SESSION 11: Quantum chaos

Chair: (Justin Dressel)
10:45am - 11:30amShohini Ghose, Wilfrid Laurier University (invited)
Chaos, stability and quantum-classical correspondence in spin systems
Abstract. Classical chaos is characterized by extreme sensitivity of a system's dynamics to small perturbations in initial conditions. At the quantum level, a similar characterization of chaos remains a challenge due to the uncertainty principle and the apparent linearity of quantum evolution. We have explored the question of quantum chaos in spin systems both theory and experiments. Various signatures of chaos and classical bifurcations can be observed in a deeply quantum regime as well as the semiclassical regime. Chaos can affect quantum phenomena such as entanglement and fidelity decay that play important roles in quantum information processing. We present a method to quantify the Bohr correspondence principle in chaotic systems, and explain previous conflicting results regarding the connection between chaos and entanglement.
11:30am - 12:00pmPablo Poggi, University of New Mexico CQuIC
Feedback-based simulation of quantum nonlinear dynamics: The Quantum Kicked Top in an ensemble of two-level atoms
Abstract. We study the implementation of a measurement-based feedback scheme to realize quantum nonlinear dynamics. We specifically study the Quantum Kicked Top (QKT), a standard paradigm of quantum chaos, in the context of an ensemble of spins. The scheme uses a sequence of (not-so) weak measurements of a collective spin variable and global rotations conditioned on the measurement outcome. We show that the resulting dynamics, ensemble averaged over many realizations, is governed by a combination of the QKT Hamiltonian and a non-unitary channel which vanishes in the semiclassical limit, recovering the Classical Kicked Top. We also analyze individual quantum trajectories, where we explore the emergence of chaotic behaviour and revisit the role of the measurement process in the quantum-to-classical transition.

SQuInT Chief Organizer
Akimasa Miyake, Associate Professor

SQuInT Local Organizers
Rafael Alexander, Postdoctoral Fellow
Chris Jackson, Postdoctoral Fellow

SQuInT Administrator
Gloria Cordova
505 277-1850

SQuInT Assistant
Wendy Jay

SQuInT Founder
Ivan Deutsch, Regents' Professor, CQuIC Director

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