극저온 방사광 X-선 나노공진기 기반 공동 광역학(Cavity Optomechanics) 복사압 냉각 양자 바닥상태 서보 아키텍처 (.NET 9 C# SIMD)

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

namespace ZeliDesk.Quantum.Optomechanics
{
    /// <summary>
    /// 공동 광역학(Cavity Optomechanics) 방사압 냉각 및 양자 바닥상태 추적 서보
    /// GC 무할당 ref struct 및 AVX-256 SIMD 가속화
    /// </summary>
    public ref struct OptomechanicalCoolingServo
    {
        private readonly ReadOnlySpan<float> _quadratureI;      // 호모다인 In-phase 신호
        private readonly ReadOnlySpan<float> _quadratureQ;      // 호모다인 Quadrature 신호
        private readonly ReadOnlySpan<float> _thermalPhonons;    // 열 포논 점유수 n_th
        private readonly Span<float> _effectivePhonons;        // 냉각 후 유효 포논 수 <n_f>
        private readonly Span<float> _piezoFeedbackVolts;      // PZT 위상 피드백 전압 (V)

        private readonly float _optomechanicalRate;  // 광역학 냉각률 Gamma_opt (Hz)
        private readonly float _mechDampingRate;     // 기계적 고유 감쇠율 gamma_m (Hz)
        private readonly float _quantumLimitPhonon;  // 양자 한계 잔류 포논 n_min
        private readonly float _feedbackGain;        // 피에조 피드백 게인 (V/nm)

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public OptomechanicalCoolingServo(
            ReadOnlySpan<float> quadratureI,
            ReadOnlySpan<float> quadratureQ,
            ReadOnlySpan<float> thermalPhonons,
            Span<float> effectivePhonons,
            Span<float> piezoFeedbackVolts,
            float optomechanicalRate = 45000.0f,
            float mechDampingRate = 120.0f,
            float quantumLimitPhonon = 0.05f,
            float feedbackGain = 1.25f)
        {
            _quadratureI = quadratureI;
            _quadratureQ = quadratureQ;
            _thermalPhonons = thermalPhonons;
            _effectivePhonons = effectivePhonons;
            _piezoFeedbackVolts = piezoFeedbackVolts;
            _optomechanicalRate = optomechanicalRate;
            _mechDampingRate = mechDampingRate;
            _quantumLimitPhonon = quantumLimitPhonon;
            _feedbackGain = feedbackGain;
        }

        /// <summary>
        /// 포논 감쇠 및 직교 위상 기반 피에조 피드백을 SIMD로 동시 연산
        /// </summary>
        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
        public void ExecuteCoolingFeedbackLoop()
        {
            int length = _thermalPhonons.Length;
            int simdLength = length - (length % 8);

            float totalGamma = _mechDampingRate + _optomechanicalRate;
            Vector256<float> vGammaM = Vector256.Create(_mechDampingRate);
            Vector256<float> vGammaOpt = Vector256.Create(_optomechanicalRate);
            Vector256<float> vTotalGammaInv = Vector256.Create(1.0f / totalGamma);
            Vector256<float> vNmin = Vector256.Create(_quantumLimitPhonon);
            Vector256<float> vGain = Vector256.Create(_feedbackGain);

            int i = 0;
            if (Avx2.IsSupported)
            {
                for (; i < simdLength; i += 8)
                {
                    Vector256<float> vNth = Vector256.Create(MemoryMarshal.Cast<float, Vector256<float>>(_thermalPhonons.Slice(i, 8))[0]);
                    Vector256<float> vI = Vector256.Create(MemoryMarshal.Cast<float, Vector256<float>>(_quadratureI.Slice(i, 8))[0]);
                    Vector256<float> vQ = Vector256.Create(MemoryMarshal.Cast<float, Vector256<float>>(_quadratureQ.Slice(i, 8))[0]);

                    // <n_f> = (gamma_m * n_th + Gamma_opt * n_min) / (gamma_m + Gamma_opt)
                    Vector256<float> vThermalTerm = Avx.Multiply(vGammaM, vNth);
                    Vector256<float> vQuantumTerm = Avx.Multiply(vGammaOpt, vNmin);
                    Vector256<float> vNf = Avx.Multiply(Avx.Add(vThermalTerm, vQuantumTerm), vTotalGammaInv);

                    // 기계 변위 변동: deltaX = sqrt(I^2 + Q^2)
                    Vector256<float> vAmpSq = Avx.Add(Avx.Multiply(vI, vI), Avx.Multiply(vQ, vQ));
                    Vector256<float> vDisp = Avx.Sqrt(vAmpSq);

                    // 피에조 보정 전압 = -Gain * deltaX
                    Vector256<float> vPzt = Avx.Multiply(Avx.Subtract(Vector256<float>.Zero, vDisp), vGain);

                    vNf.CopyTo(_effectivePhonons.Slice(i, 8));
                    vPzt.CopyTo(_piezoFeedbackVolts.Slice(i, 8));
                }
            }

            for (; i < length; i++)
            {
                float nf = (_mechDampingRate * _thermalPhonons[i] + _optomechanicalRate * _quantumLimitPhonon) / totalGamma;
                float disp = MathF.Sqrt(_quadratureI[i] * _quadratureI[i] + _quadratureQ[i] * _quadratureQ[i]);
                _effectivePhonons[i] = nf;
                _piezoFeedbackVolts[i] = -_feedbackGain * disp;
            }
        }
    }
}