Kehrein, Stefan K.

[["dc.bibliographiccitation.artnumber","50001"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","EPL (Europhysics Letters)"],["dc.bibliographiccitation.volume","115"],["dc.contributor.author","Schmitt, Markus"],["dc.contributor.author","Kehrein, Stefan"],["dc.date.accessioned","2018-11-07T10:08:57Z"],["dc.date.available","2018-11-07T10:08:57Z"],["dc.date.issued","2016"],["dc.description.abstract","The question of thermalisation in closed quantum many-body systems has received a lot of attention in the past few years. An intimately related question is whether a closed quantum system shows irreversible dynamics. However, irreversibility and what we actually mean by this in a quantum many-body system with unitary dynamics has been explored very little. In this work we investigate the dynamics of the Ising model in a transverse magnetic field involving an imperfect effective time reversal. We propose a definition of irreversibility based on the echo peak decay of observables. Inducing the effective time reversal by different protocols we find an algebraic decay of the echo peak heights or an ever persisting echo peak indicating that the dynamics in this model is well reversible. Copyright (C) EPLA, 2016"],["dc.identifier.doi","10.1209/0295-5075/115/50001"],["dc.identifier.isi","000388368800001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39573"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Epl Association, European Physical Society"],["dc.relation.issn","1286-4854"],["dc.relation.issn","0295-5075"],["dc.title","Effective time reversal and echo dynamics in the transverse field Ising model"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","324"],["dc.bibliographiccitation.journal","Annals of Physics"],["dc.bibliographiccitation.lastpage","340"],["dc.bibliographiccitation.volume","348"],["dc.contributor.author","Oberreuter, Johannes M."],["dc.contributor.author","Homrighausen, Ingo"],["dc.contributor.author","Kehrein, Stefan"],["dc.date.accessioned","2018-11-07T09:36:12Z"],["dc.date.available","2018-11-07T09:36:12Z"],["dc.date.issued","2014"],["dc.description.abstract","We study the time evolution of entanglement in a new quantum version of the Kac ring, where two spin chains become dynamically entangled by quantum gates, which are used instead of the classical markers. The features of the entanglement evolution are best understood by using knowledge about the behavior of an ensemble of classical Kac rings. For instance, the recurrence time of the quantum many-body system is twice the length of the chain and \"thermalization\" only occurs on time scales much smaller than the dimension of the Hilbert space. The model thus elucidates the relation between the results of measurements in quantum and classical systems: While in classical systems repeated measurements are performed over an ensemble of systems, the corresponding result is obtained by measuring the same quantum system prepared in an appropriate superposition repeatedly. (C) 2014 Elsevier Inc. All rights reserved."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft (DFG) [SFB 1073]"],["dc.identifier.doi","10.1016/j.aop.2014.05.019"],["dc.identifier.isi","000340306000023"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/32560"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area B | B03 Relaxation, Thermalisierung, Transport und Kondensation in hochangeregten Festkörpern"],["dc.relation.issn","1096-035X"],["dc.relation.issn","0003-4916"],["dc.title","Entanglement propagation and typicality of measurements in the quantum Kac ring"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","22"],["dc.bibliographiccitation.journal","Physical Review B"],["dc.bibliographiccitation.volume","100"],["dc.contributor.author","Schnaack, Oskar"],["dc.contributor.author","Bölter, Niklas"],["dc.contributor.author","Paeckel, Sebastian"],["dc.contributor.author","Manmana, Salvatore R."],["dc.contributor.author","Kehrein, Stefan"],["dc.contributor.author","Schmitt, Markus"],["dc.date.accessioned","2020-12-10T18:20:22Z"],["dc.date.available","2020-12-10T18:20:22Z"],["dc.date.issued","2019"],["dc.identifier.arxiv","1808.05646"],["dc.identifier.doi","10.1103/PhysRevB.100.224302"],["dc.identifier.eissn","2469-9969"],["dc.identifier.issn","2469-9950"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75540"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area B | B03 Relaxation, Thermalisierung, Transport und Kondensation in hochangeregten Festkörpern"],["dc.title","Tripartite information, scrambling, and the role of Hilbert space partitioning in quantum lattice models"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","23"],["dc.bibliographiccitation.journal","Physical Review. B"],["dc.bibliographiccitation.volume","97"],["dc.contributor.author","Köhler, Thomas"],["dc.contributor.author","Rajpurohit, Sangeeta"],["dc.contributor.author","Schumann, Ole"],["dc.contributor.author","Paeckel, Sebastian"],["dc.contributor.author","Biebl, Fabian R. A."],["dc.contributor.author","Sotoudeh, Mohsen"],["dc.contributor.author","Kramer, Stephan C."],["dc.contributor.author","Blöchl, Peter E."],["dc.contributor.author","Kehrein, Stefan K."],["dc.contributor.author","Manmana, Salvatore R."],["dc.date.accessioned","2020-12-10T18:25:06Z"],["dc.date.available","2020-12-10T18:25:06Z"],["dc.date.issued","2018"],["dc.description.abstract","We investigate the evolution of a photoexcitation in correlated materials over a wide range of time scales. The system studied is a one-dimensional model of a manganite with correlated electron, spin, orbital, and lattice degrees of freedom, which we relate to the three-dimensional material Pr$_{1-x}$Ca$_{x}$MnO$_3$. The ground-state phases for the entire composition range are determined and rationalized by a coarse-grained polaron model. At half-doping a pattern of antiferromagnetically coupled Zener polarons is realized. Using time-dependent density-matrix renormalization group (tDMRG), we treat the electronic quantum dynamics following the excitation. The emergence of quasiparticles is addressed, and the relaxation of the nonequilibrium quasiparticle distribution is investigated via a linearized quantum-Boltzmann equation. Our approach shows that the magnetic microstructure caused by the Zener polarons leads to an increase of the relaxation times of the excitation."],["dc.identifier.arxiv","1610.07246v4"],["dc.identifier.doi","10.1103/PhysRevB.97.235120"],["dc.identifier.eissn","2469-9969"],["dc.identifier.issn","2469-9950"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75574"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area B | B03 Relaxation, Thermalisierung, Transport und Kondensation in hochangeregten Festkörpern"],["dc.relation","SFB 1073 | Topical Area C | C03 Vom Elektronentransfer zur chemischen Energiespeicherung: ab-initio Untersuchungen korrelierter Prozesse"],["dc.relation.issn","2469-9950"],["dc.relation.issn","2469-9969"],["dc.title","Relaxation of photoexcitations in polaron-induced magnetic microstructures"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","205122"],["dc.bibliographiccitation.issue","20"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","88"],["dc.contributor.author","Kohler, Heiner"],["dc.contributor.author","Hackl, Andreas"],["dc.contributor.author","Kehrein, Stefan"],["dc.date.accessioned","2018-11-07T09:17:32Z"],["dc.date.available","2018-11-07T09:17:32Z"],["dc.date.issued","2013"],["dc.description.abstract","Using flowequations and equilibrium and nonequilibrium dynamics of a two-level system (TLS) is investigated, which couples Ohmically via noncommuting components to two independent oscillator baths. In equilibrium, the two-level energy splitting is protected when the TLS is coupled symmetrically to both baths. A critical asymmetry angle separates the localized from the delocalized phase. Real-time decoherence of a nonequilibrium initial state is studied as well. The short-time dynamics exhibits initial slips on the scale of the cutoff frequency of the bath modes. Moreover, whereas for a single bath decay of coherence depends crucially on the chosen initial state, for a symmetric coupling to two baths this dependence vanishes."],["dc.identifier.doi","10.1103/PhysRevB.88.205122"],["dc.identifier.isi","000327160600005"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/28193"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1550-235X"],["dc.relation.issn","1098-0121"],["dc.title","Nonequilibrium dynamics of a system with quantum frustration"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","13"],["dc.bibliographiccitation.journal","Physical Review B"],["dc.bibliographiccitation.volume","99"],["dc.contributor.author","Schmitt, Markus"],["dc.contributor.author","Sels, Dries"],["dc.contributor.author","Kehrein, Stefan"],["dc.contributor.author","Polkovnikov, Anatoli"],["dc.date.accessioned","2020-12-10T18:25:08Z"],["dc.date.available","2020-12-10T18:25:08Z"],["dc.date.issued","2019"],["dc.identifier.doi","10.1103/PhysRevB.99.134301"],["dc.identifier.eissn","2469-9969"],["dc.identifier.issn","2469-9950"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75590"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area B | B03 Relaxation, Thermalisierung, Transport und Kondensation in hochangeregten Festkörpern"],["dc.title","Semiclassical echo dynamics in the Sachdev-Ye-Kitaev model"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.contributor.author","Keunecke, Marius"],["dc.contributor.author","Schmitt, David"],["dc.contributor.author","Reutzel, Marcel"],["dc.contributor.author","Weber, Marius"],["dc.contributor.author","Möller, Christina"],["dc.contributor.author","Jansen, G. S. Matthijs"],["dc.contributor.author","Mishra, Tridev A."],["dc.contributor.author","Osterkorn, Alexander"],["dc.contributor.author","Bennecke, Wiebke"],["dc.contributor.author","Pierz, Klaus"],["dc.contributor.author","Schumacher, Hans Werner"],["dc.contributor.author","Pakdehi, Davood Momeni"],["dc.contributor.author","Steil, Daniel"],["dc.contributor.author","Manmana, Salvatore R."],["dc.contributor.author","Steil, Sabine"],["dc.contributor.author","Kehrein, Stefan"],["dc.contributor.author","Schneider, Hans Christian"],["dc.contributor.author","Mathias, Stefan"],["dc.date.accessioned","2021-10-15T10:37:07Z"],["dc.date.available","2021-10-15T10:37:07Z"],["dc.date.issued","2020-11-26"],["dc.description.abstract","Auger scattering channels are of fundamental importance to describe and understand the non-equilibrium charge carrier dynamics in graphene. While impact excitation increases the number of carriers in the conduction band and has been observed experimentally, direct access to its inverse process, Auger recombination, has so far been elusive. Here, we tackle this problem by applying our novel setup for ultrafast time-resolved photoelectron momentum microscopy. Our approach gives simultaneous access to charge carrier dynamics at all energies and in-plane momenta within the linearly dispersive Dirac cones. We thus provide direct evidence for Auger recombination on a sub-10~fs timescale by identifying transient energy- and momentum-dependent populations far above the excitation energy. We compare our results with model calculations of scattering processes in the Dirac cone to support our experimental findings."],["dc.identifier.arxiv","2012.01256v1"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/90949"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area B | B03 Relaxation, Thermalisierung, Transport und Kondensation in hochangeregten Festkörpern"],["dc.relation","SFB 1073 | Topical Area B | B07 Elementare Schritte der Energiekonversion in stark angeregten korrelierten Materialien"],["dc.title","Direct Access to Auger recombination in Graphene"],["dc.type","preprint"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","165104"],["dc.bibliographiccitation.issue","16"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","89"],["dc.contributor.author","Essler, Fabian H. L."],["dc.contributor.author","Kehrein, Stefan"],["dc.contributor.author","Manmana, Salvatore R."],["dc.contributor.author","Robinson, N. J."],["dc.date.accessioned","2018-11-07T09:41:24Z"],["dc.date.available","2018-11-07T09:41:24Z"],["dc.date.issued","2014"],["dc.description.abstract","We consider quantum quenches in an integrable quantum chain with tuneable-integrability-breaking interactions. In the case where these interactions are weak, we demonstrate that at intermediate times after the quench local observables relax to a prethermalized regime, which can be described by a density matrix that can be viewed as a deformation of a generalized Gibbs ensemble. We present explicit expressions for the approximately conserved charges characterizing this ensemble. We do not find evidence for a crossover from the prethermalized to a thermalized regime on the time scales accessible to us. Increasing the integrability-breaking interactions leads to a behavior that is compatible with eventual thermalization."],["dc.identifier.doi","10.1103/PhysRevB.89.165104"],["dc.identifier.isi","000334111400002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33719"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation","SFB 1073: Kontrolle von Energiewandlung auf atomaren Skalen"],["dc.relation","SFB 1073 | Topical Area B | B03 Relaxation, Thermalisierung, Transport und Kondensation in hochangeregten Festkörpern"],["dc.relation.issn","1550-235X"],["dc.relation.issn","1098-0121"],["dc.title","Quench dynamics in a model with tuneable integrability breaking"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Physical Review B"],["dc.bibliographiccitation.volume","99"],["dc.contributor.author","Cheipesh, Yevheniia"],["dc.contributor.author","Cevolani, Lorenzo"],["dc.contributor.author","Kehrein, Stefan"],["dc.date.accessioned","2020-12-10T18:25:08Z"],["dc.date.available","2020-12-10T18:25:08Z"],["dc.date.issued","2019"],["dc.identifier.doi","10.1103/PhysRevB.99.024422"],["dc.identifier.eissn","2469-9969"],["dc.identifier.issn","2469-9950"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75589"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Exact description of the boundary theory of the Kitaev toric code with open boundary conditions"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","094306"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW B"],["dc.bibliographiccitation.volume","88"],["dc.contributor.author","Medvedyeva, Mariya V."],["dc.contributor.author","Hoffmann, A. L."],["dc.contributor.author","Kehrein, Stefan"],["dc.date.accessioned","2018-11-07T09:19:52Z"],["dc.date.available","2018-11-07T09:19:52Z"],["dc.date.issued","2013"],["dc.description.abstract","We investigate how the Kondo screening cloud builds up as a function of space and time. Starting from an impurity spin decoupled from the conduction band, the Kondo coupling is switched on at time t = 0. We work at the Toulouse point where one can obtain exact analytical results for the ensuing spin dynamics at both zero and nonzero temperature T. For t > 0 the Kondo screening cloud starts building up in the wake of the impurity spin being transported to infinity. In this buildup process the impurity spin-conduction band spin susceptibility shows a sharp light cone due to causality, while the corresponding correlation function has a tail outside the light cone. At T = 0 this tail has a power-law decay as a function of distance from the impurity, which we interpret as due to initial entanglement in the Fermi sea."],["dc.identifier.doi","10.1103/PhysRevB.88.094306"],["dc.identifier.isi","000324485800002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/28743"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1098-0121"],["dc.title","Spatiotemporal buildup of the Kondo screening cloud"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]