diff --git a/Quasi2DBogoliubovSpectrum.m b/Quasi2DBogoliubovSpectrum.m index 2d96620..e21d5a3 100644 --- a/Quasi2DBogoliubovSpectrum.m +++ b/Quasi2DBogoliubovSpectrum.m @@ -28,48 +28,49 @@ Dy164Mass = 163.929174751*1.660539066E-27; Dy164IsotopicAbundance = 0.2826; DyMagneticMoment = 9.93*9.274009994E-24; -%% Dispersion relation of the quasiparticle excitations -AtomNumber = 1E5; -wz = 2*pi*72.4; +%% 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 = 102.4*BohrRadius; % Scattering length -Trapsize = 7.6; -alpha = 0; -phi = 0; -MeanWidth = 2.8215042184E3*lz; -k = linspace(0, 1e7, 1000); +as = 102.515*BohrRadius; % Scattering length +Trapsize = 7.5815; % Trap is assumed to be a box of finite extent , given here in units of the harmonic oscillator length +alpha = 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, 3e6, 1000); % Vector of magnitudes of k vector - -AtomNumberDensity = AtomNumber / (Trapsize * lz)^2; +AtomNumberDensity = AtomNumber / (Trapsize * lz)^2; % Areal density of atoms add = VacuumPermeability*DyMagneticMoment^2*Dy164Mass/(12*pi*PlanckConstantReduced^2); % Dipole length -eps_dd = add/as; +eps_dd = add/as; % Relative interaction strength gs = 4 * pi * PlanckConstantReduced^2/Dy164Mass * as; % Contact interaction strength +gdd = VacuumPermeability*DyMagneticMoment^2/3; -[fk,Fka,Ukk] = computePotentialInMomentumSpace(k, lz, alpha, phi, gs, eps_dd); +[Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, alpha, phi); % DDI potential in k-space % == Quantum Fluctuations term == % -gQF = ((256 * PlanckConstantReduced^2) / (15*Dy164Mass*MeanWidth^3)) * as^(5/2) * (1 + ((3/2) * eps_dd^2)); - +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',[100 100 950 750]) -% xvals = (k .* lz/sqrt(2)); +set(gcf,'Position',[50 50 950 750]) xvals = (k .* add); -yvals = EpsilonK ./ (PlanckConstantReduced * wz); +yvals = EpsilonK ./ PlanckConstant; plot(xvals, yvals,LineWidth=2.0) -% xlim([3.45, 3.65]) -% ylim([0, 0.001]) -title(horzcat(['$a_s = ',num2str(1/eps_dd),'a_{dd}, '], ['na_{dd}^2 = ',num2str(AtomNumberDensity * add^2),'$']),'fontsize',16,'interpreter','latex') -xlabel('$ka_{dd}$','fontsize',16,'interpreter','latex') -ylabel('$\epsilon(k)/\hbar \omega_z$','fontsize',16,'interpreter','latex') +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 %% -function [fk,Fka,Ukk] = computePotentialInMomentumSpace(k, lz, alpha, phi, gs, eps_dd) - fk = (3 * sqrt(pi)) * (k .* lz/sqrt(2)) .* exp((k .* lz/sqrt(2)).^2) .* erfc((k .* lz/sqrt(2))) ; - Fka = (fk .* sin(deg2rad(phi))^2 - 1) + (cos(deg2rad(alpha))^2 .* (3 - (fk .* (sin(deg2rad(phi))^2 + 1)))); - Ukk = (gs/ (sqrt(2 * pi) * lz)) .* (1 + (eps_dd .* Fka)); + +function [Go,gamma4,Fka,Ukk] = computePotentialInMomentumSpace(k, gs, gdd, MeanWidth, alpha, 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(alpha))^2 - 1) + ((3 * Go) .* ((sin(deg2rad(alpha))^2 .* sin(deg2rad(phi))^2) - cos(deg2rad(alpha))^2)); + Ukk = (gs + (gdd * Fka)) * gamma4; end \ No newline at end of file