Suppression of Unwanted 
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 Interactions in a Hybrid Two-Qubit System

Ku, Jaseung; Xu, Xuexin; Brink, Markus; McKay, David; Hertzberg, Jared; Ansari, Mohammad H.; Plourde, B. L. T.

doi:10.1103/physrevlett.125.200504

Cited by 95 publications

(54 citation statements)

References 41 publications

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“…The Hamiltonian interaction term is written as ζσ z1 σ z2 , acting on the two qubits. Typically, in superconducting systems, it arises from the interaction of the |11 state with the non-computational state in the physical qubits, and can both be used as a resource for entangling gates [21][22][23][24] or viewed as cross-talk noise that needs to be suppressed [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

Section: Physical Applicationsmentioning

confidence: 99%

“…δ 2 is the eigenenergy for diagonalizing the two-level system of |20 and |11 , consistent with Eq. (26). The notations used is the same as in Section II A 3.…”

Section: A Effective Zz Entanglement From Multi-level Non-dispersive ...mentioning

confidence: 99%

“…The second approach is to choose a hybrid qubit system with opposite anharmonicity, which allows parameter engineering to suppress the ZZ interaction. One implementation is using a transmon and a capacitively shunt flux qubit (CSFQ) [25,26]. Other methods include using additional off-resonant drive [39][40][41] and different types of qubits have also been proposed [38].…”

Section: B Zz Coupling Suppression In the Quasi-dispersive Regimementioning

confidence: 99%

“…In the first regime, where the leakagelevel-mediated ZZ interaction can be used to generate CZ gates [21][22][23][24], we consider the two-excitation manifold and compute accurate approximations of the ZZ interaction strength applicable to the full parameter regime for gate implementation. In the second scenario, we study the suppression of ZZ interactions [10,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] in the traditional setup of resonator mediated coupling without direct qubit-qubit interaction. We compute the perturbative expansion of the ZZ interaction up to the 8th order perturbation as parametric expressions.…”

mentioning

confidence: 99%

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Non-perturbative analytical diagonalization of Hamiltonians with application to coupling suppression and enhancement in cQED

Li,

Calarco,

Motzoi

2021

Preprint

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Deriving effective Hamiltonian models plays an essential role in quantum theory, with particular emphasis in recent years on control and engineering problems. In this work, we present two symbolic methods for computing effective Hamiltonian models: the Non-perturbative Analytical Diagonalization (NPAD) and the Recursive Schrieffer-Wolff Transformation (RSWT). NPAD makes use of the Jacobi iteration and works without the assumptions of perturbation theory while retaining convergence, allowing to treat a very wide range of models. In the perturbation regime, it reduces to RSWT, which takes advantage of an in-built recursive structure where remarkably the number of terms increases only linearly with perturbation order, exponentially decreasing the number of terms compared to the ubiquitous Schrieffer-Wolff method. Both methods consist of elementary algebra and can be easily automated to obtain closed-form expressions. To demonstrate the application of the methods, we study the ZZ interaction of superconducting qubits systems in two different parameter regimes. In the near-resonant regime, the method produces an analytical expression for the effective ZZ interaction strength, with an improvement of at least one order of magnitude compared to neglecting the comparably further detuned state. In the dispersive regime, we calculate perturbative corrections up to the 8th order and accurately identify a regime where ZZ interaction is suppressed in a simple model with only resonator-mediated coupling.

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Section: Physical Applicationsmentioning

confidence: 99%

“…δ 2 is the eigenenergy for diagonalizing the two-level system of |20 and |11 , consistent with Eq. (26). The notations used is the same as in Section II A 3.…”

Section: A Effective Zz Entanglement From Multi-level Non-dispersive ...mentioning

confidence: 99%

Section: B Zz Coupling Suppression In the Quasi-dispersive Regimementioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Non-perturbative analytical diagonalization of Hamiltonians with application to coupling suppression and enhancement in cQED

Li,

Calarco,

Motzoi

2021

Preprint

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“…Fixed-frequency Transmons coupled to nearest neighbor have a static and nonzero value of J. Moreover, the strength of the cross-resonance drive (used to realize CNOT gate) is proportional to J [15], [16]. Thus, the nonzero J results in an always-on-ZZ interaction whether static or driven during cross-resonance gate.…”

Section: A Quantum Crosstalkmentioning

confidence: 99%

Experimental Characterization, Modeling, and Analysis of Crosstalk in a Quantum Computer

Saki

Alam

Ghosh

2020

IEEE Trans. Quantum Eng.

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In this article, we present the experimental characterization of crosstalk in quantum information processor using idle tomography and simultaneous randomized benchmarking. We quantify both "quantum" and "classical" crosstalk in the device and analyze quantum circuits considering crosstalk. We show that simulation considering only gate-error deviates from experimental results up to 27%, whereas simulation considering both gate error and crosstalk match the experiments more accurately with an average mismatch as low as 4.52%. This article enables simulation of quantum circuits with experimental crosstalk error rates.INDEX TERMS Crosstalk, idle tomography, simultaneous randomized benchmarking, zz-interaction.

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Direct‐Current Electrical Detection of Surface‐Acoustic‐Wave‐Driven Ferromagnetic Resonance

et al. 2023

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Surface acoustic waves (SAW) provide a promising platform to study spin‐phonon coupling, which can be achieved by SAW‐driven ferromagnetic resonance (FMR) for efficient acoustic manipulation of spin. Although the magneto‐elastic effective field model has achieved great success in describing SAW‐driven FMR, the magnitude of the effective field acting on the magnetization induced by SAW still remains hard to access. Here, by integrating ferromagnetic stripes with SAW devices, direct‐current detection for SAW‐driven FMR based on electrical rectification is reported. By analyzing FMR rectified voltage, the effective fields are straightforwardly characterized and extracted, which exhibits the advantages of better integration compatibility and lower cost than traditional methods such as vector‐network analyzer‐based techniques. A large nonreciprocal rectified voltage is obtained, which is attributed to the coexistence of in‐plane and out‐of‐plane effective fields. The effective fields can be modulated by controlling the longitudinal and shear strains within the films to achieve almost 100% nonreciprocity ratio, demonstrating the potential for electrical switches. Besides its fundamental significance, this finding provides a unique opportunity for a designable spin acousto‐electronic device and its convenient signal readout.

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Suppression of Unwanted ZZ Interactions in a Hybrid Two-Qubit System

Cited by 95 publications

References 41 publications

Non-perturbative analytical diagonalization of Hamiltonians with application to coupling suppression and enhancement in cQED

Non-perturbative analytical diagonalization of Hamiltonians with application to coupling suppression and enhancement in cQED

Experimental Characterization, Modeling, and Analysis of Crosstalk in a Quantum Computer

Direct‐Current Electrical Detection of Surface‐Acoustic‐Wave‐Driven Ferromagnetic Resonance

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