Generalized Langevin theory for many‐body problems in chemical dynamics: Modelling of solid and liquid state response functions

1980 ◽  
Vol 72 (7) ◽  
pp. 3889-3898 ◽  
Author(s):  
M. Berkowitz ◽  
C. L. Brooks ◽  
S. A. Adelman
Keyword(s):  
Liquid State ◽  
Chemical Dynamics ◽  
Response Functions ◽  
Many Body ◽  
State Response ◽  
Dynamics Modelling

scholarly journals Liquid-state NMR simulations of quantum many-body problems

2005 ◽  
Vol 71 (3) ◽  
Author(s):  
C. Negrevergne ◽  
R. Somma ◽  
G. Ortiz ◽  
E. Knill ◽  
R. Laflamme
Keyword(s):  
Liquid State ◽  
Many Body

scholarly journals KEY CONCEPTS IN TIME-DEPENDENT DENSITY-FUNCTIONAL THEORY

2001 ◽  
Vol 15 (14) ◽  
pp. 1969-2023 ◽  
Author(s):  
ROBERT VAN LEEUWEN
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Time Dependent ◽  
Response Functions ◽  
Many Body ◽  
Functional Theory ◽  
Key Concepts ◽  
Initial States ◽  
Many Body Systems ◽  
Dependent Density

We give an overview of the underlying concepts of time-dependent density-functional theory. The basic relations between densities, potentials and initial states, for time-dependent many-body systems are discussed. We obtain some new results concerning the invertability of response functions. Some fundamental difficulties associated with the time-dependent action principle are discussed and we show how these difficulties can be resolved by means of the Keldysh formalism.

scholarly journals Neutrino-pair interactions in astrophysical systems

2020 ◽  
Vol 29 (09) ◽  
pp. 2050080
Author(s):  
María Paula Colombi ◽  
Osvaldo Civitarese ◽  
Ana V. Penacchioni
Keyword(s):  
Eigenvalue Problem ◽  
Body Problem ◽  
Mean Field ◽  
Response Functions ◽  
Many Body ◽  
Quasi Particle ◽  
Finite Density ◽  
Neutrino Pair ◽  
Neutrino Fluxes ◽  
Pair Interactions

We study the effects produced by interactions among neutrinos upon extra-galactic neutrino-fluxes. We have assumed a separable type of pair interactions and performed a transformation to a quasi-particle mean field followed by a Tamm–Damcoff diagonalization. In doing so, we have adopted techniques originated in the quantum many-body problem, and adapted them to this specific case. The solutions of the associated eigenvalue problem provide us with energies and amplitudes which are then used to construct the neutrino response functions at finite density and temperature. The formalism is applied to the description of neutrinos produced in a SN environment.

Effect of Pre-stress States on the Impulsive Modes of Vibration of Cylindrical Tank-liquid Systems under Horizontal Motions

2005 ◽  
Vol 11 (9) ◽  
pp. 1195-1220 ◽  
Author(s):  
Juan C. Virella ◽  
Luis E. Suarez ◽  
Luis A. Godoy
Keyword(s):  
Stress State ◽  
Liquid System ◽  
Mode Shapes ◽  
Response Functions ◽  
State Response ◽  
Hydrodynamic Response ◽  
Liquid Systems ◽  
Modes Of Vibration ◽  
Stress States ◽  
Cylindrical Tanks

In this paper we investigate the influence of hydrostatic pressure and self-weight loads (pre-stress state) on the natural periods and mode shapes of steel cylindrical tanks and on the response under horizontal motions. The tank structure is modeled with finite elements and added mass models are used to represent the liquid. Only the impulsive component of the hydrodynamic response is considered. The natural periods and mode shapes for tank-liquid systems including and neglecting the effect of the pre-stress state are computed and compared. Three tank-liquid systems with different cylinder height to diameter ratios and slenderness ratios are considered. The numerical results show that the pre-stress state has a significant influence in the natural periods and mode shapes of tank-liquid systems with thinner walls; however, for thicker shells this effect is reduced. When the pre-stress state is neglected and included, the smaller differences in natural periods occur, for modes characterized by small circumferential wavenumbers. The steady-state response of a tank-liquid system to horizontal harmonic base accelerations was also computed. Large differences were found when the pre-stress state was neglected. A comparison of the frequency response functions shows that the peak responses occur at quite different load periods and they have significantly different amplitudes.

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