NMR studies of quantum chaos in a two-qubit kicked top

TL;DR

This paper experimentally investigates quantum chaos in a two-qubit NMR system implementing the kicked top model, analyzing quantum states through tomography to explore chaos signatures and quantum-classical correspondence.

Contribution

It demonstrates the realization of the quantum kicked top model in a two-qubit NMR system and employs quantum state tomography to study chaos indicators.

Findings

Observation of quantum chaos signatures in NMR system

Correlation between quantum measures and classical phase space

Identification of symmetries and periodicity in quantum chaos

Abstract

Quantum chaotic kicked top model is implemented experimentally in a two qubit system comprising of a pair of spin-1/2 nuclei using Nuclear Magnetic Resonance techniques. The essential nonlinear interaction was realized using indirect spin-spin coupling, while the linear kicks were realized using RF pulses. After a variable number of kicks, quantum state tomography was employed to reconstruct the single-qubit density matrices using which we could extract various measures such as von Neumann entropies, Husimi distributions, and Lyapunov exponents. These measures enabled the study of correspondence with classical phase space as well as to probe distinct features of quantum chaos, such as symmetries and temporal periodicity in the two-qubit kicked top.