scholarly journals GENERAL FORMULA FOR THE FOUR-QUARK CONDENSATE AND VACUUM FACTORIZATION ASSUMPTION

2008 ◽  
Vol 23 (10) ◽  
pp. 1507-1520 ◽  
Author(s):  
HONG-SHI ZONG ◽  
DENG-KE HE ◽  
FENG-YAO HOU ◽  
WEI-MIN SUN
Keyword(s):  
General Formula ◽  
Linear Response ◽  
Chemical Potential ◽  
Background Field ◽  
Quark Propagator ◽  
Quark Condensate ◽  
Sum Rule ◽  
Factorization Problem ◽  
Field Approach ◽  
General Method

By differentiating the dressed quark propagator with respect to a variable background field, the linear response of the dressed quark propagator in the presence of the background field can be obtained. From this general method, using the vector background field as an illustration, we derive a general formula for the four-quark condensate [Formula: see text]. This formula contains the corresponding fully dressed vector vertex and it is shown that factorization for [Formula: see text] holds only when the dressed vertex is taken to be the bare one. This property also holds for all other types of four-quark condensate. By comparing this formula with the general expression for the corresponding vacuum susceptibility, it is found that there exists some intrinsic relation between these two quantities, which are usually treated as independent phenomenological inputs in the QCD sum rule external field approach. The above results are also generalized to the case of finite chemical potential and the factorization problem of the four-quark condensate at finite chemical potential is discussed.

A GENERAL METHOD FOR CALCULATING PARTITION FUNCTION OF QCD AT FINITE CHEMICAL POTENTIAL

2007 ◽  
Vol 22 (19) ◽  
pp. 3201-3209 ◽  
Author(s):  
WEI-MIN SUN ◽  
HONG-SHI ZONG
Keyword(s):  
Partition Function ◽  
Chemical Potential ◽  
Baryon Number ◽  
Quark Propagator ◽  
General Situation ◽  
Multiplicative Constant ◽  
First Case ◽  
Free Quark ◽  
Quark Theory ◽  
General Method

In this paper we propose a general method for calculating the partition function of QCD at finite chemical potential. It is found that the partition function is totally determined by the dressed quark propagator at finite chemical potential up to a multiplicative constant. From this a criterion for the phase transition between the Nambu and the Wigner phase is obtained. This general method are applied to two specific cases: the free quark theory and QCD with a model dressed quark propagator proposed in H . Pagels and S. Stokar, Phys. Rev. D20, 2947 (1979). In the first case, the standard Fermi distribution at T = 0 are reproduced. In the second case, a particular form of baryon number distribution is obtained. It is found that when μ is below a critical value, the baryon number density is identically zero, which agrees with the general conclusion in M. A. Halasz et al., Phys. Rev. D58, 096007 (1998). All the results in the present paper are obtained under the condition T = 0 and μ ≠ 0. However, they can be generalized to the the general situation T ≠ 0 and μ ≠ 0 without fundamental difficulty.

scholarly journals THE CHIRAL QUARK CONDENSATE AND THE BAG CONSTANT WITH FINITE CHEMICAL POTENTIAL

2006 ◽  
Vol 21 (16) ◽  
pp. 3387-3399 ◽  
Author(s):  
HONG-SHI ZONG ◽  
JIA-LUN PING ◽  
WEI-MIN SUN ◽  
FAN WANG ◽  
CHAO-HSI CHANG
Keyword(s):  
Chemical Potential ◽  
Interaction Model ◽  
Quark Propagator ◽  
Quark Condensate ◽  
Potential Dependence ◽  
Quark Interaction ◽  
Bag Constant

A method for obtaining the low chemical potential dependence of the dressed quark propagator from an effective quark–quark interaction model is developed. From this the chemical potential dependence of the "effective" two quark condensate and the bag constant is evaluated. A comparison with previous results is given.

scholarly journals THE QUARK CONDENSATE IN THE GELL-MANN-OAKES-RENNER RELATION

1996 ◽  
Vol 11 (16) ◽  
pp. 1331-1337 ◽  
Author(s):  
K. LANGFELD ◽  
C. KETTNER
Keyword(s):  
Quark Propagator ◽  
Quark Condensate ◽  
Usual Definition ◽  
Gluon Exchange ◽  
Current Mass ◽  
Definition Of

The quark condensate which enters the Gell-Mann-Oakes-Renner (GMOR) relation, is investigated in the framework of one-gluon-exchange models. The usual definition of the quark condensate via the trace of the quark propagator produces a logarithmic divergent condensate. In the product of current mass and condensate, this divergence is precisely compensated by the bare current mass. The finite value of the product in fact does not contradict the relation recently obtained by Cahill and Gunner. Therefore the GMOR relation is still satisfied.

Modification of charge density wave fluctuations by charge perturbations

2002 ◽  
Vol 12 (9) ◽  
pp. 77-78
Author(s):  
S. N. Artemenko
Keyword(s):  
Electric Field ◽  
Linear Response ◽  
Chemical Potential ◽  
Density Wave ◽  
Mean Field ◽  
Phase Fluctuations ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem ◽  
The Mean ◽  
Field Transition

Spectral density of fluctuations of the CDW phase are calculated taking into account electric field induced by phase fluctuations. The approach based upon the fluctuation-dissipation theorem (FDT) combined with equations of linear response of the CDW conductor is used. Fluctuating electric field is found to suppress fluctuations of the phase, while fluctuations of the electric potential are sizeable. This suggests that transition from the CDW to the normal state (which is usually observed well below the mean-field transition temperature) may he provoked by fluctuations of the chemical potential, rather than by destruction of the CDW coherence between conducting chains due to phase fluctuations.

A MODEL STUDY OF QUARK NUMBER SUSCEPTIBILITY AT FINITE CHEMICAL POTENTIAL AND ZERO TEMPERATURE

2009 ◽  
Vol 24 (12) ◽  
pp. 2241-2251 ◽  
Author(s):  
YAN-BIN ZHANG ◽  
FENG-YAO HOU ◽  
YU JIANG ◽  
WEI-MIN SUN ◽  
HONG-SHI ZONG
Keyword(s):  
General Result ◽  
Chemical Potential ◽  
Direct Method ◽  
Quark Propagator ◽  
Zero Temperature ◽  
Quark Number ◽  
Model Study ◽  
Analytic Expression ◽  
A Direct Method ◽  
Quark Number Susceptibility

In this paper, we try to provide a direct method for calculating quark number susceptibility at finite chemical potential and zero temperature. In our approach, quark number susceptibility is totally determined by G[μ](p) (the dressed quark propagator at finite chemical potential μ). By applying the general result given in Phys. Rev. C71, 015205 (2005), G[μ](p) is calculated from the model quark propagator proposed in Phys. Rev. D67, 054019 (2003). From this the full analytic expression of quark number susceptibility at finite μ and zero T is obtained.

Thermodynamic properties of light mesons and phase transition in an extended SU(2) NJL model

2019 ◽  
Vol 34 (13) ◽  
pp. 1950070
Author(s):  
J. R. Morones Ibarra ◽  
A. J. Garza Aguirre ◽  
Francisco V. Flores-Baez
Keyword(s):  
Chemical Potential ◽  
Pion Mass ◽  
Quark Condensate ◽  
The Other ◽  
Chiral Symmetry Restoration ◽  
Chiral Phase ◽  
Potential Dependence ◽  
Njl Model ◽  
The Masses ◽  
Sigma Meson

In this work, we study the temperature and chemical potential dependence of the masses of sigma and pion mesons as well as the quark condensate by using a SU(2) flavor version of the Nambu–Jona–Lassino model, introducing a prescription that mimics confinement. We have found that as the temperature increases, the mass of sigma shifts down, while the pion mass remains almost constant. On the other hand, the quark condensate decreases as the temperature and chemical potential increases. We have also analyzed the temperature and chemical potential dependence of the spectral function of the sigma meson, from which we observe at low values of T and [Formula: see text] an absence of a peak. Furthermore, as the Mott temperature is reached, its value increases abruptly and a distinct peak emerges, which is related with the dissociation of the sigma. For the case of [Formula: see text], the Mott dissociation is exhibited about the temperature of 189 MeV. We have also obtained the chiral phase diagram and the meson dissociation for different values of [Formula: see text]. From these results, we can state a relation between chiral symmetry restoration and Mott dissociation.

scholarly journals A general method of calculating the angles made by any planes of crystals, and the laws according to which they are formed

1833 ◽  
Vol 2 ◽  
pp. 227-229
Keyword(s):  
General Formula ◽  
Dihedral Angle ◽  
The Other ◽  
Plane Angle ◽  
General Process ◽  
Primitive Forms ◽  
Primary Form ◽  
General Method ◽  
Universal Application

The author, after stating the inconsistencies, inelegancies, and imperfections of the received notation for expressing the planes of a crystal, and the laws of decrement by which they arise, and of the usual methods of calculating their angles, explains the object of the present paper, which is to propose a system exempt from these inconveniencies, and adapted to reduce the mathematical portion of crystallography to a small number of simple formulae, of universal application. According to the method here followed, each plane of a crystal is represented by a symbol indicative of the laws from which it results, which, by varying only its indices, may be made to repre­sent any law whatever; and by means of these indices, and of the primary angles of the substance, we may derive a general formula expressing the dihedral angle contained between any one plane resulting from crystalline laws, and other . In the same manner we can find the angle contained between any two edges of the de­rived crystal. Conversely, having given the plane, or dihedral an­gles of any crystal, and its primary form, we can, by a direct and general process, deduce the laws of decrement according to which it is constituted. The purely mathematical part of this paper depends on two formulæ, demonstrated by the author elsewhere and here assumed as known; by means of one of which the dihedral angle included between any two planes can be calculated, when the equations of both planes are given; and by the other, the plane angle included between any two given right lines can in like manner be expressed by assigned functions of the coefficients of their equations, supposed given. These formulæ being taken for granted, nothing remains but to express by algebra­ical equations the planes which result from any assigned laws of decrement, for the different primitive forms which occur in crystallography.

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