GSoC 2019 QuTiP project

Now we have the main ingredients for this project: CircuitProcessor as the simulator and CircuitNoise representing noise, it's time to go back and fix some technical issues. There were two unsolved problems discussed in the posts before: QuTiP solver interprets the array-like coefficients as smooth function and uses a cubic spline interpolation by default. However, as mentioned in  the previous blog , in CircuitProcessor we use the coefficients as a step function, i.e. coeff = [1,2,3] means that the pulse amplitude is 1 during t=[0,1), 2 during t=[1,2) and so on. This causes a mismatch in the result and was only solved temporarily by using Python function as coefficients. The solver requires that all the coefficients have the same tlist , which makes it difficult to add noise to the processor since the noise might have a different frequency. This was mentioned at the end of the last post . To solve the first problem we need to modify the solvers. Fortunately, the recent up

We are now at the point to include noise into the simulation. The decoherent noise characterized by T1 and T2 time has already been implemented, but we want to generalize it to different types of noises and separate it from the processor class. The above flowchart is from the blog of last week, where I wrote some of my thinking about the noise that we are dealing with. After some discussion and study, I now have a relatively complete view of the noise objects. The figure above shows how the noise is processed in the circuit processor.  The noise is defined separately in a class object. When called, it takes parameters from the processor (like operators or coefficients), modifies them and returns them to the processor. However, this design has a drawback. Since the Hamiltonian saved in the circuitprocessor is a list of operators and their amplitudes. It restricts the form of the noise, for instance, it is not possible to create noise with coefficient represented by string based func