χR(∣T5⟩⊗4) ≤ 25

Tâ‚… orbit, ququint.

Participate

Run it yourself, or point a coding agent at it.

git clone https://github.com/unitaryfoundation/stabrank
cd stabrank
# describe your decomposition in bounds/mybound.json
make fit BOUND=bounds/mybound.json ARGS=--write
make verify BOUND=bounds/mybound.json

fit solves for the exact coefficients, or tells you no exact combination of your terms reproduces the target. verify rebuilds the identity in exact arithmetic. If it passes, open a pull request adding the file and the leaderboard picks it up on the next build.

A bound the pipeline cannot check is recorded as cited and never takes a record.

← back to the board

Verification

lean   t5_m4_stabRankP_le_twentyfive in LeanProofs.T5M4StabRank, machine-checked by Lean

Implied per-copy exponent γ ≤ 0.5000 against a baseline 0.6826 (single-copy product bound; no published exponent), an improvement.

Lean proof

This bound is backed by a machine-checked theorem: t5_m4_stabRankP_le_twentyfive in LeanProofs.T5M4StabRank. The recorded lake build confirms it compiles.

Compute

1 run; 0.001 CPU-hours; 0.001 h wall-clock; on Apple silicon laptop, one core; direct construction, no search.

Notes

Tensor product of the exact decompositions T5-m2-upper-5.json (taken 2 times): χ(|T5⟩⊗2) ≤ 5 x χ(|T5⟩⊗2) ≤ 5 gives χ(|T5⟩⊗4) ≤ 25, exponent 0.5000. Replaces the rank-64 tensor square of the annealed rank-8 m=2 witness (T5-m4-upper-64.json, 2026-09-23). The orbit has no published exponent and is measured against the single-copy product bound log_5(3) = 0.6826; this exponent is below that baseline because the m=2 factor already is, so it beats no published exponent and the site does not count it as one. It is the sub-multiplicative value the board already implied. Terms are the exact products (x0 and l concatenated, W and Q block diagonal) and coefficients the exact products, built by research/constructions/product_witness.py. Lean: t5_m4_stabRankP_le_twentyfive in LeanProofs.T5M4StabRank proves stabRankP 5 |T5⟩⊗4 ≤ 25 from the m=2 theorem and the multiplicativity lemma stabRankP_tensor_le; the 25 terms here are the products that lemma counts.

Attribution

this repository · stabrank research/constructions/product_witness.py · structured construction

Submission

JSON
{
  "schema_version": "0.1",
  "orbit": "T5",
  "m": 4,
  "direction": "upper",
  "rank": 25,
  "provenance": {
    "author": "this repository",
    "reference": "stabrank research/constructions/product_witness.py",
    "method": "structured construction",
    "date": "2026-09-24",
    "github": [
      "vprusso"
    ],
    "compute": {
      "cpu_hours": 0.001,
      "wall_clock_hours": 0.001,
      "runs": 1,
      "hardware": "Apple silicon laptop, one core; direct construction, no search"
    }
  },
  "notes": "Tensor product of the exact decompositions T5-m2-upper-5.json (taken 2 times): chi(|T5>^2) <= 5 x chi(|T5>^2) <= 5 gives chi(|T5>^4) <= 25, exponent 0.5000. Replaces the rank-64 tensor square of the annealed rank-8 m=2 witness (T5-m4-upper-64.json, 2026-09-23). The orbit has no published exponent and is measured against the single-copy product bound log_5(3) = 0.6826; this exponent is below that baseline because the m=2 factor already is, so it beats no published exponent and the site does not count it as one. It is the sub-multiplicative value the board already implied. Terms are the exact products (x0 and l concatenated, W and Q block diagonal) and coefficients the exact products, built by research/constructions/product_witness.py. Lean: t5_m4_stabRankP_le_twentyfive in LeanProofs.T5M4StabRank proves stabRankP 5 |T5>^4 <= 25 from the m=2 theorem and the multiplicativity lemma stabRankP_tensor_le; the 25 terms here are the products that lemma counts.",
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        ],
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          [
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          [
            0,
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            1,
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          ]
        ],
        "Q": [
          [
            0,
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          ],
          [
            0,
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          ]
        ],
        "l": [
          0,
          0
        ]
      },
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        ],
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      },
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      },
      {
        "k": 2,
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          [
            0,
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        ],
        "l": [
          2,
          2
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      },
      {
        "k": 2,
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          0,
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        ],
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          [
            1,
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            0,
            0
          ],
          [
            0,
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            1,
            4
          ]
        ],
        "Q": [
          [
            2,
            0
          ],
          [
            0,
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          ]
        ],
        "l": [
          2,
          3
        ]
      },
      {
        "k": 2,
        "x0": [
          0,
          4,
          0,
          3
        ],
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          [
            1,
            4,
            0,
            0
          ],
          [
            0,
            0,
            1,
            4
          ]
        ],
        "Q": [
          [
            2,
            0
          ],
          [
            0,
            4
          ]
        ],
        "l": [
          2,
          3
        ]
      },
      {
        "k": 2,
        "x0": [
          0,
          4,
          0,
          4
        ],
        "W": [
          [
            1,
            4,
            0,
            0
          ],
          [
            0,
            0,
            1,
            4
          ]
        ],
        "Q": [
          [
            2,
            0
          ],
          [
            0,
            2
          ]
        ],
        "l": [
          2,
          2
        ]
      }
    ],
    "coeffs": [
      "1/5",
      "exp(2*I*pi/5)/5",
      "exp(-4*I*pi/5)/5",
      "exp(4*I*pi/5)/5",
      "exp(-2*I*pi/5)/5",
      "exp(2*I*pi/5)/5",
      "exp(4*I*pi/5)/5",
      "exp(-2*I*pi/5)/5",
      "exp(-4*I*pi/5)/5",
      "1/5",
      "exp(-4*I*pi/5)/5",
      "exp(-2*I*pi/5)/5",
      "exp(2*I*pi/5)/5",
      "1/5",
      "exp(4*I*pi/5)/5",
      "exp(4*I*pi/5)/5",
      "exp(-4*I*pi/5)/5",
      "1/5",
      "exp(-2*I*pi/5)/5",
      "exp(2*I*pi/5)/5",
      "exp(-2*I*pi/5)/5",
      "1/5",
      "exp(4*I*pi/5)/5",
      "exp(2*I*pi/5)/5",
      "exp(-4*I*pi/5)/5"
    ]
  },
  "lean": {
    "module": "LeanProofs.T5M4StabRank",
    "theorem": "t5_m4_stabRankP_le_twentyfive"
  }
}