AIDT 온디바이스 STEM 방사광 X선 극저온 Si3N4 광역학 나노박막 양자 압축(Ponderomotive Squeezing) 복사압 서보 제어기

using System;
using System.Runtime.CompilerServices;

namespace ZeliDesk.Stem.QuantumOptomechanics
{
    /// <summary>
    /// MIM 광역학 캐비티 텔레메트리 상태
    /// </summary>
    public readonly ref struct OptomechanicsTelemetryState
    {
        public readonly double HomodyneNoiseVarianceDb;  // 호모다인 측정 잡음 분산 [dB (기준: 0dB Shot Noise)]
        public readonly double CurrentLoPhaseRad;        // 현재 국부 발진기(LO) 위상 [rad]
        public readonly double IntraCavityPhotonCount;   // 캐비티 내부 광자 수
        public readonly double MembraneTempKelvin;       // 나노 멤브레인 물리 온도 [K]
        public readonly double LaserDetuningKhz;         // 레이저 탈조 주파수 [kHz]

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public OptomechanicsTelemetryState(
            double noiseDb, double loPhase, double photons, double temp, double detuning)
        {
            HomodyneNoiseVarianceDb = noiseDb;
            CurrentLoPhaseRad = loPhase;
            IntraCavityPhotonCount = photons;
            MembraneTempKelvin = temp;
            LaserDetuningKhz = detuning;
        }
    }

    /// <summary>
    /// 양자 스퀴징 최적화 서보 명령
    /// </summary>
    public readonly ref struct QuantumSqueezingServoCommand
    {
        public readonly double TargetLoPhaseRad;         // 목표 LO 위상 지령 [rad]
        public readonly double SqueezingLevelDb;         // 달성된 스퀴징 깊이 [dB below SQL]
        public readonly double ThermalPhononOccupancy;   // 유효 열 포논 수 n_th
        public readonly bool SubShotNoiseAchieved;       // 샷노이즈 이하 양자 압축 성공 여부

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public QuantumSqueezingServoCommand(double loPhase, double sqzDb, double phonons, bool subShot)
        {
            TargetLoPhaseRad = loPhase;
            SqueezingLevelDb = sqzDb;
            ThermalPhononOccupancy = phonons;
            SubShotNoiseAchieved = subShot;
        }
    }

    /// <summary>
    /// 10,000Hz 주기 광역학 나노박막 양자 스퀴징 서보 엔진
    /// </summary>
    public ref struct OptomechanicalSqueezingServoEngine
    {
        private double _accumulatedLoPhase;
        private double _prevNoiseDb;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public QuantumSqueezingServoCommand CalculateServoControl(
            in OptomechanicsTelemetryState state, double dtSeconds)
        {
            // 1. 최소 잡음 골짜기(Squeezing Valley) 탐색을 위한 경사도 추정
            double noiseGradient = (dtSeconds > 1e-9) ? (state.HomodyneNoiseVarianceDb - _prevNoiseDb) / dtSeconds : 0.0;
            _prevNoiseDb = state.HomodyneNoiseVarianceDb;

            // 2. LO 위상 미세 디더링 및 극점 추적 (Extremum Seeking Loop)
            double ditherPhase = 0.02 * Math.Sin(2.0 * Math.PI * 250.0 * dtSeconds); // 250Hz 파일럿
            double phaseStep = -0.05 * noiseGradient * dtSeconds;
            _accumulatedLoPhase += phaseStep;
            _accumulatedLoPhase = Math.Clamp(_accumulatedLoPhase, -Math.PI, Math.PI);

            double commandLoPhase = _accumulatedLoPhase + ditherPhase;

            // 3. 양자 스퀴징 레벨 판정
            // 0dB 이하면 샷노이즈 돌파 (Sub-Shot-Noise)
            double squeezingDb = -state.HomodyneNoiseVarianceDb;
            bool subShot = state.HomodyneNoiseVarianceDb < -0.1;

            // 유효 포논 수 추정
            double effectivePhonons = Math.Max(0.15, (state.MembraneTempKelvin * 1.38e-23) / (1.054e-34 * 2.0 * Math.PI * 1.5e6));

            return new QuantumSqueezingServoCommand(
                commandLoPhase,
                squeezingDb,
                effectivePhonons,
                subShot
            );
        }
    }
}