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Biological and Chemical Physics Commons

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Full-Text Articles in Biological and Chemical Physics

Collective Gradient Sensing In Fish Schools, James G. Puckett, Aawaz R. Pokhrel, Julia A. Giannini May 2018

Collective Gradient Sensing In Fish Schools, James G. Puckett, Aawaz R. Pokhrel, Julia A. Giannini

Physics and Astronomy Faculty Publications

Throughout the animal kingdom, animals frequently benefit from living in groups. Models of collective behaviour show that simple local interactions are sufficient to generate group morphologies found in nature (swarms, flocks and mills). However, individuals also interact with the complex noisy environment in which they live. In this work, we experimentally investigate the group performance in navigating a noisy light gradient of two unrelated freshwater species: golden shiners (Notemigonuscrysoleucas) and rummy nose tetra (Hemigrammus bleheri). We find that tetras outperform shiners due to their innate individual ability to sense the environmental gradient. Using numerical simulations, we examine how group performance …


Universality Of Quantum Information In Chaotic Cfts, Nima Lashkari, Anatoly Dymarsky, Hong Liu Mar 2018

Universality Of Quantum Information In Chaotic Cfts, Nima Lashkari, Anatoly Dymarsky, Hong Liu

Physics and Astronomy Faculty Publications

We study the Eigenstate Thermalization Hypothesis (ETH) in chaotic conformal field theories (CFTs) of arbitrary dimensions. Assuming local ETH, we compute the reduced density matrix of a ball-shaped subsystem of finite size in the infinite volume limit when the full system is an energy eigenstate. This reduced density matrix is close in trace distance to a density matrix, to which we refer as the ETH density matrix, that is independent of all the details of an eigenstate except its energy and charges under global symmetries. In two dimensions, the ETH density matrix is universal for all theories with the …