scholarly journals Quantum quenches in an interacting field theory: Full quantum evolution versus semiclassical approximations

2022 ◽  
Vol 105 (1) ◽  
Author(s):  
D. Szász-Schagrin ◽  
I. Lovas ◽  
G. Takács
Keyword(s):  
Field Theory ◽  
Quantum Evolution ◽  
Quantum Quenches ◽  
Semiclassical Approximations ◽  
Full Quantum

scholarly journals THE LINEAR BOLTZMANN EQUATION AS THE LOW DENSITY LIMIT OF A RANDOM SCHRÖDINGER EQUATION

2005 ◽  
Vol 17 (06) ◽  
pp. 669-743 ◽  
Author(s):  
DAVID ENG ◽  
LÁSZLÓ ERDŐS
Keyword(s):  
Boltzmann Equation ◽  
Linear Boltzmann Equation ◽  
Collision Kernel ◽  
Quantum Evolution ◽  
Quantum Scattering ◽  
Low Density ◽  
Density Limit ◽  
Long Time ◽  
Low Density Limit ◽  
Full Quantum

We study the long time evolution of a quantum particle interacting with a random potential in the Boltzmann–Grad low density limit. We prove that the phase space density of the quantum evolution defined through the Husimi function converges weakly to a linear Boltzmann equation. The Boltzmann collision kernel is given by the full quantum scattering cross-section of the obstacle potential.

scholarly journals QUANTUM EVOLUTION OF SCALAR FIELDS IN ROBERTSON-WALKER SPACE-TIME

1996 ◽  
Vol 11 (21) ◽  
pp. 3957-3971 ◽  
Author(s):  
H.C. REIS ◽  
O.J.P. ÉBOLI
Keyword(s):  
Field Theory ◽  
Energy Momentum Tensor ◽  
Gaussian Approximation ◽  
Scalar Fields ◽  
Momentum Tensor ◽  
Space Time ◽  
Quantum Evolution ◽  
Coupling Constant ◽  
Pure States ◽  
Schrödinger Picture

We study the λɸ4 field theory in a flat Robertson-Walker space-time using the functional Schrödinger picture. We introduce a simple Gaussian approximation to analyze the time evolution of pure states and we establish the renormalizability of the approximation. We also show that the energy–momentum tensor in this approximation is finite once we consider the usual mass and coupling constant renormalizations.

HIGH ENERGY HADRONIC SCATTERING – THE QUANTUM EVOLUTION

2010 ◽  
Vol 25 (02n03) ◽  
pp. 524-531
Author(s):  
ALEX KOVNER
Keyword(s):  
Field Theory ◽  
Evolution Equation ◽  
High Energy ◽  
Quantum Evolution ◽  
Modern Approach ◽  
Recent Developments ◽  
Reggeon Field Theory

I review the modern approach to quantum evolution of hadronic observables with energy. Recent developments relating the (eikonal) evolution equation to the QCD Reggeon field theory and the approach to including the Pomeron loops is discussed.

scholarly journals Statistics on Lefschetz thimbles: Bell/Leggett-Garg inequalities and the classical-statistical approximation

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Peter Millington ◽  
Zong-Gang Mou ◽  
Paul M. Saffin ◽  
Anders Tranberg
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Distribution Function ◽  
Probability Distribution Function ◽  
Bell Inequalities ◽  
Quantum Field ◽  
Statistical Approximation ◽  
Free Theory ◽  
Complex Valued ◽  
Full Quantum

Abstract Inspired by Lefschetz thimble theory, we treat Quantum Field Theory as a statistical theory with a complex Probability Distribution Function (PDF). Such complex-valued PDFs permit the violation of Bell-type inequalities, which cannot be violated by a real-valued, non-negative PDF. In this paper, we consider the Classical-Statistical approximation in the context of Bell-type inequalities, viz. the familiar (spatial) Bell inequalities and the temporal Leggett-Garg inequalities. We show that the Classical-Statistical approximation does not violate temporal Bell-type inequalities, even though it is in some sense exact for a free theory, whereas the full quantum theory does. We explain the origin of this discrepancy, and point out the key difference between the spatial and temporal Bell-type inequalities. We comment on the import of this work for applications of the Classical-Statistical approximation.

scholarly journals Quantum quenches in free field theory: universal scaling at any rate

2016 ◽  
Vol 2016 (5) ◽  
Author(s):  
Sumit R. Das ◽  
Damián A. Galante ◽  
Robert C. Myers
Keyword(s):  
Field Theory ◽  
Free Field ◽  
Universal Scaling ◽  
Quantum Quenches
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