Folder renaming, restructuring.

This commit is contained in:
Karthik 2025-01-22 16:10:46 +01:00
parent 1170f6a8a6
commit cdb25d5395
12 changed files with 3575 additions and 4 deletions

View File

@ -174,15 +174,15 @@ solver.Potential = pot.trap();
OptionsStruct = struct;
OptionsStruct.NumberOfAtoms = 4.0102e+07;
OptionsStruct.NumberOfAtoms = 4.148e+07;
OptionsStruct.DipolarPolarAngle = 0;
OptionsStruct.DipolarAzimuthAngle = 0;
OptionsStruct.ScatteringLength = 101.9903;
OptionsStruct.ScatteringLength = 101.35;
OptionsStruct.TrapFrequencies = [0, 0, 72.4];
OptionsStruct.TrapPotentialType = 'None';
OptionsStruct.NumberOfGridPoints = [128, 128];
OptionsStruct.NumberOfGridPoints = [256, 256];
OptionsStruct.Dimensions = [100, 100];
OptionsStruct.TimeStepSize = 500E-6; % in s
OptionsStruct.MinimumTimeStepSize = 1E-5; % in s
@ -192,7 +192,7 @@ OptionsStruct.ResidualTolerance = 1E-05;
OptionsStruct.NoiseScaleFactor = 0.05;
OptionsStruct.MaxIterations = 10;
OptionsStruct.VariationalWidth = 5;
OptionsStruct.VariationalWidth = 6;
OptionsStruct.WidthLowerBound = 1;
OptionsStruct.WidthUpperBound = 12;
OptionsStruct.WidthCutoff = 5e-3;

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@ -0,0 +1,364 @@
%% Across range of a_s, n
% load('.\Results\ExtractingKRoton_Result_Below1000.mat')
% load('.\Results\ExtractingKRoton_Result_Above1000.mat')
load('.\Results\ExtractingKRoton_Result_Above10000.mat')
PlanckConstantReduced = 6.62607015E-34/(2*pi);
AtomicMassUnit = 1.660539066E-27;
Dy164Mass = 163.929174751*AtomicMassUnit;
VacuumPermeability = 1.25663706212E-6;
BohrMagneton = 9.274009994E-24;
BohrRadius = 5.2917721067E-11;
DyMagneticMoment = 9.93*BohrMagneton;
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
% Create a tiled layout with tighter spacing
figure(17)
clf
set(gcf,'Position',[50 50 1800 500])
t = tiledlayout(1, 3, 'TileSpacing', 'compact', 'Padding', 'compact'); % 2x2 grid
% First subplot
nexttile; % Equivalent to subplot(2, 2, 1)
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
eps_dd_values = data_struct(idx).eps_dd_values;
plot(theta_values, eps_dd_values, '-o', 'LineWidth', 2.0, 'DisplayName', ['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$', 'fontsize', 16, 'interpreter', 'latex');
ylabel('$\epsilon_{dd}$', 'fontsize', 16, 'interpreter', 'latex');
grid on
legend('location', 'northeast', 'fontsize', 10, 'Interpreter', 'latex'); % Reduced font size
% Second subplot
nexttile; % Equivalent to subplot(2, 2, 2)
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
n_values = data_struct(idx).n_values;
plot(theta_values, n_values * 1E-15, '-o', 'LineWidth', 2.0, 'DisplayName', ['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$', 'fontsize', 16, 'interpreter', 'latex');
ylabel('$n (\times 10^{3} \mu m^{-2})$', 'fontsize', 16, 'interpreter', 'latex');
grid on
legend('location', 'northeast', 'fontsize', 10, 'Interpreter', 'latex'); % Reduced font size
% Third subplot
nexttile; % Equivalent to subplot(2, 2, 3)
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
k_roton_values = data_struct(idx).k_roton_values;
plot(theta_values, k_roton_values * 1E-6, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$k_{roton} (\mu m^{-1})$','fontsize',16,'interpreter','latex');
grid on
legend('location', 'northeast','fontsize', 10, 'Interpreter','latex')
% Adjust layout to minimize space
t.TileSpacing = 'compact'; % Minimize space between tiles
t.Padding = 'compact'; % Minimize padding around the layout
% Convert to units relevant to experiment
% Create a tiled layout with tighter spacing
figure(18)
clf
set(gcf,'Position',[50 50 1800 500])
t = tiledlayout(1, 3, 'TileSpacing', 'compact', 'Padding', 'compact'); % 2x2 grid
% First subplot
nexttile; % Equivalent to subplot(2, 2, 1)
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
eps_dd_values = data_struct(idx).eps_dd_values;
plot(theta_values, (1 ./ eps_dd_values) * (add / BohrRadius), '-o', 'LineWidth', 2.0, 'DisplayName', ['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$', 'fontsize', 16, 'interpreter', 'latex');
ylabel('$a_s (\times a_o)$', 'fontsize', 16, 'interpreter', 'latex');
grid on
legend('location', 'southeast', 'fontsize', 10, 'Interpreter', 'latex'); % Reduced font size
% Second subplot
nexttile; % Equivalent to subplot(2, 2, 2)
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
n_values = data_struct(idx).n_values;
Lx = 10e-6;
Ly = 10e-6;
AtomNumber = n_values .* Lx * Ly;
plot(theta_values, AtomNumber * 1e-5, '-o', 'LineWidth', 2.0, 'DisplayName', ['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$', 'fontsize', 16, 'interpreter', 'latex');
ylabel('Atom number in a trap of area 100 $\mu m^2 (\times 10^{5})$', 'fontsize', 16, 'interpreter', 'latex');
grid on
legend('location', 'northeast', 'fontsize', 10, 'Interpreter', 'latex'); % Reduced font size
% Third subplot
nexttile; % Equivalent to subplot(2, 2, 3)
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
lambda_roton_values = (2 * pi) ./ data_struct(idx).k_roton_values;
plot(theta_values, lambda_roton_values * 1E6, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$\lambda_{roton} (\mu m)$','fontsize',16,'interpreter','latex');
grid on
legend('location', 'northeast','fontsize', 10, 'Interpreter','latex')
% Adjust layout to minimize space
t.TileSpacing = 'compact'; % Minimize space between tiles
t.Padding = 'compact'; % Minimize padding around the layout
%% Fixed Density results
load('.\Results\ExtractingKRoton_Result_FixedDensity_phi0.mat')
PlanckConstantReduced = 6.62607015E-34/(2*pi);
AtomicMassUnit = 1.660539066E-27;
Dy164Mass = 163.929174751*AtomicMassUnit;
VacuumPermeability = 1.25663706212E-6;
BohrMagneton = 9.274009994E-24;
BohrRadius = 5.2917721067E-11;
DyMagneticMoment = 9.93*BohrMagneton;
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
% Create a tiled layout with tighter spacing
figure(19)
clf
set(gcf,'Position',[50 50 1200 500])
t = tiledlayout(1, 2, 'TileSpacing', 'compact', 'Padding', 'compact'); % 2x2 grid
% First subplot
nexttile;
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
eps_dd_values = data_struct(idx).eps_dd_values;
plot(theta_values, eps_dd_values, '-o', 'LineWidth', 2.0, 'DisplayName', ['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$', 'fontsize', 16, 'interpreter', 'latex');
ylabel('$\epsilon_{dd}$', 'fontsize', 16, 'interpreter', 'latex');
grid on
legend('location', 'northeast', 'fontsize', 10, 'Interpreter', 'latex'); % Reduced font size
% Second subplot
nexttile;
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
k_roton_values = data_struct(idx).k_roton_values;
plot(theta_values, k_roton_values * 1E-6, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$k_{roton} (\mu m^{-1})$','fontsize',16,'interpreter','latex');
grid on
legend('location', 'northeast','fontsize', 10, 'Interpreter','latex')
% Adjust layout to minimize space
t.TileSpacing = 'compact'; % Minimize space between tiles
t.Padding = 'compact'; % Minimize padding around the layout
% Create a tiled layout with tighter spacing
figure(20)
clf
set(gcf,'Position',[50 50 1200 500])
t = tiledlayout(1, 2, 'TileSpacing', 'compact', 'Padding', 'compact'); % 2x2 grid
% First subplot
nexttile;
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
eps_dd_values = data_struct(idx).eps_dd_values;
plot(theta_values, (1 ./ eps_dd_values) * (add / BohrRadius), '-o', 'LineWidth', 2.0, 'DisplayName', ['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$', 'fontsize', 16, 'interpreter', 'latex');
ylabel('$a_s (\times a_o)$', 'fontsize', 16, 'interpreter', 'latex');
grid on
legend('location', 'northwest', 'fontsize', 10, 'Interpreter', 'latex'); % Reduced font size
% Second subplot
nexttile;
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
lambda_roton_values = (2 * pi) ./ data_struct(idx).k_roton_values;
semilogy(theta_values, lambda_roton_values * 1E6, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
% ylim([0 2])
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$\lambda_{roton} (\mu m)$','fontsize',16,'interpreter','latex');
grid on
legend('location', 'southeast','fontsize', 10, 'Interpreter','latex')
% Adjust layout to minimize space
t.TileSpacing = 'compact'; % Minimize space between tiles
t.Padding = 'compact'; % Minimize padding around the layout
%% Fixed Density results - compare two orthogonal directions
data0 = load('.\Results\ExtractingKRoton_Result_FixedDensity_phi0.mat');
data90 = load('.\Results\ExtractingKRoton_Result_FixedDensity_phi90.mat');
PlanckConstantReduced = 6.62607015E-34/(2*pi);
AtomicMassUnit = 1.660539066E-27;
Dy164Mass = 163.929174751*AtomicMassUnit;
VacuumPermeability = 1.25663706212E-6;
BohrMagneton = 9.274009994E-24;
BohrRadius = 5.2917721067E-11;
DyMagneticMoment = 9.93*BohrMagneton;
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
% Create a tiled layout with tighter spacing
figure(21)
clf
set(gcf,'Position',[50 50 1200 500])
t = tiledlayout(1, 2, 'TileSpacing', 'compact', 'Padding', 'compact'); % 2x2 grid
idx = 4;
% First subplot
nexttile;
theta_values = data0.data_struct(idx).theta_values;
eps_dd_values = data0.data_struct(idx).eps_dd_values;
plot(theta_values, eps_dd_values, '-o', 'LineWidth', 2.0, 'DisplayName', ['$w_z = 2 \pi \times $', num2str(data0.data_struct(idx).wz_value), ' Hz; $\phi = 0^\circ$']);
hold on
theta_values = data90.data_struct(idx).theta_values;
eps_dd_values = data90.data_struct(idx).eps_dd_values;
plot(theta_values, eps_dd_values, '-o', 'LineWidth', 2.0, 'DisplayName', ['$w_z = 2 \pi \times $', num2str(data90.data_struct(idx).wz_value), ' Hz; $\phi = 90^\circ$']);
xlabel('$\theta$', 'fontsize', 16, 'interpreter', 'latex');
ylabel('$\epsilon_{dd}$', 'fontsize', 16, 'interpreter', 'latex');
grid on
legend('location', 'northeast', 'fontsize', 10, 'Interpreter', 'latex'); % Reduced font size
% Second subplot
nexttile;
theta_values = data0.data_struct(idx).theta_values;
k_roton_values = data0.data_struct(idx).k_roton_values;
plot(theta_values, k_roton_values * 1E-6, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data0.data_struct(idx).wz_value), ' Hz; $\phi = 0^\circ$']);
hold on
theta_values = data90.data_struct(idx).theta_values;
k_roton_values = data90.data_struct(idx).k_roton_values;
plot(theta_values, k_roton_values * 1E-6, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data90.data_struct(idx).wz_value), ' Hz; $\phi = 90^\circ$']);
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$k_{roton} (\mu m^{-1})$','fontsize',16,'interpreter','latex');
grid on
legend('location', 'northeast','fontsize', 10, 'Interpreter','latex')
% Adjust layout to minimize space
t.TileSpacing = 'compact'; % Minimize space between tiles
t.Padding = 'compact'; % Minimize padding around the layout
% Create a tiled layout with tighter spacing
figure(22)
clf
set(gcf,'Position',[50 50 1200 500])
t = tiledlayout(1, 2, 'TileSpacing', 'compact', 'Padding', 'compact'); % 2x2 grid
% First subplot
nexttile;
theta_values = data0.data_struct(idx).theta_values;
eps_dd_values = data0.data_struct(idx).eps_dd_values;
plot(theta_values, (1 ./ eps_dd_values) * (add / BohrRadius), '-o', 'LineWidth', 2.0, 'DisplayName', ['$w_z = 2 \pi \times $', num2str(data0.data_struct(idx).wz_value), ' Hz; $\phi = 0^\circ$']);
hold on
theta_values = data90.data_struct(idx).theta_values;
eps_dd_values = data90.data_struct(idx).eps_dd_values;
plot(theta_values, (1 ./ eps_dd_values) * (add / BohrRadius), '-o', 'LineWidth', 2.0, 'DisplayName', ['$w_z = 2 \pi \times $', num2str(data90.data_struct(idx).wz_value), ' Hz; $\phi = 90^\circ$']);
xlabel('$\theta$', 'fontsize', 16, 'interpreter', 'latex');
ylabel('$a_s (\times a_o)$', 'fontsize', 16, 'interpreter', 'latex');
grid on
legend('location', 'northwest', 'fontsize', 10, 'Interpreter', 'latex'); % Reduced font size
% Second subplot
nexttile;
theta_values = data0.data_struct(idx).theta_values;
k_roton_values = data0.data_struct(idx).k_roton_values;
lambda_roton_values = (2 * pi) ./ k_roton_values;
semilogy(theta_values, lambda_roton_values * 1E6, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data0.data_struct(idx).wz_value), ' Hz; $\phi = 0^\circ$']);
hold on
theta_values = data90.data_struct(idx).theta_values;
k_roton_values = data90.data_struct(idx).k_roton_values;
lambda_roton_values = (2 * pi) ./ k_roton_values;
semilogy(theta_values, lambda_roton_values * 1E6, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data90.data_struct(idx).wz_value), ' Hz; $\phi = 90^\circ$']);
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$\lambda_{roton} (\mu m)$','fontsize',16,'interpreter','latex');
grid on
legend('location', 'northwest','fontsize', 10, 'Interpreter','latex')
% Adjust layout to minimize space
t.TileSpacing = 'compact'; % Minimize space between tiles
t.Padding = 'compact'; % Minimize padding around the layout
%%
%{
figure(13)
clf
set(gcf,'Position',[50 50 950 750])
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
eps_dd_values = data_struct(idx).eps_dd_values;
plot(theta_values, eps_dd_values, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$\epsilon_{dd}$','fontsize',16,'interpreter','latex');
% title([''],'fontsize',16,'interpreter','latex')
grid on
legend('location', 'northeast','fontsize', 16, 'Interpreter','latex')
figure(14)
clf
set(gcf,'Position',[50 50 950 750])
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
eps_dd_values = data_struct(idx).eps_dd_values;
plot(theta_values, (1./eps_dd_values) * (add/BohrRadius), '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$a_s (\times a_o)$','fontsize',16,'interpreter','latex');
% title([''],'fontsize',16,'interpreter','latex')
grid on
legend('location', 'southeast','fontsize', 16, 'Interpreter','latex')
figure(15)
clf
set(gcf,'Position',[50 50 950 750])
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
n_values = data_struct(idx).n_values;
plot(theta_values, n_values * 1E-15, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$n (\times 10^{3} \mu m^{-2})$','fontsize',16,'interpreter','latex');
% title([''],'fontsize',16,'interpreter','latex')
grid on
legend('location', 'northeast','fontsize', 16, 'Interpreter','latex')
figure(16)
clf
set(gcf,'Position',[50 50 950 750])
for idx = 1:length(data_struct)
theta_values = data_struct(idx).theta_values;
k_roton_values = data_struct(idx).k_roton_values;
plot(theta_values, k_roton_values * 1E-6, '-o', LineWidth=2.0, DisplayName=['$w_z = 2 \pi \times $', num2str(data_struct(idx).wz_value), ' Hz']);
hold on
end
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$k_{roton} (\mu m^{-1})$','fontsize',16,'interpreter','latex');
% title([''],'fontsize',16,'interpreter','latex')
grid on
legend('location', 'northeast','fontsize', 16, 'Interpreter','latex')
%}

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@ -0,0 +1,251 @@
%% Physical constants
PlanckConstant = 6.62607015E-34;
PlanckConstantReduced = 6.62607015E-34/(2*pi);
FineStructureConstant = 7.2973525698E-3;
ElectronMass = 9.10938291E-31;
GravitationalConstant = 6.67384E-11;
ProtonMass = 1.672621777E-27;
AtomicMassUnit = 1.660539066E-27;
BohrRadius = 5.2917721067E-11;
BohrMagneton = 9.274009994E-24;
BoltzmannConstant = 1.38064852E-23;
StandardGravityAcceleration = 9.80665;
SpeedOfLight = 299792458;
StefanBoltzmannConstant = 5.670373E-8;
ElectronCharge = 1.602176634E-19;
VacuumPermeability = 1.25663706212E-6;
DielectricConstant = 8.8541878128E-12;
ElectronGyromagneticFactor = -2.00231930436153;
AvogadroConstant = 6.02214076E23;
ZeroKelvin = 273.15;
GravitationalAcceleration = 9.80553;
VacuumPermittivity = 1 / (SpeedOfLight^2 * VacuumPermeability);
HartreeEnergy = ElectronCharge^2 / (4 * pi * VacuumPermittivity * BohrRadius);
AtomicUnitOfPolarizability = (ElectronCharge^2 * BohrRadius^2) / HartreeEnergy; % Or simply 4*pi*VacuumPermittivity*BohrRadius^3
% Dy specific constants
Dy164Mass = 163.929174751*AtomicMassUnit;
Dy164IsotopicAbundance = 0.2826;
DyMagneticMoment = 9.93*BohrMagneton;
%% 2-D DDI Potential in k-space, with Gaussian ansatz width determined by constrained minimization
% With user-defined values of interaction, density and tilt
% w0 = 2*pi*61.6316; % Angular frequency unit [s^-1]
% l0 = sqrt(PlanckConstantReduced/(Dy164Mass*w0));
% % Defining a harmonic oscillator length - heredue to the choice of w0, l0
% is 1 micrometer
wz = 2 * pi * 300; % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
% Number of grid points in each direction
Params.Nx = 128;
Params.Ny = 128;
Params.Lx = 150*1e-6;
Params.Ly = 150*1e-6;
[Transf] = setupSpace(Params);
nadd2s = 0.110; % Number density * add^2
as_to_add = 0.782; % 1/edd
Params.theta = 57; % Polar angle of dipole moment
Params.eta = 0; % Azimuthal angle of dipole moment
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
gdd = VacuumPermeability*DyMagneticMoment^2/3;
x0 = 5;
Aineq = [];
Bineq = [];
Aeq = [];
Beq = [];
lb = [1];
ub = [10];
nonlcon = [];
fminconopts = optimoptions(@fmincon,'Display','off', 'StepTolerance', 1.0000e-11, 'MaxIterations',1500);
AtomNumberDensity = nadd2s / add^2; % Number density of atoms
as = as_to_add * add; % Scattering length
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
TotalEnergyPerParticle = @(x) computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced);
sigma = fmincon(TotalEnergyPerParticle, x0, Aineq, Bineq, Aeq, Beq, lb, ub, nonlcon, fminconopts);
MeanWidth = sigma * lz;
% == 2-D DDI Potential in k-space == %
VDk = compute2DPotentialInMomentumSpace(Transf, Params, MeanWidth);
VDk_fftshifted = fftshift(VDk);
figure(8)
clf
set(gcf,'Position',[50 50 950 750])
imagesc(fftshift(Transf.kx)*1e-6, fftshift(Transf.ky)*1e-6, VDk_fftshifted); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
cbar1 = colorbar;
cbar1.Label.Interpreter = 'latex';
xlabel('$k_x l_o$','fontsize',16,'interpreter','latex');
ylabel('$k_y l_o$','fontsize',16,'interpreter','latex');
title(['2-D DDI Potential: $\theta = ',num2str(Params.theta), '; \eta = ', num2str(Params.eta),'$'],'fontsize',16,'interpreter','latex')
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
EpsilonK = zeros(length(Transf.ky), length(Transf.kx));
gs_tilde = gs / (sqrt(2*pi) * MeanWidth);
% == Dispersion relation == %
for idx = 1:length(Transf.kx)
for jdx = 1:length(Transf.ky)
DeltaK = ((PlanckConstantReduced^2 .* (Transf.kx(idx).^2 + Transf.ky(jdx).^2)) ./ (2 * Dy164Mass)) + (2 * AtomNumberDensity * gs_tilde) + ((2 * AtomNumberDensity) .* VDk_fftshifted(jdx, idx)) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK(jdx, idx) = sqrt(((PlanckConstantReduced^2 .* (Transf.kx(idx).^2 + Transf.ky(jdx).^2)) ./ (2 * Dy164Mass)) .* DeltaK);
end
end
EpsilonK = double(imag(EpsilonK) ~= 0); % 'isreal' returns 0 for complex numbers and 1 for real numbers, so we negate it
figure(9)
clf
set(gcf,'Position',[50 50 950 750])
imagesc(fftshift(Transf.kx)*1e-6, fftshift(Transf.ky)*1e-6, EpsilonK); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
cbar1 = colorbar;
cbar1.Label.Interpreter = 'latex';
xlabel('$k_x l_o$','fontsize',16,'interpreter','latex');
ylabel('$k_y l_o$','fontsize',16,'interpreter','latex');
title(['2-D Dispersion: $\theta = ',num2str(Params.theta), '; \eta = ', num2str(Params.eta),'$'],'fontsize',16,'interpreter','latex')
%% Cycle through angles
% Define values for theta and eta
theta_values = 0:10:90; % Range of theta values (you can modify this)
eta_values = 0:10:90; % Range of eta values (you can modify this)
% Set up VideoWriter object to produce a movie
% v = VideoWriter('potential_movie', 'MPEG-4'); % Create a video object
% v.FrameRate = 5; % Frame rate of the video
% open(v); % Open the video file
% Loop over theta and eta values
for theta = theta_values
for eta = eta_values
% Update Params with current theta and eta
Params.theta = theta;
Params.eta = eta;
% Compute the potential for the current theta and eta
% == 2-D DDI Potential in k-space == %
VDk = compute2DPotentialInMomentumSpace(Transf, Params, MeanWidth);
VDk_fftshifted = fftshift(VDk);
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
EpsilonK = zeros(length(Transf.ky), length(Transf.kx));
gs_tilde = gs / (sqrt(2*pi) * MeanWidth);
% == Dispersion relation == %
for idx = 1:length(Transf.kx)
for jdx = 1:length(Transf.ky)
DeltaK = ((PlanckConstantReduced^2 .* (Transf.kx(idx).^2 + Transf.ky(jdx).^2)) ./ (2 * Dy164Mass)) + (2 * AtomNumberDensity * gs_tilde) + ((2 * AtomNumberDensity) .* VDk_fftshifted(jdx, idx)) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK(jdx, idx) = sqrt(((PlanckConstantReduced^2 .* (Transf.kx(idx).^2 + Transf.ky(jdx).^2)) ./ (2 * Dy164Mass)) .* DeltaK);
end
end
EpsilonK = double(imag(EpsilonK) ~= 0); % 'isreal' returns 0 for complex numbers and 1 for real numbers, so we negate it
% Plot the result
figure(10)
clf
set(gcf,'Position',[50 50 950 750])
imagesc(fftshift(Transf.kx)*1e-6, fftshift(Transf.ky)*1e-6, EpsilonK); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
cbar1 = colorbar;
cbar1.Label.Interpreter = 'latex';
xlabel('$k_x l_o$','fontsize',16,'interpreter','latex');
ylabel('$k_y l_o$','fontsize',16,'interpreter','latex');
title(['2-D Dispersion: $\theta = ',num2str(Params.theta), '; \eta = ', num2str(Params.eta),'$'],'fontsize',16,'interpreter','latex')
% Capture the frame and write to video
% frame = getframe(gcf); % Capture the current figure
% writeVideo(v, frame); % Write the frame to the video
end
end
% Close the video file
% close(v);
%%
function [Transf] = setupSpace(Params)
Transf.Xmax = 0.5*Params.Lx;
Transf.Ymax = 0.5*Params.Ly;
Nx = Params.Nx;
Ny = Params.Ny;
% Fourier grids
x = linspace(-0.5*Params.Lx,0.5*Params.Lx-Params.Lx/Params.Nx,Params.Nx);
Kmax = pi*Params.Nx/Params.Lx;
kx = linspace(-Kmax,Kmax,Nx+1);
kx = kx(1:end-1);
dkx = kx(2)-kx(1);
kx = fftshift(kx);
y = linspace(-0.5*Params.Ly,0.5*Params.Ly-Params.Ly/Params.Ny,Params.Ny);
Kmax = pi*Params.Ny/Params.Ly;
ky = linspace(-Kmax,Kmax,Ny+1);
ky = ky(1:end-1);
dky = ky(2)-ky(1);
ky = fftshift(ky);
[Transf.X,Transf.Y] = ndgrid(x,y);
[Transf.KX,Transf.KY] = ndgrid(kx,ky);
Transf.x = x;
Transf.y = y;
Transf.kx = kx;
Transf.ky = ky;
Transf.dx = x(2)-x(1);
Transf.dy = y(2)-y(1);
Transf.dkx = dkx;
Transf.dky = dky;
end
function VDk = compute2DPotentialInMomentumSpace(Transf, Params, MeanWidth)
% == Calculating the DDI potential in Fourier space with appropriate cutoff == %
% Angles of the dipole moment are defined in and away from the X-Z plane
% Interaction in K space
QX = Transf.KX*MeanWidth/sqrt(2);
QY = Transf.KY*MeanWidth/sqrt(2);
Qsq = QX.^2 + QY.^2;
absQ = sqrt(Qsq);
QDsq = QX.^2*cos(Params.eta)^2 + QY.^2*sin(Params.eta)^2; % eta here is the azimuthal angle of the dipole moment (angle from the x-axis)
% Bare interaction
Fpar = -1 + 3*sqrt(pi)*QDsq.*erfcx(absQ)./absQ; % Scaled complementary error function erfcx(x) = e^(x^2) * erfc(x)
Fperp = 2 - 3*sqrt(pi).*absQ.*erfcx(absQ);
Fpar(absQ == 0) = -1;
% Full DDI
VDk = (Fpar*sin(Params.theta)^2 + Fperp*cos(Params.theta)^2); % theta here is the polar angle of the dipole moment (angle from the z-axis)
end
function ret = computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced)
eps_dd = add/as; % Relative interaction strength
MeanWidth = x * lz;
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2)); % Quantum Fluctuations term
gamma4 = 1/(sqrt(2*pi) * MeanWidth);
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
Energy_AxialComponent = (PlanckConstantReduced * wz) * ((lz^2/(4 * MeanWidth^2)) + (MeanWidth^2/(4 * lz^2)));
Energy_TransverseComponent = (0.5 * (gs + (2*gdd)) * gamma4 * AtomNumberDensity) + ((2/5) * gQF * AtomNumberDensity^(3/2));
ret = (Energy_AxialComponent + Energy_TransverseComponent) / (PlanckConstantReduced * wz);
end

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@ -0,0 +1,503 @@
%% Physical constants
PlanckConstant = 6.62607015E-34;
PlanckConstantReduced = 6.62607015E-34/(2*pi);
FineStructureConstant = 7.2973525698E-3;
ElectronMass = 9.10938291E-31;
GravitationalConstant = 6.67384E-11;
ProtonMass = 1.672621777E-27;
AtomicMassUnit = 1.660539066E-27;
BohrRadius = 5.2917721067E-11;
BohrMagneton = 9.274009994E-24;
BoltzmannConstant = 1.38064852E-23;
StandardGravityAcceleration = 9.80665;
SpeedOfLight = 299792458;
StefanBoltzmannConstant = 5.670373E-8;
ElectronCharge = 1.602176634E-19;
VacuumPermeability = 1.25663706212E-6;
DielectricConstant = 8.8541878128E-12;
ElectronGyromagneticFactor = -2.00231930436153;
AvogadroConstant = 6.02214076E23;
ZeroKelvin = 273.15;
GravitationalAcceleration = 9.80553;
VacuumPermittivity = 1 / (SpeedOfLight^2 * VacuumPermeability);
HartreeEnergy = ElectronCharge^2 / (4 * pi * VacuumPermittivity * BohrRadius);
AtomicUnitOfPolarizability = (ElectronCharge^2 * BohrRadius^2) / HartreeEnergy; % Or simply 4*pi*VacuumPermittivity*BohrRadius^3
% Dy specific constants
Dy164Mass = 163.929174751*AtomicMassUnit;
Dy164IsotopicAbundance = 0.2826;
DyMagneticMoment = 9.93*BohrMagneton;
%% Extracting values from the roton instability boundary for tilted dipoles
%-------TEST-------%
% nadd2s = 0.05:0.005:0.25;
% as_to_add = 0.76:0.001:0.81;
%-------DEPLOY-------%
nadd2s = 0.005:0.005:0.5;
as_to_add = 0.250:0.001:1.15;
data_struct = struct;
% wz_values = [150, 300, 500, 750];
% kvec = linspace(0, 5e6, 1000); % Vector of magnitudes of k vector
wz_values = [1000, 3000, 5000, 7000];
kvec = linspace(0, 15e6, 1000); % Vector of magnitudes of k vector
% wz_values = [10000, 13000, 15000];
% kvec = linspace(0, 25e6, 1000); % Vector of magnitudes of k vector
theta_values = 0:5:45; % Range of theta values
phi = 0; % Azimuthal angle of momentum vector
for mainloop_idx = 1:length(wz_values)
format long
PlanckConstantReduced = 6.62607015E-34/(2*pi);
AtomicMassUnit = 1.660539066E-27;
Dy164Mass = 163.929174751*AtomicMassUnit;
VacuumPermeability = 1.25663706212E-6;
BohrMagneton = 9.274009994E-24;
DyMagneticMoment = 9.93*BohrMagneton;
wz = 2 * pi * wz_values(mainloop_idx); % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
gdd = VacuumPermeability*DyMagneticMoment^2/3;
var_widths = zeros(length(as_to_add), length(nadd2s));
x0 = 5;
Aineq = [];
Bineq = [];
Aeq = [];
Beq = [];
lb = [1];
ub = [10];
nonlcon = [];
fminconopts = optimoptions(@fmincon,'Display','off', 'StepTolerance', 1.0000e-11, 'MaxIterations',1500);
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
as = (as_to_add(jdx) * add); % Scattering length
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
TotalEnergyPerParticle = @(x) computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced);
sigma = fmincon(TotalEnergyPerParticle, x0, Aineq, Bineq, Aeq, Beq, lb, ub, nonlcon, fminconopts);
var_widths(jdx, idx) = sigma;
end
end
eps_dd_values = zeros(length(theta_values), 1);
n_values = zeros(length(theta_values), 1);
k_roton_values = zeros(length(theta_values), 1);
for idx = 1:length(theta_values)
theta = theta_values(idx);
[eps_dd_values(idx), n_values(idx), k_roton_values(idx)] = extractFromBoundaryCurve(theta, phi, nadd2s, as_to_add, var_widths, wz, lz, kvec);
end
data_struct(mainloop_idx).wz_value = wz / (2 * pi);
data_struct(mainloop_idx).theta_values = theta_values;
data_struct(mainloop_idx).eps_dd_values = eps_dd_values;
data_struct(mainloop_idx).n_values = n_values;
data_struct(mainloop_idx).k_roton_values = k_roton_values;
%{
figure(13)
clf
set(gcf,'Position',[50 50 950 750])
plot(theta_values, eps_dd_values, '-o', LineWidth=2.0)
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$\epsilon_{dd}$','fontsize',16,'interpreter','latex');
% title([''],'fontsize',16,'interpreter','latex')
grid on
figure(14)
clf
set(gcf,'Position',[50 50 950 750])
plot(theta_values, (1./eps_dd_values) * (add/BohrRadius), '-o', LineWidth=2.0)
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$a_s (\times a_o)$','fontsize',16,'interpreter','latex');
% title([''],'fontsize',16,'interpreter','latex')
grid on
figure(15)
clf
set(gcf,'Position',[50 50 950 750])
plot(theta_values, n_values * 1E-15, '-o', LineWidth=2.0)
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$n (\times 10^{3} \mu m^{-2})$','fontsize',16,'interpreter','latex');
% title([''],'fontsize',16,'interpreter','latex')
grid on
figure(16)
clf
set(gcf,'Position',[50 50 950 750])
plot(theta_values, k_roton_values * 1E-6, '-o', LineWidth=2.0)
xlabel('$\theta$','fontsize',16,'interpreter','latex');
ylabel('$k_{roton} (\mu m^{-1})$','fontsize',16,'interpreter','latex');
% title([''],'fontsize',16,'interpreter','latex')
grid on
%}
end
save('.\Results\ExtractingKRoton_Result.mat', 'data_struct');
%% Extracting values from the roton instability boundary for tilted dipoles - fixed atom number, trap frequency
%-------DEPLOY-------%
N = 1E5;
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
area = 100; % in square micrometers
ppmum = N / area;
nadd2s = ppmum*1E12*add^2;
as_to_add = 0.150:0.001:1.15;
data_struct = struct;
wz_values = [500, 750, 1000, 2000];
kvec = linspace(0, 15e6, 1000); % Vector of magnitudes of k vector
theta_values = 0:5:90; % Range of theta values
phi = 90; % Azimuthal angle of momentum vector
for mainloop_idx = 1:length(wz_values)
format long
PlanckConstantReduced = 6.62607015E-34/(2*pi);
AtomicMassUnit = 1.660539066E-27;
Dy164Mass = 163.929174751*AtomicMassUnit;
VacuumPermeability = 1.25663706212E-6;
BohrMagneton = 9.274009994E-24;
DyMagneticMoment = 9.93*BohrMagneton;
wz = 2 * pi * wz_values(mainloop_idx); % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
gdd = VacuumPermeability*DyMagneticMoment^2/3;
var_widths = zeros(length(as_to_add), length(nadd2s));
x0 = 5;
Aineq = [];
Bineq = [];
Aeq = [];
Beq = [];
lb = [1];
ub = [10];
nonlcon = [];
fminconopts = optimoptions(@fmincon,'Display','off', 'StepTolerance', 1.0000e-11, 'MaxIterations',1500);
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
as = (as_to_add(jdx) * add); % Scattering length
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
TotalEnergyPerParticle = @(x) computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced);
sigma = fmincon(TotalEnergyPerParticle, x0, Aineq, Bineq, Aeq, Beq, lb, ub, nonlcon, fminconopts);
var_widths(jdx, idx) = sigma;
end
end
eps_dd_values = zeros(length(theta_values), 1);
k_roton_values = zeros(length(theta_values), 1);
for idx = 1:length(theta_values)
theta = theta_values(idx);
[eps_dd_values(idx), k_roton_values(idx)] = extractFromBoundaryPoint(theta, phi, nadd2s, as_to_add, var_widths, wz, lz, kvec);
end
data_struct(mainloop_idx).wz_value = wz / (2 * pi);
data_struct(mainloop_idx).theta_values = theta_values;
data_struct(mainloop_idx).eps_dd_values = eps_dd_values;
data_struct(mainloop_idx).k_roton_values = k_roton_values;
end
save('.\Results\ExtractingKRoton_Result_FixedDensity_phi90.mat', 'data_struct');
%%
function [Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi)
Go = sqrt(pi) * (k * MeanWidth/sqrt(2)) .* exp((k * MeanWidth/sqrt(2)).^2) .* erfc((k * MeanWidth/sqrt(2)));
gamma4 = 1/(sqrt(2*pi) * MeanWidth);
Fka = (3 * cos(deg2rad(theta))^2 - 1) + ((3 * Go) .* ((sin(deg2rad(theta))^2 .* sin(deg2rad(phi))^2) - cos(deg2rad(theta))^2));
Ukk = (gs + (gdd * Fka)) * gamma4;
end
function ret = computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced)
eps_dd = add/as; % Relative interaction strength
MeanWidth = x * lz;
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2)); % Quantum Fluctuations term
gamma4 = 1/(sqrt(2*pi) * MeanWidth);
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
Energy_AxialComponent = (PlanckConstantReduced * wz) * ((lz^2/(4 * MeanWidth^2)) + (MeanWidth^2/(4 * lz^2)));
Energy_TransverseComponent = (0.5 * (gs + (2*gdd)) * gamma4 * AtomNumberDensity) + ((2/5) * gQF * AtomNumberDensity^(3/2));
ret = (Energy_AxialComponent + Energy_TransverseComponent) / (PlanckConstantReduced * wz);
end
function [eps_dd, AtomNumberDensity, k_roton] = extractFromBoundaryCurve(theta, phi, nadd2s, as_to_add, var_widths, wz, lz, kvec)
format long
PlanckConstantReduced = 6.62607015E-34/(2*pi);
AtomicMassUnit = 1.660539066E-27;
Dy164Mass = 163.929174751*AtomicMassUnit;
VacuumPermeability = 1.25663706212E-6;
BohrMagneton = 9.274009994E-24;
DyMagneticMoment = 9.93*BohrMagneton;
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
gdd = VacuumPermeability*DyMagneticMoment^2/3;
phase_diagram = zeros(length(as_to_add), length(nadd2s));
w0 = 2 * pi * 61.6316; % Trap frequency in the tight confinement direction
l0 = sqrt(PlanckConstantReduced/(Dy164Mass * w0)); % Defining a harmonic oscillator length
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
as = (as_to_add(jdx) * add); % Scattering length
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
MeanWidth = var_widths(jdx, idx) * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(kvec, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* kvec.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* kvec.^2) ./ (2 * Dy164Mass)) .* DeltaK);
phase_diagram(jdx, idx) = ~isreal(EpsilonK);
end
end
%{
figure(11)
clf
set(gcf,'Position',[50 50 950 750])
imagesc(nadd2s, as_to_add, phase_diagram); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
colorbar; % Add a colorbar
xlabel('$na_{dd}^2$','fontsize',16,'interpreter','latex');
ylabel('$a_s/a_{dd}$','fontsize',16,'interpreter','latex');
title(['$\theta = ',num2str(theta), '; \phi = 0','$', '(Along Y)'],'fontsize',16,'interpreter','latex')
%}
%-------------%
matrix = phase_diagram;
% Initialize arrays to store row and column indices of transitions
row_indices = [];
col_indices = [];
% Loop through the matrix to find transitions from 0 to 1
[rows, cols] = size(matrix);
for j = 1:cols
for i = 2:rows
if matrix(i-1, j) == 1 && matrix(i, j) == 0
row_indices = [row_indices; i-1];
col_indices = [col_indices; j];
break; % Stop after the first transition in the column
end
end
end
% Now extract the values from the corresponding vectors
xvals = zeros(length(col_indices), 1);
yvals = zeros(length(row_indices), 1);
for k = 1:length(row_indices)
row = row_indices(k);
col = col_indices(k);
xvals(k) = nadd2s(col);
yvals(k) = as_to_add(row);
end
instability_boundary = [xvals, yvals];
%-------------%
% Degree of the polynomial to fit
n = 5; % For a quadratic fit
% Fit the polynomial
p = polyfit(xvals, yvals, n);
% Display the polynomial coefficients
% disp('Polynomial coefficients:');
% disp(p);
% Evaluate the polynomial at points in x
y_fit = polyval(p, xvals);
%{
% Plot the original data and the fitted polynomial curve
figure(12);
clf
set(gcf,'Position',[50 50 950 750])
plot(xvals, yvals, 'o', 'LineWidth', 2.0, 'DisplayName', 'Extracted boundary points'); % Original data
hold on;
plot(xvals, y_fit, '-r','LineWidth', 2.0, 'DisplayName', ['Polynomial Fit (degree ' num2str(n) ')']); % Fitted curve
ylim([min(as_to_add) max(as_to_add)])
xlabel('$na_{dd}^2$','fontsize',16,'interpreter','latex');
ylabel('$a_s/a_{dd}$','fontsize',16,'interpreter','latex')
title(['$\theta = ',num2str(theta), '; \phi = 0','$', '(Along Y)'],'fontsize',16,'interpreter','latex')
legend('show');
grid on;
%}
[val, idx] = max(y_fit);
% Round down to 4 decimal places
rounded_val = floor(val * 10^4) / 10^4;
% Find nearest from original vector of boundary points
[~, nearest_idx] = min(abs(instability_boundary(:, 2) - rounded_val));
nearest_val = instability_boundary(nearest_idx, 2);
% Choose the scalar value between the two
if ~isscalar(nearest_val)
val = rounded_val;
else
val = nearest_val;
idx = nearest_idx;
end
AtomNumberDensity = xvals(idx) / add^2; % Areal density of atoms
as = val * add; % Scattering length
eps_dd = 1/val; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
x0 = 5;
Aineq = [];
Bineq = [];
Aeq = [];
Beq = [];
lb = [1];
ub = [10];
nonlcon = [];
fminconopts = optimoptions(@fmincon,'Display','off', 'StepTolerance', 1.0000e-11, 'MaxIterations',1500);
TotalEnergyPerParticle = @(x) computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced);
sigma = fmincon(TotalEnergyPerParticle, x0, Aineq, Bineq, Aeq, Beq, lb, ub, nonlcon, fminconopts);
MeanWidth = sigma * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(kvec, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
DeltaK = ((PlanckConstantReduced^2 .* kvec.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* kvec.^2) ./ (2 * Dy164Mass)) .* DeltaK);
k_roton_indices = find(imag(EpsilonK) ~= 0);
if ~isempty(k_roton_indices)
k_roton = median(kvec(k_roton_indices));
else
k_roton = NaN;
end
end
function [eps_dd, k_roton] = extractFromBoundaryPoint(theta, phi, nadd2s, as_to_add, var_widths, wz, lz, kvec)
format long
PlanckConstantReduced = 6.62607015E-34/(2*pi);
AtomicMassUnit = 1.660539066E-27;
Dy164Mass = 163.929174751*AtomicMassUnit;
VacuumPermeability = 1.25663706212E-6;
BohrMagneton = 9.274009994E-24;
DyMagneticMoment = 9.93*BohrMagneton;
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
gdd = VacuumPermeability*DyMagneticMoment^2/3;
phase_diagram = zeros(length(as_to_add), length(nadd2s));
w0 = 2 * pi * 61.6316; % Trap frequency in the tight confinement direction
l0 = sqrt(PlanckConstantReduced/(Dy164Mass * w0)); % Defining a harmonic oscillator length
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
as = (as_to_add(jdx) * add); % Scattering length
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
MeanWidth = var_widths(jdx, idx) * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(kvec, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* kvec.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* kvec.^2) ./ (2 * Dy164Mass)) .* DeltaK);
phase_diagram(jdx, idx) = ~isreal(EpsilonK);
end
end
matrix = phase_diagram;
% Initialize arrays to store row and column indices of transitions
row_indices = [];
col_indices = [];
% Loop through the matrix to find transitions from 0 to 1
[rows, cols] = size(matrix);
for j = 1:cols
for i = 2:rows
if matrix(i-1, j) == 1 && matrix(i, j) == 0
row_indices = [row_indices; i-1];
col_indices = [col_indices; j];
break; % Stop after the first transition in the column
end
end
end
% Now extract the values from the corresponding vectors
xvals = zeros(length(col_indices), 1);
yvals = zeros(length(row_indices), 1);
for k = 1:length(row_indices)
row = row_indices(k);
col = col_indices(k);
xvals(k) = nadd2s(col);
yvals(k) = as_to_add(row);
end
instability_boundary = [xvals, yvals];
if ~isempty(instability_boundary)
val = instability_boundary(2);
AtomNumberDensity = instability_boundary(1) / add^2; % Areal density of atoms
as = val * add; % Scattering length
eps_dd = 1/val; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
x0 = 5;
Aineq = [];
Bineq = [];
Aeq = [];
Beq = [];
lb = [1];
ub = [10];
nonlcon = [];
fminconopts = optimoptions(@fmincon,'Display','off', 'StepTolerance', 1.0000e-11, 'MaxIterations',1500);
TotalEnergyPerParticle = @(x) computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced);
sigma = fmincon(TotalEnergyPerParticle, x0, Aineq, Bineq, Aeq, Beq, lb, ub, nonlcon, fminconopts);
MeanWidth = sigma * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(kvec, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
DeltaK = ((PlanckConstantReduced^2 .* kvec.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* kvec.^2) ./ (2 * Dy164Mass)) .* DeltaK);
k_roton_indices = find(imag(EpsilonK) ~= 0);
if ~isempty(k_roton_indices)
k_roton = median(kvec(k_roton_indices));
else
k_roton = NaN;
end
else
eps_dd = NaN;
k_roton = NaN;
end
end

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%% Physical constants
PlanckConstant = 6.62607015E-34;
PlanckConstantReduced = 6.62607015E-34/(2*pi);
FineStructureConstant = 7.2973525698E-3;
ElectronMass = 9.10938291E-31;
GravitationalConstant = 6.67384E-11;
ProtonMass = 1.672621777E-27;
AtomicMassUnit = 1.660539066E-27;
BohrRadius = 5.2917721067E-11;
BohrMagneton = 9.274009994E-24;
BoltzmannConstant = 1.38064852E-23;
StandardGravityAcceleration = 9.80665;
SpeedOfLight = 299792458;
StefanBoltzmannConstant = 5.670373E-8;
ElectronCharge = 1.602176634E-19;
VacuumPermeability = 1.25663706212E-6;
DielectricConstant = 8.8541878128E-12;
ElectronGyromagneticFactor = -2.00231930436153;
AvogadroConstant = 6.02214076E23;
ZeroKelvin = 273.15;
GravitationalAcceleration = 9.80553;
VacuumPermittivity = 1 / (SpeedOfLight^2 * VacuumPermeability);
HartreeEnergy = ElectronCharge^2 / (4 * pi * VacuumPermittivity * BohrRadius);
AtomicUnitOfPolarizability = (ElectronCharge^2 * BohrRadius^2) / HartreeEnergy; % Or simply 4*pi*VacuumPermittivity*BohrRadius^3
% Dy specific constants
Dy164Mass = 163.929174751*AtomicMassUnit;
Dy164IsotopicAbundance = 0.2826;
DyMagneticMoment = 9.93*BohrMagneton;
%% Roton instability boundary for tilted dipoles
wz = 2 * pi * 72.4; % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
gdd = VacuumPermeability*DyMagneticMoment^2/3;
nadd2s = 0.05:0.001:0.25;
as_to_add = 0.76:0.001:0.81;
var_widths = zeros(length(as_to_add), length(nadd2s));
x0 = 5;
Aineq = [];
Bineq = [];
Aeq = [];
Beq = [];
lb = [1];
ub = [10];
nonlcon = [];
fminconopts = optimoptions(@fmincon,'Display','off', 'StepTolerance', 1.0000e-11, 'MaxIterations',1500);
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
as = (as_to_add(jdx) * add); % Scattering length
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
TotalEnergyPerParticle = @(x) computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced);
sigma = fmincon(TotalEnergyPerParticle, x0, Aineq, Bineq, Aeq, Beq, lb, ub, nonlcon, fminconopts);
var_widths(jdx, idx) = sigma;
end
end
% ====================================================================================================================================================== %
theta = 0; % Polar angle of dipole moment
phi = 0; % Azimuthal angle of momentum vector
k = linspace(0, 2.25e6, 1000); % Vector of magnitudes of k vector
instability_boundary = zeros(length(as_to_add), length(nadd2s));
ScatteringLengths = zeros(length(as_to_add), 1);
AtomNumber = zeros(length(nadd2s), 1);
w0 = 2 * pi * 61.6316; % Trap frequency in the tight confinement direction
l0 = sqrt(PlanckConstantReduced/(Dy164Mass * w0)); % Defining a harmonic oscillator length
tsize = 10 * l0;
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
AtomNumber(idx) = AtomNumberDensity*tsize^2;
as = (as_to_add(jdx) * add); % Scattering length
ScatteringLengths(jdx) = as/BohrRadius;
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
MeanWidth = var_widths(jdx, idx) * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) .* DeltaK);
instability_boundary(jdx, idx) = ~isreal(EpsilonK);
end
end
nadd2s_from_figure = [0.04974, 0.05383, 0.05655, 0.06609, 0.06916, 0.07291, 0.07836, 0.08517, 0.09063, 0.0978, 0.10459, 0.11345, 0.11822, 0.12231, 0.12674, 0.13117, 0.13560, 0.14003, 0.14548, 0.15127, 0.15775, 0.16660, 0.17546, 0.18364, 0.19557, 0.20579, 0.21839, 0.23850, 0.25144];
as_to_add_from_figure = [0.76383, 0.76766, 0.76974, 0.77543, 0.77675, 0.77828, 0.78003, 0.78178, 0.78288, 0.7840, 0.78474, 0.78540, 0.78562, 0.78572, 0.78583, 0.78583, 0.78583, 0.78583, 0.78567, 0.78551, 0.78529, 0.78485, 0.78441, 0.78386, 0.78310, 0.78233, 0.78135, 0.77970, 0.77861];
figure(6)
clf
set(gcf,'Position',[50 50 950 750])
%
imagesc(nadd2s, as_to_add, instability_boundary); % Specify x and y data for axes
hold on
plot(nadd2s_from_figure, as_to_add_from_figure, 'r*-', 'LineWidth', 2); % Plot the curve (red line)
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
colorbar; % Add a colorbar
xlabel('$na_{dd}^2$','fontsize',16,'interpreter','latex');
ylabel('$a_s/a_{dd}$','fontsize',16,'interpreter','latex');
%{
imagesc(AtomNumber*1E-5, ScatteringLengths, instability_boundary); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
cbar1 = colorbar;
cbar1.Label.Interpreter = 'latex';
ylabel(cbar1,'$(\times 10^{-31})$','FontSize',16,'Rotation',270)
xlabel(' Atom number for a trap area of 100$\mu m^2 ~ (\times 10^5)$','fontsize',16,'interpreter','latex');
ylabel('Scattering length ($\times a_0$)','fontsize',16,'interpreter','latex');
%}
title('Roton instability boundary','fontsize',16,'interpreter','latex')
%%
function [Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi)
Go = sqrt(pi) * (k * MeanWidth/sqrt(2)) .* exp((k * MeanWidth/sqrt(2)).^2) .* erfc((k * MeanWidth/sqrt(2)));
gamma4 = 1/(sqrt(2*pi) * MeanWidth);
Fka = (3 * cos(deg2rad(theta))^2 - 1) + ((3 * Go) .* ((sin(deg2rad(theta))^2 .* sin(deg2rad(phi))^2) - cos(deg2rad(theta))^2));
Ukk = (gs + (gdd * Fka)) * gamma4;
end
function ret = computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced)
eps_dd = add/as; % Relative interaction strength
MeanWidth = x * lz;
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2)); % Quantum Fluctuations term
gamma4 = 1/(sqrt(2*pi) * MeanWidth);
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
Energy_AxialComponent = (PlanckConstantReduced * wz) * ((lz^2/(4 * MeanWidth^2)) + (MeanWidth^2/(4 * lz^2)));
Energy_TransverseComponent = (0.5 * (gs + (2*gdd)) * gamma4 * AtomNumberDensity) + ((2/5) * gQF * AtomNumberDensity^(3/2));
ret = (Energy_AxialComponent + Energy_TransverseComponent) / (PlanckConstantReduced * wz);
end

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%% Physical constants
PlanckConstant = 6.62607015E-34;
PlanckConstantReduced = 6.62607015E-34/(2*pi);
FineStructureConstant = 7.2973525698E-3;
ElectronMass = 9.10938291E-31;
GravitationalConstant = 6.67384E-11;
ProtonMass = 1.672621777E-27;
AtomicMassUnit = 1.660539066E-27;
BohrRadius = 5.2917721067E-11;
BohrMagneton = 9.274009994E-24;
BoltzmannConstant = 1.38064852E-23;
StandardGravityAcceleration = 9.80665;
SpeedOfLight = 299792458;
StefanBoltzmannConstant = 5.670373E-8;
ElectronCharge = 1.602176634E-19;
VacuumPermeability = 1.25663706212E-6;
DielectricConstant = 8.8541878128E-12;
ElectronGyromagneticFactor = -2.00231930436153;
AvogadroConstant = 6.02214076E23;
ZeroKelvin = 273.15;
GravitationalAcceleration = 9.80553;
VacuumPermittivity = 1 / (SpeedOfLight^2 * VacuumPermeability);
HartreeEnergy = ElectronCharge^2 / (4 * pi * VacuumPermittivity * BohrRadius);
AtomicUnitOfPolarizability = (ElectronCharge^2 * BohrRadius^2) / HartreeEnergy; % Or simply 4*pi*VacuumPermittivity*BohrRadius^3
% Dy specific constants
Dy164Mass = 163.929174751*AtomicMassUnit;
Dy164IsotopicAbundance = 0.2826;
DyMagneticMoment = 9.93*BohrMagneton;
%% Roton instability boundary for tilted dipoles
wz = 2 * pi * 72.4; % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
gdd = VacuumPermeability*DyMagneticMoment^2/3;
nadd2s = 0.005:0.0025:0.5;
as_to_add = 0.3:0.025:0.95;
var_widths = zeros(length(as_to_add), length(nadd2s));
x0 = 5;
Aineq = [];
Bineq = [];
Aeq = [];
Beq = [];
lb = [1];
ub = [10];
nonlcon = [];
fminconopts = optimoptions(@fmincon,'Display','off', 'StepTolerance', 1.0000e-11, 'MaxIterations',1500);
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
as = (as_to_add(jdx) * add); % Scattering length
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
TotalEnergyPerParticle = @(x) computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced);
sigma = fmincon(TotalEnergyPerParticle, x0, Aineq, Bineq, Aeq, Beq, lb, ub, nonlcon, fminconopts);
var_widths(jdx, idx) = sigma;
end
end
%% ====================================================================================================================================================== %
figure(7)
clf
set(gcf,'Position',[50 50 1850 750])
theta = 66; % Polar angle of dipole moment
phi = 0; % Azimuthal angle of momentum vector
k = linspace(0, 2.25e6, 1000); % Vector of magnitudes of k vector
instability_boundary = zeros(length(as_to_add), length(nadd2s));
ScatteringLengths = zeros(length(as_to_add), 1);
AtomNumber = zeros(length(nadd2s), 1);
w0 = 2 * pi * 61.6316; % Trap frequency in the tight confinement direction
l0 = sqrt(PlanckConstantReduced/(Dy164Mass * w0)); % Defining a harmonic oscillator length
tsize = 10 * l0;
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
AtomNumber(idx) = AtomNumberDensity*tsize^2;
as = (as_to_add(jdx) * add); % Scattering length
ScatteringLengths(jdx) = as/BohrRadius;
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
MeanWidth = var_widths(jdx, idx) * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) .* DeltaK);
instability_boundary(jdx, idx) = ~isreal(EpsilonK);
end
end
subplot(1, 2, 1); % 1 row, 2 columns, first subplot
imagesc(nadd2s, as_to_add, instability_boundary); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
colorbar; % Add a colorbar
caxis([0 1])
xlabel('$na_{dd}^2$','fontsize',16,'interpreter','latex');
ylabel('$a_s/a_{dd}$','fontsize',16,'interpreter','latex');
title(['Along Y: $\theta = ',num2str(theta), '; \phi = ', num2str(phi),'$'],'fontsize',16,'interpreter','latex')
theta = 66; % Polar angle of dipole moment
phi = 90; % Azimuthal angle of momentum vector
k = linspace(0, 2.25e6, 1000); % Vector of magnitudes of k vector
instability_boundary = zeros(length(as_to_add), length(nadd2s));
ScatteringLengths = zeros(length(as_to_add), 1);
AtomNumber = zeros(length(nadd2s), 1);
w0 = 2 * pi * 61.6316; % Trap frequency in the tight confinement direction
l0 = sqrt(PlanckConstantReduced/(Dy164Mass * w0)); % Defining a harmonic oscillator length
tsize = 10 * l0;
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
AtomNumber(idx) = AtomNumberDensity*tsize^2;
as = (as_to_add(jdx) * add); % Scattering length
ScatteringLengths(jdx) = as/BohrRadius;
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
MeanWidth = var_widths(jdx, idx) * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) .* DeltaK);
instability_boundary(jdx, idx) = ~isreal(EpsilonK);
end
end
% set(gcf,'Position',[50 50 950 750])
subplot(1, 2, 2); % 1 row, 2 columns, first subplot
imagesc(nadd2s, as_to_add, instability_boundary); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
colorbar; % Add a colorbar
caxis([0 1])
xlabel('$na_{dd}^2$','fontsize',16,'interpreter','latex');
ylabel('$a_s/a_{dd}$','fontsize',16,'interpreter','latex');
title(['Along X: $\theta = ',num2str(theta), '; \phi = ', num2str(phi),'$'],'fontsize',16,'interpreter','latex')
%{
imagesc(AtomNumber*1E-5, ScatteringLengths, instability_boundary); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
cbar1 = colorbar;
cbar1.Label.Interpreter = 'latex';
caxis([0 1])
% ylabel(cbar1,'$(\times 10^{-31})$','FontSize',16,'Rotation',270)
xlabel(' Atom number for a trap area of 100$\mu m^2 ~ (\times 10^5)$','fontsize',16,'interpreter','latex');
ylabel('Scattering length ($\times a_0$)','fontsize',16,'interpreter','latex');
%}
sgtitle('Mean-field instability boundary','fontsize',16,'interpreter','latex')
%% Cycle through angles
% Define values for theta and phi
theta_values = 0:2:90; % Range of theta values (you can modify this)
% Set up VideoWriter object to produce a movie
v = VideoWriter('rib_movie', 'MPEG-4'); % Create a video object
v.FrameRate = 5; % Frame rate of the video
open(v); % Open the video file
for theta = theta_values
figure(7)
clf
set(gcf,'Position',[50 50 1850 750])
phi = 0; % Azimuthal angle of momentum vector
k = linspace(0, 2.25e6, 1000); % Vector of magnitudes of k vector
instability_boundary = zeros(length(as_to_add), length(nadd2s));
ScatteringLengths = zeros(length(as_to_add), 1);
AtomNumber = zeros(length(nadd2s), 1);
w0 = 2 * pi * 61.6316; % Trap frequency in the tight confinement direction
l0 = sqrt(PlanckConstantReduced/(Dy164Mass * w0)); % Defining a harmonic oscillator length
tsize = 10 * l0;
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
AtomNumber(idx) = AtomNumberDensity*tsize^2;
as = (as_to_add(jdx) * add); % Scattering length
ScatteringLengths(jdx) = as/BohrRadius;
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
MeanWidth = var_widths(jdx, idx) * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) .* DeltaK);
instability_boundary(jdx, idx) = ~isreal(EpsilonK);
end
end
subplot(1, 2, 1); % 1 row, 2 columns, first subplot
imagesc(nadd2s, as_to_add, instability_boundary); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
colorbar; % Add a colorbar
caxis([0 1])
xlabel('$na_{dd}^2$','fontsize',16,'interpreter','latex');
ylabel('$a_s/a_{dd}$','fontsize',16,'interpreter','latex');
title(['Along Y: $\theta = ',num2str(theta), '; \phi = ', num2str(phi),'$'],'fontsize',16,'interpreter','latex')
phi = 90; % Azimuthal angle of momentum vector
k = linspace(0, 2.25e6, 1000); % Vector of magnitudes of k vector
instability_boundary = zeros(length(as_to_add), length(nadd2s));
ScatteringLengths = zeros(length(as_to_add), 1);
AtomNumber = zeros(length(nadd2s), 1);
w0 = 2 * pi * 61.6316; % Trap frequency in the tight confinement direction
l0 = sqrt(PlanckConstantReduced/(Dy164Mass * w0)); % Defining a harmonic oscillator length
tsize = 10 * l0;
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
AtomNumber(idx) = AtomNumberDensity*tsize^2;
as = (as_to_add(jdx) * add); % Scattering length
ScatteringLengths(jdx) = as/BohrRadius;
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
MeanWidth = var_widths(jdx, idx) * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) .* DeltaK);
instability_boundary(jdx, idx) = ~isreal(EpsilonK);
end
end
% set(gcf,'Position',[50 50 950 750])
subplot(1, 2, 2); % 1 row, 2 columns, first subplot
imagesc(nadd2s, as_to_add, instability_boundary); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
colorbar; % Add a colorbar
caxis([0 1])
xlabel('$na_{dd}^2$','fontsize',16,'interpreter','latex');
ylabel('$a_s/a_{dd}$','fontsize',16,'interpreter','latex');
title(['Along X: $\theta = ',num2str(theta), '; \phi = ', num2str(phi),'$'],'fontsize',16,'interpreter','latex')
%{
imagesc(AtomNumber*1E-5, ScatteringLengths, instability_boundary); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
cbar1 = colorbar;
cbar1.Label.Interpreter = 'latex';
caxis([0 1])
% ylabel(cbar1,'$(\times 10^{-31})$','FontSize',16,'Rotation',270)
xlabel(' Atom number for a trap area of 100$\mu m^2 ~ (\times 10^5)$','fontsize',16,'interpreter','latex');
ylabel('Scattering length ($\times a_0$)','fontsize',16,'interpreter','latex');
%}
% Capture the frame and write to video
frame = getframe(gcf); % Capture the current figure
writeVideo(v, frame); % Write the frame to the video
% sgtitle('Mean-field instability boundary','fontsize',16,'interpreter','latex')
end
% Close the video file
close(v);
%%
function [Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi)
Go = sqrt(pi) * (k * MeanWidth/sqrt(2)) .* exp((k * MeanWidth/sqrt(2)).^2) .* erfc((k * MeanWidth/sqrt(2)));
gamma4 = 1/(sqrt(2*pi) * MeanWidth);
Fka = (3 * cos(deg2rad(theta))^2 - 1) + ((3 * Go) .* ((sin(deg2rad(theta))^2 .* sin(deg2rad(phi))^2) - cos(deg2rad(theta))^2));
Ukk = (gs + (gdd * Fka)) * gamma4;
end
function ret = computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced)
eps_dd = add/as; % Relative interaction strength
MeanWidth = x * lz;
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2)); % Quantum Fluctuations term
gamma4 = 1/(sqrt(2*pi) * MeanWidth);
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
Energy_AxialComponent = (PlanckConstantReduced * wz) * ((lz^2/(4 * MeanWidth^2)) + (MeanWidth^2/(4 * lz^2)));
Energy_TransverseComponent = (0.5 * (gs + (2*gdd)) * gamma4 * AtomNumberDensity) + ((2/5) * gQF * AtomNumberDensity^(3/2));
ret = (Energy_AxialComponent + Energy_TransverseComponent) / (PlanckConstantReduced * wz);
end

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%% Physical constants
PlanckConstant = 6.62607015E-34;
PlanckConstantReduced = 6.62607015E-34/(2*pi);
FineStructureConstant = 7.2973525698E-3;
ElectronMass = 9.10938291E-31;
GravitationalConstant = 6.67384E-11;
ProtonMass = 1.672621777E-27;
AtomicMassUnit = 1.660539066E-27;
BohrRadius = 5.2917721067E-11;
BohrMagneton = 9.274009994E-24;
BoltzmannConstant = 1.38064852E-23;
StandardGravityAcceleration = 9.80665;
SpeedOfLight = 299792458;
StefanBoltzmannConstant = 5.670373E-8;
ElectronCharge = 1.602176634E-19;
VacuumPermeability = 1.25663706212E-6;
DielectricConstant = 8.8541878128E-12;
ElectronGyromagneticFactor = -2.00231930436153;
AvogadroConstant = 6.02214076E23;
ZeroKelvin = 273.15;
GravitationalAcceleration = 9.80553;
VacuumPermittivity = 1 / (SpeedOfLight^2 * VacuumPermeability);
HartreeEnergy = ElectronCharge^2 / (4 * pi * VacuumPermittivity * BohrRadius);
AtomicUnitOfPolarizability = (ElectronCharge^2 * BohrRadius^2) / HartreeEnergy; % Or simply 4*pi*VacuumPermittivity*BohrRadius^3
% Dy specific constants
Dy164Mass = 163.929174751*AtomicMassUnit;
Dy164IsotopicAbundance = 0.2826;
DyMagneticMoment = 9.93*BohrMagneton;
%% Bogoliubov excitation spectrum for quasi-2D dipolar gas with QF correction
AtomNumber = 1E5; % Total atom number in the system
wz = 2 * pi * 72.4; % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
as = 102.515 * BohrRadius; % Scattering length
Trapsize = 7.5815 * lz; % Trap is assumed to be a box of finite extent , given here in units of the harmonic oscillator length
theta = 0; % Polar angle of dipole moment
phi = 0; % Azimuthal angle of momentum vector
MeanWidth = 5.7304888515 * lz; % Mean width of Gaussian ansatz
k = linspace(0, 2e6, 1000); % Vector of magnitudes of k vector
% no = 2.0429e+15, eps_dd = 1.2755, as = 5.4249e-09
AtomNumberDensity = AtomNumber / Trapsize^2; % Areal density of atoms
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) .* DeltaK);
figure(1)
set(gcf,'Position',[50 50 950 750])
xvals = (k .* add);
yvals = EpsilonK ./ PlanckConstant;
plot(xvals, yvals,LineWidth=2.0)
title(horzcat(['$a_s = ',num2str(round(1/eps_dd,3)),'a_{dd}, '], ['na_{dd}^2 = ',num2str(round(AtomNumberDensity * add^2,4)),'$']),'fontsize',16,'interpreter','latex')
xlabel('$k_{\rho}a_{dd}$','fontsize',16,'interpreter','latex')
ylabel('$\epsilon(k_{\rho})/h$ (Hz)','fontsize',16,'interpreter','latex')
grid on
%% For different interaction strengths
AtomNumber = 1E5; % Total atom number in the system
wz = 2 * pi * 72.4; % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
Trapsize = 7.5815 * lz; % Trap is assumed to be a box of finite extent , given here in units of the harmonic oscillator length
theta = 0; % Polar angle of dipole moment
phi = 0; % Azimuthal angle of momentum vector
MeanWidth = 5.7304888515 * lz; % Mean width of Gaussian ansatz
k = linspace(0, 2e6, 1000); % Vector of magnitudes of k vector
AtomNumberDensity = AtomNumber / Trapsize^2; % Areal density of atoms
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
ScatteringLengths = [108.5, 105.9, 103.3, 102.5150];
eps_dds = zeros(1, length(ScatteringLengths));
EpsilonKs = zeros(length(k), length(ScatteringLengths));
for idx = 1:length(ScatteringLengths)
as = ScatteringLengths(idx) * BohrRadius; % Scattering length
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) .* DeltaK);
eps_dds(idx) = eps_dd;
EpsilonKs(:,idx) = EpsilonK;
end
figure(2)
clf
set(gcf,'Position',[50 50 950 750])
xvals = (k .* add);
yvals = EpsilonKs(:, 1) ./ PlanckConstant;
plot(xvals, yvals,LineWidth=2.0, DisplayName=['$a_s = ',num2str(round(1/eps_dds(1),3)),'a_{dd}$'])
hold on
for idx = 2:length(ScatteringLengths)
yvals = EpsilonKs(:, idx) ./ PlanckConstant;
plot(xvals, yvals,LineWidth=2.0, DisplayName=['$a_s = ',num2str(round(1/eps_dds(idx),3)),'a_{dd}$'])
end
title(['$na_{dd}^2 = ',num2str(round(AtomNumberDensity * add^2,4)),'$'],'fontsize',16,'interpreter','latex')
xlabel('$k_{\rho}a_{dd}$','fontsize',16,'interpreter','latex')
ylabel('$\epsilon(k_{\rho})/h$ (Hz)','fontsize',16,'interpreter','latex')
grid on
legend('location', 'northwest','fontsize',16, 'Interpreter','latex')
%% For 3 points on the roton instability boundary
wz = 2 * pi * 72.4; % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
theta = 0; % Polar angle of dipole moment
phi = 0; % Azimuthal angle of momentum vector
k = linspace(0, 2.25e6, 1000); % Vector of magnitudes of k vector
nadd2s = [0.0844, 0.0978, 0.123];
as_to_add = [0.7730, 0.7840, 0.7819];
var_widths = [4.97165, 5.7296048721, 5.93178];
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
EpsilonKs = zeros(length(k), length(nadd2s));
ScatteringLengths = zeros(length(as_to_add), 1);
AtomNumber = zeros(length(nadd2s), 1);
w0 = 2 * pi * 61.6316; % Trap frequency in the tight confinement direction
l0 = sqrt(PlanckConstantReduced/(Dy164Mass * w0)); % Defining a harmonic oscillator length
tsize = 10 * l0;
for idx = 1:length(nadd2s)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
AtomNumber(idx) = AtomNumberDensity*tsize^2;
as = (as_to_add(idx) * add); % Scattering length
ScatteringLengths(idx) = as/BohrRadius;
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
MeanWidth = var_widths(idx) * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) .* DeltaK);
EpsilonKs(:,idx) = EpsilonK;
end
figure(3)
clf
set(gcf,'Position',[50 50 950 750])
xvals = (k .* add);
yvals = EpsilonKs(:, 1) ./ PlanckConstant;
plot(xvals, yvals,LineWidth=2.0, DisplayName=['$a_s = ',num2str(round(as_to_add(1),4)),'a_{dd}, na_{dd}^2 = ',num2str(round(nadd2s(1),4)),'$'])
hold on
for idx = 2:length(nadd2s)
yvals = EpsilonKs(:, idx) ./ PlanckConstant;
plot(xvals, yvals,LineWidth=2.0, DisplayName=['$a_s = ',num2str(round(as_to_add(idx),4)),'a_{dd}, na_{dd}^2 = ',num2str(round(nadd2s(idx),4)),'$'])
end
xlabel('$k_{\rho}a_{dd}$','fontsize',16,'interpreter','latex')
ylabel('$\epsilon(k_{\rho})/h$ (Hz)','fontsize',16,'interpreter','latex')
grid on
legend('location', 'northwest','fontsize',16, 'Interpreter','latex')
%% Mean widths of the variational Gaussian ansatz - extremize the total mean field energy per particle wrt to the variational parameter
wz = 2 * pi * 72.4; % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
gdd = VacuumPermeability*DyMagneticMoment^2/3;
AtomNumberDensity = 0.0978 / add^2;
as = 0.784 * add; % Scattering length
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
TotalEnergyPerParticle = @(x) computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced);
x0 = 5;
Aineq = [];
Bineq = [];
Aeq = [];
Beq = [];
lb = [1];
ub = [7];
nonlcon = [];
fminconopts = optimoptions(@fmincon,'Display','off', 'StepTolerance', 1.0000e-11, 'MaxIterations',1500);
sigma = fmincon(TotalEnergyPerParticle, x0, Aineq, Bineq, Aeq, Beq, lb, ub, nonlcon, fminconopts);
fprintf(['Variational width of Gaussian ansatz = ' num2str(sigma) ' * lz \n'])
%% Mean widths of the variational Gaussian ansatz - extremize the total mean field energy per particle wrt to the variational parameter
wz = 2 * pi * 72.4; % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
gdd = VacuumPermeability*DyMagneticMoment^2/3;
nadd2s = 0.05:0.001:0.25;
as_to_add = 0.74:0.001:0.79;
var_widths = zeros(length(as_to_add), length(nadd2s));
x0 = 5;
Aineq = [];
Bineq = [];
Aeq = [];
Beq = [];
lb = [1];
ub = [10];
nonlcon = [];
fminconopts = optimoptions(@fmincon,'Display','off', 'StepTolerance', 1.0000e-11, 'MaxIterations',1500);
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
as = (as_to_add(jdx) * add); % Scattering length
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
TotalEnergyPerParticle = @(x) computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced);
sigma = fmincon(TotalEnergyPerParticle, x0, Aineq, Bineq, Aeq, Beq, lb, ub, nonlcon, fminconopts);
var_widths(jdx, idx) = sigma;
end
end
figure(4)
clf
set(gcf,'Position',[50 50 950 750])
imagesc(nadd2s, as_to_add, var_widths); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
colorbar; % Add a colorbar
xlabel('$na_{dd}^2$','fontsize',16,'interpreter','latex');
ylabel('$a_s/a_{dd}$','fontsize',16,'interpreter','latex');
% ====================================================================================================================================================== %
theta = 0; % Polar angle of dipole moment
phi = 0; % Azimuthal angle of momentum vector
k = linspace(0, 2.25e6, 1000); % Vector of magnitudes of k vector
instability_boundary = zeros(length(as_to_add), length(nadd2s));
ScatteringLengths = zeros(length(as_to_add), 1);
AtomNumber = zeros(length(nadd2s), 1);
w0 = 2 * pi * 61.6316; % Trap frequency in the tight confinement direction
l0 = sqrt(PlanckConstantReduced/(Dy164Mass * w0)); % Defining a harmonic oscillator length
tsize = 10 * l0;
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
AtomNumber(idx) = AtomNumberDensity*tsize^2;
as = (as_to_add(jdx) * add); % Scattering length
ScatteringLengths(jdx) = as/BohrRadius;
eps_dd = add/as; % Relative interaction strength
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
gdd = VacuumPermeability*DyMagneticMoment^2/3;
MeanWidth = var_widths(jdx, idx) * lz; % Mean width of Gaussian ansatz
[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi); % DDI potential in k-space
% == Quantum Fluctuations term == %
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
% == Dispersion relation == %
DeltaK = ((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) + ((2 * AtomNumberDensity) .* Ukk) + (3 * gQF * AtomNumberDensity^(3/2));
EpsilonK = sqrt(((PlanckConstantReduced^2 .* k.^2) ./ (2 * Dy164Mass)) .* DeltaK);
instability_boundary(jdx, idx) = ~isreal(EpsilonK);
end
end
nadd2s_from_figure = [0.04974, 0.05383, 0.05655, 0.06609, 0.06916, 0.07291, 0.07836, 0.08517, 0.09063, 0.0978, 0.10459, 0.11345, 0.11822, 0.12231, 0.12674, 0.13117, 0.13560, 0.14003, 0.14548, 0.15127, 0.15775, 0.16660, 0.17546, 0.18364, 0.19557, 0.20579, 0.21839, 0.23850, 0.25144];
as_to_add_from_figure = [0.76383, 0.76766, 0.76974, 0.77543, 0.77675, 0.77828, 0.78003, 0.78178, 0.78288, 0.7840, 0.78474, 0.78540, 0.78562, 0.78572, 0.78583, 0.78583, 0.78583, 0.78583, 0.78567, 0.78551, 0.78529, 0.78485, 0.78441, 0.78386, 0.78310, 0.78233, 0.78135, 0.77970, 0.77861];
figure(5)
clf
set(gcf,'Position',[50 50 950 750])
imagesc(nadd2s, as_to_add, instability_boundary); % Specify x and y data for axes
hold on
plot(nadd2s_from_figure, as_to_add_from_figure, 'r*-', 'LineWidth', 2); % Plot the curve (red line)
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
colorbar; % Add a colorbar
xlabel('$na_{dd}^2$','fontsize',16,'interpreter','latex');
ylabel('$a_s/a_{dd}$','fontsize',16,'interpreter','latex');
%{
imagesc(AtomNumber*1E-5, ScatteringLengths, instability_boundary); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
cbar1 = colorbar;
cbar1.Label.Interpreter = 'latex';
ylabel(cbar1,'$(\times 10^{-31})$','FontSize',16,'Rotation',270)
xlabel(' Atom number for a trap area of 100$\mu m^2 ~ (\times 10^5)$','fontsize',16,'interpreter','latex');
ylabel('Scattering length ($\times a_0$)','fontsize',16,'interpreter','latex');
title('Roton instability boundary','fontsize',16,'interpreter','latex')
%}
%%
function [Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, theta, phi)
Go = sqrt(pi) * (k * MeanWidth/sqrt(2)) .* exp((k * MeanWidth/sqrt(2)).^2) .* erfc((k * MeanWidth/sqrt(2)));
gamma4 = 1/(sqrt(2*pi) * MeanWidth);
Fka = (3 * cos(deg2rad(theta))^2 - 1) + ((3 * Go) .* ((sin(deg2rad(theta))^2 .* sin(deg2rad(phi))^2) - cos(deg2rad(theta))^2));
Ukk = (gs + (gdd * Fka)) * gamma4;
end
function ret = computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced)
eps_dd = add/as; % Relative interaction strength
MeanWidth = x * lz;
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2)); % Quantum Fluctuations term
gamma4 = 1/(sqrt(2*pi) * MeanWidth);
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
Energy_AxialComponent = (PlanckConstantReduced * wz) * ((lz^2/(4 * MeanWidth^2)) + (MeanWidth^2/(4 * lz^2)));
Energy_TransverseComponent = (0.5 * (gs + (2*gdd)) * gamma4 * AtomNumberDensity) + ((2/5) * gQF * AtomNumberDensity^(3/2));
ret = (Energy_AxialComponent + Energy_TransverseComponent) / (PlanckConstantReduced * wz);
end

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%% Physical constants
PlanckConstant = 6.62607015E-34;
PlanckConstantReduced = 6.62607015E-34/(2*pi);
FineStructureConstant = 7.2973525698E-3;
ElectronMass = 9.10938291E-31;
GravitationalConstant = 6.67384E-11;
ProtonMass = 1.672621777E-27;
AtomicMassUnit = 1.660539066E-27;
BohrRadius = 5.2917721067E-11;
BohrMagneton = 9.274009994E-24;
BoltzmannConstant = 1.38064852E-23;
StandardGravityAcceleration = 9.80665;
SpeedOfLight = 299792458;
StefanBoltzmannConstant = 5.670373E-8;
ElectronCharge = 1.602176634E-19;
VacuumPermeability = 1.25663706212E-6;
DielectricConstant = 8.8541878128E-12;
ElectronGyromagneticFactor = -2.00231930436153;
AvogadroConstant = 6.02214076E23;
ZeroKelvin = 273.15;
GravitationalAcceleration = 9.80553;
VacuumPermittivity = 1 / (SpeedOfLight^2 * VacuumPermeability);
HartreeEnergy = ElectronCharge^2 / (4 * pi * VacuumPermittivity * BohrRadius);
AtomicUnitOfPolarizability = (ElectronCharge^2 * BohrRadius^2) / HartreeEnergy; % Or simply 4*pi*VacuumPermittivity*BohrRadius^3
% Dy specific constants
Dy164Mass = 163.929174751*AtomicMassUnit;
Dy164IsotopicAbundance = 0.2826;
DyMagneticMoment = 9.93*BohrMagneton;
%% Scaling of the QF term
wz = 2 * pi * 72.4; % Trap frequency in the tight confinement direction
lz = sqrt(PlanckConstantReduced/(Dy164Mass * wz)); % Defining a harmonic oscillator length
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length
gdd = VacuumPermeability*DyMagneticMoment^2/3;
nadd2s = 0.05:0.01:0.25;
as_to_add = 0.76:0.01:0.81;
QF = zeros(length(as_to_add), length(nadd2s));
ScatteringLengths = zeros(length(as_to_add), 1);
AtomNumber = zeros(length(nadd2s), 1);
w0 = 2 * pi * 61.6316; % Trap frequency in the tight confinement direction
l0 = sqrt(PlanckConstantReduced/(Dy164Mass * w0)); % Defining a harmonic oscillator length
tsize = 10 * l0;
x0 = 5;
Aineq = [];
Bineq = [];
Aeq = [];
Beq = [];
lb = [1];
ub = [10];
nonlcon = [];
fminconopts = optimoptions(@fmincon,'Display','off', 'StepTolerance', 1.0000e-11, 'MaxIterations',1500);
for idx = 1:length(nadd2s)
for jdx = 1:length(as_to_add)
AtomNumberDensity = nadd2s(idx) / add^2; % Areal density of atoms
AtomNumber(idx) = AtomNumberDensity*tsize^2;
as = (as_to_add(jdx) * add); % Scattering length
gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength
ScatteringLengths(jdx) = as/BohrRadius;
TotalEnergyPerParticle = @(x) computeTotalEnergyPerParticle(x, as, AtomNumberDensity, wz, lz, gs, add, gdd, PlanckConstantReduced);
sigma = fmincon(TotalEnergyPerParticle, x0, Aineq, Bineq, Aeq, Beq, lb, ub, nonlcon, fminconopts);
eps_dd = add/as; % Relative interaction strength
% == Quantum Fluctuations term == %
MeanWidth = sigma * lz;
gammaQF = (32/3) * gs * (as^3/pi)^(1/2) * (1 + ((3/2) * eps_dd^2));
gamma5 = sqrt(2/5) / (sqrt(pi) * MeanWidth)^(3/2);
gQF = gamma5 * gammaQF;
QF(jdx, idx) = 3 * gQF * AtomNumberDensity^(3/2);
end
end
figure
clf
set(gcf,'Position',[50 50 950 750])
imagesc(AtomNumber*1E-5, ScatteringLengths, QF * 1E31); % Specify x and y data for axes
set(gca, 'YDir', 'normal'); % Correct the y-axis direction
cbar1 = colorbar;
cbar1.Label.Interpreter = 'latex';
ylabel(cbar1,'$(\times 10^{-31})$','FontSize',16,'Rotation',270)
xlabel(' Atom number for a trap area of 100$\mu m^2 ~ (\times 10^5)$','fontsize',16,'interpreter','latex');
ylabel('Scattering length ($\times a_0$)','fontsize',16,'interpreter','latex');
title('Scaling of the quantum fluctuations term','fontsize',16,'interpreter','latex')

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#!/bin/bash
########### Begin SLURM header ###########
#Partition
#SBATCH --partition=cpu-single
# Request number of nodes and CPU cores per node for job
#SBATCH --nodes=1
#SBATCH --ntasks-per-node=1
#SBATCH --cpus-per-task=10
#SBATCH --mem=2G
# Estimated wallclock time for job
#SBATCH --time=00:30:00
#SBATCH --job-name=simulation
#SBATCH --error=simulation.err
#SBATCH --output=simulation.out
########### End SLURM header ##########
echo "Working Directory: $PWD"
echo "Running on host $HOSTNAME"
echo "Job id: $SLURM_JOB_ID"
echo "Job name: $SLURM_JOB_NAME"
echo "Number of nodes allocated to job: $SLURM_JOB_NUM_NODES"
echo "Number of cores allocated to job: $SLURM_JOB_CPUS_PER_NODE"
# Load module
module load math/matlab/R2023a
echo Directory is `pwd`
echo "Initiating Job..."
# Start a Matlab program
matlab -nodisplay -nosplash -r "ExtractingKRoton"
# notice for tests
echo "Job terminated successfully"
exit

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