scholarly journals Frequency and damping of hydrodynamic modes in a trapped Bose-condensed gas

2004 ◽  
Vol 69 (2) ◽  
Author(s):  
Tetsuro Nikuni ◽  
Allan Griffin
Keyword(s):  
2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
M. Asadi ◽  
H. Soltanpanahi ◽  
F. Taghinavaz

Abstract We investigate the time-dependent perturbations of strongly coupled $$ \mathcal{N} $$ N = 4 SYM theory at finite temperature and finite chemical potential with a second order phase transition. This theory is modelled by a top-down Einstein-Maxwell-dilaton description which is a consistent truncation of the dimensional reduction of type IIB string theory on AdS5×S5. We focus on spin-1 and spin-2 sectors of perturbations and compute the linearized hydrodynamic transport coefficients up to the third order in gradient expansion. We also determine the radius of convergence of the hydrodynamic mode in spin-1 sector and the lowest non-hydrodynamic modes in spin-2 sector. Analytically, we find that all the hydrodynamic quantities have the same critical exponent near the critical point θ = $$ \frac{1}{2} $$ 1 2 . Moreover, we propose a relation between symmetry enhancement of the underlying theory and vanishing of the only third order hydrodynamic transport coefficient θ1, which appears in the shear dispersion relation of a conformal theory on a flat background.


1998 ◽  
Vol 57 (4) ◽  
pp. 2938-2941 ◽  
Author(s):  
G. M. Kavoulakis ◽  
C. J. Pethick ◽  
H. Smith

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Matteo Baggioli ◽  
Sebastian Grieninger ◽  
Li Li

Abstract We perform a detailed analysis of a large class of effective holographic models with broken translations at finite charge density and magnetic field. We exhaustively discuss the dispersion relations of the hydrodynamic modes at zero magnetic field and successfully match them to the predictions from charged hydrodynamics. At finite magnetic field, we identify the presence of an expected type-B Goldstone boson Re[ω] ∼ k2, known as magnetophonon and its gapped partner — the magnetoplasmon. We discuss their properties in relation to the effective field theory and hydrodynamics expectations. Finally, we compute the optical conductivities and the quasinormal modes at finite magnetic field. We observe that the pinning frequency of the magneto-resonance peak increases with the magnetic field, in agreement with experimental data on certain 2D materials, revealing the quantum nature of the holographic pinning mechanism.


2008 ◽  
Vol 77 (3) ◽  
Author(s):  
E. Taylor ◽  
H. Hu ◽  
X.-J. Liu ◽  
A. Griffin

Author(s):  
Da Ke ◽  
Wei Zhong ◽  
Sergey V Dmitriev ◽  
Daxing Xiong

Abstract We develop an effective numerical scheme to capture hydrodynamic modes in general classical anharmonic chains. This scheme is based on the hydrodynamic theory suggested by Ernst-Hauge-van Leeuwen, which takes full role of pressure fluctuations into account. With this scheme we show that the traditional pictures given by the current nonlinear fluctuating hydrodynamic theory are valid only when the system's pressure is zero and the pressure fluctuations are weak. For nonvanishing pressure, the hydrodynamic modes can, however, respond to small and large pressure fluctuations and relax in some distinct manners. Our results shed new light on understanding thermal transport from the perspective of hydrodynamic theory.


Author(s):  
P. Oshkai ◽  
A. Velikorodny ◽  
T. Yan

Fully turbulent inflow past a coaxial side branch resonator mounted in a duct can give rise to pronounced flow oscillations due to coupling between separated shear layers and standing acoustic waves. Experimental investigation of acoustically-coupled shear layers is conducted using digital particle image velocimetry in conjunction with unsteady pressure measurements. Global instantaneous flow images, as well as phase-averaged images, are evaluated to provide insight into the flow physics during tone generation. The emphasis is on the effect of shear layer interaction on the acoustic response of the resonator during the first and second hydrodynamic modes of the shear layer oscillation. Onset of the locked-on resonant states is characterized in terms of the acoustic pressure amplitudes and the quality factors of the corresponding spectral peaks. Moreover, patterns of generated acoustic power are calculated using a semi-empirical approach. As the level of interaction between the separated shear layers is increased, spatial structure of the acoustic source undergoes a substantial transformation.


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