scholarly journals A holographic superfluid symphony

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Daniel Areán ◽  
Matteo Baggioli ◽  
Sebastian Grieninger ◽  
Karl Landsteiner
Keyword(s):  
Constitutive Relations ◽  
Quasinormal Modes ◽  
Role Reversal ◽  
Hydrodynamic Theory ◽  
Hydrodynamic Dispersion ◽  
Complex Frequency ◽  
Hydrodynamic Modes ◽  
Weakly Coupled ◽  
Reversal Phenomenon ◽  
Theory Framework

Abstract We study the hydrodynamic excitations of backreacted holographic superfluids by computing the full set of quasinormal modes (QNMs) at finite momentum and matching them to the existing hydrodynamic theory of superfluids. Additionally, we analyze the behavior of the low-energy excitations in real frequency and complex momentum, going beyond the standard QNM picture. Finally, we carry out a novel type of study of the model by computing the support of the hydrodynamic modes across the phase diagram. We achieve this by determining the support of the corresponding QNMs on the different operators in the dual theory, both in complex frequency and complex momentum space. From the support, we are able to reconstruct the hydrodynamic dispersion relations using the hydrodynamic constitutive relations. Our analysis rules out a role-reversal phenomenon between first and second sound in this model, contrary to results obtained in a weakly coupled field theory framework.

scholarly journals Quasinormal modes in charged fluids at complex momentum

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Aron Jansen ◽  
Christiana Pantelidou
Keyword(s):  
Quasinormal Modes ◽  
Quantitative Agreement ◽  
Dispersion Relations ◽  
Radius Of Convergence ◽  
Complex Frequency ◽  
Branch Points ◽  
Charged Fluids ◽  
Hydrodynamic Modes ◽  
Momentum Plane ◽  
The One

Abstract We investigate the convergence of relativistic hydrodynamics in charged fluids, within the framework of holography. On the one hand, we consider the analyticity properties of the dispersion relations of the hydrodynamic modes on the complex frequency and momentum plane and on the other hand, we perform a perturbative expansion of the dispersion relations in small momenta to a very high order. We see that the locations of the branch points extracted using the first approach are in good quantitative agreement with the radius of convergence extracted perturbatively. We see that for different values of the charge, different types of pole collisions set the radius of convergence. The latter turns out to be finite in the neutral case for all hydrodynamic modes, while it goes to zero at extremality for the shear and sound modes. Furthermore, we also establish the phenomenon of pole-skipping for the Reissner-Nordström black hole, and we find that the value of the momentum for which this phenomenon occurs need not be within the radius of convergence of hydrodynamics.

scholarly journals Magnetophonons & type-B Goldstones from hydrodynamics to holography

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Matteo Baggioli ◽  
Sebastian Grieninger ◽  
Li Li
Keyword(s):  
Magnetic Field ◽  
2D Materials ◽  
Goldstone Boson ◽  
Quasinormal Modes ◽  
Effective Field ◽  
Zero Magnetic Field ◽  
Type B ◽  
Hydrodynamic Modes ◽  
Pinning Mechanism ◽  
The Magnetic Field

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.

Unconventional relaxation of hydrodynamic modes in anharmonic chains under strong pressure fluctuations

2021 ◽  
Author(s):  
Da Ke ◽  
Wei Zhong ◽  
Sergey V Dmitriev ◽  
Daxing Xiong
Keyword(s):  
Thermal Transport ◽  
Numerical Scheme ◽  
Pressure Fluctuations ◽  
Hydrodynamic Theory ◽  
Hydrodynamic Modes ◽  
Large Pressure

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.

scholarly journals Convergence of hydrodynamic modes: insights from kinetic theory and holography

2021 ◽  
Vol 10 (6) ◽  
Author(s):  
Michal P. Heller ◽  
Alexandre Serantes ◽  
Michal Spalinski ◽  
Viktor Svensson ◽  
Benjamin Withers
Keyword(s):  
Kinetic Theory ◽  
Green’S Function ◽  
Green's Function ◽  
Dispersion Relations ◽  
Radius Of Convergence ◽  
Hydrodynamic Dispersion ◽  
Hydrodynamic Modes ◽  
Complex Singularities ◽  
Relaxation Time Approximation ◽  
New Feature

We study the mechanisms setting the radius of convergence of hydrodynamic dispersion relations in kinetic theory in the relaxation time approximation. This introduces a quali\-tatively new feature with respect to holography: a nonhydrodynamic sector represented by a branch cut in the retarded Green's function. In contrast with existing holographic examples, we find that the radius of convergence in the shear channel is set by a collision of the hydrodynamic pole with a branch point. In the sound channel it is set by a pole-pole collision on a non-principal sheet of the Green's function. More generally, we examine the consequences of the Implicit Function Theorem in hydrodynamics and give a prescription to determine a set of points that necessarily includes all complex singularities of the dispersion relation. This may be used as a practical tool to assist in determining the radius of convergence of hydrodynamic dispersion relations.

scholarly journals Near-extremal fluid mechanics

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Upamanyu Moitra ◽  
Sunil Kumar Sake ◽  
Sandip P. Trivedi
Keyword(s):  
Fluid Mechanics ◽  
Chemical Potential ◽  
Driving Forces ◽  
Constitutive Relations ◽  
Temperature Limit ◽  
Perturbative Expansion ◽  
Boundary Theory ◽  
Hydrodynamic Modes ◽  
Attractor Behaviour ◽  
The One

Abstract We analyse near-extremal black brane configurations in asymptotically AdS4 spacetime with the temperature T, chemical potential μ, and three-velocity uν, varying slowly. We consider a low-temperature limit where the rate of variation is much slower than μ, but much bigger than T. This limit is different from the one considered for conventional fluid-mechanics in which the rate of variation is much smaller than both T, μ. We find that in our limit, as well, the Einstein-Maxwell equations can be solved in a systematic perturbative expansion. At first order, in the rate of variation, the resulting constitutive relations for the stress tensor and charge current are local in the boundary theory and can be easily calculated. At higher orders, we show that these relations become non-local in time but the perturbative expansion is still valid. We find that there are four linearised modes in this limit; these are similar to the hydrodynamic modes found in conventional fluid mechanics with the same dispersion relations. We also study some linearised time independent perturbations exhibiting attractor behaviour at the horizon — these arise in the presence of external driving forces in the boundary theory.

Does Locus of Control Influence Parentification and Anxiety in Father–Daughter Relationships?

2021 ◽  
pp. 0192513X2199318
Author(s):  
Cindy J. Mays ◽  
Lacy E. Krueger
Keyword(s):  
Locus Of Control ◽  
Role Reversal ◽  
Boundary Violations ◽  
Undergraduate Women ◽  
Reversal Phenomenon ◽  
The Relationship ◽  
At Home

Parentification is a role-reversal phenomenon in which boundary violations occur such as children being their parents’ physical or emotional caretakers. Researchers have shown that childhood parentification can produce anxiety, but locus of control (LOC) moderates this relationship. We sought to examine the influence of LOC on the parentification-anxiety relationship in father–daughter dyads, as this dyad is under-represented in the parentification literature. One hundred and eighty-one undergraduate women completed an anxiety measure, parentification questionnaire, and an LOC inventory. Higher levels of parentification and lower levels of internal LOC were associated with higher reports of anxiety, but internal LOC did not appear to moderate the anxiety-parentification relationship. For individuals residing at home, parentification predicted anxiety, whereas internal LOC predicted anxiety among those not residing at home. These results further the paternal parentification literature, as well as show the relationship between childhood parentification and women’s anxiety for those currently living at home.

STATISTICAL MECHANICS OF CERTAIN HYDRODYNAMIC DISPERSION PHENOMENA

1965 ◽  
Vol 43 (10) ◽  
pp. 1776-1794 ◽  
Author(s):  
Narayan M. Chaudhari ◽  
Adrian E. Scheidegger
Keyword(s):  
Statistical Mechanics ◽  
Markov Processes ◽  
Irreversible Thermodynamics ◽  
Hydrodynamic Dispersion ◽  
Mechanics Of Solids ◽  
Interaction Function ◽  
Onsager Relations ◽  
Weakly Coupled ◽  
Dispersion Systems ◽  
Mass Dispersion

This paper explores the extent of an analogy postulated earlier between the usual energy-based statistical mechanics and mass-dispersion phenomena. It is shown that in the equilibrium case the interaction function as used in the energy-based statistical mechanics of solids or weakly coupled gases entails a corresponding result in mass-dispersion systems. Examples of specific transport equations are calculated. The analogy can also be extended to irreversible thermodynamics. It is shown that Ziegler's generalized Onsager relations entail corresponding results in the case of mass dispersion.It is shown that an approach based on the theory of Markov processes can also be used for the description of mass-based statistical mechanics. The conditions necessary for the maintenance of canonical invariance are indicated. Applications of the above theory to hydrological problems are indicated.

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