Experimental signatures of a $σ_zσ_x$ beam-splitter interaction between a Kerr-cat and transmon qubit

• URL: http://arxiv.org/abs/2511.21972v1
• Date: Wed, 26 Nov 2025 23:11:55 GMT
• Title: Experimental signatures of a $σ_zσ_x$ beam-splitter interaction between a Kerr-cat and transmon qubit
• Authors: Josiah Cochran, Haley M. Cole, Hebah Goderya, Zhuoqun Hao, Yao-Chun Chang, Theo Shaw, Aikaterini Kargioti, Shyam Shankar,
• Abstract summary: In superconducting quantum circuits, Kerr-cat qubits (KCQs) exhibit strongly biased noise.<n>We experimentally demonstrate a beamsplitter interaction between a KCQ and a transmon, realizing an effective $_z_x$ coupling.<n>These results establish a step towards hybrid architectures that combine transmons as data qubits with noise-biased bosonic ancillas.
• Score: 0.34117876175071693
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Quantum error correction (QEC) requires ancilla qubits to extract error syndromes from data qubits which store quantum information. However, ancilla errors can propagate back to the data qubits, introducing additional errors and limiting fault-tolerance. In superconducting quantum circuits, Kerr-cat qubits (KCQs), which exhibit strongly biased noise, have been proposed as ancillas to suppress this back-action and enhance QEC performance. Here, we experimentally demonstrate a beamsplitter interaction between a KCQ and a transmon, realizing an effective $σ_zσ_x$ coupling that can be employed for parity measurements in QEC protocols. We characterize the interaction across a range of cat sizes and drive amplitudes, confirming the expected scaling of the interaction rate. These results establish a step towards hybrid architectures that combine transmons as data qubits with noise-biased bosonic ancillas, enabling hardware-efficient syndrome extraction and advancing the development of fault-tolerant quantum processors.

Related papers

• Enhancing Kerr-Cat Qubit Coherence with Controlled Dissipation [64.05054054401175]
  Kerr-cat qubit (KCQ) is a bosonic quantum processor.<n>KCQs are experimentally compatible with on-chip architectures and high-fidelity operations.<n>We present direct evidence that the bit-flip time in a KCQ is limited by leakage out of the qubit manifold.
  arXiv  Detail & Related papers  (2025-11-02T17:58:36Z)
• Quantum Control of an Oscillator with a Kerr-cat Qubit [0.0]
  Bosonic codes offer a hardware-efficient strategy for quantum error correction by redundantly encoding quantum information. The Kerr-cat qubit has been proposed as an ancilla for these codes due to its theoretically-exponential noise bias. We experimentally realize driven coupling of a Kerr-cat qubit to a high-quality-factor microwave cavity.
  arXiv  Detail & Related papers  (2024-07-15T17:38:34Z)
• Fault-tolerant quantum architectures based on erasure qubits [49.227671756557946]
  We exploit the idea of erasure qubits, relying on an efficient conversion of the dominant noise into erasures at known locations. We propose and optimize QEC schemes based on erasure qubits and the recently-introduced Floquet codes. Our results demonstrate that, despite being slightly more complex, QEC schemes based on erasure qubits can significantly outperform standard approaches.
  arXiv  Detail & Related papers  (2023-12-21T17:40:18Z)
• Mitigating crosstalk errors by randomized compiling: Simulation of the BCS model on a superconducting quantum computer [41.94295877935867]
  Crosstalk errors, stemming from CNOT two-qubit gates, are a crucial source of errors on numerous quantum computing platforms. We develop and apply an extension of the randomized compiling protocol that includes a special treatment of neighboring qubits. Our twirling of neighboring qubits is shown to dramatically improve the noise estimation protocol without the need to add new qubits or circuits.
  arXiv  Detail & Related papers  (2023-05-03T18:00:02Z)
• Witnessing entanglement in trapped-ion quantum error correction under realistic noise [41.94295877935867]
  Quantum Error Correction (QEC) exploits redundancy by encoding logical information into multiple physical qubits. We present a detailed microscopic error model to estimate the average gate infidelity of two-qubit light-shift gates used in trapped-ion platforms. We then apply this realistic error model to quantify the multipartite entanglement generated by circuits that act as QEC building blocks.
  arXiv  Detail & Related papers  (2022-12-14T20:00:36Z)
• Measuring NISQ Gate-Based Qubit Stability Using a 1+1 Field Theory and Cycle Benchmarking [50.8020641352841]
  We study coherent errors on a quantum hardware platform using a transverse field Ising model Hamiltonian as a sample user application. We identify inter-day and intra-day qubit calibration drift and the impacts of quantum circuit placement on groups of qubits in different physical locations on the processor. This paper also discusses how these measurements can provide a better understanding of these types of errors and how they may improve efforts to validate the accuracy of quantum computations.
  arXiv  Detail & Related papers  (2022-01-08T23:12:55Z)
• Scalable Method for Eliminating Residual $ZZ$ Interaction between Superconducting Qubits [14.178204625914194]
  We show a practically approach for complete cancellation of residual $ZZ$ interaction between fixed-frequency transmon qubits. We verify the cancellation performance by measuring vanishing two-qubit entangling phases and $ZZ$ correlations. Our method allows independent addressability of each qubit-qubit connection, and is applicable to both nontunable and tunable couplers.
  arXiv  Detail & Related papers  (2021-11-26T02:04:49Z)
• Suppression of crosstalk in superconducting qubits using dynamical decoupling [0.0]
  Super superconducting quantum processors with interconnected transmon qubits are noisy and prone to various errors. ZZ-coupling between qubits in fixed frequency transmon architectures is always present and contributes to both coherent and incoherent crosstalk errors. We propose the use of dynamical decoupling to suppress the crosstalk, and demonstrate the success of this scheme through experiments on several IBM quantum cloud processors.
  arXiv  Detail & Related papers  (2021-08-10T09:16:05Z)
• Fault-tolerant parity readout on a shuttling-based trapped-ion quantum computer [64.47265213752996]
  We experimentally demonstrate a fault-tolerant weight-4 parity check measurement scheme. We achieve a flag-conditioned parity measurement single-shot fidelity of 93.2(2)%. The scheme is an essential building block in a broad class of stabilizer quantum error correction protocols.
  arXiv  Detail & Related papers  (2021-07-13T20:08:04Z)
• Crosstalk Suppression for Fault-tolerant Quantum Error Correction with Trapped Ions [62.997667081978825]
  We present a study of crosstalk errors in a quantum-computing architecture based on a single string of ions confined by a radio-frequency trap, and manipulated by individually-addressed laser beams. This type of errors affects spectator qubits that, ideally, should remain unaltered during the application of single- and two-qubit quantum gates addressed at a different set of active qubits. We microscopically model crosstalk errors from first principles and present a detailed study showing the importance of using a coherent vs incoherent error modelling and, moreover, discuss strategies to actively suppress this crosstalk at the gate level.
  arXiv  Detail & Related papers  (2020-12-21T14:20:40Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.