scholarly journals Ghost spectral function from the spectral Dyson-Schwinger equation

2021 ◽  
Vol 104 (7) ◽  
Author(s):  
Jan Horak ◽  
Joannis Papavassiliou ◽  
Jan M. Pawlowski ◽  
Nicolas Wink
Keyword(s):  
Spectral Function

scholarly journals Non-Debye Relaxations: Two Types of Memories and Their Stieltjes Character

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 477
Author(s):  
Katarzyna Górska ◽  
Andrzej Horzela
Keyword(s):  
Stochastic Processes ◽  
Spectral Function ◽  
Evolution Equations ◽  
Memory Function ◽  
Relaxation Phenomena ◽  
Stieltjes Function ◽  
Infinitely Divisible ◽  
Spectral Functions ◽  
Debye Relaxation ◽  
Relaxation Functions

In this paper, we show that spectral functions relevant for commonly used models of the non-Debye relaxation are related to the Stieltjes functions supported on the positive semi-axis. Using only this property, it can be shown that the response and relaxation functions are non-negative. They are connected to each other and obey the time evolution provided by integral equations involving the memory function M(t), which is the Stieltjes function as well. This fact is also due to the Stieltjes character of the spectral function. Stochastic processes-based approach to the relaxation phenomena gives the possibility to identify the memory function M(t) with the Laplace (Lévy) exponent of some infinitely divisible stochastic processes and to introduce its partner memory k(t). Both memories are related by the Sonine equation and lead to equivalent evolution equations which may be freely interchanged in dependence of our knowledge on memories governing the process.

scholarly journals Exact Spectral Function of a Tonks-Girardeau Gas in a Lattice

2021 ◽  
Vol 126 (6) ◽  
Author(s):  
J. Settino ◽  
N. Lo Gullo ◽  
F. Plastina ◽  
A. Minguzzi
Keyword(s):  
Spectral Function

scholarly journals Hearing the shape of a compact Riemannian manifold with a finite number of piecewise impedance boundary conditions

1997 ◽  
Vol 20 (2) ◽  
pp. 397-402 ◽  
Author(s):  
E. M. E. Zayed
Keyword(s):  
Riemannian Manifold ◽  
Boundary Conditions ◽  
Finite Number ◽  
Spectral Function ◽  
Compact Riemannian Manifold ◽  
Smooth Boundary ◽  
Beltrami Operator ◽  
Smooth Functions ◽  
Impedance Boundary ◽  
Impedance Boundary Conditions

The spectral functionΘ(t)=∑i=1∞exp(−tλj), where{λj}j=1∞are the eigenvalues of the negative Laplace-Beltrami operator−Δ, is studied for a compact Riemannian manifoldΩof dimension “k” with a smooth boundary∂Ω, where a finite number of piecewise impedance boundary conditions(∂∂ni+γi)u=0on the parts∂Ωi(i=1,…,m)of the boundary∂Ωcan be considered, such that∂Ω=∪i=1m∂Ωi, andγi(i=1,…,m)are assumed to be smooth functions which are not strictly positive.

Asymptotic SU(5) symmetry and spectral-function sum rules

1979 ◽  
Vol 5 (7) ◽  
pp. 885-891 ◽  
Author(s):  
V P Gautam ◽  
B Bagchi
Keyword(s):  
Spectral Function ◽  
Sum Rules

SO(5) SYMMETRY AND SINGLE PARTICLE SPECTRA

1999 ◽  
Vol 13 (24n25) ◽  
pp. 3039-3047
Author(s):  
M. G. ZACHER ◽  
A. DORNEICH ◽  
R. EDER ◽  
W. HANKE ◽  
S. C. ZHANG
Keyword(s):  
Spectral Function ◽  
Single Particle ◽  
Photoemission Spectrum ◽  
Two Dimensional ◽  
Ladder Model ◽  
Particle Spectra ◽  
Key Features

We discuss properties of a recently proposed SO(5) symmetric ladder model. Key features of the single particle spectral function that are emerging from the symmetry are numerically identified in the ladder model and in the photoemission spectrum of the two-dimensional t–J model.

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