Speaker
Description
We study the effect of conserved charges on thermalization in quantum chaotic systems. Holographically, in the presence of a chemical potential, a non-monotonicity appears in the thermalization time as a function of chemical potential for small regions. To shed light on this behavior from the quantum side we study the dynamics of out of equilibrium states in finite-dimensional spin chains. Our constructed Hamiltonian embeds a mixed field Ising model of qubits into a larger qutrit Hilbert space, admitting a variable conserved charge $Q$. We find that a non-monotonicity is present in the entropy saturation times as a function of $Q$, and find corresponding behavior in the entanglement velocities as well. Additionally, we find that the entropy saturation value grows with the size of the charge superselection sector, maximizing when $Q$ is $1/3$ of its maximal value. We also study the behavior of Pauli matrices acting on the qubit subsystem of each lattice site and show the behavior matches the nearly time-independent behavior of local operators predicted by the Eigenstate Thermalization Hypothesis.
