Nonperturbative leakage elimination for a logical qubit encoded in a mechanical oscillator

• URL: http://arxiv.org/abs/2008.09953v1
• Date: Sun, 23 Aug 2020 04:01:08 GMT
• Title: Nonperturbative leakage elimination for a logical qubit encoded in a mechanical oscillator
• Authors: Shasha Zheng, Qiongyi He, Mark S. Byrd, and Lian-Ao Wu
• Abstract summary: We introduce a nonperturbative leakage elimination operator (LEO) specifically designed for this purpose. Remarkably, our LEO can be used to analytically derive exact equations of motion without approximations.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Continuous-variable (CV) systems are attracting increasing attention in the realization of universal quantum computation. Several recent experiments have shown the feasibility of using CV systems to, e.g., encode a qubit into a trapped-ion mechanical oscillator and perform logic gates [Nature 566, 513-517 (2019)]. The essential next step is to protect the encoded qubit from quantum decoherence, e.g., the motional decoherence due to the interaction between a mechanical oscillator and its environment. Here we propose a scheme to suppress quantum decoherence of a single-mode harmonic oscillator used to encode qubits by introducing a nonperturbative leakage elimination operator (LEO) specifically designed for this purpose. Remarkably, our nonperturbative LEO can be used to analytically derive exact equations of motion without approximations. It also allows us to prove that the effectiveness of these LEOs only depends on the integral of the pulse sequence in the time domain, while details of the pulse shape does not make a significant difference when the time period is chosen appropriately. This control method can be applied to a system at an arbitrary temperature and arbitrary system-bath coupling strength which makes it extremely useful for general open quantum systems.

Related papers

• Going beyond quantum Markovianity and back to reality: An exact master equation study [0.0]
  An analytical depiction of an open quantum system is provided. The steady-state excitation number (AEN) of the system shows rapid escalation with increasing non-Markovianity. The Mpemba effect can be observed in the non-Markovian regime in a surprisingly super-cooling-like effect.
  arXiv  Detail & Related papers  (2024-11-26T08:10:35Z)
• Qubit-environment entanglement in time-dependent pure dephasing [0.0]
  We show that the methods for quantifying system-environment entanglement can be straightforwardly generalized to time-dependent Hamiltonians. We use these methods to study the nature of the decoherence of a qubit-oscillator system.
  arXiv  Detail & Related papers  (2023-12-05T11:23:25Z)
• Decoherence Limits the Cost to Simulate an Anharmonic Oscillator [0.0]
  We study how decoherence washes out the fine-grained subPlanck structure associated with phase-space quantum interference in a quantum system. Open quantum dynamics can be more efficiently simulated using a coarse-grained finite-difference numerical integration. We show that this regression does not have the form of a convex noise model, such as for a depolarizing noise channel.
  arXiv  Detail & Related papers  (2023-07-03T04:49:10Z)
• Quantum process tomography of continuous-variable gates using coherent states [49.299443295581064]
  We demonstrate the use of coherent-state quantum process tomography (csQPT) for a bosonic-mode superconducting circuit. We show results for this method by characterizing a logical quantum gate constructed using displacement and SNAP operations on an encoded qubit.
  arXiv  Detail & Related papers  (2023-03-02T18:08:08Z)
• Quantum Lyapunov exponent in dissipative systems [68.8204255655161]
  The out-of-time order correlator (OTOC) has been widely studied in closed quantum systems. We study the interplay between these two processes. The OTOC decay rate is closely related to the classical Lyapunov.
  arXiv  Detail & Related papers  (2022-11-11T17:06:45Z)
• Dispersive qubit readout with machine learning [0.08399688944263842]
  Open quantum systems can undergo dissipative phase transitions, and their critical behavior can be exploited in sensing applications. A recently introduced measurement protocol uses the parametric (two-photon driven) Kerr resonator's driven-dissipative phase transition to reach single-qubit detection fidelity of 99.9%. We use machine learning-based classification algorithms to extract information from this critical dynamics.
  arXiv  Detail & Related papers  (2021-12-10T04:25:43Z)
• Designing Kerr Interactions for Quantum Information Processing via Counterrotating Terms of Asymmetric Josephson-Junction Loops [68.8204255655161]
  static cavity nonlinearities typically limit the performance of bosonic quantum error-correcting codes. Treating the nonlinearity as a perturbation, we derive effective Hamiltonians using the Schrieffer-Wolff transformation. Results show that a cubic interaction allows to increase the effective rates of both linear and nonlinear operations.
  arXiv  Detail & Related papers  (2021-07-14T15:11:05Z)
• Universal quantum computation with symmetric qubit clusters coupled to an environment [0.3670422696827526]
  We propose a scalable scheme for universal quantum computation where cores play the role of quantum-computational transistors, quansistors. We include quantum errors as a main source of decoherence, and show that symmetry makes logical operations particularly resilient to untimely anisotropic qubit rotations. Many of our results can be generalized to higher-level omega-rotation-invariant systems, or adapted to clusters with other symmetries.
  arXiv  Detail & Related papers  (2021-06-01T19:59:41Z)
• Fast and differentiable simulation of driven quantum systems [58.720142291102135]
  We introduce a semi-analytic method based on the Dyson expansion that allows us to time-evolve driven quantum systems much faster than standard numerical methods. We show results of the optimization of a two-qubit gate using transmon qubits in the circuit QED architecture.
  arXiv  Detail & Related papers  (2020-12-16T21:43:38Z)
• Stoquasticity in circuit QED [78.980148137396]
  We show that scalable sign-problem free path integral Monte Carlo simulations can typically be performed for such systems. We corroborate the recent finding that an effective, non-stoquastic qubit Hamiltonian can emerge in a system of capacitively coupled flux qubits.
  arXiv  Detail & Related papers  (2020-11-02T16:41:28Z)
• Simulating nonnative cubic interactions on noisy quantum machines [65.38483184536494]
  We show that quantum processors can be programmed to efficiently simulate dynamics that are not native to the hardware. On noisy devices without error correction, we show that simulation results are significantly improved when the quantum program is compiled using modular gates.
  arXiv  Detail & Related papers  (2020-04-15T05:16:24Z)

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.