Localization and topology protected quantum coherence at the edge of 'hot' matter
Ehud Altman University of California, Berkeley
PIRSA:14050077
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Long-time behavior of periodically driven isolated interacting quantum systems
Luca D'Alessio Boston University
PIRSA:14050073 -
Light-Cone Effects after Quantum Quenches and Excitations at Finite Entropy
Fabian Essler University of Oxford
PIRSA:14050072 -
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Towards Scaling Relations in Relativistic Hydrodynamics and Gravity
Ryan Westernacher-Schneider Leiden University
PIRSA:14050054 -
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Modeling of RNA Nanotube using Molecular Dynamics Simulation
Shyam Badu Wilfrid Laurier University
PIRSA:14050058
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Localization and topology protected quantum coherence at the edge of 'hot' matter
Ehud Altman University of California, Berkeley
PIRSA:14050077Topological phases are often characterized by special edge states confined near the boundaries by an energy gap in the bulk. On raising temperature, these edge states are lost in a clean system due to mobile thermal excitations. Recently however, it has been established that disorder can localize an isolated many body system, potentially allowing for a sharply defined topological phase even in a highly excited state.I will show this to be the case for the topological phase of a one dimensional magnet with quenched disorder, which features spin one-half excitations at the edges. The time evolution of a simple, highly excited, initial state is used to reveal quantum coherent edge spins. In particular, I will demonstrate, using theoretical arguments and numerical simulation, the coherent revival of an edge spin over a time scale that grows exponentially bigger with system size. This is in sharp contrast to the general expectation that quantum bits strongly coupled to a 'hot' many body system will rapidly lose coherence. -
Long-time behavior of periodically driven isolated interacting quantum systems
Luca D'Alessio Boston University
PIRSA:14050073We show that generic interacting quantum systems, which are isolated and finite, periodically driven by sudden quenches exhibit three physical regimes. For short driving periods the Floquet Hamiltonian is well approximated by the time-averaged Hamiltonian, while for long periods the evolution operator exhibits properties of random matrices of a Circular Ensemble (CE). In-between, there is a crossover
regime. We argue that, in the thermodynamic limit and for nonvanishing driving periods, the evolution operator always exhibits properties of CE random matrices. Consequently, driving leads to infinite temperature at infinite time and to an unphysical Floquet Hamiltonian. -
Light-Cone Effects after Quantum Quenches and Excitations at Finite Entropy
Fabian Essler University of Oxford
PIRSA:14050072 -
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Dynamical analogue quantum simulators
Jens Eisert Freie Universität Berlin
PIRSA:14050068Complex quantum systems out of equilibrium are at the basis of a number of long-standing questions in physics. This talk will be concerned on the one hand with recent progress on understanding how quantum many-body systems out of equilibrium eventually come to rest, thermalise and cross phase transitions, on the other hand with dynamical analogue quantum simulations using cold atoms [1-4]. In an outlook, we will discuss the question of certification of quantum simulators, and will how this problem also arises in other related settings, such as in Boson samplers [5,6]. [1] S. Braun, M. Friesdorf, S. S. Hodgman, M. Schreiber, J. P. Ronzheimer, A. Riera, M. del Rey, I. Bloch, J. Eisert, U. Schneider, arXiv:1403.7199.
[2] M. Kliesch, M. Kastoryano, C. Gogolin, A. Riera, J. Eisert, arXiv:1309:0816.
[3] S. Trotzky, Y.-A. Chen, A. Flesch, I. P. McCulloch, U. Schollwoeck, J. Eisert, I. Bloch, Nature Physics 8, 325 (2012).
[4] A. Riera, C. Gogolin, M. Kliesch, J. Eisert, in preparation (2014).
[5] C. Gogolin, M. Kliesch, L. Aolita, J. Eisert, in preparation (2014) and arXiv:1306.3995.
[6] S. Aaronson, A. Arkhipov, arXiv:1309.7460. -
Quantum Quenches in Thermodynamic Limit
Marcos Rigol Pennsylvania State University
PIRSA:14050067Studies of the quantum dynamics of isolated systems are currently providing fundamental insights into how statistical mechanics emerges under unitary time evolution. Thermalization seems ubiquitous, but experiments with ultracold gases have shown that it need not always occur, particularly near an integrable point. Unfortunately, computational studies of generic (nonintegrable) models are limited to small systems, for which arbitrarily long times can be calculated, or short times, for which large or infinite system sizes can be solved. Consequently, what happens in the thermodynamic limit after long times has been inaccessible to theoretical studies. In this talk, we introduce a linked-cluster based computational approach that allows one to address the latter question in lattice systems. We provide numerical evidence that, in the thermodynamic limit, thermalization occurs in the nonintegrable regime but fails at integrability. A phase transition-like behavior separates the two regimes. -
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Critical Behavior of the Classical XY-model on Fractal Structures
PIRSA:14050060There has been considerable interest in determining whether the universality hypothesis extends to systems which are of non-integer dimension or to systems which are scale invariant (fractals). Specifically research into these types of systems is concerned with determining the relevance of topological properties to their critical phenomena. We have performed Monte Carlo simulations for the XY model on three fractal lattices with different topological properties: the Sierpinski pyramid Menger sponge and Sierpinski carpet. We will give an overview of our results and show that while some properties such as the order of ramification are important in determining the critical behavior of these structures the fractal dimension is not. -
Towards Scaling Relations in Relativistic Hydrodynamics and Gravity
Ryan Westernacher-Schneider Leiden University
PIRSA:14050054Turbulence is ubiquitous in hydrodynamics and its study is dominated by statistical methods and dimensional arguments. Even so analytic results tend to rely heavily on statistical symmetries. I will discuss some such results in non-relativistic turbulence and possible extensions to the relativistic case. The 2+1 dimensionality of our numerical setup allows for gaining insight about 3+1 gravity through the fluid/gravity duality. This work aims to further our understanding of the fluid side in its own right. This partly entails determining the robustness of some recently derived relativistic hydrodynamic scaling relations which may have holographic applications. -
Simulations of Binary Neutron Star Mergers
Marcelo Ponce University of Toronto
PIRSA:14050053By numerically solving Einstein equations we are able to study the strong regime of gravity. In many astrophysical scenarios strong gravity plays a fundamental role such as compact binary systems: e.g. Black Hole binaries binary Neutron Stars and Black Hole-Neutron Star systems. In this talk I will discuss the simulations our group has been conducting in binary Neutron Star system where we can study the dynamics and gravitational radiation of the systems but also establish important connections with electromagnetic counterparts and even testing alternatives theories of gravity (i.e. Scalar-Tensor theories). -
Validation of predicted mRNA splicing mutations using high-throughput transcriptome data
PIRSA:14050059This work has been published:Viner C Dorman SN Shirley BC and Rogan PK (2014)Validation of predicted mRNA splicing mutations using high-throughput transcriptome data [v1; ref status: indexedhttp://f1000r.es/2no]F1000Research20143:8 (doi:10.12688/f1000research.3-8.v1)Additionally this work has been accepted for a highlights presentation at the upcoming Great Lakes Bioinformatics Conference (GLBIO) in Cincinnati Ohio and it was recently presented as a poster at London Health Research Day (LHRD).Abstract:Interpretation of variants present in complete genomes or exomes reveals numerous sequence changes only a fraction of which are likely to be pathogenic. Variants predicted to alter mRNA splicing in particular can be validated by manual inspection of transcriptome sequencing data however this approach is intractable for large datasets. We show that abnormal mRNA splicing patterns are characterized by reads demonstrating either exon skipping cryptic splice site use and high levels of intron inclusion or combinations of these properties. This paper presents Veridical an in silico method for the automatic validation of DNA sequencing variants that alter mRNA splicing. Veridical leverages large numbers of control samples (that lack a putative mutation) applying z-tests to Yeo-Johnson transformed data to normalize read counts of abnormal RNA species in mutant versus non-mutant tissues. With the transformed data the null hypothesis based mainly on either counts of intronic or junctional reads can be rejected for true splicing mutations using conventional parametric statistical methods. -
Modeling of RNA Nanotube using Molecular Dynamics Simulation
Shyam Badu Wilfrid Laurier University
PIRSA:14050058We construct the novel RNA nanpclusters- the RNAnanotubes made of several nanorings. We study the struc-tural properties (i.e. the Root Mean Square Deviation (RMSD)the radius of gyration and radial distribution function) ofRNA nanotube up to the size of about 20nm in physilogicalsolution that can be used for drug delivery into human body.We model RNA nanotube by utilizing molecular dynamicssimulation method implemented in NAMD and VMD. Thepatterns of energy and temperature variations of the systemsare also discussed. Furthermore we study the number of ionsaround the tube as a function of time at a particular temper-ature. We find that if the temperature increases the numberof ions increases within certain distance of the tube. We re-port that the number of ions within a certain distance aroundthe tubes decrease in quenched run. This indicates that someions evaporate with decrease in temperature a