Semicoherent Symmetric Quantum Processes: Theory and Applications

Discovering pragmatic and efficient approaches to synthesize ε-approximations to quantum operators such as real (imaginary) time-evolution propagators in terms of the basic quantum operations (gates) is challenging. These invaluable ε-approximations enable the compilation of classical and quantum algorithms modeling, e.g., dynamical properties. In parallel, symmetries are powerful tools concisely describing the fundamental laws of nature; the symmetrical underpinnings of physical laws having consistently provided profound insights and substantially increased predictive power. In this work, we consider the interplay between ε-approximations processes and symmetries in a semi-coherent context–where measurements occur at each logical clock cycle. We draw inspiration from Pascual Jordan's groundbreaking formulation of non-associative, but commutative, algebraic forms. Our symmetrized formalism is applied in various domains such as quantum random walks, real-time-evolutions, variational algorithms ansatzes, and efficient entanglement verification. Our work paves the way for a deeper understanding and greater appreciation of how symmetries can be used to control quantum dynamics in the near-term.