Effective degrees of freedom of the quark–gluon plasma

In this work, we present a unified approach to the thermodynamics of hadron–quark–gluon matter at finite temperatures on the basis of a quark cluster expansion in the form of a generalized Beth–Uhlenbeck approach with a generic ansatz for the hadronic phase shifts that fulfills the Levinson theorem. The change in the composition of the system from a hadron resonance gas to a quark–gluon plasma takes place in the narrow temperature interval of 150–190 MeV, where the Mott dissociation of hadrons is triggered by the dropping quark mass as a result of the restoration of chiral symmetry. The deconfinement of quark and gluon degrees of freedom is regulated by the Polyakov loop variable that signals the breaking of the Z(3) center symmetry of the color SU(3) group of QCD. We suggest a Polyakov-loop quark–gluon plasma model with O(αs) virial correction and solve the stationarity condition of the thermodynamic potential (gap equation) for the Polyakov loop. The resulting pressure is in excellent agreement with lattice QCD simulations up to high temperatures.

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Quasiparticle degrees of freedom versus the perfect fluid as descriptors of the quark-gluon plasma

Physical Review C ◽

10.1103/physrevc.78.044905 ◽

2008 ◽

Vol 78 (4) ◽

Cited By ~ 7

Author(s):

L. A. Linden Levy ◽

J. L. Nagle ◽

C. Rosen ◽

P. Steinberg

Keyword(s):

Perfect Fluid ◽

Quark Gluon Plasma ◽

Degrees Of Freedom ◽

Gluon Plasma

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Holographic Multiquarks in the Quark-Gluon Plasma: A Review

Advances in High Energy Physics ◽

10.1155/2011/123184 ◽

2011 ◽

Vol 2011 ◽

pp. 1-40 ◽

Cited By ~ 1

Author(s):

Piyabut Burikham ◽

Ekapong Hirunsirisawat

Keyword(s):

Magnetic Field ◽

Phase Diagram ◽

Magnetic Properties ◽

Quark Gluon Plasma ◽

Bound States ◽

Degrees Of Freedom ◽

Gluon Plasma ◽

Screening Length ◽

Holographic Approach ◽

Multiquark States

We review the holographic multiquark states in the deconfined quark-gluon plasma. Nuclear matter can become deconfined by extremely high temperature and/or density. In the deconfined nuclear medium, bound states with colour degrees of freedom are allowed to exist. Using holographic approach, the binding energy and the screening length of the multiquarks can be calculated. Using the deconfined Sakai-Sugimoto model, the phase diagram of the multiquark phase, the vacuum phase, and the chiral-symmetric quark-gluon plasma can be obtained. Then we review the magnetic properties of the multiquarks and their phase diagrams. The multiquark phase is compared with the pure pion gradient, the magnetized vacuum, and the chiral-symmetric quark-gluon plasma phases. For moderate temperature and sufficiently large density at a fixed magnetic field, the mixed phase of multiquark and pion gradient is the most energetically preferred phase.

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Degrees of Freedom of the Quark Gluon Plasma, Tested by Heavy Mesons

New Horizons in Fundamental Physics ◽

10.1007/978-3-319-44165-8_12 ◽

2016 ◽

pp. 151-165 ◽

Cited By ~ 1

Author(s):

H. Berrehrah ◽

M. Nahrgang ◽

T. Song ◽

V. Ozvenchuck ◽

P. B. Gossiaux ◽

...

Keyword(s):

Quark Gluon Plasma ◽

Degrees Of Freedom ◽

Gluon Plasma ◽

Heavy Mesons

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EFFECTIVE MESONIC AND BARYONIC DEGREES OF FREEDOM IN NEUTRON STARS

International Journal of Modern Physics D ◽

10.1142/s0218271804005559 ◽

2004 ◽

Vol 13 (07) ◽

pp. 1365-1373 ◽

Cited By ~ 2

Author(s):

MANFRED DILLIG ◽

MATHIAS SCHOTT ◽

EDUARDO F. LÜTZ ◽

ALEXANDRE MESQUITA ◽

CÉSAR A. Z. VASCONCELLOS

Keyword(s):

Neutron Stars ◽

Quark Gluon Plasma ◽

Degrees Of Freedom ◽

Gluon Plasma ◽

Hadronic Matter

We present a sketchy survey on the role of effective mesonic and baryonic degrees of freedom in dense hadronic matter and briefly mention still very crude attempts to include constituent quarks degrees of freedom for a transition to a quark gluon plasma.

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THE PHYSICS OF GLUEBALLS

International Journal of Modern Physics E ◽

10.1142/s0218301309012124 ◽

2009 ◽

Vol 18 (01) ◽

pp. 1-49 ◽

Cited By ~ 165

Author(s):

VINCENT MATHIEU ◽

NIKOLAI KOCHELEV ◽

VICENTE VENTO

Keyword(s):

Lattice Qcd ◽

Gauge Field ◽

Quark Gluon Plasma ◽

Degrees Of Freedom ◽

Sum Rules ◽

Dominant Role ◽

Gluon Plasma ◽

Qcd Sum Rules ◽

Technical Developments

Glueballs are particles whose valence degrees of freedom are gluons and therefore in their description the gauge field plays a dominant role. We review recent results in the physics of glueballs with the aim set on phenomenology and discuss the possibility of finding them in conventional hadronic experiments and in the Quark Gluon Plasma. In order to describe their properties we resort to a variety of theoretical treatments which include, lattice QCD, constituent models, AdS/QCD methods, and QCD sum rules. The review is supposed to be an informed guide to the literature. Therefore, we do not discuss in detail technical developments but refer the reader to the appropriate references.

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Three regimes of QCD

International Journal of Modern Physics A ◽

10.1142/s0217751x20440315 ◽

2021 ◽

pp. 2044031

Author(s):

L. Ya. Glozman

Keyword(s):

Dirac Operator ◽

Quark Gluon Plasma ◽

Degrees Of Freedom ◽

Magnetic Interaction ◽

Gluon Plasma ◽

Magnetic Interactions ◽

Hadron Spectrum ◽

Zero Modes ◽

Electric Interaction ◽

Hadron Gas

While the QCD Lagrangian as the whole is only chirally symmetric, its electric part has larger chiral-spin [Formula: see text] and [Formula: see text] symmetries. This allows separation of the electric and magnetic interactions in a given reference frame. Artificial truncation of the near-zero modes of the Dirac operator results in the emergence of the [Formula: see text] and [Formula: see text] symmetries in hadron spectrum. This implies that while the confining electric interaction is distributed among all modes of the Dirac operator, the magnetic interaction is located at least predominantly in the near-zero modes. Given this observation one could anticipate that above the pseudocritical temperature, where the near-zero modes of the Dirac operator are suppressed, QCD is [Formula: see text] and [Formula: see text] symmetric, which means absence of deconfinement in this regime. Solution of the [Formula: see text] QCD on the lattice with a chirally symmetric Dirac operator reveals that indeed in the interval [Formula: see text] QCD is approximately [Formula: see text] and [Formula: see text] symmetric which implies that degrees of freedom are chirally symmetric quarks bound by the chromoelectric field into color-singlet objects without the chromomagnetic effects. This regime is referred to as a Stringy Fluid. At larger temperatures this emergent symmetry smoothly disappears and QCD approaches the Quark–Gluon Plasma regime with quasifree quarks. The Hadron Gas, the Stringy Fluid and the Quark–Gluon Plasma differ by symmetries, degrees of freedom and properties.

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Mass Gap in Nonperturbative Quantization à La Heisenberg

Universe ◽

10.3390/universe5020050 ◽

2019 ◽

Vol 5 (2) ◽

pp. 50

Author(s):

Vladimir Dzhunushaliev ◽

Vladimir Folomeev

Keyword(s):

Energy Spectrum ◽

Approximate Method ◽

Quark Gluon Plasma ◽

Degrees Of Freedom ◽

Finite Energy ◽

Gluon Plasma ◽

Spherically Symmetric ◽

Mass Gap ◽

Infinite Set ◽

Nonperturbative Quantization

The approximate method of solving nonperturbative Dyson-Schwinger equations by cutting off this infinite set of equations to three equations is considered. The gauge noninvariant decomposition of SU(3) degrees of freedom into SU(2) × U(1) and SU(3)/(SU(2) × U(1)) degrees of freedom is used. SU(2) × U(1) degrees of freedom have nonzero quantum average, and SU(3)/(SU(2) × U(1)) have zero quantum average. To close these equations, some approximations are employed. Regular spherically symmetric finite energy solutions of these equations are obtained. Energy spectrum of these solutions is studied. The presence of a mass gap is shown. The obtained solutions describe quasi-particles in a quark-gluon plasma.

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