TY - BOOK

T1 - Momentum evolution numerics of an impurity in a quantum quench

AU - Malcomson, Matthew

PY - 2016

Y1 - 2016

N2 - A discussion on the momentum evolution of an impurity interacting via a finitedelta potential repulsion with a non-interacting fermionic background gas is presented.It has recently been shown that the momentum evolution of this systemdisplays two interesting features, namely a non-zero thermalised value and a longlived quantum mechanical oscillation around this plateau named “quantum flutter” [Mathy, Zvonarev, Demler, Nat. Phys. 2012]. We discuss revivals in themomentum of the impurity, which have been seen before but not yet thoroughlyinvestigated. Subsequently it is shown the quantum flutter and revivals are caused by disjoint sets of eigenstate transitions, and this fact is used to interpret some of their aspects. This attribution of momentum features to different eigenstate subsets allows quantitative reproduction of these features with much less computational expense than has so far been possible. Finally some results on the distribution of the momentum of eigenstates and their relation to the momentum of the impurity once the system has been thermalised are presented along with a discussion on the time averaged infinite time value of the momentum and its comparison to different eigenstate subsets.

AB - A discussion on the momentum evolution of an impurity interacting via a finitedelta potential repulsion with a non-interacting fermionic background gas is presented.It has recently been shown that the momentum evolution of this systemdisplays two interesting features, namely a non-zero thermalised value and a longlived quantum mechanical oscillation around this plateau named “quantum flutter” [Mathy, Zvonarev, Demler, Nat. Phys. 2012]. We discuss revivals in themomentum of the impurity, which have been seen before but not yet thoroughlyinvestigated. Subsequently it is shown the quantum flutter and revivals are caused by disjoint sets of eigenstate transitions, and this fact is used to interpret some of their aspects. This attribution of momentum features to different eigenstate subsets allows quantitative reproduction of these features with much less computational expense than has so far been possible. Finally some results on the distribution of the momentum of eigenstates and their relation to the momentum of the impurity once the system has been thermalised are presented along with a discussion on the time averaged infinite time value of the momentum and its comparison to different eigenstate subsets.

M3 - Doctoral Thesis

PB - Lancaster University

ER -