58 lines
1.7 KiB
Matlab
58 lines
1.7 KiB
Matlab
function [m_Order] = calculateOrderParameter(~,psi,Transf,Params,VDk,V,T,muchem)
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NumRealiz = 100;
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Mx = numel(Transf.x);
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My = numel(Transf.y);
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Mz = numel(Transf.z);
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r = normrnd(0,1,size(psi));
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theta = rand(size(psi));
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noise = r.*exp(2*pi*1i*theta);
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KEop= 0.5*(Transf.KX.^2+Transf.KY.^2+Transf.KZ.^2);
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Gamma = 1-1i*Params.gamma_S;
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dt = Params.dt;
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avgpsi = 0;
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avgpsi2 = 0;
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for jj = 1:NumRealiz
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%generate initial state
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xi = sqrt(2*Params.gamma_S*Params.kbol*T*10^(-9)*dt/(Params.hbar*Params.w0*Transf.dx*Transf.dy*Transf.dz));
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swapx = randi(length(Transf.x),1,length(Transf.x));
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swapy = randi(length(Transf.y),1,length(Transf.y));
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swapz = randi(length(Transf.z),1,length(Transf.z));
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psi_j = psi + xi * noise(swapx,swapy,swapz);
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% --- % propagate forward in time 1 time step:
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%kin
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psi_j = fftn(psi_j);
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psi_j = psi_j.*exp(-0.5*1i*Gamma*dt*KEop);
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psi_j = ifftn(psi_j);
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%DDI
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frho = fftn(abs(psi_j).^2);
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Phi = real(ifftn(frho.*VDk));
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%Real-space
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psi_j = psi_j.*exp(-1i*Gamma*dt*(V + Params.gs*abs(psi_j).^2 + Params.gammaQF*abs(psi_j).^3 + Params.gdd*Phi - muchem));
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%kin
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psi_j = fftn(psi_j);
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psi_j = psi_j.*exp(-0.5*1i*Gamma*dt*KEop);
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psi_j = ifftn(psi_j);
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%Projection
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kcut = sqrt(2*Params.e_cut);
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K = (Transf.KX.^2+Transf.KY.^2+Transf.KZ.^2)<kcut.^2;
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psi_j = ifftn(K.*fftn(psi_j));
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% --- %
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avgpsi = avgpsi + abs(sum(psi_j(:)))/NumRealiz;
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avgpsi2 = avgpsi2 + sum(abs(psi_j(:)).^2)/NumRealiz;
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end
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m_Order = 1/sqrt(Mx*My*Mz)*avgpsi/sqrt(avgpsi2);
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end |