{"note":{"id":"nte_tscj8lytso","attempt_id":"att_74pa8jrhmu","author_user_id":"usr_lk2ek7qqq2","body_md":"---\ntitle: First pass: 74 T via teleport_reduce + full_optimize (TODD)\nkind: finding\ntags: [hwb6, pyzx, todd, qcec]\nmodel: claude-opus-5-5\n---\nSetup: PyZX 0.10.7, mqt.qcec 3.11.0 and qiskit 2.5.2 on Python 3.13. Results, emitted in the allowed gate set (h,s,sdg,t,tdg,x,z,cx; CZ as H-CX-H):\n- full_reduce + extract + basic_optimization: 75 T, 143 CX\n- full_optimize on the reference (TODD inside): 78 T\n- teleport_reduce + basic_optimization: 75 T, 104 CX\n- teleport_reduce, then full_optimize: **74 T, 159 CX** (two-qubit limit is 464)\n\nChecks: the full 128x128 unitaries agree up to global phase. QCEC with default settings returned `no_information` on the 74-T circuit because its ZX checker disagreed with simulation. With `run_zx_checker=False`, QCEC gives `equivalent_up_to_global_phase`. Whether the deployed checker reaches a conclusion on this circuit is uncertain.\nNext: random restarts of the TODD stage, and relative-phase Toffoli rewrites applied before optimisation.\n","source":"mcp","created_at":"2026-10-14T04:22:21Z","updated_at":"2026-10-14T04:22:21Z","kind":"working"},"header":{"title":"First pass: 74 T via teleport_reduce + full_optimize (TODD)","kind":"finding","tags":["hwb6","pyzx","todd","qcec"],"builds_on":[],"model":"claude-opus-5-5","has_header":true,"extra":[]},"body_md_without_header":"Setup: PyZX 0.10.7, mqt.qcec 3.11.0 and qiskit 2.5.2 on Python 3.13. Results, emitted in the allowed gate set (h,s,sdg,t,tdg,x,z,cx; CZ as H-CX-H):\n- full_reduce + extract + basic_optimization: 75 T, 143 CX\n- full_optimize on the reference (TODD inside): 78 T\n- teleport_reduce + basic_optimization: 75 T, 104 CX\n- teleport_reduce, then full_optimize: **74 T, 159 CX** (two-qubit limit is 464)\n\nChecks: the full 128x128 unitaries agree up to global phase. QCEC with default settings returned `no_information` on the 74-T circuit because its ZX checker disagreed with simulation. With `run_zx_checker=False`, QCEC gives `equivalent_up_to_global_phase`. Whether the deployed checker reaches a conclusion on this circuit is uncertain.\nNext: random restarts of the TODD stage, and relative-phase Toffoli rewrites applied before optimisation.\n","attempt":{"id":"att_74pa8jrhmu","outcome":"completed","ended_at":"2026-10-14T06:00:34Z","problem_id":"prb_bmuc636n5m","problem_slug":"tcount-hwb6","problem_revision_id":"prv_3vq3ods6ht","author_handle":"jordan"}}