Wider research context - Understanding the rich phenomenology of complex quantum many-body systems remains a key challenge across the natural sciences. Richard Feynman’s idea to address this problem by using one quantum system to simulate another has sparked decades of research on quantum control into a new era of quantum science and technology. Cold-atom research has played a key role in these developments by pioneering techniques to isolate complex quantum systems from their environment, control their microscopic properties, and steer their dynamics with astonishing precision. Currently, we are in the midst of another leap forward that promises to transform quantum simulations and is establishing neutral atoms as prime candidates for practical quantum information tasks. At the heart of these developments are recent advances in engineering long-range interactions to create highly connected quantum many-body systems with collective properties far beyond their microscopic constituents.
Objectives - Our project will explore this frontier of highly connected quantum systems using neutral atoms. The SFB QNAct makes this possible by seizing a unique and timely opportunity for combining recent breakthroughs within a coordinated research program on the next generation of quantum architectures with strong interactions. Together, we will advance these novel platforms and develop new approaches to understand and exploit their emerging properties. Our research thereby promises broad impact, aiming to (i) radically expand the scope of quantum simulations to access long elusive regimes of many-body physics, (ii) fundamentally elevate the performance of quantum processors to lay a viable path towards practical applications, and (iii) explore uncharted regimes of quantum optics, based on the collective coupling and correlations across large numbers of highly connected particles.
Methods - Our efforts, thus, aim at providing essential tools, concepts, and technology to realize new kinds of quantum systems and to tap the full potential of these platforms. Unravelling the rich phenomenology of complex many-body systems with finite-range interactions remains an outstanding challenge that will be addressed by all theory teams from diverse angles and with complementary approaches (e.g., phase-space methods, Monte Carlo approaches, tensor networks, and machine learning). These will not only yield methodological links and find applications across the theory projects but will also provide vital input to our experiments in QNAct. We will focus on 4 platforms that are distinct in their physical implementation, but closely connected through underlying theoretical concepts and with regards to experimental technologies: (i) lattices of dysprosium atoms that feature extraordinarily high magnetic dipole moments, (ii) ultracold CaF molecules with exceedingly strong electric dipole interactions, (iii) arrays of atoms in optical resonators that yield programmable interactions, and (iv) arrays of Rydberg atoms with strong van der Waals interactions.
Innovation - Reaching these objectives requires original and unconventional solutions, which the SFB will facilitate through the transfer of ideas across different quantum systems and the sharing of complementary methods in theory and experiment. The planned research will necessarily drive crucial technology advancements with broad scientific impact, and it will contribute to the pursuit of long-standing milestones and address some of the most pressing questions in the field: from simulating fermionic models inregimes relevant to high-Tc superconductivity, and understanding the spreading of entanglement in complex quantum systems, to unraveling the physics of exotic dynamical phases and the emergence of classicality due to high connectivity, measurements, and dissipation. This broad scientific scope of our SFB firmly rests upon the focussed research approach of the entire consortium. Jointly, we will work to define and advance the state-of-the-art of neutral-atom quantum platforms whose scientific perspectives reach well beyond the first 4-year funding period and will contribute substantially at the forefront of worldwide quantum research.
Added value - Research on atomic systems with long-range interactions is becoming a national focus area in quantum science, not least reflected in recent recruitments of 4 of our project leaders. Concurrently with a virtual explosion of international initiatives, these developments present an opportune time to build on this momentum and establish a coordinated research and much needed training network of strategic significance and positive impact that will exceed the SFB’s intrinsic added value of collaborations and exchange of researchers, ideas, and technology.
