Entanglement Dynamics in Atom-Field Systems

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dc.contributor.advisorHu, Bei-Loken_US
dc.contributor.authorCummings, Nicholas Immanuelen_US
dc.contributor.departmentPhysicsen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2011-07-07T05:46:53Z
dc.date.available2011-07-07T05:46:53Z
dc.date.issued2011en_US
dc.description.abstractWe consider the time evolution of quantum entanglement in the context of interactions between atoms and the electromagnetic field. We explore the influence of interatomic separation and the degree to which this can change the qualitative character of those dynamics, including entanglement generation, protection, and sudden death (SD). We find that the qualitative features of entanglement dynamics can be changed entirely in few-mode models when atomic spacing is varied, allowing for particular choices of configuration that are favorable for maintaining entanglement. We also examine the inaccuracies introduced by the use of common approximations: We characterize unexpected errors that result from using perturbative master equations as well as those that result from using the rotating-wave approximation (RWA). We find that in dissipative systems the errors introduced by these approximations can lead to an incorrect picture of late-time dynamics. Standard perturbative master equations using the RWA are constrained to predict that late-time SD occurs to only some initial states at zero temperature, but this is merely an artifact of those approximation and generally not correct. The same master equations predict that at finite temperature all states are separable asymptotically at late times and must undergo SD. In fact a proper accounting of environmentally-induced corrections to the steady state of the system shows that for low temperatures it is possible to have asymptotic entanglement in some cases. We derive a master equation for two atoms interacting with the free field without using the RWA and solve it to obtain the dynamics, including the effects of distance. From these dynamics we find that, in fact, all initial states of atoms separated by any positive distance undergo SD even at zero temperature, though there are sub-radiant states that can be quite long-lived for closely spaced atoms.en_US
dc.identifier.urihttp://hdl.handle.net/1903/11707
dc.subject.pqcontrolledQuantum physicsen_US
dc.subject.pqcontrolledAtomic Physicsen_US
dc.subject.pqcontrolledTheoretical Physicsen_US
dc.subject.pquncontrolledentanglement sudden deathen_US
dc.subject.pquncontrollednon-Markovian dynamicsen_US
dc.subject.pquncontrolledopen quantum systemsen_US
dc.subject.pquncontrolledperturbative master equationsen_US
dc.subject.pquncontrolledquantum entanglement dynamicsen_US
dc.subject.pquncontrolledrotating-wave approximationen_US
dc.titleEntanglement Dynamics in Atom-Field Systemsen_US
dc.typeDissertationen_US

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