scholarly journals Anomalous density fluctuations in a random t−J model

2020 ◽  
Vol 102 (16) ◽  
Author(s):  
Darshan G. Joshi ◽  
Subir Sachdev
Keyword(s):  
Density Fluctuations ◽  
Anomalous Density

scholarly journals Density Fluctuations and Energy Spectra of 3D Bacterial Suspensions

Soft Matter ◽  
2021 ◽  
Author(s):  
Zhengyang Liu ◽  
Wei Zeng ◽  
Xiaolei Ma ◽  
Xiang Cheng
Keyword(s):  
Density Fluctuations ◽  
Energy Spectra ◽  
Nonequilibrium Dynamics ◽  
Two Dimensional ◽  
Anomalous Density

Giant number fluctuations are often considered as a hallmark of the emergent nonequilibrium dynamics of active fluids. However, these anomalous density fluctuations have only been reported experimentally in two-dimensional dry...

scholarly journals Dynamic nuclear structure emerges from chromatin crosslinks and motors

2020 ◽  
Author(s):  
Kuang Liu ◽  
Alison E. Patteson ◽  
Edward J. Banigan ◽  
J. M. Schwarz
Keyword(s):  
Motor Activity ◽  
Density Fluctuations ◽  
Nuclear Shape ◽  
Chromatin Dynamics ◽  
Chromosome Dynamics ◽  
Shell System ◽  
Physical Mechanisms ◽  
Correlated Motions ◽  
Anomalous Density ◽  
Motor Strength

The cell nucleus houses the chromosomes, which are linked to a soft shell of lamin filaments. Experiments indicate that correlated chromosome dynamics and nuclear shape fluctuations arise from motor activity. To identify the physical mechanisms, we develop a model of an active, crosslinked Rouse chain bound to a polymeric shell. System-sized correlated motions occur but require both motor activity and crosslinks. Contractile motors, in particular, enhance chromosome dynamics by driving anomalous density fluctuations. Nuclear shape fluctuations depend on motor strength, crosslinking, and chromosome-lamina binding. Therefore, complex chromatin dynamics and nuclear shape emerge from a minimal, active chromosome-lamina system.

scholarly journals Anomalous density fluctuations in a strange metal

2018 ◽  
Vol 115 (21) ◽  
pp. 5392-5396 ◽  
Author(s):  
M. Mitrano ◽  
A. A. Husain ◽  
S. Vig ◽  
A. Kogar ◽  
M. S. Rak ◽  
...  
Keyword(s):  
Low Temperature ◽  
Power Law ◽  
High Temperature Superconductivity ◽  
High Energy ◽  
Energy Scale ◽  
Density Fluctuations ◽  
Inelastic Electron ◽  
Anomalous Density ◽  
Dynamic Charge ◽  
New Type

A central mystery in high-temperature superconductivity is the origin of the so-called strange metal (i.e., the anomalous conductor from which superconductivity emerges at low temperature). Measuring the dynamic charge response of the copper oxides, χ″(q,ω), would directly reveal the collective properties of the strange metal, but it has never been possible to measure this quantity with millielectronvolt resolution. Here, we present a measurement of χ″(q,ω) for a cuprate, optimally doped Bi2.1Sr1.9CaCu2O8+x (Tc = 91 K), using momentum-resolved inelastic electron scattering. In the medium energy range 0.1–2 eV relevant to the strange metal, the spectra are dominated by a featureless, temperature- and momentum-independent continuum persisting to the electronvolt energy scale. This continuum displays a simple power-law form, exhibiting q2 behavior at low energy and q2/ω2 behavior at high energy. Measurements of an overdoped crystal (Tc = 50 K) showed the emergence of a gap-like feature at low temperature, indicating deviation from power law form outside the strange-metal regime. Our study suggests the strange metal exhibits a new type of charge dynamics in which excitations are local to such a degree that space and time axes are decoupled.

Ballooning structure in density fluctuations observed with the 2 MeV heavy ion beam probe on the TEXT-U tokamak

1995 ◽  
Author(s):  
A. Fujisawa ◽  
A. Ouroua ◽  
J.W. Heard ◽  
T.P. Crowley ◽  
P.M. Schoch ◽  
...  
Keyword(s):  
Ion Beam ◽  
Heavy Ion ◽  
Density Fluctuations ◽  
Heavy Ion Beam ◽  
Heavy Ion Beam Probe

scholarly journals Looking for a proxy of the ionospheric turbulence with Swarm data

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paola De Michelis ◽  
Giuseppe Consolini ◽  
Alessio Pignalberi ◽  
Roberta Tozzi ◽  
Igino Coco ◽  
...  
Keyword(s):  
Electron Density ◽  
Geomagnetic Activity ◽  
Density Fluctuations ◽  
Rate Of Change ◽  
Topside Ionosphere ◽  
Joint Probability Distribution ◽  
Activity Levels ◽  
Scaling Exponents ◽  
Electron Density Fluctuations ◽  
Scaling Features

AbstractThe present work focuses on the analysis of the scaling features of electron density fluctuations in the mid- and high-latitude topside ionosphere under different conditions of geomagnetic activity. The aim is to understand whether it is possible to identify a proxy that may provide information on the properties of electron density fluctuations and on the possible physical mechanisms at their origin, as for instance, turbulence phenomena. So, we selected about 4 years (April 2014–February 2018) of 1 Hz electron density measurements recorded on-board ESA Swarm A satellite. Using the Auroral Electrojet (AE) index, we identified two different geomagnetic conditions: quiet (AE < 50 nT) and active (AE > 300 nT). For both datasets, we evaluated the first- and second-order scaling exponents and an intermittency coefficient associated with the electron density fluctuations. Then, the joint probability distribution between each of these quantities and the rate of change of electron density index was also evaluated. We identified two families of plasma density fluctuations characterized by different mean values of both the scaling exponents and the considered ionospheric index, suggesting that different mechanisms (instabilities/turbulent processes) can be responsible for the observed scaling features. Furthermore, a clear different localization of the two families in the magnetic latitude—magnetic local time plane is found and its dependence on geomagnetic activity levels is analyzed. These results may well have a bearing about the capability of recognizing the turbulent character of irregularities using a typical ionospheric plasma irregularity index as a proxy.

scholarly journals Cosmological model parameter dependence of the matter power spectrum covariance from the DEUS-PUR Cosmo simulations

2020 ◽  
Vol 500 (2) ◽  
pp. 2532-2542
Author(s):  
Linda Blot ◽  
Pier-Stefano Corasaniti ◽  
Yann Rasera ◽  
Shankar Agarwal
Keyword(s):  
Dark Energy ◽  
Power Spectrum ◽  
Cold Dark Matter ◽  
Matter Density ◽  
Density Fluctuations ◽  
Matrix Analysis ◽  
Model Parameter ◽  
Matter Power Spectrum ◽  
Non Gaussian ◽  
The Impact

ABSTRACT Future galaxy surveys will provide accurate measurements of the matter power spectrum across an unprecedented range of scales and redshifts. The analysis of these data will require one to accurately model the imprint of non-linearities of the matter density field. In particular, these induce a non-Gaussian contribution to the data covariance that needs to be properly taken into account to realize unbiased cosmological parameter inference analyses. Here, we study the cosmological dependence of the matter power spectrum covariance using a dedicated suite of N-body simulations, the Dark Energy Universe Simulation–Parallel Universe Runs (DEUS-PUR) Cosmo. These consist of 512 realizations for 10 different cosmologies where we vary the matter density Ωm, the amplitude of density fluctuations σ8, the reduced Hubble parameter h, and a constant dark energy equation of state w by approximately $10{{\ \rm per\ cent}}$. We use these data to evaluate the first and second derivatives of the power spectrum covariance with respect to a fiducial Λ-cold dark matter cosmology. We find that the variations can be as large as $150{{\ \rm per\ cent}}$ depending on the scale, redshift, and model parameter considered. By performing a Fisher matrix analysis we explore the impact of different choices in modelling the cosmological dependence of the covariance. Our results suggest that fixing the covariance to a fiducial cosmology can significantly affect the recovered parameter errors and that modelling the cosmological dependence of the variance while keeping the correlation coefficient fixed can alleviate the impact of this effect.

Measurement of axial phase difference of density fluctuations owing to spontaneously excited waves by using microwave reflectometer on GAMMA 10/PDX

2021 ◽  
Vol 92 (5) ◽  
pp. 053506
Author(s):  
R. Sekine ◽  
M. Hirata ◽  
R. Ikezoe ◽  
S. Jang ◽  
Y. Kubota ◽  
...  
Keyword(s):  
Phase Difference ◽  
Density Fluctuations
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