Bit flips, saturation, and quantum chaos in dissipative cat qubits

• URL: http://arxiv.org/abs/2605.24100v1
• Date: Fri, 22 May 2026 18:05:44 GMT
• Title: Bit flips, saturation, and quantum chaos in dissipative cat qubits
• Abstract summary: We study the properties of bit flips in realistic dissipative cat qubits.<n>We find that bit flips manifest as chaotic bursts within otherwise regular dynamics.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Bosonic cat qubits promise hardware-efficient quantum error correction because their logical bit-flip rate is exponentially suppressed with the photon number of the cat state. However, several experiments report a saturation of this suppression at large photon numbers, thus limiting the achievable protection. Combining quantum-trajectory simulations, semiclassical analysis, and Liouvillian spectral methods, we investigate the properties of bit flips in realistic dissipative cat qubits, where a memory mode hosting quantum information interacts with a dissipative buffer cavity. We show that bit flips are dynamical processes inherently involving both the memory and buffer, and therefore cannot be captured by single-mode approximate descriptions. We identify a reflection symmetry, resulting in a phase-locking condition at the semiclassical level and for quantum trajectories, as the main requirement for regular bit-flip dynamics. Its breakdown is the origin of the saturation, and we find that it occurs when two conditions are met. First, the adiabatic approximation, where the state of the buffer instantaneously follows that of the memory, must not be valid, which typically happens at large photon numbers. Second, key parameters such as the cross-Kerr interaction and dephasing must be present, leading to irregular dynamics in which memory fluctuations are amplified by the buffer during bit flips. In this regime, we find that bit flips manifest as chaotic bursts within otherwise regular dynamics, as evidenced by both changes in the topology of quantum trajectories and in the Liouvillian spectrum and its associated eigenmodes involved in these switching events. Finally, we verify our predictions against experimental data, highlighting the detrimental role of dissipative chaotic behavior in bosonic error-correcting codes.

Related papers

• Comparison of the standard and dressed-picture master equations for the quantum Rabi model in the ultrastrong coupling regime [78.55450146498553]
  This chapter investigates the effects of relaxation and dephasing on the quantum Rabi model in the ultrastrong coupling regime.<n>It provides explicit formulas to implement and numerically solve the resulting nonunitary dynamics.
  arXiv  Detail & Related papers  (2026-04-10T01:22:07Z)
• 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)
• Bit-flip errors in dissipative cat qubits: second-order perturbation theory [0.0]
  We develop a second-order perturbation theory on top of a nonlinear dissipative Lindbladian.<n>We derive an analytical expression for the exponentially small bit-flip rate due to single-photon loss.<n>We also apply our scheme to other perturbations, such as frequency detuning and the Z gate, and find the corresponding bit-flip rates.
  arXiv  Detail & Related papers  (2024-07-24T14:14:15Z)
• Error-Tolerant Amplification and Simulation of the Ultrastrong-Coupling Quantum Rabi Model [3.1716226579025255]
  Cat-state qubits formed by photonic cat states have a biased noise channel, i.e., one type of error dominates over all the others. We demonstrate that such biased-noise qubits are also promising for error-tolerant simulations of the quantum Rabi model (and its varieties) by coupling a cat-state qubit to an optical cavity.
  arXiv  Detail & Related papers  (2024-02-01T06:55:59Z)
• Experimental realization of deterministic and selective photon addition in a bosonic mode assisted by an ancillary qubit [33.7054351451505]
  Bosonic quantum error correcting codes are primarily designed to protect against single-photon loss.<n>Error correction requires a recovery operation that maps the error states -- which have opposite parity -- back onto the code states.<n>Here, we realize a collection of photon-number-selective, simultaneous photon addition operations on a bosonic mode.
  arXiv  Detail & Related papers  (2022-12-22T23:32:21Z)
• Quantum emulation of the transient dynamics in the multistate Landau-Zener model [50.591267188664666]
  We study the transient dynamics in the multistate Landau-Zener model as a function of the Landau-Zener velocity. Our experiments pave the way for more complex simulations with qubits coupled to an engineered bosonic mode spectrum.
  arXiv  Detail & Related papers  (2022-11-26T15:04:11Z)
• A critical Schr\"odinger cat qubit [0.0]
  In cat qubits, an engineered dissipation scheme combining two-photon drive and loss has been used to stabilize this manifold. In Kerr cat qubits, where highly-performing gates can be engineered, two-photon drive and Kerr nonlinearity cooperate to confine the system. We show that large detunings and small, but non-negligible, two-photon loss rates are fundamental to achieve optimal performance.
  arXiv  Detail & Related papers  (2022-08-09T17:44:00Z)
• Reminiscence of classical chaos in driven transmons [117.851325578242]
  We show that even off-resonant drives can cause strong modifications to the structure of the transmon spectrum rendering a large part of it chaotic. Results lead to a photon number threshold characterizing the appearance of chaos-induced quantum demolition effects.
  arXiv  Detail & Related papers  (2022-07-19T16:04:46Z)
• Candidate for a passively-protected quantum memory in two dimensions [1.8667700177663704]
  A quantum memory stable against finite-temperature effects is only known in four spatial dimensions or higher. We propose a new model which appears to passively correct against both bit-flip and phase-flip errors in two dimensions.
  arXiv  Detail & Related papers  (2022-05-19T18:00:01Z)
• Quantum asymmetry and noisy multi-mode interferometry [55.41644538483948]
  Quantum asymmetry is a physical resource which coincides with the amount of coherence between the eigenspaces of a generator. We show that the asymmetry may emphincrease as a result of a emphdecrease of coherence inside a degenerate subspace.
  arXiv  Detail & Related papers  (2021-07-23T07:30:57Z)
• Transmon platform for quantum computing challenged by chaotic fluctuations [55.41644538483948]
  We investigate the stability of a variant of a many-body localized (MBL) phase for system parameters relevant to current quantum processors. We find that these computing platforms are dangerously close to a phase of uncontrollable chaotic fluctuations.
  arXiv  Detail & Related papers  (2020-12-10T19:00:03Z)

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.