중력파 검출기(LIGO) 광학 스프링(Optical Spring) & 양자 압축진공(Squeezed Light) 잡음 제거 1,000Hz 0-Alloc C# 시공간 왜곡 해석 엔진

using System;
using System.Runtime.CompilerServices;

namespace ZeliDesk.Stem.Gravitational;

public readonly ref struct GwInterferometerState
{
    public readonly double ReconstructedStrain;
    public readonly double OpticalSpringForceN;
    public readonly double ShotNoiseReductionDb;
    public readonly double SignalToNoiseRatio;
    public readonly bool IsChirpEventDetected;

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public GwInterferometerState(double strain, double force, double noiseRedDb, double snr, bool eventDetected)
    {
        ReconstructedStrain = strain;
        OpticalSpringForceN = force;
        ShotNoiseReductionDb = noiseRedDb;
        SignalToNoiseRatio = snr;
        IsChirpEventDetected = eventDetected;
    }
}

public ref struct GwInterferometerSimulator
{
    private const double ArmLengthMeters = 4000.0; // 4 km
    private const double LaserWavelengthMeters = 1064.0e-9; // 1064 nm Nd:YAG
    private const double SpeedOfLight = 299792458.0;

    private double _squeezingDb;
    private double _opticalSpringK;
    private double _mirrorDisplacement;

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public GwInterferometerSimulator(double squeezingDb = 10.0, double springK = 1.2e5)
    {
        _squeezingDb = squeezingDb;
        _opticalSpringK = springK;
        _mirrorDisplacement = 0.0;
    }

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public GwInterferometerState Step(double photodiodeCurrentAmp, double groundSeismicDisplacementM)
    {
        // 1. 광학 스프링 복원력 계산
        double springForce = -_opticalSpringK * (_mirrorDisplacement - groundSeismicDisplacementM);

        // 2. 광학 위상 편차로부터 미세 변위 delta L 산출
        // 명실 다이오드 전류 변조 신호 -> 위상차 -> 변위
        double phaseShiftRad = photodiodeCurrentAmp * 1.5e6;
        double deltaL = (phaseShiftRad * LaserWavelengthMeters) / (4.0 * Math.PI);
        _mirrorDisplacement = deltaL;

        // 3. 중력파 무차원 변형률 h(t) 복원
        double hStrain = (2.0 * deltaL) / ArmLengthMeters;

        // 4. 양자 압축 진공 주입에 따른 잡음 감쇠 및 SNR 추정
        double noiseReductionFactor = Math.Pow(10.0, -_squeezingDb / 20.0);
        double quantumNoiseFloor = 1.0e-22 * noiseReductionFactor;
        double snr = Math.Abs(hStrain) / Math.Max(1.0e-24, quantumNoiseFloor);

        // 5. 처프(Chirp) 병합 이벤트 트리거
        bool chirp = snr > 8.0 && Math.Abs(hStrain) > 5.0e-22;

        return new GwInterferometerState(hStrain, springForce, _squeezingDb, snr, chirp);
    }
}