qgate 0.5.1

Quantum Trajectory Filter — runtime post-selection conditioning for quantum circuits

qgate — Quantum Trajectory Filter

Runtime post-selection conditioning for quantum circuits.

This package explores runtime trajectory filtering concepts from US Patent Application Nos. 63/983,831 & 63/989,632 and Israeli Patent Application No. 326915. The underlying invention is patent pending.

---

Installation

pip install qgate                # core (numpy, pydantic, typer)
pip install qgate[csv]           # + pandas for CSV logging
pip install qgate[parquet]       # + pandas + pyarrow for Parquet logging
pip install qgate[qiskit]        # + IBM Qiskit adapter
pip install qgate[cirq]          # + Google Cirq adapter (stub)
pip install qgate[pennylane]     # + PennyLane adapter (stub)
pip install qgate[all]           # everything

Note: pandas is not required for core filtering; it is only needed if you write logs to CSV or Parquet. The default JSONL logger uses only the standard library.

For development:

git clone https://github.com/ranbuch/qgate-trajectory-filter.git
cd qgate-trajectory-filter/packages/qgate
pip install -e ".[dev]"

---

Quick Start

New API — TrajectoryFilter

from qgate import TrajectoryFilter, GateConfig
from qgate.adapters import MockAdapter

config = GateConfig(
    n_subsystems=4,
    n_cycles=2,
    shots=1024,
    variant="score_fusion",
)
adapter = MockAdapter(error_rate=0.05, seed=42)
tf = TrajectoryFilter(config, adapter)
result = tf.run()

print(f"Accepted: {result.accepted_shots}/{result.total_shots}")
print(f"P_accept: {result.acceptance_probability:.4f}")
print(f"TTS:      {result.tts:.2f}")

Dynamic Thresholding

from qgate import GateConfig, DynamicThresholdConfig, TrajectoryFilter
from qgate.adapters import MockAdapter

config = GateConfig(
    shots=200,
    dynamic_threshold=DynamicThresholdConfig(
        enabled=True, baseline=0.65, z_factor=1.0,
    ),
)
tf = TrajectoryFilter(config, MockAdapter(seed=42))

for _ in range(10):
    result = tf.run()
    print(f"threshold={tf.current_threshold:.4f}  P_acc={result.acceptance_probability:.4f}")

Galton Adaptive Thresholding

Distribution-aware gating that maintains a stable acceptance fraction by adapting to the empirical score distribution. Supports quantile and robust z-score sub-modes.

from qgate import GateConfig, DynamicThresholdConfig, TrajectoryFilter
from qgate.adapters import MockAdapter

config = GateConfig(
    shots=1000,
    variant="score_fusion",
    dynamic_threshold=DynamicThresholdConfig(
        mode="galton",            # distribution-aware adaptive gating
        window_size=1000,         # per-shot rolling window
        min_window_size=100,      # warmup period
        target_acceptance=0.05,   # target ~5% acceptance
        robust_stats=True,        # MAD-based sigma (outlier-resilient)
        use_quantile=True,        # empirical quantile (recommended)
    ),
)
tf = TrajectoryFilter(config, MockAdapter(error_rate=0.1, seed=42))
result = tf.run()

print(f"Threshold: {tf.current_threshold:.4f}")
print(f"Accepted:  {result.accepted_shots}/{result.total_shots}")
# Galton telemetry in result.metadata["galton"]

CLI

qgate version
qgate validate config.json
qgate run config.json --adapter mock --seed 42
qgate run config.json --adapter mock --output results.jsonl
qgate run config.json --adapter mock --error-rate 0.1 --verbose
qgate run config.json --adapter mock --quiet          # suppress info logs
qgate adapters                                         # list installed adapters
qgate schema                                           # print JSON Schema for GateConfig

Legacy API (backward compatible)

from qgate import decide_hierarchical, MultiRateMonitor
from qgate.conditioning import ParityOutcome

outcome = ParityOutcome(4, 2, [[0, 0, 1, 0], [0, 0, 0, 0]])
assert decide_hierarchical(outcome, k_fraction=0.75) is True

---

Architecture

qgate/
├── __init__.py        # Public API re-exports (backward-compatible)
├── config.py          # Pydantic v2 config models (GateConfig, FusionConfig, …)
│                        All models are frozen & extra="forbid"
├── filter.py          # TrajectoryFilter — main API class
│                        Vectorised scoring via score_batch()
├── scoring.py         # Fuse-scores, score_outcome, score_batch (NumPy)
├── threshold.py       # Dynamic threshold: rolling z-score + Galton adaptive
├── run_logging.py     # JSON-Lines / CSV / Parquet structured logging
│                        RunLogger is a context manager; Parquet is buffered
├── cli.py             # Typer CLI (run, validate, schema, adapters, version)
├── compat/            # Backward-compatible wrappers
│   ├── conditioning.py    # ParityOutcome (ndarray), decision rules
│   └── monitors.py        # MultiRateMonitor, should_abort_batch
├── conditioning.py    # Re-export from compat/conditioning
├── monitors.py        # Re-export from compat/monitors
└── adapters/
    ├── base.py            # BaseAdapter ABC + MockAdapter
    ├── registry.py        # list_adapters() / load_adapter()
    ├── qiskit_adapter.py  # Full Qiskit implementation (copy-safe)
    ├── grover_adapter.py  # Grover vs TSVF-Chaotic Grover adapter
    ├── qaoa_adapter.py    # QAOA vs TSVF-QAOA MaxCut adapter
    ├── vqe_adapter.py     # VQE vs TSVF-VQE (TFIM) adapter
    ├── qpe_adapter.py     # QPE vs TSVF-QPE Phase Estimation adapter
    ├── cirq_adapter.py    # Stub
    └── pennylane_adapter.py  # Stub

Key Design Decisions

• ParityOutcome stores an np.ndarray — shape (n_cycles, n_subsystems), dtype int8. Lists are coerced on construction.
• All configuration is immutable — GateConfig and sub-models are Pydantic frozen models. Create a new config to change parameters.
• pandas is optional — only imported lazily when CSV/Parquet logging is used. Core filtering needs only numpy + pydantic.
• Structured logging — all modules use logging.getLogger("qgate.*") so users can control verbosity with standard Python logging.

---

Conditioning Strategies

Strategy	Config	Scaling
Global	variant="global"	Exponential decay at N ≥ 2
Hierarchical k-of-N	variant="hierarchical", k_fraction=0.9	O(1) — scales to N = 64+
Score Fusion	variant="score_fusion"	Most robust on real hardware

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Algorithm-Specific TSVF Adapters

qgate ships with four algorithm-specific adapters that apply trajectory filtering to canonical quantum algorithms. Each adapter builds both a standard circuit and a TSVF variant (with chaotic perturbation + ancilla phase/parity probe), runs them, and extracts algorithm-specific metrics.

Adapter	Algorithm	Entry Point	IBM Validated
GroverTSVFAdapter	Grover search	grover_tsvf	✅ IBM Fez — 7.3× advantage
QAOATSVFAdapter	QAOA MaxCut	qaoa_tsvf	✅ IBM Torino — 1.88× advantage
VQETSVFAdapter	VQE for TFIM	vqe_tsvf	✅ IBM Fez — barren plateau avoidance
QPETSVFAdapter	QPE phase est.	qpe_tsvf	✅ IBM Fez — phase coherence study

Utility-Scale Validation (IBM Torino, 133 Qubits)

The VQETSVFAdapter has been stress-tested at utility scale on IBM Torino (133 physical qubits, 16,709 ISA gate depth). At 37× T₁ decoherence, the Galton filter achieved a negative cooling delta (Δ = −0.080), extracting correlated thermodynamic signal from ~99% thermal noise. See the simulations/tfim_127q directory for full reproduction steps and raw data.

from qgate.adapters.grover_adapter import GroverTSVFAdapter
from qgate.adapters.qaoa_adapter import QAOATSVFAdapter
from qgate.adapters.vqe_adapter import VQETSVFAdapter
from qgate.adapters.qpe_adapter import QPETSVFAdapter

---

Run Logging

from qgate import TrajectoryFilter, GateConfig
from qgate.adapters import MockAdapter
from qgate.run_logging import RunLogger

config = GateConfig(shots=500, variant="score_fusion")
tf = TrajectoryFilter(config, MockAdapter(seed=42))

with RunLogger("results.jsonl") as logger:
    result = tf.run()
    logger.log(result)
    # For CSV: RunLogger("results.csv")   — requires pip install qgate[csv]
    # For Parquet: RunLogger("results.parquet") — requires pip install qgate[parquet]

Each logged record includes a deterministic run ID (SHA-256 prefix), full config JSON, acceptance probability, TTS, and a UTC timestamp.

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Running Tests

cd packages/qgate
pip install -e ".[dev]"
pytest -v tests/            # 376 tests, ~3 s
pytest --cov=qgate tests/   # with coverage

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License

QGATE Source Available Evaluation License v1.2 — see LICENSE.

Academic research, peer review, and internal corporate evaluation are freely permitted. Commercial deployment requires a separate license.