극저온 조셉슨 진행파 모수증폭기(JTWPA) 기반 4-파동 혼합(4WM) 양자 큐비트 초저잡음 증폭 및 위상 정합 분산 엔지니어링 C# SIMD 서보

3. Zero-Allocation C# SIMD JTWPA 위상 정합 서보 엔진

초광대역 스펙트럼 데이터를 실시간 분석하여 초전도 마그넷 온칩 자속 편이와 마이크로파 펌프 파워를 10,000 Hz로 정밀 제어하는 C# .NET 9.0 엔진입니다.

using System;
using System.Runtime.CompilerServices;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;

namespace ZeliDesk.Quantum.JtwpaReadout
{
    public readonly ref struct JtwpaSpectrumTelemetry
    {
        public readonly float MeasuredSignalGainDb;     // e.g. 19.8 dB
        public readonly float PumpCarrierPowerDbm;      // e.g. -58.5 dBm
        public readonly float PumpFrequencyGhz;         // e.g. 6.20 GHz
        public readonly float IdlerPhaseResidualRad;    // Phase mismatch
        public readonly float SystemNoiseTemperatureK;  // Cryo noise ~0.35 K

        public JtwpaSpectrumTelemetry(float gain, float pPwr, float pFreq, float idlerPhase, float tNoise)
        {
            MeasuredSignalGainDb = gain;
            PumpCarrierPowerDbm = pPwr;
            PumpFrequencyGhz = pFreq;
            IdlerPhaseResidualRad = idlerPhase;
            SystemNoiseTemperatureK = tNoise;
        }
    }

    public ref struct JtwpaServoCommands
    {
        public float OnChipFluxBiasMilliPhi0;
        public float PumpPowerAdjustmentDb;
        public float TargetBandwidthGhz;
        public float QuantumEfficiencyPercentage;
        public bool NearQuantumLimited;
    }

    public static class JosephsonTravelingWaveAmplifierEngine
    {
        private const float TargetGainDb = 20.0f; // 20 dB power gain
        private const float QuantumLimitNoiseTempAt6Ghz = 0.144f; // hbar * omega / (2 kB) at 6 GHz = ~144 mK

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void OptimizeJtwpaOperatingPoint(
            in JtwpaSpectrumTelemetry telemetry,
            ref JtwpaServoCommands output)
        {
            // 1. Gain Error and Pump Power Feedforward Control
            float gainError = TargetGainDb - telemetry.MeasuredSignalGainDb;
            float pwrAdj = gainError * 0.18f; // dB adjustment
            output.PumpPowerAdjustmentDb = Math.Clamp(pwrAdj, -3.0f, 3.0f);

            // 2. Resonant Phase-Matching (RPM) Closed-Loop Flux Servo
            // Phase mismatch delta_k nulling via on-chip SNAIL/SQUID flux bias
            float fluxStep = -telemetry.IdlerPhaseResidualRad * 15.0f; // mPhi0 per rad
            output.OnChipFluxBiasMilliPhi0 = Math.Clamp(fluxStep, -150.0f, 150.0f);

            // 3. Operational Bandwidth Estimation (3 dB drop range)
            float effectiveBandwidth = 3.8f - MathF.Abs(gainError) * 0.12f;
            output.TargetBandwidthGhz = MathF.Max(1.5f, effectiveBandwidth);

            // 4. Quantum Noise Efficiency
            // eta_quant = T_quantum_limit / T_measured
            float tMeas = MathF.Max(0.145f, telemetry.SystemNoiseTemperatureK);
            float qEfficiency = (QuantumLimitNoiseTempAt6Ghz / tMeas) * 100.0f;
            output.QuantumEfficiencyPercentage = Math.Clamp(qEfficiency, 0.0f, 98.0f);

            // Near quantum limited flag: T_noise < 2 * T_quantum_limit (eta > 50%)
            output.NearQuantumLimited = (qEfficiency >= 50.0f);
        }
    }
}