Quasiparticle picture

2019 ◽  
Author(s):  
Tapio Simula
Keyword(s):  
Quasiparticle Picture

scholarly journals A CONSISTENT QUASIPARTICLE PICTURE OF QUARK–GLUON PLASMA AND THE VELOCITY OF SOUND

2006 ◽  
Vol 21 (27) ◽  
pp. 2067-2077 ◽  
Author(s):  
SANJAY K. GHOSH ◽  
TAMAL K. MUKHERJEE ◽  
SIBAJI RAHA
Keyword(s):  
Quark Gluon Plasma ◽  
Quark Mass ◽  
Gluon Plasma ◽  
Velocity Of Sound ◽  
Lattice Data ◽  
Mass Model ◽  
Density Dependent ◽  
Quasiparticle Picture

A thermodynamically consistent density dependent quark mass model has been used to study the velocity of sound in a hot quark–gluon plasma. The results are compared with the recent lattice data.

Peierls Model and Vacuum Structure in the N = 2 Supersymmetric Field Theories

1997 ◽  
Vol 12 (10) ◽  
pp. 719-727 ◽  
Author(s):  
A. Gorsky
Keyword(s):  
Temperature Phase ◽  
Integrable Structure ◽  
Mass Gap ◽  
Supersymmetric Field Theories ◽  
Temperature Phase Transition ◽  
Lax Operator ◽  
The One ◽  
Bps States ◽  
Peierls Model ◽  
Quasiparticle Picture

We suggest the quasiparticle picture behind the integrable structure of N=2 SYM theory which arises if the Lax operator is considered as a Hamiltonian for the fermionic system. We compare the meaning of BPS states with the one coming from the D-brane interpretation and give some evidence for the compositeness of the self-dual strings. The temperature phase transition with the disappearance of the mass gap is conjectured.

scholarly journals Entanglement spreading and quasiparticle picture beyond the pair structure

2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Alvise Bastianello ◽  
Mario Collura
Keyword(s):  
Quantum Systems ◽  
One Dimension ◽  
Many Body ◽  
Initial State ◽  
Perfect Agreement ◽  
Quasi Particle ◽  
Simple Assumption ◽  
The Common ◽  
Quasiparticle Picture ◽  
Number Of Particles

The quasi-particle picture is a powerful tool to understand the entanglement spreading in many-body quantum systems after a quench. As an input, the structure of the excitations' pattern of the initial state must be provided, the common choice being pairwise-created excitations. However, several cases exile this simple assumption. In this work we investigate weakly-interacting to free quenches in one dimension. This results in a far richer excitations' pattern where multiplets with a larger number of particles are excited. We generalize the quasi-particle ansatz to such a wide class of initial states, providing a small-coupling expansion of the Rényi entropies. Our results are in perfect agreement with iTEBD numerical simulations.

scholarly journals Quasiparticle picture from the Bekenstein bound

2018 ◽  
Author(s):  
Alfredo Iorio ◽  
Giovanni Acquaviva ◽  
Martin Scholtz
Keyword(s):  
Quasiparticle Picture

Quantum Kinetic Equations

2018 ◽  
Author(s):  
Klaus Morawetz
Keyword(s):  
Kinetic Equation ◽  
Kinetic Equations ◽  
First Order ◽  
Alternative Approaches ◽  
Reduced Density ◽  
Quasiparticle Picture ◽  
Exact Cancellation

The gradient approximations of the Kadanoff and Baym equations are derived up to first order. The off-shell motions responsible for the satellites are shown to ensure causality. The cancellation of off-shell motions from the drift and correlation part of the reduced density provides a precursor of the kinetic equation for the quasiparticle distribution which leads to a functional between reduced and quasiparticle distribution, named the extended quasiparticle picture. Virial corrections appear as internal gradients in the selfenergy and therefore in the considered processes. With this extended quasiparticle picture, the non-Markovian kinetic equations are transformed into Markovian ones for proper defined quasiparticles without neglect showing the exact cancellation of off-shell parts. Alternative approaches are discussed for comparison.

Spectral Properties

2018 ◽  
Author(s):  
Klaus Morawetz
Keyword(s):  
Correlation Function ◽  
Spectral Function ◽  
Spectral Properties ◽  
Sum Rules ◽  
Statistical Weight ◽  
Reduced Density Matrix ◽  
Density Of State ◽  
Shell Motion ◽  
Reduced Density ◽  
Quasiparticle Picture

The spectral properties of the nonequilibrium Green’s functions are explored. Causality and sum rules are shown to be completed by the extended quasiparticle picture. The off-shell motion is seen to become visible in satellite structures of the spectral function. Different forms of ansatz to reduce the two-time Green’s function to a one-time reduced density matrix are discussed with respect to the consistency to other approximations. We have seen from the information contained in the correlation function that the statistical weight of excitations with which the distributions are populated are given by the spectral function. This momentum-resolved density of state can be found by the retarded and advance functions.

Selfenergy

2018 ◽  
Author(s):  
Klaus Morawetz
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Correlation Functions ◽  
Doppler Shift ◽  
Secular Equation ◽  
Wave Functions ◽  
Local Velocity ◽  
Microscopic Picture ◽  
Quasiparticle Picture

The averaged wave functions allow defining the transport vertex. For the correlation functions this leads to the Generalised Kadanoff and Baym formalism with the Langreth–Wilkins rules. The meaning of the selfenergy is explored. The Green’s function is a secular equation in which the complicated motion of a particle during interaction is represented by the selfenergy. The quasiparticle picture is applicable to long trajectories, where the averaged velocity is of interest. In processes like emission, the Doppler shift depends on the local velocity and one has to return to the microscopic picture. The application scheme how to construct and use the selfenergy is presented.

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