Playing with a Quantum Computer

Abstract

The new quantum technologies are currently attracting a great deal of public attention. This application area of quantum physics is expected to provide significant technological and economic opportunities. Major projects such as the Quantum Flagship of the EU [1] or the US National Quantum Initiative [2] have been launched with the aim of bringing quantum technologies into industrial application. The development of quantum computers, which is being vigorously pursued, is attracting particular interest. Journals and internet news channels regularly report on progress. The high public attention given to quantum computing shows that it is perceived as an interesting topic. We want to utilize this motivating effect for the teaching and learning of quantum physics. Specifically, we want to take advantage of the access to real quantum computers, which various providers make available free of charge. A number of platforms (e.g. IBM Quantum [3] or TU Delft’s Quantum Inspire [4]) allow users to register for cloud-based quantum computer access. In these environments, users can try out quantum algorithms on real quantum hardware. In addition, there are user-friendly simulators such as Quirk [5, 6] and environments with extensive learning materials for learning hardware-related programming languages (e.g. IBM Qiskit [7], Microsoft Q# [8] or Google Cirq [9]). New providers and approaches appear regularly [10]. An overview of freely available quantum programming resources is provided by the regularly updated GitHub collection “Open-Source Quantum Software Projects” [11]. The approach of teaching quantum physics via quantum technologies has one major advantage: the basic entities are physically simple. Qubits are described as two-state systems – the simplest possible quantum systems. The polarization of light, which plays a major role in quantum cryptography and communication, is also very easy to describe quantum mechanically. Another teaching advantage is that quantum technologies directly address the genuinely non-classical features of quantum physics: topics such as superposition, measurement, entanglement are essential in this area. The physics underlying the new quantum technologies is not new: It is still the same quantum physics developed in the days of Heisenberg and Schrödinger. But its technological application in quantum computers, with novel concepts as qubits and quantum gates, allows a new teaching approach to quantum physics. The new approach is focused more on information science than the traditional approach. It opens up new opportunities for application orientation and allows for fresh examples and exercise tasks. In this article we would like to show a direct and straightforward way to use quantum computers in an introductory course on quantum physics. The technical possibilities are already available: The platforms listed above provide learners with the opportunity to