Allowing for phenomena such as the ability of a particle to be in two places at the same time, quantum mechanics is extremely weird. In the past few decades, physicists have been trying to harness this weirdness to build new technologies such as extremely fast quantum computers, provably secure quantum communication devices, and exotic quantum materials. Most quantum systems feature short-range interactions, that is, interactions between adjacent particles only. On the other hand, many recently engineered AMO (atomic, molecular, and optical) systems, such as ultracold atomic ions, polar molecules, and highly excited neutral atoms, feature long-range interactions, that is direct interactions extending far beyond adjacent particles. These long-range interacting AMO systems are arguably the most controllable, tunable, and strongly interacting quantum systems. Precise control over them has recently opened a new paradigm for quantum computing, quantum communication, and engineering of new materials. The goal of this project is to advance the frontier of this new paradigm by exploring the - still largely unknown - potential of these systems. First, concepts from mathematical physics will be used to tackle the challenge of establishing and saturating new limits on how rapidly one can send information across these long-range interacting quantum systems, with applications to quantum communication and quantum computing. Second, methods from quantum information theory will be used to study how long-range interactions can speed up the generation of some of the most complex and exotic quantum states, states that are as different from classical states as possible. The ability to prepare these exotic quantum states will significantly enhance the precision of quantum-based metrology, including clocks, magnetometry, and gravimetry. In synergy with parallel developments in condensed matter physics, the ability to prepare these exotic states may also lead to the design of materials with unprecedented electromagnetic, thermal, or structural properties. All of the above-mentioned groundbreaking quantum-enabled technologies are bound to improve national security and increase economic competitiveness of the United States.
Postdocs and graduate students will be advised and trained and undergraduates will be involved in this research during the summers. New opportunities to increase public scientific literacy by giving talks to non-science audiences will be explored. Being highly interdisciplinary, this work will also naturally foster synergistic interdisciplinary interactions between AMO physicists, condensed matter physicists, computer scientists, and mathematicians.
AMO (atomic, molecular, and optical) systems with long-range interactions, such as Rydberg atoms and polar molecules, are arguably the most controllable, tunable, and strongly interacting quantum systems. Precise control over them has recently opened a new paradigm for quantum computing and communication, entanglement generation, and engineering of new phases of matter. This work will advance the frontier of this new paradigm by exploring the - still largely unknown - potential of these systems, which are often evolving in time far out of equilibrium. First, concepts from mathematical physics, such as Lieb-Robinson bounds, will be employed to tackle the challenge of establishing and saturating new limits on how fast information can propagate in a long-range interacting quantum system. Second, the quantum-information concept of tensor networks will be used to study how long-range interactions can speed up the generation of complex entanglement patterns in quantum systems. In addition to proving mathematical statements, the generated results will be used to engineer experimentally accessible systems to break the limits imposed by short-range interactions and to saturate the new limits that may hold in the presence of long-range interactions. These newly developed entanglement generation protocols will be used to enable the preparation, in AMO labs, of long-range entangled states, such as the fractional quantum Hall state, with applications to fault-tolerant topological quantum computing.
The proposed new Lieb-Robinson bounds on how fast one can transmit quantum information directly advance and define the frontier in various Lieb-Robinson-based fields ranging from quantum state transfer and quantum communication to the study of correlations in gapped ground states. Through the understanding of the structure and time evolution of entanglement in strongly-correlated long-range interacting quantum systems, this work will play a crucial role in harnessing entanglement for metrology, quantum computing, and quantum communication. The proposed use of quantum information science and long-range interacting AMO systems to advance the frontier in both fields will have a particularly transformative impact in synergy with parallel developments to interpret the new long-range-interacting phenomena in the context of condensed matter theory. In particular, this synergy will advance the frontier in understanding and classifying many-body quantum phases and quantum dynamics, which may in turn lead to the design of materials with unprecedented electromagnetic, thermal, or structural properties. All of the above-mentioned groundbreaking quantum-enabled technologies are bound to improve national security and increase economic competitiveness of the United States.
