9,175 research outputs found

    The Utopian

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    The paper was concerned with the future of the social housing complex in Poplar, East London called Robin Hood Gardens designed, conceived and built in the late 60's by Alison and Peter Smithson. The project and publication centred on the possible future for the building through a series of articles and conceptual visions created by us as the authors

    Two-dimensional conformal field theory and the butterfly effect

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    We study chaotic dynamics in two-dimensional conformal field theory through out-of-time order thermal correlators of the form W(t)VW(t)V\langle W(t)VW(t)V\rangle. We reproduce bulk calculations similar to those of [1], by studying the large cc Virasoro identity block. The contribution of this block to the above correlation function begins to decrease exponentially after a delay of tβ2πlogβ2EwEv\sim t_* - \frac{\beta}{2\pi}\log \beta^2E_w E_v, where tt_* is the scrambling time β2πlogc\frac{\beta}{2\pi}\log c, and Ew,EvE_w,E_v are the energy scales of the W,VW,V operators.Comment: v1: 14 pages plus appendices, 2 figures. v2: references updated and minor changes to the text. v3: minor error corrected in Appendix B, but the conclusion is unchange

    Lieb-Robinson and the butterfly effect

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    As experiments are increasingly able to probe the quantum dynamics of systems with many degrees of freedom, it is interesting to probe fundamental bounds on the dynamics of quantum information. We elaborate on the relationship between one such bound---the Lieb-Robinson bound---and the butterfly effect in strongly-coupled quantum systems. The butterfly effect implies the ballistic growth of local operators in time, which can be quantified with the "butterfly" velocity vBv_B. Similarly, the Lieb-Robinson velocity places a state independent ballistic upper bound on the size of time evolved operators in non-relativistic lattice models. Here, we argue that vBv_B is a state-dependent effective Lieb-Robinson velocity. We study the butterfly velocity in a wide variety of quantum field theories using holography and compare with free particle computations to understand the role of strong coupling. We find that, depending on the way length and time scale, vBv_B acquires a temperature dependence and decreases towards the IR. We also comment on experimental prospects and on the relationship between the butterfly velocity and signaling.Comment: 5+5 pages, 0 figures. v2: updated references and additional clarification

    Development of Cranberry Girdler, \u3ci\u3eChrysoteuchia Topiaria\u3c/i\u3e (Lepidoptera: Pyraliadae) in Relation to Temperature

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    The development of Chrysoteuchia topiaria was studied in controlled-temperature chambers. Estimates of the threshold temperatures for the egg, larval, and prepupal-pupal stages were 9.4,6.8, and 9.8°C, respectively. An overall threshold temperature for egg to adult development was estimated to be 8.8°C. Degree-day summations above thresholds averaged 107, 484, and 388 for the egg, larval, and prepupal-pupal stages, respectively

    The goldstone and goldstino of supersymmetric inflation

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    We construct the minimal effective field theory (EFT) of supersymmetric inflation, whose field content is a real scalar, the goldstone for time-translation breaking, and a Weyl fermion, the goldstino for supersymmetry (SUSY) breaking. The inflating background can be viewed as a single SUSY-breaking sector, and the degrees of freedom can be efficiently parameterized using constrained superfields. Our EFT is comprised of a chiral superfield X_NL containing the goldstino and satisfying X_NL^2 = 0, and a real superfield B_NL containing both the goldstino and the goldstone, satisfying X_NL B_NL = B_NL^3 = 0. We match results from our EFT formalism to existing results for SUSY broken by a fluid background, showing that the goldstino propagates with subluminal velocities. The same effect can also be derived from the unitary gauge gravitino action after embedding our EFT in supergravity. If the gravitino mass is comparable to the Hubble scale during inflation, we identify a new parameter in the EFT related to a time-dependent phase of the gravitino mass parameter. We briefly comment on the leading contributions of goldstino loops to inflationary observables.Comment: 32 pages, 2 figures. v3: clarifications and references added. Matches JHEP version. v2: typos fixed, footnote and references adde

    Localized shocks

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    We study products of precursors of spatially local operators, Wxn(tn)...Wx1(t1)W_{x_{n}}(t_{n}) ... W_{x_1}(t_1), where Wx(t)=eiHtWxeiHtW_x(t) = e^{-iHt} W_x e^{iHt}. Using chaotic spin-chain numerics and gauge/gravity duality, we show that a single precursor fills a spatial region that grows linearly in tt. In a lattice system, products of such operators can be represented using tensor networks. In gauge/gravity duality, they are related to Einstein-Rosen bridges supported by localized shock waves. We find a geometrical correspondence between these two descriptions, generalizing earlier work in the spatially homogeneous case.Comment: 23 pages plus appendices, 12 figures. v2: minor error in Appendix B corrected. v3: figure added to the introduction comparing the butterfly effect cone with the standard light con

    Hawking-Page transition in holographic massive gravity

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    We study the Hawking-Page transition in a holographic model of field theories with momentum dissipation. We find that the deconfinement temperature strictly decreases as momentum dissipation is increased. For sufficiently strong momentum dissipation, the critical temperature goes to zero, indicating a zero-temperature deconfinement transition in the dual field theory.Comment: 17 pages, 1 figure, uncomment \newcommand*{\ShowCalculations}{} in the tex file for additional details. Journal version (PRD). Presentation clarified, reference added, and line spacing and title update
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