spiderpilot89/josephson-phase-coherence-500ghz

Zero-Trust Physics: 500GHz Josephson Phase Coherence Sweep (G^G)

5,000 superconducting transmon qubit trajectories at 500GHz (dt = 2ps) — deterministic, first-principles, SHA-256 sealed.

The "quantum state" of a Josephson junction is governed by a classical pendulum ODE. G^G solves it deterministically at 500GHz, sweeping the operating envelope of a transmon qubit and mapping the exact boundary conditions under which coherence collapses.

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Physics Model

The RCSJ (Resistively and Capacitively Shunted Junction) model for a transmon qubit:

$$\frac{d^2\varphi }{d{\tau }^2}+\gamma \frac{d\varphi }{d\tau }+{\omega }_p^2\sin \varphi =\eta I_{\text{bias}}(\tau )\backslash frac\{d^2\backslash phi\}\{d\backslash tau^2\}\; +\; \backslash gamma\backslash frac\{d\backslash phi\}\{d\backslash tau\}\; +\; \backslash omega\_p^2\; \backslash sin\backslash phi\; =\; \backslash eta\; I\_\{\backslash text\{bias\}\}(\backslash tau)$$

Parameter	Value	Physical meaning
ωₚ²	600 ns⁻²	Plasma frequency² (junction inductance + capacitance)
γ	10 ns⁻¹	Damping (shunt resistance)
η	30 nA⁻¹·ns⁻²	Control coupling
dt	0.002 ns (2 ps)	500 GHz integration rate
Duration	50 ns	25,000 steps per trajectory

Coherence collapse conditions:

• Phase slip: |φ| > 2π destroys quantum coherence
• Thermal runaway: dilution refrigerator exceeds 100mK → quench
• Thermal noise modeled via Box-Muller, std ∝ √T

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Parameter Space

5-dimensional sweep covering the transmon operating envelope:

Parameter	Range	Steps
Temperature	10 mK → 100 mK	10
Pulse amplitude	0 → 45 nA	10
Control frequency	3.0 → 4.98 GHz	10 (sweeps ±1 GHz around 3.9 GHz resonance)
Pulse duration	5 → 23 ns	10
Initial phase	0 → 1.35 rad	10

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Results (5,000 trajectories)

• Quench rate: 0.10% (5 decoherence events)
• ZTP residual anomalies: 0 (physics self-consistent at every step)
• Master proof hash: b27576bb6bee42676dc89e954cab2c1e8e70b0388f0679bdd3b2a656d41c501c

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Schema

Column	Description
temp_mk	Dilution refrigerator temperature (mK)
pulse_amplitude_na	Microwave pulse amplitude (nA)
control_frequency_ghz	Drive frequency (GHz)
pulse_duration_ns	Gate pulse duration (ns)
initial_phase	Initial junction phase (rad)
quenched	Whether coherence collapsed during the run
final_coherence	Coherence at end of trajectory (0–1)
max_residual	Peak ZTP RCSJ Lagrangian residual
proof_hash	SHA-256 chain seal for this trajectory

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Loading

from datasets import load_dataset
import pandas as pd

dataset = load_dataset("spiderpilot89/josephson-phase-coherence-500ghz", split="train")
df = dataset.to_pandas()

# Find the quench boundary
quenched = df[df["quenched"] == True]
print(f"Quench events: {len(quenched)}")
print(quenched[["temp_mk", "control_frequency_ghz", "final_coherence"]])

# Coherence vs temperature
import matplotlib.pyplot as plt
df.groupby("temp_mk")["final_coherence"].mean().plot()

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License

MIT — free to use, modify, and distribute with attribution.

John Kruze · ZeroTrustPhysics.com