Institut für Theoretische Physik

[["dc.bibliographiccitation.artnumber","086403"],["dc.bibliographiccitation.issue","8"],["dc.bibliographiccitation.journal","Physical Review Letters"],["dc.bibliographiccitation.volume","116"],["dc.contributor.author","Lenz, Benjamin"],["dc.contributor.author","Manmana, Salvatore R."],["dc.contributor.author","Pruschke, Thomas"],["dc.contributor.author","Assaad, Fakher F."],["dc.contributor.author","Raczkowski, Marcin"],["dc.date.accessioned","2020-12-10T18:25:39Z"],["dc.date.available","2020-12-10T18:25:39Z"],["dc.date.issued","2016"],["dc.description.abstract","We present evidence for Mott quantum criticality in an anisotropic two-dimensional system of coupled Hubbard chains at half-filling. In this scenario emerging from variational cluster approximation and cluster dynamical mean-field theory, the interchain hopping t(perpendicular to) acts as a control parameter driving the second-order critical end point T-c of the metal-insulator transition down to zero at t(perpendicular to)(c)/t similar or equal to 0.2. Below t(perpendicular to)(,)(c) the volume of the hole and electron Fermi pockets of a compensated metal vanishes continuously at the Mott transition. Above t(perpendicular to)(c), the volume reduction of the pockets is cut off by a first-order transition. We discuss the relevance of our findings to a putative quantum critical point in layered organic conductors, whose location remains elusive so far."],["dc.identifier.doi","10.1103/PhysRevLett.116.086403"],["dc.identifier.eissn","1079-7114"],["dc.identifier.isi","000370847100007"],["dc.identifier.issn","0031-9007"],["dc.identifier.pmid","26967431"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75780"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1079-7114"],["dc.relation.issn","0031-9007"],["dc.title","Mott Quantum Criticality in the Anisotropic 2D Hubbard Model"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","14001"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","EPL"],["dc.bibliographiccitation.volume","120"],["dc.contributor.author","Mokhtari, Zahra"],["dc.contributor.author","Aspelmeier, Timo"],["dc.contributor.author","Zippelius, Annette"],["dc.date.accessioned","2020-12-10T18:41:38Z"],["dc.date.available","2020-12-10T18:41:38Z"],["dc.date.issued","2017"],["dc.identifier.doi","10.1209/0295-5075/120/14001"],["dc.identifier.eissn","1286-4854"],["dc.identifier.issn","0295-5075"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/77635"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Collective rotations of active particles interacting with obstacles"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2004922"],["dc.bibliographiccitation.issue","44"],["dc.bibliographiccitation.journal","Small"],["dc.bibliographiccitation.volume","16"],["dc.contributor.author","Liu, Huan"],["dc.contributor.author","Pang, Bo"],["dc.contributor.author","Tang, Qiyun"],["dc.contributor.author","Müller, Marcus"],["dc.contributor.author","Zhang, Hua"],["dc.contributor.author","Dervişoğlu, Riza"],["dc.contributor.author","Zhang, Kai"],["dc.date.accessioned","2021-04-14T08:32:17Z"],["dc.date.available","2021-04-14T08:32:17Z"],["dc.date.issued","2020"],["dc.description.abstract","Abstract For the first time Janus‐like films of surface‐acylated cellulose nanowhiskers (CNWs) with or without graphene oxide (GO) via one‐step evaporation‐driven self‐assembly process are reported, which have reconstructible time‐dependent micro‐/nanostructures and asymmetric wettability. The heterogeneous aggregation of CNWs on rough Teflon substrates favors the formation of uniform films, leading to hydrophobic smooth bottom surface. The homogeneous nucleation of residual CNWs in bulk suspensions promotes the growth of patchy microspheres with an average diameter of 22.7 ± 2.1 µm, which precipitate on the top surface leading to enhanced hydrophobicity. These patchy microspheres are thermoresponsive and vanish after heating at 60 °C within 1 min, while they are reconstructed at room temperature with time‐dependent evolving micro‐/nanostructures in dry state within 2 d. The thermoresponsive transition of patchy microparticles leads to accompanied switchable change between transparency and opacity of Janus‐like films. Furthermore, the incorporation of GO generates more patchy microspheres with an average diameter of 13.5 ± 1.3 µm on the top surface of hybrid Janus‐like films. Different distributions of CNWs and GO in Janus‐like films and the solvent‐responsive self‐assembled patchy microparticles of CNWs facilitate their reversible actuation by showing fast curling in THF within 6 s and flattening in water for at least 25 cycles."],["dc.description.abstract","Janus‐like films of self‐assembled surface‐acylated cellulose nanowhiskers (CNWs) with or without graphene oxide (GO) have asymmetric topographies on their top and bottom surfaces showing different wettabilities, allowing fast solvent‐responsive actuation. Self‐assembled patchy microspheres on the top surface vanish upon heating and recover after cooling down to room temperature with time‐dependent morphologies, while the bottom surface remains smooth. image"],["dc.description.sponsorship","German Research Foundation http://dx.doi.org/10.13039/501100001659"],["dc.description.sponsorship","Georg‐August‐University of Goettingen"],["dc.description.sponsorship","China Scholarship Council http://dx.doi.org/10.13039/501100004543"],["dc.identifier.doi","10.1002/smll.202004922"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/83873"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-399"],["dc.relation.eissn","1613-6829"],["dc.relation.issn","1613-6810"],["dc.rights","This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes."],["dc.title","Self‐Assembly of Surface‐Acylated Cellulose Nanowhiskers and Graphene Oxide for Multiresponsive Janus‐Like Films with Time‐Dependent Dry‐State Structures"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","063622"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW A"],["dc.bibliographiccitation.volume","90"],["dc.contributor.author","Hazzard, Kaden R. A."],["dc.contributor.author","van den Worm, Mauritz"],["dc.contributor.author","Foss-Feig, Michael"],["dc.contributor.author","Manmana, Salvatore R."],["dc.contributor.author","Dalla Torre, Emanuele G."],["dc.contributor.author","Pfau, Tilman"],["dc.contributor.author","Kastner, Michael"],["dc.contributor.author","Rey, Ana Maria"],["dc.date.accessioned","2018-11-07T09:31:16Z"],["dc.date.available","2018-11-07T09:31:16Z"],["dc.date.issued","2014"],["dc.description.abstract","By applying complementary analytic and numerical methods, we investigate the dynamics of spin-1/2 XXZ models with variable-range interactions in arbitrary dimensions. The dynamics we consider is initiated from uncorrelated states that are easily prepared in experiments; it can be equivalently viewed as either Ramsey spectroscopy or a quantum quench. Our primary focus is the dynamical emergence of correlations and entanglement in these far-from-equilibrium interacting quantum systems: We characterize these correlations by the entanglement entropy, concurrence, and squeezing, which are inequivalent measures of entanglement corresponding to different quantum resources. In one spatial dimension, we show that the time evolution of correlation functions manifests a nonperturbative dynamic singularity. This singularity is characterized by a universal power-law exponent that is insensitive to small perturbations. Explicit realizations of these models in current experiments using polar molecules, trapped ions, Rydberg atoms, magnetic atoms, and alkaline-earth and alkali-metal atoms in optical lattices, along with the relative merits and limitations of these different systems, are discussed."],["dc.identifier.doi","10.1103/PhysRevA.90.063622"],["dc.identifier.isi","000346375900010"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/31504"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1094-1622"],["dc.relation.issn","1050-2947"],["dc.title","Quantum correlations and entanglement in far-from-equilibrium spin systems"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","214905"],["dc.bibliographiccitation.issue","21"],["dc.bibliographiccitation.journal","The Journal of Chemical Physics"],["dc.bibliographiccitation.volume","124"],["dc.contributor.author","Wald, Christian"],["dc.contributor.author","Goldbart, Paul M."],["dc.contributor.author","Zippelius, Annette"],["dc.date.accessioned","2018-11-07T09:41:48Z"],["dc.date.available","2018-11-07T09:41:48Z"],["dc.date.issued","2006"],["dc.description.abstract","We consider a microscopic model of a polymer blend that is prone to phase separation. Permanent cross-links are introduced between randomly chosen pairs of monomers, drawn from the Deam-Edwards distribution. Thereby, not only density but also concentration fluctuations of the melt are quenched-in in the gel state, which emerge upon sufficient cross-linking. We derive a Landau expansion in terms of the order parameters for gelation and phase separation, and analyze it on the mean-field level, including Gaussian fluctuations. The mixed gel is characterized by thermal as well as time-persistent (glassy) concentration fluctuations. Whereas the former are independent of the preparation state, the latter reflect the concentration fluctuations at the instant of cross-linking, provided the mesh size is smaller than the correlation length of phase separation. The mixed get becomes unstable to microphase separation upon lowering the temperature in the gel phase. Whereas the length scale of microphase separation is given by the mesh size, at least close to the transition, the emergent microstructure depends on the composition and compressibility of the melt. Hexagonal structures, as well as lamellas or random structures with a unique wavelength, can be energetically favorable. (c) 2006 American Institute of Physics."],["dc.identifier.doi","10.1063/1.2200697"],["dc.identifier.isi","000238758700049"],["dc.identifier.pmid","16774440"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33812"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Inst Physics"],["dc.relation.issn","1089-7690"],["dc.relation.issn","0021-9606"],["dc.title","Glassy correlations and microstructures in randomly cross-linked homopolymer blends"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","051802"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Physical Review. E"],["dc.bibliographiccitation.volume","77"],["dc.contributor.author","Xing, Xiangjun"],["dc.contributor.author","Pfahl, Stephan"],["dc.contributor.author","Mukhopadhyay, Swagatam"],["dc.contributor.author","Goldbart, Paul M."],["dc.contributor.author","Zippelius, Annette"],["dc.date.accessioned","2018-11-07T11:15:48Z"],["dc.date.available","2018-11-07T11:15:48Z"],["dc.date.issued","2008"],["dc.description.abstract","A Landau theory is constructed for the gelation transition in cross-linked polymer systems possessing spontaneous nematic ordering, based on symmetry principles and the concept of an order parameter for the amorphous solid state. This theory is substantiated with help of a simple microscopic model of cross-linked dimers. Minimization of the Landau free energy in the presence of nematic order yields the neoclassical theory of the elasticity of nematic elastomers and, in the isotropic limit, the classical theory of isotropic elasticity. These phenomenological theories of elasticity are thereby derived from a microscopic model, and it is furthermore demonstrated that they are universal mean-field descriptions of the elasticity for all chemical gels and vulcanized media."],["dc.identifier.doi","10.1103/PhysRevE.77.051802"],["dc.identifier.isi","000256885400084"],["dc.identifier.pmid","18643092"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54445"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1539-3755"],["dc.title","Nematic elastomers: From a microscopic model to macroscopic elasticity theory"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3161"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Macromolecules"],["dc.bibliographiccitation.lastpage","3164"],["dc.bibliographiccitation.volume","43"],["dc.contributor.author","von der Heydt, Alice"],["dc.contributor.author","Mueller, Marcus"],["dc.contributor.author","Zippelius, Annette"],["dc.date.accessioned","2018-11-07T08:44:08Z"],["dc.date.available","2018-11-07T08:44:08Z"],["dc.date.issued","2010"],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft [SFB-602/B6]"],["dc.identifier.doi","10.1021/ma100192n"],["dc.identifier.isi","000276232800010"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/20130"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","0024-9297"],["dc.title","Sequence Fractionation in Symmetric Random Block Copolymers"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5360"],["dc.bibliographiccitation.issue","25"],["dc.bibliographiccitation.journal","Physical Review Letters"],["dc.bibliographiccitation.lastpage","5363"],["dc.bibliographiccitation.volume","85"],["dc.contributor.author","Broderix, K."],["dc.contributor.author","Bhattacharya, K. K."],["dc.contributor.author","Cavagna, A."],["dc.contributor.author","Zippelius, Annette"],["dc.contributor.author","Giardina, I."],["dc.date.accessioned","2018-11-07T09:17:56Z"],["dc.date.available","2018-11-07T09:17:56Z"],["dc.date.issued","2000"],["dc.description.abstract","Molecular dynamics simulations are used to generate an ensemble of saddles of the potential energy of a Lennard-Jones liquid. Classifying all extrema by their potential energy u and number of unstable directions k, a well-defined relation k(u) is revealed. The degree of instability of typical stationary points vanishes at a threshold potential energy u(th), which lies above the energy of the lowest glassy minima of the system. The energies of the inherent states, as obtained by the Stillinger-Weber method, approach u(th) at a temperature close to the mode-coupling transition temperature T-c."],["dc.identifier.doi","10.1103/PhysRevLett.85.5360"],["dc.identifier.isi","000165884200025"],["dc.identifier.pmid","11135996"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/28291"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","American Physical Soc"],["dc.relation.issn","0031-9007"],["dc.title","Energy landscape of a Lennard-Jones liquid: Statistics of stationary points"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","032701"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Physical Review. E"],["dc.bibliographiccitation.volume","88"],["dc.contributor.author","von der Heydt, Alice"],["dc.contributor.author","Wilkin, Daniel"],["dc.contributor.author","Benetatos, Panayotis"],["dc.contributor.author","Zippelius, Annette"],["dc.date.accessioned","2018-11-07T09:20:01Z"],["dc.date.available","2018-11-07T09:20:01Z"],["dc.date.issued","2013"],["dc.description.abstract","Aiming at the mechanical properties of cross-linked biopolymers, we set up and analyze a model of two weakly bending wormlike chains subjected to a tensile force, with regularly spaced inter-chain bonds (cross-links) represented by harmonic springs. Within this model, we compute the force-extension curve and the differential stiffness exactly and discuss several limiting cases. Cross-links effectively stiffen the chain pair by reducing thermal fluctuations transverse to the force and alignment direction. The extra alignment due to cross-links increases both with growing number and with growing strength of the cross-links, and is most prominent for small force f. For large f, the additional, cross-link-induced extension is subdominant except for the case of linking the chains rigidly and continuously along their contour. In this combined limit, we recover asymptotically the elasticity of a weakly bending wormlike chain without constraints, stiffened by a factor of 4. The increase in differential stiffness can be as large as 100% for small f or large numbers of cross-links."],["dc.identifier.doi","10.1103/PhysRevE.88.032701"],["dc.identifier.fs","599508"],["dc.identifier.isi","000323895200005"],["dc.identifier.pmid","24125288"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10511"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/28777"],["dc.notes","Financial support by the DFG Grants No. SFB-937/A1 and No. SFB-937/A4"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","2470-0053"],["dc.relation.issn","2470-0045"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","Elasticity of cross-linked semiflexible biopolymers under tension"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","64"],["dc.bibliographiccitation.journal","BMC Neuroscience"],["dc.bibliographiccitation.volume","10"],["dc.contributor.author","Jaiswal, Manoj Kumar"],["dc.contributor.author","Zech, Wolf-Dieter"],["dc.contributor.author","Goos, Miriam"],["dc.contributor.author","Leutbecher, Christine"],["dc.contributor.author","Ferri, Alberto"],["dc.contributor.author","Zippelius, Annette"],["dc.contributor.author","Carri, Maria Teresa"],["dc.contributor.author","Nau, Roland"],["dc.contributor.author","Keller, Bernhard U."],["dc.date.accessioned","2018-11-07T08:28:40Z"],["dc.date.available","2018-11-07T08:28:40Z"],["dc.date.issued","2009"],["dc.description.abstract","Background: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the selective loss of motor neurons (MN) in the brain stem and spinal cord. Intracellular disruptions of cytosolic and mitochondrial calcium have been associated with selective MN degeneration, but the underlying mechanisms are not well understood. The present evidence supports a hypothesis that mitochondria are a target of mutant SOD1-mediated toxicity in familial amyotrophic lateral sclerosis (fALS) and intracellular alterations of cytosolic and mitochondrial calcium might aggravate the course of this neurodegenerative disease. In this study, we used a fluorescence charged cool device (CCD) imaging system to separate and simultaneously monitor cytosolic and mitochondrial calcium concentrations in individual cells in an established cellular model of ALS. Results: To gain insights into the molecular mechanisms of SOD1(G93A) associated motor neuron disease, we simultaneously monitored cytosolic and mitochondrial calcium concentrations in individual cells. Voltage - dependent cytosolic Ca(2+) elevations and mitochondria - controlled calcium release mechanisms were monitored after loading cells with fluorescent dyes fura-2 and rhod-2. Interestingly, comparable voltage-dependent cytosolic Ca(2+) elevations in WT (SH-SY5Y(WT)) and G93A (SH-SY5Y(G93A)) expressing cells were observed. In contrast, mitochondrial intracellular Ca(2+) release responses evoked by bath application of the mitochondrial toxin FCCP were significantly smaller in G93A expressing cells, suggesting impaired calcium stores. Pharmacological experiments further supported the concept that the presence of G93A severely disrupts mitochondrial Ca(2+) regulation. Conclusion: In this study, by fluorescence measurement of cytosolic calcium and using simultaneous [Ca(2+)]i and [Ca(2+)](mito) measurements, we are able to separate and simultaneously monitor cytosolic and mitochondrial calcium concentrations in individual cells an established cellular model of ALS. The primary goals of this paper are (1) method development, and (2) screening for deficits in mutant cells on the single cell level. On the technological level, our method promises to serve as a valuable tool to identify mitochondrial and Ca(2+)-related defects during G93A-mediated MN degeneration. In addition, our experiments support a model where a specialized interplay between cytosolic calcium profiles and mitochondrial mechanisms contribute to the selective degeneration of neurons in ALS."],["dc.identifier.doi","10.1186/1471-2202-10-64"],["dc.identifier.isi","000268695200001"],["dc.identifier.pmid","19545440"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/5754"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/16476"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.notes.submitter","Najko"],["dc.relation.issn","1471-2202"],["dc.rights","CC BY 2.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/2.0"],["dc.title","Impairment of mitochondrial calcium handling in a mtSOD1 cell culture model of motoneuron disease"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]