Nonequilibrium Dynamics in Open Quantum Systems

dc.contributor.advisorRolston, Steven Len_US
dc.contributor.advisorGorshkov, Alexey Ven_US
dc.contributor.authorYoung, Jeremyen_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.accessioned2020-02-01T06:38:52Z
dc.date.available2020-02-01T06:38:52Z
dc.date.issued2019en_US
dc.description.abstractDue to the variety of tools available to control atomic, molecular, and optical (AMO) systems, they provide a versatile platform for studying many-body physics, quantum simulation, and quantum computation. Although extensive efforts are employed to reduce coupling between the system and the environment, the effects of the environment can never fully be avoided, so it is important to develop a comprehensive understanding of open quantum systems. The system-environment coupling often leads to loss via dissipation, which can be countered by a coherent drive. Open quantum systems subject to dissipation and drive are known as driven-dissipative systems, and they provide an excellent platform for studying many-body nonequilibrium physics. The first part of this dissertation will focus on driven-dissipative phase transitions. Despite the nonequilibrium nature of these systems, the corresponding phase transitions tend to exhibit emergent equilibrium behavior. However, we will show that in the vicinity of a multicritical point where multiple phase transitions intersect, genuinely nonequilibrium criticality can emerge, even though the individual phase transitions on their own exhibit equilibrium criticality. These nonequilibrium multicritical points can exhibit a variety of exotic phenomena not possible for their equilibrium counterparts, including the emergence of complex critical exponents, which lead to discrete scale invariance and spiraling phase boundaries. Furthermore, the Liouvillian gap can take on complex values, and the fluctuation-dissipation theorem is violated, corresponding to an effective temperature which gets "hotter" and "hotter" at longer and longer wavelengths. The second part of this dissertation will focus on Rydberg atoms. In particular, we study how the spontaneous generation of contaminant Rydberg states drastically modifies the behavior of a driven-dissipative Rydberg system due to the resultant dipole-dipole interactions. These interactions lead to a complicated competition of both blockade and anti-blockade effects, leading to strongly enhanced Rydberg populations for far-detuned drive and reduced Rydberg populations for resonant drive.en_US
dc.identifierhttps://doi.org/10.13016/xo69-zilg
dc.identifier.urihttp://hdl.handle.net/1903/25432
dc.language.isoenen_US
dc.subject.pqcontrolledQuantum physicsen_US
dc.subject.pqcontrolledStatistical physicsen_US
dc.subject.pqcontrolledAtomic physicsen_US
dc.subject.pquncontrolledDriven-dissipativeen_US
dc.subject.pquncontrolledNonequilibriumen_US
dc.subject.pquncontrolledOpen quantum systemsen_US
dc.subject.pquncontrolledPhase transitionen_US
dc.subject.pquncontrolledRydberg atomsen_US
dc.titleNonequilibrium Dynamics in Open Quantum Systemsen_US
dc.typeDissertationen_US

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