RQC Seminar

284th RQC Seminar

• Speaker

  Mr. Bora Baran
  ( Forschungszentrum Jülich )

• Date

  15:00 - 15:50, (3:00 p.m.- 3:50 p.m.) Tuesday, June 16, 2026

• Venue

  Hybrid( Zoom,
  345-347 Seminar Room, 3F, Main Research Building, Wako Campus / 和光地区 研究本館3階 セミナー室 (345-347) (C01))

• Title

  Interaction-resolved multi-qubit optimal control via computational-basis phases

• Inquiries

  norilab_rqc_assist[at]ml.riken.jp

Abstract
In multi-qubit quantum control, target unitary operations are commonly specified through full-unitary target descriptions and assessed through global comparison measures. In this work, we introduce an interaction-resolved decomposition of n-qubit unitaries that provides explicit access to their many-body interaction structure through computational-basis phases collected in a diagonalizing frame. Such a frame is conveniently obtained through local rotations for many operationally relevant operations, including gates generated by single Pauli strings or commuting sets of Pauli strings, such as stabilizer operations, controlled-phase gates, Toffoli-type operations, and Ising interactions. We derive parity-weighted sums of these computational-basis phases that exactly and uniquely resolve k-body interaction terms supported on arbitrary qubit subsets, which we term support-selective phase invariants. These invariants provide an interaction-resolved coordinate system, enabling the formulation of interaction-specific control targets for synthesizing desired combinations of many-body interaction terms. We supplement this theoretical framework with numerical demonstrations on a representative hardware model, a realistic nitrogen-vacancy spin register, where we synthesize isolated tripartite interactions up to local equivalence within a single control pulse, for both diagonal (ZZZ) and non-diagonal (XZZ) terms.