High-Fidelity Measurement of a Superconducting Qubit Using an On-Chip Microwave Photon Counter

Opremcak, Alex; Liu, Chuan-Hong; Wilen, Christopher D.; Okubo, Koichi; Christensen, Barbara L.; Sank, D.; White, Theodore C.; Giustina, Marissa; Megrant, A.; Burkett, Brian; Plourde, B. L. T.; McDermott, Robert

doi:10.1103/physrevx.11.011027

Cited by 26 publications

(10 citation statements)

References 61 publications

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“…In the numerical simulation, we select a group of experimentally reported pa-rameters as Ω p = 2𝜋 × 0.3 MHz, g k = 2𝜋 × 45 MHz, and Δ k = 2𝜋 × 1.35 GHz. [67][68][69][70] To illustrate the validity of the effective Hamiltonian Equation (6), we simulate the comparison between the full dynamics and the effective dynamics in Figure 2, corresponding to Equations ( 1) and ( 6), respectively. In the numerical simulation, to better distinguish the population of each calculated state in the figure, the initial state of the odd-parity (even-parity) case is set to…”

Section: Ideal Situation and Protocol Modificationmentioning

confidence: 99%

Precise Nondestructive Parity Measurement of Artificial Atoms Using a Superconducting Resonator and Homodyne Measurement

et al. 2023

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In this paper, a robust and accurate protocol is proposed to realize nondestructive parity measurement of artificial atoms using a superconducting resonator and homodyne measurement. With the help of an additional microwave driving field, the cavity field evolves into a coherent state or remains in a vacuum state according to the parity of the atoms. Consequently, the parity information of atoms can be read out by a homodyne measurement on the cavity. Parity information can be obtained without destroying the original state of the system, which means that the state can be further applied to other quantum information processing tasks after a parity measurement. The numerical simulation results show that the protocol is robust against systematic error, random noise, and decoherence. Therefore, this protocol can provide a feasible viewpoint for nondestructive parity measurement.

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Section: Ideal Situation and Protocol Modificationmentioning

confidence: 99%

Precise Nondestructive Parity Measurement of Artificial Atoms Using a Superconducting Resonator and Homodyne Measurement

et al. 2023

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“…If the qubit were in state |1〉, it would decay to |0〉 and emit a photon of energy ℏ ω into the photon counter. It is challenging in practice to realize a microwave photon counter because the single photon energy is so small in the few-GHz regime, but such a device (which is essentially a modified superconducting phase qubit) has been demonstrated with readout fidelity as high as 98.4 % [ 96 ], [ 97 ].…”

Section: Measuring the State Of A Qubitmentioning

confidence: 99%

Microwaves in Quantum Computing

2021

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Quantum information processing systems rely on a broad range of microwave technologies and have spurred development of microwave devices and methods in new operating regimes. Here we review the use of microwave signals and systems in quantum computing, with specific reference to three leading quantum computing platforms: trapped atomic ion qubits, spin qubits in semiconductors, and superconducting qubits. We highlight some key results and progress in quantum computing achieved through the use of microwave systems, and discuss how quantum computing applications have pushed the frontiers of microwave technology in some areas. We also describe open microwave engineering challenges for the construction of large-scale, fault-tolerant quantum computers.

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“…Gaussian noise is ubiquitous in real experiments. For instance, electronic noise in the readout of semiconductor spin qubits [37,39,42,44,45,47,[49][50][51][52]56] as well as quantum noise in the readout of superconducting qubits [41,43,54,57] are well modelled by additive Gaussian noise. An application of Eq.…”

Section: B Example 1: Gaussian Distributed Readout Outcomesmentioning

confidence: 99%

Generalized figure of merit for qubit readout

D'Anjou

2020

Preprint

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Many promising approaches to fault-tolerant quantum computation require repeated quantum nondemolition (QND) readout of binary observables such as quantum bits (qubits). A commonly used figure of merit for readout performance is the error rate for binary assignment in a single repetition. However, it is known that this figure of merit is insufficient. Indeed, real-world readout outcomes are typically analog instead of binary. Binary assignment therefore discards important information on the level of confidence in the analog outcomes. Here, a generalized figure of merit that fully captures the information contained in the analog readout outcomes is proposed. This figure of merit is the Chernoff information associated with the statistics of the analog readout outcomes in one repetition. Unlike the single-repetition error rate, the Chernoff information uniquely determines the cumulative error rate for arbitrary readout noise. Importantly, this universal description persists for the small number of repetitions and non-QND imperfections relevant to real experiments. It follows that arbitrary non-Gaussian readout noise common in experiments can be replaced by effective Gaussian noise with the same Chernoff information. This correspondence leads to a simple universal expression to estimate the cumulative error rate of a QND readout. In addition, the Chernoff information is used to rigorously quantify the amount of information discarded by analog-to-binary conversion. These results provide a unified framework for qubit readout and should facilitate optimization and engineering of near-term quantum devices across all platforms.

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High-Fidelity Measurement of a Superconducting Qubit Using an On-Chip Microwave Photon Counter

Cited by 26 publications

References 61 publications

Precise Nondestructive Parity Measurement of Artificial Atoms Using a Superconducting Resonator and Homodyne Measurement

Precise Nondestructive Parity Measurement of Artificial Atoms Using a Superconducting Resonator and Homodyne Measurement

Microwaves in Quantum Computing

Generalized figure of merit for qubit readout

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