In response to the urgent challenges facing modern democracies, the European City Squared project will use real and synthetic data, along with the latest advances in quantum and classical computational social science, to develop an agent-based computer simulation environment that integrates recent advances in science and technology with social choice theory. This interdisciplinary approach, involving leading scientists, city governments, universities, entrepreneurs, and civil society representatives, will explore the effectiveness of various voting mechanisms, with a primary focus on Quadratic Voting. This novel method of voting has potential to enhance public good allocation and foster an emergent and natural altruism, addressing concerns such as polarization and trust in government. Our methodology will be underpinned by a rigorous adherence to data protection standards, ensuring GDPR compliance and the ethical integrity of our research. By employing mathematical models inspired by natural phenomena, we will identify algorithms conducive to robust democratic decision-making. These algorithms will be tested in real-world scenarios, in collaboration with our government partners, particularly the city of Aarhus, Denmark. The project aims to not only provide groundbreaking insights into democratic governance but also to contribute practical tools for enhancing efficiency and participation in democratic processes. If successful, our research promises to offer significant contributions to the fields of political science, computational modeling, and social choice theory, with the potential to bring unprecedented efficiency gains for European democracies.