundamental building blocks of quantum algorithms. Decomposing n-control-NOT gates (C(X)) into arbitrary single-qubit and CNOT gates, is a crucial but non-trivial task. This study introduces C(X) circuits outperforming previous methods in the asymptotic and non-asymptotic regimes.
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