Celso J. Villas-Boas

Building Block For Universal Continuous Variables Computation In Superconducting Devices

  1. Bruno A. Veloso,
  2. Ciro M. Diniz,
  3. Luiz O. R. Solak,
  4. Antonio S. M. de Castro,
  5. Daniel Z. Rossatto,
  6. and Celso J. Villas-Bôas
Continuous variable (CV) quantum computation offers an alternative to qubit-based computing by exploiting the infinite-dimensional Hilbert space of bosonic modes. Despite recent progress,
superconducting platforms have yet to demonstrate a scalable architecture capable of universal this http URL, we design and numerically simulate a two-layer superconducting architecture that implements all five interactions of the universal CV gate set (rotation, displacement, squeezing, Kerr, and beam splitter) within experimentally accessible regimes. To this end, we employ a DC-SQUID as the bosonic mode, a fluxonium qubit to mediate nonlinear interactions, and two ancillary qubits that enable Gaussian and multi-mode operations. By tuning fluxes and frequencies, we achieve high fidelities (≥98%) across all gates within state-of-the-art parameter ranges. The modular nature of the design allows straightforward scaling, establishing a feasible pathway toward high-fidelity, universal CV quantum computation based on superconducting circuits.
arxiv pdf

Optimizing resetting of superconducting qubits

  1. Ciro M. Diniz,
  2. Rogerio J. de Assis,
  3. Norton G. de Almeida,
  4. and Celso J. Villas-Boas
Many quantum algorithms demand a large number of repetitions to obtain reliable statistical results. Thus, at each repetition it is necessary to reset the qubits efficiently and precisely
in the shortest possible time, so that quantum computers actually have advantages over classical ones. In this work, we perform a detailed analysis on three different models for information resetting in superconducting qubits. Our experimental setup consists of a main qubit coupled to different auxiliary dissipative systems, that are employed in order to perform the erasing of the information of the main qubit. Our analysis shows that it is not enough to increase the coupling and the dissipation rate associated with the auxiliary systems to decrease the resetting time of the main qubit, a fact that motivates us to find the optimal set of parameters for each studied approach, allowing a significant decrease in the reset time of the three models analyzed.
arxiv pdf