Quiver plot with a Third feature using background colour

Could someone tell how can we add a third feature which is represented by the background color in the quiver plot?

As explained in a previous question and answer thread, how can we add an another property which is expectation value of sigma_z.

Manipulating a multidimensional array

In the code above if we want to add another two line.

% before the 'for' loop
sigma_z = [1,0;0,-1]; %sigma_z
%After the for loop
expz = pagemtimes(pagemtimes(Psi,'ctranspose',sigma_z,'none'),Psi); % BL's change here
expz = reshape(expz,[M M]); % BL's change here

And if we want to reflect the magnitude of espectation value of z by background color of the quiver plot, is it possible in MATLAB?

PS: The magnitude of expz is very small (zero), still I want to know the way.

Answer 1

[Aditya]

Hi Shubham,

I understand that you want to add a third feature which is represented by background color in the quiver plot. You can achieve this by using the “imagesc” function. Here's how you can modify your code to include it:

% Create the quiver plot with background color 
figure; 
imagesc(kx, ky, abs(expz)); % Plot the background color based on |expz| 
colormap('jet'); % Set the colormap 
colorbar; % Show the colorbar 
hold on; 
quiver(KX, KY, expx, expy); % Overlay the quiver plot 
hold off; 

In the code above, “abs(expz)” determines the color intensity of each point in the background, with the colormap set to “jet” for a range of colors. The “colorbar” provides a reference for the magnitude of “expz”.

For more information on the “imagesc” function and its properties, you can refer the below MATLAB documentation:

• Imagesc: https://www.mathworks.com/help/releases/R2022a/matlab/ref/imagesc.html

Hope this helps!