Psitrum and Simulation of Decoherence in Quantum Algorithms

Quantum computation is a radical new candidate for a technology that is capable to make a paradigm shift in information processing. However, current promising devices are limited in performance due to many decoherence mechanisms. Quantum computer simulators are thus important for understanding and solving existing problems of the current noisy intermediate-scale quantum (NISQ) processors. In this work, we present Psitrum – a universal gate-model based quantum computer simulator implemented on classical hardware. The simulator allows to emulate and debug quantum algorithms in form of quantum circuits for many applications with the choice of adding quantum noise that limit coherence of quantum circuits. We will show how to use visualization tools available in the software to demonstrate the simulation of quantum circuits for various quantum algorithms. In addition, we will present the factorization problem using standard Variational quantum eigensolver (VQE) on Psitrum and present the results of several circuits to factorize prime numbers and show the effect of decoherence on the solution probability and training of cost function. This is when decoherence is modeled by deleterious effects of depolarizing channels imposed on quantum gates. This also demonstrates that, Psitrum provides features for simulating noisy and noiseless quantum circuits to solve a wide class of quantum algorithms available for current NISQ processors. In future, by adding more features, Psitrum will help to provide a good starting point to newcomers for a good experience with our visual learning tools. Psitrum software and source codes are freely available at: https://github.com/MoGhadeer/Psitrum.