Speaker
Description
Recent years have witnessed major advances in the understanding of quantum circuit dynamics — progress essential to the success of the field as quantum hardware increasingly moves beyond the reach of classical simulation. The emerging “theory” of quantum devices is largely discrete in character, with prevalent concepts drawn from statistical mechanics, tensor networks, or the combinatorics of random matrices. At the same time, quantum field theory — physics’ established lingua franca for the understanding of complex many-body systems — remains strangely underrepresented, raising the question of why this is so.
In this talk we discuss two paradigmatic aspects of circuit dynamics, thermalization toward ergodic late-time regimes and entanglement generation, to suggest some answers. We argue that quantum field theory provides both access to system classes that may be difficult to approach otherwise and insight into non-perturbative aspects of irreversible circuit evolution. We further argue that these aspects can be relevant to the understanding of realistic hardware, substantiating this claim through comparison with exact diagonalization results for small-system prototypes.