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Qubit

About: Qubit is a research topic. Over the lifetime, 29978 publications have been published within this topic receiving 723084 citations. The topic is also known as: quantum bit & qbit.


Papers
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Journal ArticleDOI
TL;DR: A new analysis of quantum error mitigation, which attempts to limit the effects of errors in near-term quantum computers, shows that two proposed techniques can work in small systems without the need for extra qubits or peripheral devices.
Abstract: A new analysis of quantum error mitigation, which attempts to limit the effects of errors in near-term quantum computers, shows that two proposed techniques can work in small systems without the need for extra qubits or peripheral devices.

396 citations

Posted Content
TL;DR: In this paper, a linear-depth ripple-carry quantum addition circuit with only a single ancillary qubit has been proposed, which has lower depth and fewer gates than previous ripple carry adders.
Abstract: We present a new linear-depth ripple-carry quantum addition circuit. Previous addition circuits required linearly many ancillary qubits; our new adder uses only a single ancillary qubit. Also, our circuit has lower depth and fewer gates than previous ripple-carry adders.

396 citations

Journal ArticleDOI
TL;DR: Using a hybrid quantum circuit combining a superconducting qubit and an ensemble of electronic spins, a superposition of the qubit states is prepared that is stored into collective excitations of the spin ensemble and retrieved back into the qubits later on.
Abstract: We report the experimental realization of a hybrid quantum circuit combining a superconducting qubit and an ensemble of electronic spins. The qubit, of the transmon type, is coherently coupled to the spin ensemble consisting of nitrogen-vacancy centers in a diamond crystal via a frequency-tunable superconducting resonator acting as a quantum bus. Using this circuit, we prepare a superposition of the qubit states that we store into collective excitations of the spin ensemble and retrieve back into the qubit later on. These results constitute a proof of concept of spin-ensemble based quantum memory for superconducting qubits.

393 citations

Journal ArticleDOI
TL;DR: In this paper, a single-electron spin qubit with isotopically-enriched phase coherence time (20 microseconds) and fast electrical control speed (up to 30 MHz) mediated by extrinsic spin-electric coupling is shown.
Abstract: Recent advances towards spin-based quantum computation have been primarily fuelled by elaborate isolation from noise sources, such as surrounding nuclear spins and spin-electric susceptibility, to extend spin coherence. In the meanwhile, addressable single-spin and spin-spin manipulations in multiple-qubit systems will necessitate sizable spin-electric coupling. Given background charge fluctuation in nanostructures, however, its compatibility with enhanced coherence should be crucially questioned. Here we realise a single-electron spin qubit with isotopically-enriched phase coherence time (20 microseconds) and fast electrical control speed (up to 30 MHz) mediated by extrinsic spin-electric coupling. Using rapid spin rotations, we reveal that the free-evolution dephasing is caused by charge (instead of conventional magnetic) noise featured by a 1/f spectrum over seven decades of frequency. The qubit nevertheless exhibits superior performance with single-qubit gate fidelities exceeding 99.9% on average. Our work strongly suggests that designing artificial spin-electric coupling with account taken of charge noise is a promising route to large-scale spin-qubit systems having fault-tolerant controllability.

392 citations

Journal ArticleDOI
TL;DR: Spectroscopic data is reported that shows a level splitting characteristic of coupling between a two-state qubit and a two -level system and Rabi oscillations whose "coherence amplitude" is significantly degraded by the presence of these spurious microwave resonators.
Abstract: Although Josephson junction qubits show great promise for quantum computing, the origin of dominant decoherence mechanisms remains unknown. Improving the operation of a Josephson junction based phase qubit has revealed microscopic two-level systems or resonators within the tunnel barrier that cause decoherence. We report spectroscopic data that show a level splitting characteristic of coupling between a two-state qubit and a two-level system. Furthermore, we show Rabi oscillations whose "coherence amplitude" is significantly degraded by the presence of these spurious microwave resonators. The discovery of these resonators impacts the future of Josephson qubits as well as existing Josephson technologies.

391 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231,977
20224,380
20213,014
20203,119
20192,594
20182,228