Supervisors info:
Δημήτριος Γκιζόπουλος, Καθηγητής, Τμήμα Πληροφορικής & Τηλεπικοινωνιών, ΕΚΠΑ
Summary:
Quantum computers is a research field of study with increasing interest. The idea behind them is fundamentally different from the classical digital computers and for that reason they require new manufacturing technologies, new design methods and new algorithms. The existing infrastructure of quantum computers is minimal, and makes the research difficult due to the lack of large scale real systems for implementation and testing of theory and ideas.
The purpose of this master's thesis is to help in the search for a solution to this problem with the creation of a quantum circuit simulator on which they can be tested quantum algorithms. This tool will be easily accessible and it will not require a lot of resources for its execution. It will simulate emphasizing on better performance in terms of execution time and in terms of the ability of performing on a large number of qubits.
To achieve this purpose it was decided to use graphics cards (GPU), the architectures of which allow the massive parallel execution of operations, a fact that serves the enormous amount of operations that quantum computations require. Specifically the NVidia CUDA development platform was chosen because it is popular and widely used option, and the there are numerous laboratories with that type of cards.
The first step of this project was the study of the required theory. This includes the understanding of the fundamental quantum elements, the quantum gates, the quantum calculations and how they are implemented. In terms of the GPU, it includes the existing architectures, their characteristics, how they implement parallel computations and how to be properly used to exploit their potential to the fullest.
After understanding the theory, the next step was to design the theoretical algorithm that performs the calculations. In addition, the form of the user’s input to the tool was designed, how the data will be read, stored and processed. Then, the real code was developed with attention to the compliance of the above. After that, the testing of the code started on real cards, so to become apparent the results of the theoretical design and to improve the code by practice. Some known quantum algorithms and circuits were implemented and their performance was analyzed by using special tools.
The operation of the simulator in short, is the following. The user enters a text file which contains the circuit written in a description language designed for this purpose. The tool analyses the text, sends the data to the card and the necessary operations are executed. When all the calculations are completed, the results return from the card and they are written in text files in order the user can read them.
Keywords:
quantum circuits, GPU, CUDA, simulation, parallel computation
