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Removed unnecessary calculations, corrected a major bug in the computation of trap potential and other minor aesthetic changes.

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Karthik 2025-03-27 19:39:29 +01:00
parent d97d68cc97
commit 4ccee92af1
9 changed files with 45 additions and 133 deletions
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6
Dipolar-Gas-Simulator/+Scripts/run_locally.m
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@ -22,9 +22,9 @@ OptionsStruct.Dimensions = [18, 18, 18];
OptionsStruct.IncludeDDICutOff = true;
OptionsStruct.CutoffType = 'Cylindrical';
OptionsStruct.SimulationMode = 'ImaginaryTimeEvolution'; % 'ImaginaryTimeEvolution' | 'RealTimeEvolution'
OptionsStruct.TimeStepSize = 0.001; % in s
OptionsStruct.MinimumTimeStepSize = 1E-5; % in s
OptionsStruct.TimeCutOff = 1E6; % in s
OptionsStruct.TimeStepSize = 0.002; % in s
OptionsStruct.MinimumTimeStepSize = 1E-6; % in s
OptionsStruct.TimeCutOff = 2E6; % in s
OptionsStruct.EnergyTolerance = 5E-10;
OptionsStruct.ResidualTolerance = 1E-05;
OptionsStruct.NoiseScaleFactor = 0.01;

58
Dipolar-Gas-Simulator/+Simulator/@Calculator/calculateOrderParameter.m
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@ -1,58 +0,0 @@
function [m_Order] = calculateOrderParameter(~,psi,Transf,Params,VDk,V,T,muchem)
NumRealiz = 100;
Mx = numel(Transf.x);
My = numel(Transf.y);
Mz = numel(Transf.z);
r = normrnd(0,1,size(psi));
theta = rand(size(psi));
noise = r.*exp(2*pi*1i*theta);
KEop = 0.5*(Transf.KX.^2+Transf.KY.^2+Transf.KZ.^2);
Gamma = 1-1i*Params.gamma_S;
dt = Params.dt;
avgpsi1 = 0;
avgpsi2 = 0;
for jj = 1:NumRealiz
% Generate initial state
xi = sqrt(2*Params.gamma_S*Params.kbol*T*10^(-9)*dt/(Params.hbar*Params.w0*Transf.dx*Transf.dy*Transf.dz));
swapx = randi(length(Transf.x),1,length(Transf.x));
swapy = randi(length(Transf.y),1,length(Transf.y));
swapz = randi(length(Transf.z),1,length(Transf.z));
psi_j = psi + xi * noise(swapx,swapy,swapz);
% --- % propagate forward in time 1 time step:
% Kin
psi_j = fftn(psi_j);
psi_j = psi_j.*exp(-0.5*1i*Gamma*dt*KEop);
psi_j = ifftn(psi_j);
% DDI
frho = fftn(abs(psi_j).^2);
Phi = real(ifftn(frho.*VDk));
% Real-space
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));
% Kin
psi_j = fftn(psi_j);
psi_j = psi_j.*exp(-0.5*1i*Gamma*dt*KEop);
psi_j = ifftn(psi_j);
% Projection
kcut = sqrt(2*Params.e_cut);
K = (Transf.KX.^2+Transf.KY.^2+Transf.KZ.^2)<kcut.^2;
psi_j = ifftn(K.*fftn(psi_j));
% --- %
avgpsi1 = avgpsi1 + abs(sum(psi_j(:))) /NumRealiz;
avgpsi2 = avgpsi2 + sum(abs(psi_j(:)).^2)/NumRealiz;
end
m_Order = 1/sqrt(Mx*My*Mz)*avgpsi1/sqrt(avgpsi2);
end

21
Dipolar-Gas-Simulator/+Simulator/@Calculator/calculatePhaseCoherence.m
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@ -1,21 +0,0 @@
function [PhaseC] = calculatePhaseCoherence(~,psi,Transf,Params)
norm = sum(sum(sum(abs(psi).^2,1),2),3)*Transf.dx*Transf.dy*Transf.dz;
psi = psi/sqrt(norm);
NumGlobalShifts = 800;
betas = [];
phishift = [];
for jj = 1:NumGlobalShifts
phishift(jj) = -pi + 2*pi*(jj-1)/NumGlobalShifts;
betas(jj) = sum(sum(sum(abs(angle(psi*exp(-1i*phishift(jj)))).*abs(psi).^2)));
end
[minbeta,minidx] = min(betas);
psi = psi*exp(-1i*phishift(minidx));
phi = angle(psi);
avgphi = sum(sum(sum(phi.*abs(psi).^2,1),2),3)*Transf.dx*Transf.dy*Transf.dz;
PhaseC = sum(sum(sum(abs(angle(psi)-avgphi).*abs(psi).^2)))*Transf.dx*Transf.dy*Transf.dz;
end

4
Dipolar-Gas-Simulator/+Simulator/@Calculator/calculateVDk.m
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@ -8,6 +8,7 @@ function VDk = calculateVDk(this,Params,Transf,TransfRad,IncludeDDICutOff)
% Cylindrical (semianalytic)
% Cylindrical infinite Z, polarized along x (analytic)
% Spherical
% Custom Cylindrical
if IncludeDDICutOff
switch this.CutOffType
@ -81,7 +82,4 @@ function VDk = calculateVDk(this,Params,Transf,TransfRad,IncludeDDICutOff)
alph(1) = pi/2;
VDk = cos(alph).^2-1/3;
end
VDk = 3 * VDk;
end

46
Dipolar-Gas-Simulator/+Simulator/@DipolarGas/propagateWavefunction.m
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@ -1,9 +1,8 @@
function [psi] = propagateWavefunction(this,psi,Params,Transf,VDk,V,t_idx,Observ)
set(0,'defaulttextInterpreter','latex')
set(groot, 'defaultAxesTickLabelInterpreter','latex'); set(groot, 'defaultLegendInterpreter','latex');
switch this.SimulationMode
case 'ImaginaryTimeEvolution'
dt = -1j*abs(this.TimeStepSize); % Imaginary Time
KEop = 0.5*(Transf.KX.^2+Transf.KY.^2+Transf.KZ.^2);
@ -11,39 +10,40 @@ function [psi] = propagateWavefunction(this,psi,Params,Transf,VDk,V,t_idx,Observ
Observ.res = 1;
muchem = this.Calculator.calculateChemicalPotential(psi,Params,Transf,VDk,V);
AdaptIdx = 0;
if this.PlotLive
Plotter.plotLive(psi,Params,Transf,Observ)
drawnow
end
AdaptIdx = 0;
while t_idx < Params.sim_time_cut_off
% kin
psi = fftn(psi);
psi = psi.*exp(-0.5*1i*dt*KEop);
psi = ifftn(psi);
psi = fftn(psi);
psi = psi.*exp(-0.5*1i*dt*KEop);
psi = ifftn(psi);
% DDI
frho = fftn(abs(psi).^2);
Phi = real(ifftn(frho.*VDk));
frho = fftn(abs(psi).^2);
Phi = real(ifftn(frho.*VDk));
% Real-space
psi = psi.*exp(-1i*dt*(V + Params.gs*abs(psi).^2 + Params.gdd*Phi + Params.gammaQF*abs(psi).^3 - muchem));
psi = psi.*exp(-1i*dt*(V + Params.gs*abs(psi).^2 + Params.gammaQF*abs(psi).^3 + Params.gdd*Phi - muchem));
% kin
psi = fftn(psi);
psi = psi.*exp(-0.5*1i*dt*KEop);
psi = ifftn(psi);
psi = fftn(psi);
psi = psi.*exp(-0.5*1i*dt*KEop);
psi = ifftn(psi);
% Renorm
Norm = sum(abs(psi(:)).^2)*Transf.dx*Transf.dy*Transf.dz;
psi = sqrt(Params.N)*psi/sqrt(Norm);
Norm = sum(abs(psi(:)).^2)*Transf.dx*Transf.dy*Transf.dz;
psi = sqrt(Params.N)*psi/sqrt(Norm);
muchem = this.Calculator.calculateChemicalPotential(psi,Params,Transf,VDk,V);
if mod(t_idx,500) == 0
muchem = this.Calculator.calculateChemicalPotential(psi,Params,Transf,VDk,V);
if mod(t_idx,1000) == 0
% Change in Energy
E = this.Calculator.calculateTotalEnergy(psi,Params,Transf,VDk,V);
@ -93,10 +93,6 @@ function [psi] = propagateWavefunction(this,psi,Params,Transf,VDk,V,t_idx,Observ
E = E/Norm;
Observ.EVec = [Observ.EVec E];
% Phase coherence
[PhaseC] = this.Calculator.calculatePhaseCoherence(psi,Transf,Params);
Observ.PCVec = [Observ.PCVec PhaseC];
Observ.res_idx = Observ.res_idx + 1;
disp('Run completed!');
@ -145,10 +141,6 @@ function [psi] = propagateWavefunction(this,psi,Params,Transf,VDk,V,t_idx,Observ
E = E/Norm;
Observ.EVec = [Observ.EVec E];
% Phase coherence
[PhaseC] = this.Calculator.calculatePhaseCoherence(psi,Transf);
Observ.PCVec = [Observ.PCVec PhaseC];
Observ.tVecPlot = [Observ.tVecPlot tVal];
Observ.res_idx = Observ.res_idx + 1;

1
Dipolar-Gas-Simulator/+Simulator/@DipolarGas/setupParameters.m
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@ -63,6 +63,7 @@ function [Params] = setupParameters(this)
% DDI strength
Params.gdd = 4*pi*Params.add/l0;
Params.gdd = 3 * Params.gdd; % <------------- Necessary for the 3-D case
% Trap gamma
Params.gx = (Params.wx/w0)^2;

32
Dipolar-Gas-Simulator/+Simulator/@DipolarGas/setupSpaceRadial.m
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@ -3,31 +3,31 @@ function [Transf] = setupSpaceRadial(~,Params,morder)
Params.Lr = 0.5*min(Params.Lx,Params.Ly);
Params.Nr = max(Params.Nx,Params.Ny);
Zmax = 0.5*Params.Lz;
Rmax = Params.Lr;
Nz = Params.Nz;
Nr = Params.Nr;
Zmax = 0.5*Params.Lz;
Rmax = Params.Lr;
Nz = Params.Nz;
Nr = Params.Nr;
if(nargin==2)
morder=0; %only do Bessel J0
end
% Fourier grids
z=linspace(-Zmax,Zmax,Nz+1);
z=z(1:end-1);
dz=z(2)-z(1);
Kmax=Nz*2*pi/(4*Zmax);
kz=linspace(-Kmax,Kmax,Nz+1);
kz=kz(1:end-1);
z = linspace(-Zmax,Zmax,Nz+1);
z = z(1:end-1);
dz = z(2)-z(1);
Kmax = Nz*2*pi/(4*Zmax);
kz = linspace(-Kmax,Kmax,Nz+1);
kz = kz(1:end-1);
% Hankel grids and transform
H = hankelmatrix(morder,Rmax,Nr);
r=H.r(:);
kr=H.kr(:);
T = diag(H.J/H.kmax)*H.T*diag(Rmax./H.J)*dz*(2*pi);
H = hankelmatrix(morder,Rmax,Nr);
r = H.r(:);
kr = H.kr(:);
T = diag(H.J/H.kmax)*H.T*diag(Rmax./H.J)*dz*(2*pi);
Tinv = diag(H.J./Rmax)*H.T'*diag(H.kmax./H.J)/dz/(2*pi);
wr=H.wr;
wk=H.wk;
wr = H.wr;
wk = H.wk;
% H.T'*diag(H.J/H.vmax)*H.T*diag(Rmax./H.J)
[Transf.R,Transf.Z]=ndgrid(r,z);

8
Dipolar-Gas-Simulator/+Simulator/@DipolarGas/setupWavefunction.m
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@ -8,9 +8,9 @@ function [psi] = setupWavefunction(~,Params,Transf)
elly = sqrt(Params.hbar/(Params.m*Params.wy))/Params.l0;
ellz = sqrt(Params.hbar/(Params.m*Params.wz))/Params.l0;
Rx = 4*ellx;
Ry = 4*elly;
Rz = 4*ellz;
Rx = 8*ellx;
Ry = 8*elly;
Rz = 8*ellz;
X0 = 0.0*Transf.Xmax;
Y0 = 0.0*Transf.Ymax;
Z0 = 0*Transf.Zmax;
@ -28,5 +28,5 @@ function [psi] = setupWavefunction(~,Params,Transf)
% Renormalize wavefunction
Norm = sum(abs(psi(:)).^2)*Transf.dx*Transf.dy*Transf.dz;
psi = sqrt(Params.N)*psi/sqrt(Norm);
end

2
Dipolar-Gas-Simulator/+Simulator/@Potentials/setupParameters.m
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@ -1,7 +1,7 @@
function [Params] = setupParameters(this)
CONSTANTS = Helper.PhysicsConstants;
hbar = CONSTANTS.PlanckConstantReduced; % [J.s]
w0 = 2*pi*100; % Angular frequency unit [s^-1]
w0 = 2*pi*61.658214297935530; % Angular frequency unit [s^-1]
% Mass, length scale
Params.m = CONSTANTS.Dy164Mass;