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Artículos de revistas sobre el tema "Collective fluctuations"

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Publicado: 4 de mayo de 2024

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1

Qian, Wei-Liang, Kai Lin, Chong Ye, Jin Li, Yu Pan y Rui-Hong Yue. "On Statistical Fluctuations in Collective Flows". Universe 9, n.º 2 (27 de enero de 2023): 67. http://dx.doi.org/10.3390/universe9020067.

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In relativistic heavy-ion collisions, event-by-event fluctuations are known to have non-trivial implications. Even though the probability distribution is geometrically isotropic for the initial conditions, the anisotropic εn still differs from zero owing to the statistical fluctuations in the energy profile. On the other hand, the flow harmonics extracted from the hadron spectrum using the multi-particle correlators are inevitably subjected to non-vanishing variance due to the finite number of hadrons emitted in individual events. As one aims to extract information on the fluctuations in the initial conditions via flow harmonics and their fluctuations, finite multiplicity may play a role in interfering with such an effort. In this study, we explore the properties and impacts of such fluctuations in the initial and final states, which both notably appear to be statistical ones originating from the finite number of quanta of the underlying system. We elaborate on the properties of the initial-state eccentricities for the smooth and event-by-event fluctuating initial conditions and their distinct impacts on the resulting flow harmonics. Numerical simulations are performed. The possible implications of the present study are also addressed.

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2

Mendels, Dan, GiovanniMaria Piccini y Michele Parrinello. "Collective Variables from Local Fluctuations". Journal of Physical Chemistry Letters 9, n.º 11 (7 de mayo de 2018): 2776–81. http://dx.doi.org/10.1021/acs.jpclett.8b00733.

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3

Benhassine, B., M. Farine, E. S. Hernandez, D. Idier, B. Remaud y F. Sebille. "Phase space fluctuations and dynamics of fluctuations of collective variables". Nuclear Physics A 545, n.º 1-2 (agosto de 1992): 81–86. http://dx.doi.org/10.1016/0375-9474(92)90448-s.

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4

Klimin, Serghei, Jacques Tempere y Hadrien Kurkjian. "Low-Lying Collective Excitations of Superconductors and Charged Superfluids". Condensed Matter 8, n.º 2 (3 de mayo de 2023): 42. http://dx.doi.org/10.3390/condmat8020042.

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We investigate theoretically the momentum-dependent frequency and damping of low-lying collective excitations of superconductors and charged superfluids in the BCS–BEC crossover regime. The study is based on the Gaussian pair-and-density fluctuation method for the propagator of Gaussian fluctuations of the pair and density fields. Eigenfrequencies and damping rates are determined in a mutually consistent nonperturbative way as complex poles of the fluctuation propagator. Particular attention is paid to new features with respect to preceding theoretical studies, which were devoted to collective excitations of superconductors in the far BCS regime. We find that at a sufficiently strong coupling, new branches of collective excitations appear, which manifest different behavior as functions of the momentum and the temperature.

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5

Masuda, Naoki, Yoji Kawamura y Hiroshi Kori. "Collective fluctuations in networks of noisy components". New Journal of Physics 12, n.º 9 (6 de septiembre de 2010): 093007. http://dx.doi.org/10.1088/1367-2630/12/9/093007.

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6

Perarnau-Llobet, Martí y Raam Uzdin. "Collective operations can extremely reduce work fluctuations". New Journal of Physics 21, n.º 8 (12 de agosto de 2019): 083023. http://dx.doi.org/10.1088/1367-2630/ab36a9.

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7

König, Jürgen, John Schliemann, T. Jungwirth y A. H. MacDonald. "Collective spin fluctuations in diluted magnetic semiconductors". Physica E: Low-dimensional Systems and Nanostructures 12, n.º 1-4 (enero de 2002): 379–82. http://dx.doi.org/10.1016/s1386-9477(01)00308-3.

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8

Wan, Yi y Richard M. Stratt. "Collective fluctuations of conserved variables in liquids". Journal of Chemical Physics 98, n.º 4 (15 de febrero de 1993): 3224–39. http://dx.doi.org/10.1063/1.464095.

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9

Pfitzner, A., L. M�nchow y P. M�dler. "One-body dynamics modified by collective fluctuations". Zeitschrift f�r Physik A Atomic Nuclei 331, n.º 1 (marzo de 1988): 43–51. http://dx.doi.org/10.1007/bf01289429.

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10

Tsytovich, V. N., R. Bingham, U. de Angelis y A. Forlani. "Collective effects in bremsstrahlung in plasmas". Journal of Plasma Physics 56, n.º 1 (agosto de 1996): 127–47. http://dx.doi.org/10.1017/s0022377800019140.

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The results of recent developments in the theory of fluctuations in plasmas show that the previously used theory of bremsstrahlung is incomplete and the exact expressions for bremsstrahlung should include transition bremsstrahlung. The collective effects in bremsstrahlung known previously as Debye screening are changed to a qualitatively different structure, which removes the effect of ion polarization in bremsstrahlung and introduces a new effective polarization which depends on an effective ion charge and electron velocity. The results may be relevant for applications in plasmas when the wavelength is greater than the Debye length. It is shown that for the problem of photon transport in the solar interior the correct collective corrections to the bremsstrahlung change the opacity by only about −0·35%, which is less than was calculated previously when collective effects in bremsstrahlung where estimated without taking recent results of plasma fluctuation theory into account.

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11

Zhang, H. P., A. Be'er, E. L. Florin y H. L. Swinney. "Collective motion and density fluctuations in bacterial colonies". Proceedings of the National Academy of Sciences 107, n.º 31 (19 de julio de 2010): 13626–30. http://dx.doi.org/10.1073/pnas.1001651107.

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12

Ziherl, P., A. Šarlah y S. Žumer. "Collective fluctuations and wetting in nematic liquid crystals". Physical Review E 58, n.º 1 (1 de julio de 1998): 602–9. http://dx.doi.org/10.1103/physreve.58.602.

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13

Prakashchand, Dube Dheeraj, Navjeet Ahalawat, Satyabrata Bandyopadhyay, Surajit Sengupta y Jagannath Mondal. "Nonaffine Displacements Encode Collective Conformational Fluctuations in Proteins". Journal of Chemical Theory and Computation 16, n.º 4 (24 de marzo de 2020): 2508–16. http://dx.doi.org/10.1021/acs.jctc.9b01100.

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14

Fulde, P. y K. W. Becker. "Collective density fluctuations in heavy‐fermion systems (invited)". Journal of Applied Physics 63, n.º 8 (15 de abril de 1988): 3673–75. http://dx.doi.org/10.1063/1.340682.

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15

Mädler, P., L. Münchow y A. Pfitzner. "Randomization of single-particle motion by collective fluctuations". Physics Letters B 198, n.º 1 (noviembre de 1987): 25–28. http://dx.doi.org/10.1016/0370-2693(87)90150-x.

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16

MATHAI, NEBU JOHN y TAKIS ZOURNTOS. "EMERGENT FLUCTUATIONS IN THE TRAJECTORIES OF AGENT COLLECTIVES". Fluctuation and Noise Letters 07, n.º 04 (diciembre de 2007): L429—L437. http://dx.doi.org/10.1142/s0219477507004057.

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Characteristics of the collective behavior of groups have been studied in diverse disciplines; in this work, we present an approach grounded in robotics. We first specify a model for collective behavior based on a formulation of a multi-agent robotic system. In contrast to some models found in the literature, we do not use stochastic mechanisms to introduce fluctuations. Rather, we present a fully deterministic model where fluctuations emerge due to the complex dynamics of a high-dimensional coupling of dynamical systems. We investigate the emergence of fluctuations in the trajectories of individual agents about the group average trajectory, and present an illustration of the onset of these fluctuations as inter-agent coupling is increased. A selection of behavioral modes are also provided, illustrating the nature of these fluctuations.

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17

Khudaiberdiev, Daniiar, Ze Don Kvon, Matvey V. Entin, Dmitriy A. Kozlov, Nikolay N. Mikhailov y Maxim Ryzhkov. "Mesoscopic Conductance Fluctuations in 2D HgTe Semimetal". Nanomaterials 13, n.º 21 (31 de octubre de 2023): 2882. http://dx.doi.org/10.3390/nano13212882.

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Mesoscopic conductance fluctuations were discovered in a weak localization regime of a strongly disordered two-dimensional HgTe-based semimetal. These fluctuations exist in macroscopic samples with characteristic sizes of 100 μm and exhibit anomalous dependences on the gate voltage, magnetic field, and temperature. They are absent in the regime of electron metal (at positive gate voltages) and strongly depend on the level of disorder in the system. All the experimental facts lead us to the conclusion that the origin of the fluctuations is a special collective state in which the current is conducted through the percolation network of electron resistances. We suppose that the network is formed by fluctuation potential whose amplitude is higher than the Fermi level of electrons due to their very low density.

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18

LESHANSKY, ALEXANDER M., JEFFREY F. MORRIS y JOHN F. BRADY. "Collective diffusion in sheared colloidal suspensions". Journal of Fluid Mechanics 597 (1 de febrero de 2008): 305–41. http://dx.doi.org/10.1017/s0022112007009834.

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Collective diffusivity in a suspension of rigid particles in steady linear viscous flows is evaluated by investigating the dynamics of the time correlation of long-wavelength density fluctuations. In the absence of hydrodynamic interactions between suspended particles in a dilute suspension of identical hard spheres, closed-form asymptotic expressions for the collective diffusivity are derived in the limits of low and high Péclet numbers, where the Péclet number ${\it Pe}\,{=}\,\gamdot a^2/D_0$ with $\gamdot$ being the shear rate and D0 = kBT/6πη a is the Stokes–Einstein diffusion coefficient of an isolated sphere of radius a in a fluid of viscosity η. The effect of hydrodynamic interactions is studied in the analytically tractable case of weakly sheared (Pe ≪ 1) suspensions.For strongly sheared suspensions, i.e. at high Pe, in the absence of hydrodynamics the collective diffusivity Dc = 6 Ds∞, where Ds∞ is the long-time self-diffusivity and both scale as $\phi \gamdot a^2$, where φ is the particle volume fraction. For weakly sheared suspensions it is shown that the leading dependence of collective diffusivity on the imposed flow is proportional to D0 φPeÊ, where Ê is the rate-of-strain tensor scaled by $\gamdot$, regardless of whether particles interact hydrodynamically. When hydrodynamic interactions are considered, however, correlations of hydrodynamic velocity fluctuations yield a weakly singular logarithmic dependence of the cross-gradient-diffusivity on k at leading order as ak → 0 with k being the wavenumber of the density fluctuation. The diagonal components of the collective diffusivity tensor, both with and without hydrodynamic interactions, are of O(φPe2), quadratic in the imposed flow, and finite at k = 0.At moderate particle volume fractions, 0.10 ≤ φ ≤ 0.35, Brownian Dynamics (BD) numerical simulations in which there are no hydrodynamic interactions are performed and the transverse collective diffusivity in simple shear flow is determined via time evolution of the dynamic structure factor. The BD simulation results compare well with the derived asymptotic estimates. A comparison of the high-Pe BD simulation results with available experimental data on collective diffusivity in non-Brownian sheared suspensions shows a good qualitative agreement, though hydrodynamic interactions prove to be important at moderate concentrations.

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19

Schlickeiser, R. y P. H. Yoon. "Quasilinear theory of general electromagnetic fluctuations including discrete particle effects for magnetized plasmas: General analysis". Physics of Plasmas 29, n.º 9 (septiembre de 2022): 092105. http://dx.doi.org/10.1063/5.0104709.

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The general quasilinear Fokker–Planck kinetic equation for the gyrophase-averaged plasma particle distribution functions in magnetized plasmas is derived, making no restrictions on the energy of the particles and on the frequency of the electromagnetic fluctuations and avoiding the often made Coulomb approximation of the electromagnetic interactions. The inclusion of discrete particle effects breaks the dichotomy of nonlinear kinetic plasma theory divided into the test particle and the test fluctuation approximation because it provides expression of both the non-collective and collective electromagnetic fluctuation spectra in terms of the plasma particle distribution functions. Within the validity of the quasilinear approach, the resulting full quasilinear transport equation can be regarded as a determining nonlinear equation for the time evolution of the plasma particle distribution functions.

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20

Hwang, E. H. y S. Das Sarma. "Collective Charge Density Fluctuations in Superconducting Layered Systems with Bilayer Unit Cells". International Journal of Modern Physics B 12, n.º 27n28 (10 de noviembre de 1998): 2769–83. http://dx.doi.org/10.1142/s0217979298001617.

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Collective modes of bilayered superconducting superlattices (e.g., YBCO) are investigated within the conserving gauge-invariant ladder diagram approximation including both the nearest interlayer single electron tunneling and the Josephson-type Cooper pair tunneling. By calculating the density–density response function including Coulomb and pairing interactions, we examine the two collective mode branches corresponding to the in-phase and out-of-phase charge fluctuations between the two layers in the unit cell. The out-of-phase collective mode develops a long wavelength plasmon gap whose magnitude depends on the tunneling strength with the mode dispersions being insensitive to the specific tunneling mechanism (i.e., single electron or Josephson). We also show that in the presence of tunneling the oscillator strength of the out-of-phase mode overwhelms that of the in-phase-mode at k‖ = 0 and finite kz, where kz and k‖ are respectively the mode wave vectors perpendicular and along the layer. We discuss the possible experimental observability of the phase fluctuation modes in the context of our theoretical results for the mode dispersion and spectral weight.

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21

Šuvakov, Milovan y Bosiljka Tadić. "Collective charge fluctuations in single-electron processes on nanonetworks". Journal of Statistical Mechanics: Theory and Experiment 2009, n.º 02 (4 de febrero de 2009): P02015. http://dx.doi.org/10.1088/1742-5468/2009/02/p02015.

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22

Kawaguchi, Koji, Koichi Murase y Tetsufumi Hirano. "Multiplicity fluctuations and collective flow in small colliding systems". Nuclear Physics A 967 (noviembre de 2017): 357–60. http://dx.doi.org/10.1016/j.nuclphysa.2017.07.010.

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23

Rozgacheva, I. K. "Collective dynamics of density fluctuations in a gravitating medium". Astrophysics 28, n.º 3 (1988): 368–73. http://dx.doi.org/10.1007/bf01112975.

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24

Zakhvataev, V. E., O. S. Volodko, L. A. Kompaniets y D. V. Zlobin. "Numerical study of a model of terahertz collective modes in DNA". Journal of Physics: Conference Series 2094, n.º 2 (1 de noviembre de 2021): 022012. http://dx.doi.org/10.1088/1742-6596/2094/2/022012.

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Abstract Terahertz density fluctuations in DNA have been recognized to be associated with biological function of DNA and widely studied both experimentally and theoretically. In the present work, we investigate numerically a new model for the terahertz dynamics of density fluctuations in DNA, proposed earlier. This model considers the length scales corresponding to wave numbers up to the position of the maximum of the static structure factor and allows to reflect structural effects caused by the dependence of the static structure factor on wave number. We study the parametric dependencies of the model to elucidate the effect of dlocalization of the dynamics of density fluctuations caused by structural effects.

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25

Hofmann, H. y D. Kiderlen. "A Self-Consistent Treatment of Damped Motion for Stable and Unstable Collective Modes". International Journal of Modern Physics E 07, n.º 02 (abril de 1998): 243–74. http://dx.doi.org/10.1142/s0218301398000105.

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We address the dynamics of damped collective modes in terms of first and second moments. The modes are introduced in a self-consistent fashion with the help of a suitable application of linear response theory. Quantum effects in the fluctuations are governed by diffusion coefficients Dμν. The latter are obtained through a fluctuation dissipation theorem generalized to allow for a treatment of unstable modes. Numerical evaluations of the Dμν are presented. We discuss briefly how this picture may be used to describe global motion within a locally harmonic approximation. Relations to other methods are discussed, like "dissipative tunneling", RPA at finite temperature and generalizations of the "Static Path Approximation".

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26

GNANAPRAGASAM, G. y M. P. DAS. "COLLECTIVE MODES OF TRAPPED INTERACTING BOSONS". International Journal of Modern Physics B 22, n.º 25n26 (20 de octubre de 2008): 4349–57. http://dx.doi.org/10.1142/s0217979208050103.

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The derivation for collective modes of an interacting Bose gas trapped by an isotropic harmonic oscillator potential is presented using field-theoretic method. The presence of the two-body scattering term beyond the mean-field is seen to appear inevitably in the calculations, even in the simplest approximation. As a result we see the occurrence of a small number of non-condensate atoms in the ground state density fluctuations.

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27

Zverevich, Dmitry y Alex Levchenko. "Transport signatures of plasmon fluctuations in electron hydrodynamics". Low Temperature Physics 49, n.º 12 (1 de diciembre de 2023): 1376–84. http://dx.doi.org/10.1063/10.0022363.

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In two-dimensional electron systems, plasmons are gapless and long-lived collective excitations of propagating charge density oscillations. We study the fluctuation mechanism of plasmon-assisted transport in the regime of electron hydrodynamics. We consider pristine electron liquids where charge fluctuations are thermally induced by viscous stresses and intrinsic currents, while attenuation of plasmons is determined by the Maxwell mechanism of charge relaxation. It is shown that, while the contribution of plasmons to the shear viscosity and thermal conductivity of a Fermi liquid is small, plasmon resonances in the bilayer devices enhance the drag resistance. In systems without Galilean invariance, fluctuation-driven contributions to dissipative coefficients can be described only in terms of hydrodynamic quantities: intrinsic conductivity, viscosity, and plasmon dispersion relation.

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28

Clausen, Sigmund, Geir Helgesen y Arne T. Skjeltorp. "Braid description of collective fluctuations in a few-body system". Physical Review E 58, n.º 4 (1 de octubre de 1998): 4229–37. http://dx.doi.org/10.1103/physreve.58.4229.

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29

Sano, Yukie. "Correlations and fluctuations in the word sets of collective emotions". Nonlinear Theory and Its Applications, IEICE 9, n.º 3 (2018): 382–90. http://dx.doi.org/10.1587/nolta.9.382.

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30

Csernai, László P. "Collective dynamics, fluctuations and instabilities in relativistic heavy-ion collisions". EPJ Web of Conferences 117 (2016): 03001. http://dx.doi.org/10.1051/epjconf/201611703001.

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31

Salman, Hanna, Yoav Soen y Erez Braun. "Voltage Fluctuations and Collective Effects in Ion-Channel Protein Ensembles". Physical Review Letters 77, n.º 21 (18 de noviembre de 1996): 4458–61. http://dx.doi.org/10.1103/physrevlett.77.4458.

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32

Takahashi, Akira, Hong Xiang Wang y Shaul Mukamel. "Collective charge density fluctuations and nonlinear optical responce of C60". Chemical Physics Letters 216, n.º 3-6 (diciembre de 1993): 394–98. http://dx.doi.org/10.1016/0009-2614(93)90115-h.

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33

Bartolotta, Antonino, Gaetano Di Marco, Cirino Vasi, Placido Migliardo y Marco Villa. "Dynamical properties of LiI⋅D2O: Ion diffusion and collective fluctuations". Physical Review B 33, n.º 11 (1 de junio de 1986): 7481–87. http://dx.doi.org/10.1103/physrevb.33.7481.

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34

Giraud, B. G., S. Karataglidis y T. Sami. "Fluctuations of collective coordinates and convexity theorems for energy surfaces". Annals of Physics 376 (enero de 2017): 296–310. http://dx.doi.org/10.1016/j.aop.2016.11.015.

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35

Antoniou, Dimitri y Steven D. Schwartz. "Low-Frequency Collective Motions in Proteins". Journal of Theoretical and Computational Chemistry 02, n.º 02 (junio de 2003): 163–69. http://dx.doi.org/10.1142/s0219633603000458.

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There are several kinds of low-frequency collective motions in proteins, which are believed to have a significant effect on their properties. We propose that a new kind of global collective motion in proteins are density fluctuations, which are slowly-varying, long-lived, propagating disturbances. These can be studied using the linear response formalism, which is a dynamical approximation that uses the full anharmonic interatomic potential. We have performed a molecular dynamics simulation of a realistic protein and have found results that are consistent with the theoretical predictions of linear response theory.

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36

Wiechen, H. "New aspects of plasma sheet dynamics - MHD and kinetic theory". Annales Geophysicae 17, n.º 5 (31 de mayo de 1999): 595–603. http://dx.doi.org/10.1007/s00585-999-0595-2.

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Abstract. Magnetic reconnection is a process of fundamental importance for the dynamics of the Earth's plasma sheet. In this context, the development of thin current sheets in the near-Earth plasma sheet is a topic of special interest because they could be a possible cause of microscopic fluctuations acting as collective non-idealness from a macroscopic point of view. Simulations of the near-Earth plasma sheet including boundary perturbations due to localized inflow through the northern (or southern) plasma sheet boundary show developing thin current sheets in the near-Earth plasma sheet about 810 RE tailwards of the Earth. This location is largely independent from the localization of the perturbation. The second part of the paper deals with the problem of the macroscopic non-ideal consequences of microscopic fluctuations. A new model is presented that allows the quantitative calculation of macroscopic non-idealness without considering details of microscopic instabilities or turbulence. This model is only based on the assumption of a strongly fluctuating, mixing dynamics on microscopic scales in phase space. The result of this approach is an expression for anomalous non-idealness formally similar to the Krook resistivity but now describing the macroscopic consequences of collective microscopic fluctuations, not of collisions.Key words. Magnetospheric physics (plasma sheet) · Space plasma physics (kinetic and MHD theory; magnetic reconnection)

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37

Robbins, Bruce. "Single? Great? Collective?" South Atlantic Quarterly 119, n.º 4 (1 de octubre de 2020): 789–98. http://dx.doi.org/10.1215/00382876-8663699.

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Fredric Jameson’s latest book, Allegory and Ideology (2019), returns to the provocative proposition that he floated in The Political Unconscious: Narrative as a Socially Symbolic Act (1981): that humankind’s cultural past is only available to us today if we believe that “the human adventure is one”—a series of efforts to wrest a realm of freedom from the realm of necessity. This essay examines the new book for evidence of possible fluctuations in Jameson’s commitment to a “single great collective story,” underlining in particular the subversiveness of the adjective “great” but also his re-affirmation of a particular Jamesonian version of constructivism, the Marxist spin he puts on loose and generalized notions of “X is a construct” and “everything is narrative.” Jameson’s loyalty to the concept of “ideology” is read here as another moment in his long-lasting dialogue with the late Hayden White. And his loyalty to the concept of “allegory” is read as dialectical in an especially courageous sense: a willingness to concede that the ability to affirm a “single great collective story” depends both on allegory, which works by a respectful but not reverential attention to cultural differences, and on the model of imperial power, which provides Jameson with his 1981 model of four-fold interpretation.

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38

Lecheval, Valentin, Li Jiang, Pierre Tichit, Clément Sire, Charlotte K. Hemelrijk y Guy Theraulaz. "Social conformity and propagation of information in collective U-turns of fish schools". Proceedings of the Royal Society B: Biological Sciences 285, n.º 1877 (25 de abril de 2018): 20180251. http://dx.doi.org/10.1098/rspb.2018.0251.

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Moving animal groups such as schools of fishes or flocks of birds often undergo sudden collective changes of their travelling direction as a consequence of stochastic fluctuations in heading of the individuals. However, the mechanisms by which these behavioural fluctuations arise at the individual level and propagate within a group are still unclear. In this study, we combine an experimental and theoretical approach to investigate spontaneous collective U-turns in groups of rummy-nose tetra ( Hemigrammus rhodostomus ) swimming in a ring-shaped tank. U-turns imply that fish switch their heading between the clockwise and anticlockwise direction. We reconstruct trajectories of individuals moving alone and in groups of different sizes. We show that the group decreases its swimming speed before a collective U-turn. This is in agreement with previous theoretical predictions showing that speed decrease facilitates an amplification of fluctuations in heading in the group, which can trigger U-turns. These collective U-turns are mostly initiated by individuals at the front of the group. Once an individual has initiated a U-turn, the new direction propagates through the group from front to back without amplification or dampening, resembling the dynamics of falling dominoes. The mean time between collective U-turns sharply increases as the size of the group increases. We develop an Ising spin model integrating anisotropic and asymmetrical interactions between fish and their tendency to follow the majority of their neighbours nonlinearly (social conformity). The model quantitatively reproduces key features of the dynamics and the frequency of collective U-turns observed in experiments.

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39

Shiratani, Masaharu, Masahiro Soejima, Hyun Woong Seo, Naho Itagaki y Kazunori Koga. "Fluctuation of Position and Energy of a Fine Particle in Plasma Nanofabrication". Materials Science Forum 879 (noviembre de 2016): 1772–77. http://dx.doi.org/10.4028/www.scientific.net/msf.879.1772.

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We are developing plasma nanofabrication, namely, nanoand micro scale guided assembly using plasmas. We manipulate nanoand micro objects using electrostatic, electromagnetic, ion drag, neutral drag, and optical forces. The accuracy of positioning the objects depends on fluctuation of position and energy of a fine particle (= each object) in plasmas. Here we evaluate such fluctuations and discuss the mechanism behind them. In the first experiment, we grabbed a fine particle in plasma using an optical tweezers. The fine particle moves in a potential well made by the optical tweezers. This is a kind of Brownian motion and the position fluctuation can be caused by neutral molecule collisions, ion collisions, and fluctuation of electrostatic force. Among theses possible causes, fluctuation of electrostatic force may be main one. In the second experiment, we deduced interaction potential between two fine particles during their Coulomb collision. We found that there exist repulsive and attractive forces between them. The repulsive force is a screened Coulomb one, whereas the attractive force is likely a force due to a shadow effect, a non-collective attractive force. Moreover, we noted that there is a fluctuation of the potential, probably due to fluctuation of electrostatic force. These position and potential energy fluctuations may limit the accuracy of guided assembly using plasmas.

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40

Llanes-Estrada, Felipe J., Belén Martínez Carmona y Jose L. Muñoz Martínez. "Velocity fluctuations of fission fragments". International Journal of Modern Physics E 25, n.º 02 (febrero de 2016): 1650009. http://dx.doi.org/10.1142/s0218301316500099.

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We propose event by event velocity fluctuations of nuclear fission fragments as an additional interesting observable that gives access to the nuclear temperature in an independent way from spectral measurements and relates the diffusion and friction coefficients for the relative fragment coordinate in Kramers-like models (in which some aspects of fission can be understood as the diffusion of a collective variable through a potential barrier). We point out that neutron emission by the heavy fragments can be treated in effective theory if corrections to the velocity distribution are needed.

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41

Vidal, F., M. V. Ramallo, J. Mosqueira y C. Carballeira. "Superconducting Fluctuations Above TC and the Uncertainty Principle: How Small may the Coherence Length be?" International Journal of Modern Physics B 17, n.º 18n20 (10 de agosto de 2003): 3470–72. http://dx.doi.org/10.1142/s0217979203021228.

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We summarize here some of our recent results on the superconducting fluctuation effects above TC in different low- and high-TC superconductors, at high reduced-temperatures and magnetic fields. These results confirm our proposal that the collective behaviour of the fluctuating Cooper pairs in the short-wavelength fluctuation regime is dominated by the uncertainty principle, which imposes a limit to the shrinkage of the superconducting wave function when T increases well above TC or H becomes of the order of Hc2(0), the upper critical magnetic field amplitude extrapolated to T = 0 K .

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42

Moreno-Gámez, Stefany. "How bacteria navigate varying environments". Science 378, n.º 6622 (25 de noviembre de 2022): 845. http://dx.doi.org/10.1126/science.adf4444.

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43

Tsytovich, Vadim N. "Description of collective processes and fluctuations in classical and quantum plasmas". Uspekhi Fizicheskih Nauk 159, n.º 10 (1989): 335. http://dx.doi.org/10.3367/ufnr.0159.198910d.0335.

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44

Hallatschek, O. y L. Geyrhofer. "Collective Fluctuations in the Dynamics of Adaptation and Other Traveling Waves". Genetics 202, n.º 3 (27 de enero de 2016): 1201–27. http://dx.doi.org/10.1534/genetics.115.181271.

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45

Su, Zhongqian, Yanchao Wang, Dayi Song y Weining Zhang. "Fluctuations of collective flows for event-by-event hydrodynamic evolution sources". Journal of Physics: Conference Series 1053 (julio de 2018): 012085. http://dx.doi.org/10.1088/1742-6596/1053/1/012085.

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46

Rouet, J. L. y M. R. Feix. "Persistence of collective fluctuations inN-body metaequilibrium gravitating and plasma systems". Physical Review E 59, n.º 1 (1 de enero de 1999): 73–83. http://dx.doi.org/10.1103/physreve.59.73.

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47

Bulanin, Victor V. "Collective CO2-Laser Scattering of Low Friquency Small-Scale Plasma Fluctuations". Fusion Technology 35, n.º 1T (enero de 1999): 141–45. http://dx.doi.org/10.13182/fst99-a11963839.

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48

Rabani, Eran y David R. Reichman. "A fully self-consistent treatment of collective fluctuations in quantum liquids". Journal of Chemical Physics 120, n.º 3 (15 de enero de 2004): 1458–65. http://dx.doi.org/10.1063/1.1631436.

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49

Russo, Daniela, Alessio Laloni, Alessandra Filabozzi y Matthias Heyden. "Pressure effects on collective density fluctuations in water and protein solutions". Proceedings of the National Academy of Sciences 114, n.º 43 (9 de octubre de 2017): 11410–15. http://dx.doi.org/10.1073/pnas.1705279114.

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Neutron Brillouin scattering and molecular dynamics simulations have been used to investigate protein hydration water density fluctuations as a function of pressure. Our results show significant differences between the pressure and density dependence of collective dynamics in bulk water and in concentrated protein solutions. Pressure-induced changes in the tetrahedral order of the water HB network have direct consequences for the high-frequency sound velocity and damping coefficients, which we find to be a sensitive probe for changes in the HB network structure as well as the wetting of biomolecular surfaces.

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50

Kurbatov, A. A. y E. A. Titov. "The influence of collective effects on quantum fluctuations of laser radiation". Optics and Spectroscopy 120, n.º 5 (mayo de 2016): 818–22. http://dx.doi.org/10.1134/s0030400x16050179.

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