Calculations/Estimations/DipolarDispersionAndRotonInstabilityBoundary/ScalingOfTheQFTerm.m

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2025-01-10 11:16:00 +01:00
%% 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(7)
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')