Efficient qutrit gate-set tomography on a transmon

Cao, Shuxiang; Lall, Deep; Bakr, Mustafa S.; Campanaro, Giulio; Fasciati, Simone; Wills, James; Chidambaram, Vivek; Shteynas, Boris; Rungger, Ivan; Leek, Peter

doi:10.48550/arxiv.2210.04857

Cited by 3 publications

(3 citation statements)

References 44 publications

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“…The two-qubit emulator is built on a single transmon with a coaxial geometry and off-chip wiring [55,56], where the lowest 4 quantum states of the transmon are used as the computational space. The same device has also been previously used as a qutrit [57]. The two-qubit emulator maps the physical states |0⟩, |1⟩, |2⟩, |3⟩ of the transmon to the |00⟩, |01⟩, |10⟩, |11⟩ states of a virtual two-qubit device, see figure 1(a).…”

Section: Implementation Of the Emulatormentioning

confidence: 99%

Emulating two qubits with a four-level transmon qudit for variational quantum algorithms

Cao,

Bakr,

Campanaro

et al. 2024

Quantum Sci. Technol.

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Using quantum systems with more than two levels, or qudits, can scale the computational space of quantum processors more eﬃciently than using qubits, which may oﬀer an easier physical implementation for larger Hilbert spaces. However, individual qudits may exhibit larger noise, and algorithms designed for qubits require to be recompiled to qudit algorithms for execution. In this work, we implemented a two-qubit emulator using a 4-level superconducting transmon qudit for variational quantum algorithm applications and analyzed its noise model. The major source of error for the variational algorithm was readout misclassiﬁcation error and amplitude damping. To improve the accuracy of the results, we applied error-mitigation techniques to reduce the eﬀects of the misclassiﬁcation and qudit decay event. The ﬁnal predicted energy value is within the range of chemical accuracy. Our work demonstrates that transmon qudits are a practical alternative to qubits for variational algorithms.

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Section: Implementation Of the Emulatormentioning

confidence: 99%

Emulating two qubits with a four-level transmon qudit for variational quantum algorithms

Cao,

Bakr,

Campanaro

et al. 2024

Quantum Sci. Technol.

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show abstract

“…The two-qubit emulator is built using a single transmon with a coaxial geometry and off-chip packaging [44,45], where the lowest 4 quantum states of the transmon are used as the computation space. The device has also been previously used as a qutrit [46]. The two-qubit emulator maps the physical states |0 , |1 , |2 , |3 of the transmon to the |00 , |01 , |10 , |11 states of a virtual two-qubit device.…”

Section: Implementation Of the Emulatormentioning

confidence: 99%

Emulating two qubits with a four-level transmon qudit for variational quantum algorithms

Cao¹,

Bakr²,

Campanaro³

et al. 2023

Preprint

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Using quantum systems with more than two levels, or qudits, can scale the computation space of quantum processors more efficiently than using qubits, which may offer an easier physical implementation for larger Hilbert spaces. However, individual qudits may exhibit larger noise, and algorithms designed for qubits require to be recompiled to qudit algorithms for execution. In this work, we implemented a two-qubit emulator using a 4-level superconducting transmon qudit for variational quantum algorithm applications and analyzed its noise model. The major source of error for the variational algorithm was readout misclassification error and amplitude damping. To improve the accuracy of the results, we applied error-mitigation techniques to reduce the effects of the misclassification and qudit decay event. The final predicted energy value is within the range of chemical accuracy. Our work demonstrates that qudits are a practical alternative to qubits for variational algorithms.

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“…Treating them as proper quantum multilevel systems can be leveraged in several ways, including enhanced hardware efficiency and functionality of quantum error correction [29,30], faulttolerant protocols [2,31], and versatile quantum simulations with less mapping overhead [32][33][34][35][36]. As a result, the utilization of the higher excited states has recently garnered substantial interest, witnessed through the demonstrations of qutrit operations and algorithms with transmons [21,[37][38][39][40][41][42][43][44][45], other superconducting quantum devices [46,47], as well as trapped ion and photonic platforms [48,49].…”

Section: Introductionmentioning

confidence: 99%

Dissipation and Dephasing of Interacting Photons in Transmon Arrays

Busel¹,

Laine²,

Mansikkamäki³

et al. 2023

Preprint

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Transmon arrays are one of the most promising platforms for quantum information science. Despite being often considered simply as qubits, transmons are inherently quantum mechanical multilevel systems. Being experimentally controllable with high fidelity, the higher excited states beyond the qubit subspace provide an important resource for hardware-efficient many-body quantum simulations, quantum error correction, and quantum information protocols. Alas, dissipation and dephasing phenomena generated by couplings to various uncontrollable environments yield a practical limiting factor to their utilization. To quantify this in detail, we present here the primary consequences of single-transmon dissipation and dephasing to the many-body dynamics of transmon arrays. We use analytical methods from perturbation theory and quantum trajectory approach together with numerical simulations, and deliberately consider the full Hilbert space including the higher excited states. The three main non-unitary processes are many-body decoherence, many-body dissipation, and heating/cooling transitions between different anharmonicity manifolds. Of these, the many-body decoherence -being proportional to the squared distance between the many-body Fock states -gives the strictest limit for observing effective unitary dynamics. Considering experimentally relevant parameters, including also the inevitable site-to-site disorder, our results show that the state-of-theart transmon arrays should be ready for the task of demonstrating coherent many-body dynamics using the higher excited states. However, the wider utilization of transmons for ternary-and-beyond quantum computing calls for improving their coherence properties.

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Efficient qutrit gate-set tomography on a transmon

Cited by 3 publications

References 44 publications

Emulating two qubits with a four-level transmon qudit for variational quantum algorithms

Emulating two qubits with a four-level transmon qudit for variational quantum algorithms

Emulating two qubits with a four-level transmon qudit for variational quantum algorithms

Dissipation and Dephasing of Interacting Photons in Transmon Arrays

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