Seminario Decoherence vs Complexity in a Phase Space
Imparte: Tzula Propp
30 de marzo, 12:00 horas
Salón 200 A del Edificio Anexo del IIMAS
Resumen: We study the competition between decoherence and quantum complexity in
a toy model, and discuss its implications for computation in the era
of Noisy Intermediate Scale Quantum (NISQ) devices. Our toy model is a
single Bosonic mode evolving under the non-linear Kerr interaction.
This is a structure generating process: for the closed Kerr system, an
initial coherent state evolves into a superposition of coherent states
exhibiting both negativity and sub-Planckian features in the quantum
state’s Wigner function. However, only certain measurements are
sensitive to the quantum features of these superpositions, with the
measurement expectation values connected to the states by their shared
symmetry of the cyclic group Z_n. Introducing weak decoherence, the
quantum nature of these expectation values disappears and is replaced
with semiclassical behavior well-described by the Truncated Wigner
Approximation. We also find that these expectation values are
numerically calculable with decreased computational cost for stronger
decoherence. Lastly, we discuss implications of this for NISQ-era
quantum computation and briefly revisit the question of modeling
decoherence more generally using new state-independent formalisms.