In our everyday life we rarely think about the effects of quantum mechanics --- and yet they are constantly around us, determining the properties of every material object in our world. The laws of quantum physics define every property of matter, from the behaviour of individual atoms, to how the atoms bind together to form materials, to the characteristics of these resultant materials. Our understanding of this chain of influence is one of the greatest triumphs of modern science. It is only through this understanding that scientists have engineered modern technologies and devices such as computers, mobile phones, and fibre-optic communications.
In the field of quantum condensed matter, we are concerned with materials, and the quantum mechanics of matter, at a very microscopic scale. Our aim is to uncover new principles, predict new behaviours, new types of matter, and enable new applications.
A key concept that we focus on is the idea of quantum mechanical coherence in matter. The word "coherence" here implies that many microscopic objects are acting together in concert. Such behaviour, when it occurs, allows for the effects of quantum physics to be greatly enhanced. A prime example of coherent behaviour occurs in a superconductor, where due to the effects of quantum mechanics, electrons can flow forever with zero resistance and zero energy loss. In the last decades it has become clear in our community that quantum-mechanical coherence in materials is much more common than we previously expected, although its effects are often subtle and well hidden from our view.
Understanding coherent effects in systems made of many particles (i.e., in material substances) is the main aim of the research supported by this grant. We use a combination of modern mathematical and computational tools to investigate the puzzles of our field. The physics we study is highly complex because in such systems, the many constituent particles interact strongly with each other. As a consequence, qualitatively different behaviour emerges. Because of the novelty of these effects, this field of study is both challenging and exciting, attracting some of the best and the brightest young scientists.
We have divided our effort into three main themes:
Understanding Quantum Many-Body Dynamics: the investigation of how quantum mechanics effects the time evolution of material systems on a microscopic scale. We aim to determine new principles for how coherence is created, spreads, and is destroyed, and how this affects the properties of the substance.
Exploring Quantum Behaviour Far From the Ground State: for over a century it was believed that if heat energy is put into a physical system at one point, it will inevitably spread out to other regions. In the last few years, however, it has become clear that due to the effects of quantum coherence in interacting disordered systems, added energy may remain localized in one region in a stable fashion. We aim to understand better the properties of systems that present such stable and/or coherent high energy states.
Identifying Topological Platforms for Quantum Coherent Phenomena: topological matter exhibits subtle long-range patterns of coherence that cannot be understood by local descriptions. Because of these global effects, such materials are believed to be particularly well suited for robust quantum computing applications. The study of these substances therefore has attracted researchers from physics, mathematics, and computer science. We will explore these materials, where they exist in nature, how they might be engineered, and what their applications are.
While our research is mainly academic in nature, we hope that, analogous to discoveries in basic semiconductor physics a century ago, our discoveries may enable technological revolutions of the future.
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