The quantromon: A qubit-resonator system with orthogonal qubit and readout modes
Fuente:
arXiv
Gespeichert in:
| Hauptverfasser: | , , , , , |
|---|---|
| Format: | Preprint |
| Veröffentlicht: |
2025
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1866929690500923392 |
|---|---|
| author | Salunkhe, Kishor V. Kundu, Suman Das, Srijita Deshmukh, Jay Patankar, Meghan P. Vijay, R. |
| author_facet | Salunkhe, Kishor V. Kundu, Suman Das, Srijita Deshmukh, Jay Patankar, Meghan P. Vijay, R. |
| contents | The measurement of a superconducting qubit is implemented by coupling it to a resonator. The common choice is transverse coupling, which, in the dispersive approximation, introduces an interaction term which enables the measurement. This cross-Kerr term provides a qubit-state dependent dispersive shift in the resonator frequency with the device parameters chosen carefully to get sufficient signal while minimizing Purcell decay of the qubit. We introduce a two-mode circuit, nicknamed quantromon, with two orthogonal modes implementing a qubit and a resonator. Unlike before, where the coupling term emerges as a perturbative expansion, the quantromon has intrinsic cross-Kerr coupling by design. Our experiments implemented in a hybrid 2D-3D cQED architecture demonstrate some unique features of the quantromon like weak dependence of the dispersive shift on the qubit-resonator detuning and intrinsic Purcell protection. In a tunable qubit-frequency device, we show that the dispersive shift ($2χ/2π$) changes by only $0.8$ MHz while the qubit-resonator detuning ($Δ/2π$) is varied between $0.398$ GHz - $3.288$ GHz. We also demonstrate Purcell protection in a second device where we tune the orthogonality between the two modes. Finally, we demonstrate a single-shot readout fidelity of $98.3\%$ without using a parametric amplifier which is comparable to the state-of-the-art and suggests a potential simplification of the measurement circuitry for scaling up quantum processors. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_17439 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | The quantromon: A qubit-resonator system with orthogonal qubit and readout modes Salunkhe, Kishor V. Kundu, Suman Das, Srijita Deshmukh, Jay Patankar, Meghan P. Vijay, R. Quantum Physics The measurement of a superconducting qubit is implemented by coupling it to a resonator. The common choice is transverse coupling, which, in the dispersive approximation, introduces an interaction term which enables the measurement. This cross-Kerr term provides a qubit-state dependent dispersive shift in the resonator frequency with the device parameters chosen carefully to get sufficient signal while minimizing Purcell decay of the qubit. We introduce a two-mode circuit, nicknamed quantromon, with two orthogonal modes implementing a qubit and a resonator. Unlike before, where the coupling term emerges as a perturbative expansion, the quantromon has intrinsic cross-Kerr coupling by design. Our experiments implemented in a hybrid 2D-3D cQED architecture demonstrate some unique features of the quantromon like weak dependence of the dispersive shift on the qubit-resonator detuning and intrinsic Purcell protection. In a tunable qubit-frequency device, we show that the dispersive shift ($2χ/2π$) changes by only $0.8$ MHz while the qubit-resonator detuning ($Δ/2π$) is varied between $0.398$ GHz - $3.288$ GHz. We also demonstrate Purcell protection in a second device where we tune the orthogonality between the two modes. Finally, we demonstrate a single-shot readout fidelity of $98.3\%$ without using a parametric amplifier which is comparable to the state-of-the-art and suggests a potential simplification of the measurement circuitry for scaling up quantum processors. |
| title | The quantromon: A qubit-resonator system with orthogonal qubit and readout modes |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2501.17439 |