Optimized cross-resonance gate for coupled transmon systems
Susanna Kirchhoff, Torsten Keßler, Per J. Liebermann, Elie Assémat, Shai Machnes, Felix Motzoi, Frank K. Wilhelm
DOI 10.1103/PhysRevA.97.042348 · Physical Review A
Active bibliographic source — not scientific approval
Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.
Abstract
The cross-resonance (CR) gate is an entangling gate for fixed-frequency superconducting qubits. While being simple and extensible, it is comparatively slow, at 160 ns, and thus of limited fidelity due to on-going incoherent processes. Using two different optimal control algorithms, we estimate the quantum speed limit for a controlled-not cnot gate in this system to be 10 ns, indicating a potential for great improvements. We show that the ability to approach this limit depends strongly on the choice of ansatz used to describe optimized control pulses and limitations placed on their complexity. Using a piecewise-constant ansatz, with a single carrier and bandwidth constraints, we identify an experimentally feasible 70-ns pulse shape. Further, an ansatz based on the two dominant frequencies involved in the optimal control problem allows for an optimal solution more than twice as fast again, at under 30 ns, with smooth features and limited complexity. This is twice as fast as gate realizations using tunable-frequency, resonantly coupled qubits. Compared to current CR-gate implementations, we project our scheme will provide a sixfold speed-up and thus a sixfold reduction in fidelity loss due to incoherent effects.
Similar papers
Fast ZZ-free entangling gates for superconducting qubits assisted by a driven resonator
similarity 0.91Ziwen Huang et al.
Source status unknown — claims are unverified
Controlled-Controlled-Phase Gates for Superconducting Qubits Mediated by a Shared Tunable Coupler
similarity 0.91Niklas J. Glaser et al.
Source status unknown — claims are unverified
Fast CZ gate via energy-level engineering in superconducting qubits with a tunable coupler
similarity 0.91Benzheng Yuan et al.
Source status unknown — claims are unverified
Universal Nonadiabatic Control of Small-Gap Superconducting Qubits
similarity 0.90Daniel L. Campbell et al.
Source status unknown — claims are unverified
Impact of Spectators on a Two-Qubit Gate in a Tunable Coupling Superconducting Circuit
similarity 0.90T.-Q. Cai et al.
Source status unknown — claims are unverified
Fast, High-Fidelity Conditional-Phase Gate Exploiting Leakage Interference in Weakly Anharmonic Superconducting Qubits
similarity 0.90M. A. Rol et al.
Source status unknown — claims are unverified