scholarly journals ON THE POSSIBILITY OF CONSTRUCTING COVARIANT CHROMOMAGNETIC FIELD MODELS

1995 ◽  
Vol 10 (32) ◽  
pp. 2413-2425 ◽  
Author(s):  
ALEJANDRO CABO ◽  
SIANNAH PEÑARANDA ◽  
RENE MARTINEZ
Keyword(s):  
Perturbation Theory ◽  
Ground State ◽  
Mass Term ◽  
Spontaneous Generation ◽  
Polarization Tensor ◽  
Long Range Order ◽  
Loop Expansion ◽  
Gluon Condensates ◽  
Chromomagnetic Field ◽  
The One

Expressions for SO(4) invariant Euclidean QCD generating functionals are introduced which should produce nonvanishing gluon condensates. We consider first the loop expansion of the corresponding effectíve action searching for a description differing from the usual perturbation theory. At this level, we consider special free propagators which have off-diagonal long range order. The calculation of the polarization tensor leads to a gluon mass term which is proportional to the squared root of the finite value for <G2>. The summation of all the one-loop contributions to the energy having only mass insertions, indicates the spontaneous generation of the condensate from the perturbative ground state in a way resembling the similar effect in the case of chromomagnetic field models.

scholarly journals Massive loops in thermal SU(2) Yang–Mills theory: Radiative corrections to the pressure beyond two loops

2017 ◽  
Vol 32 (19n20) ◽  
pp. 1750118 ◽  
Author(s):  
Ingolf Bischer ◽  
Thierry Grandou ◽  
Ralf Hofmann
Keyword(s):  
Low Temperature ◽  
Ground State ◽  
Analytical Continuation ◽  
Radiative Corrections ◽  
Loop Order ◽  
Strong Suppression ◽  
Yang Mills ◽  
Loop Expansion ◽  
The One ◽  
Lower Loop

We address the loop expansion of the pressure in the deconfining phase of SU(2) Yang–Mills thermodynamics. We devise an efficient book-keeping of excluded energy-sign and scattering-channel combinations for the loop four-momenta associated with massive quasiparticles, circulating in (connected) bubble diagrams subject to vertex constraints inherited from the thermal ground state. These radiative corrections modify the one-loop pressure exerted by free thermal quasiparticles. Increasing the loop order in two-particle irreducible (2PI) bubble diagrams, we exemplarily demonstrate a suppressing effect of the vertex constraints on the number of valid combinations. This increasingly strong suppression gave rise to the conjecture in arXiv:hep-th/0609033 that the loop expansion would terminate at a finite order. Albeit the low-temperature dependence of the 2PI 3-loop diagram complies with this behavior, a thorough analysis of the high-temperature situation reveals that the leading power in temperature is thirteen such that this diagram dominates all lower loop orders for sufficiently high temperatures. An all-loop-order resummation of 2PI diagrams with dihedral symmetry is thus required, defining an extremely well-bounded analytical continuation of the low-temperature result.

scholarly journals LONG RANGE CHROMOMAGNETIC FIELDS AT HIGH TEMPERATURE

2011 ◽  
Vol 26 (27n28) ◽  
pp. 4831-4843 ◽  
Author(s):  
S. ANTROPOV ◽  
M. BORDAG ◽  
V. DEMCHIK ◽  
V. SKALOZUB
Keyword(s):  
Monte Carlo ◽  
High Temperature ◽  
Magnetic Flux ◽  
Monte Carlo Simulations ◽  
Long Range ◽  
Dyson Equation ◽  
Polarization Tensor ◽  
Chromomagnetic Field ◽  
Magnetic Mass ◽  
The One

The magnetic mass of neutral gluons in Abelian chromomagnetic field at high temperature is calculated in SU(2) gluodynamics. It is noted that such fields are spontaneously generated at high temperature. The mass is computed either from the Schwinger–Dyson equation accounting for the one-loop polarization tensor or in Monte Carlo simulations on a lattice. In latter case, an average magnetic flux penetrating a plaquette is measured for a number of lattices. Both calculations are in agreement with each other and result in zero magnetic mass. Some applications of the results obtained are discussed.

scholarly journals Two-term expansion of the ground state one-body density matrix of a mean-field Bose gas

2021 ◽  
Vol 60 (3) ◽  
Author(s):  
Phan Thành Nam ◽  
Marcin Napiórkowski
Keyword(s):  
Density Matrix ◽  
Ground State ◽  
Mean Field ◽  
Interaction Strength ◽  
Bose Gas ◽  
Body Density ◽  
The Mean ◽  
The One ◽  
Mean Field Regime ◽  
Number Of Particles

AbstractWe consider the homogeneous Bose gas on a unit torus in the mean-field regime when the interaction strength is proportional to the inverse of the particle number. In the limit when the number of particles becomes large, we derive a two-term expansion of the one-body density matrix of the ground state. The proof is based on a cubic correction to Bogoliubov’s approximation of the ground state energy and the ground state.

van der Waals perturbation theory for fermion and boson ground-state matter

1987 ◽  
Vol 35 (9) ◽  
pp. 3901-3910 ◽  
Author(s):  
V. C. Aguilera-Navarro ◽  
R. Guardiola ◽  
C. Keller ◽  
M. de Llano ◽  
M. Popovic ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Ground State ◽  
Van Der Waals

scholarly journals Off-Diagonal Long-Range Order in Generalized Hubbard Models

1997 ◽  
Vol 11 (11) ◽  
pp. 1311-1335 ◽  
Author(s):  
Kristel Michielsen ◽  
Hans De Raedt
Keyword(s):  
Density Matrix ◽  
Hubbard Model ◽  
Long Range ◽  
Ground State ◽  
Size Dependence ◽  
State Energy ◽  
System Size ◽  
Range Order ◽  
Long Range Order ◽  
Hubbard Models

We present stochastic diagonalization results for the ground-state energy and the largest eigenvalue of the two-fermion density matrix of the BCS reduced Hamiltonian, the Hubbard model, and the Hubbard model with correlated hopping. The system-size dependence of this eigenvalue is used to study the existence of Off-Diagonal Long-Range Order in these models. We show that the model with correlated hopping and repulsive on-site interaction can exhibit Off-Diagonal Long-Range Order. Analytical results for some special limiting cases indicate that Off-Diagonal Long-Range Order not always implies superconductivity.

scholarly journals On the connection between quark propagation and hadronization

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Alberto Accardi ◽  
Andrea Signori
Keyword(s):  
Sum Rules ◽  
Mass Term ◽  
Final State ◽  
Mass Generation ◽  
Gauge Invariant ◽  
Dynamical Generation ◽  
Dynamical Quark Mass ◽  
Complete Set ◽  
Fragmentation Functions ◽  
The One

AbstractWe investigate the properties and structure of the recently discussed “fully inclusive jet correlator”, namely, the gauge-invariant field correlator characterizing the final state hadrons produced by a free quark as this propagates in the vacuum. Working at the operator level, we connect this object to the single-hadron fragmentation correlator of a quark, and exploit a novel gauge invariant spectral decomposition technique to derive a complete set of momentum sum rules for quark fragmentation functions up to twist-3 level; known results are recovered, and new sum rules proposed. We then show how one can explicitly connect quark hadronization and dynamical quark mass generation by studying the inclusive jet’s gauge-invariant mass term. This mass is, on the one hand, theoretically related to the integrated chiral-odd spectral function of the quark, and, on the other hand, is experimentally accessible through the E and $${\widetilde{E}}$$ E ~ twist-3 fragmentation function sum rules. Thus, measurements of these fragmentation functions in deep inelastic processes provide one with an experimental gateway into the dynamical generation of mass in Quantum Chromodynamics.

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