scholarly journals Chiral condensate at finite density using the chiral Ward identity

2013 ◽  
Vol 88 (6) ◽  
Author(s):  
Soichiro Goda ◽  
Daisuke Jido
Keyword(s):  
Ward Identity ◽  
Chiral Condensate ◽  
Finite Density

scholarly journals Chirality production with mass effects — Schwinger pair production and the axial Ward identity

2020 ◽  
Vol 35 (28) ◽  
pp. 203005
Author(s):  
Patrick Copinger ◽  
Shi Pu
Keyword(s):  
Ward Identity ◽  
Chiral Condensate ◽  
Magnetic Effect ◽  
Chiral Anomaly ◽  
Expectation Values ◽  
Mass Effects ◽  
Chiral Magnetic Effect ◽  
Time Formalism ◽  
Background Fields ◽  
Schwinger Mechanism

The anomalous generation of chirality with mass effects via the axial Ward identity and its dependence on the Schwinger mechanism is reviewed, utilizing parity violating homogeneous electromagnetic background fields. The role vacuum asymptotic states play on the interpretation of expectation values is examined. It is discussed that observables calculated with an in–out scattering matrix element predict a scenario under Euclidean equilibrium. A notable ramification of which is a vanishing of the chiral anomaly. In contrast, it is discussed observables calculated under an in–in, or real-time, formalism predict a scenario out-of equilibrium, and capture effects of mean produced particle–antiparticle pairs due to the Schwinger mechanism. The out-of equilibrium chiral anomaly is supplemented with exponential quadratic mass suppression as anticipated for the Schwinger mechanism. Similar behavior in and out-of equilibrium is reviewed for applications including the chiral magnetic effect and chiral condensate.

scholarly journals Inhomogeneous chiral condensate in the Schwinger model at finite density

1994 ◽  
Vol 50 (2) ◽  
pp. 1165-1166 ◽  
Author(s):  
Yeong-Chuan Kao ◽  
Yu-Wen Lee
Keyword(s):  
Chiral Condensate ◽  
Finite Density ◽  
Schwinger Model

scholarly journals Meson Effects on the Chiral Condensate at Finite Density

2002 ◽  
Vol 38 (2) ◽  
pp. 181-184 ◽  
Author(s):  
Huang Mei ◽  
Zhuang Peng-Fei ◽  
Zhao Wei-Qin
Keyword(s):  
Chiral Condensate ◽  
Finite Density

The chiral condensate in SU(2) QCD at finite density

1987 ◽  
Vol 197 (1-2) ◽  
pp. 195-199 ◽  
Author(s):  
C.F. Baillie ◽  
K.C. Bowler ◽  
P.E. Gibbs ◽  
I.M. Barbour ◽  
M. Rafique
Keyword(s):  
Chiral Condensate ◽  
Finite Density

Finite Size Effect on the in-Medium Chiral Condensate at Finite Density

2014 ◽  
Vol 31 (4) ◽  
pp. 041101
Author(s):  
Cheng-Jun Xia ◽  
Guang-Xiong Peng ◽  
Jia-Xun Hou
Keyword(s):  
Size Effect ◽  
Finite Size ◽  
Chiral Condensate ◽  
Finite Size Effect ◽  
Finite Density

scholarly journals POSSIBILITY OF FORMING A LARGE DCC IN ULTRA-RELATIVISTIC HEAVY-ION COLLISIONS

2000 ◽  
Vol 15 (15) ◽  
pp. 2269-2288
Author(s):  
SANATAN DIGAL ◽  
RAJARSHI RAY ◽  
SUPRATIM SENGUPTA ◽  
AJIT M. SRIVASTAVA
Keyword(s):  
Three Dimensional ◽  
Thermal Fluctuations ◽  
Heavy Ion ◽  
High Energy ◽  
Chiral Condensate ◽  
Relativistic Heavy Ion Collisions ◽  
Maximum Temperature ◽  
Chiral Field ◽  
Heavy Nuclei ◽  
True Vacuum

We demonstrate the possibility of forming a single, large domain of disoriented chiral condensate (DCC) in a heavy-ion collision. In our scenario, rapid initial heating of the parton system provides a driving force for the chiral field, moving it away from the true vacuum and forcing it to go to the opposite point on the vacuum manifold. This converts the entire hot region into a single DCC domain. Subsequent rolling down of the chiral field to its true vacuum will then lead to emission of a large number of (approximately) coherent pions. The requirement of suppression of thermal fluctuations to maintain the (approximate) coherence of such a large DCC domain, favors three-dimensional expansion of the plasma over the longitudinal expansion even at very early stages of evolution. This also constrains the maximum temperature of the system to lie within a window. We roughly estimate this window to be about 200–400 MeV. These results lead us to predict that extremely high energy collisions of very small nuclei (possibly hadrons) are better suited for observing signatures of a large DCC. Another possibility is to focus on peripheral collisions of heavy nuclei.

scholarly journals Covariant phase space and soft factorization in non-Abelian gauge theories

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Temple He ◽  
Prahar Mitra
Keyword(s):  
Phase Space ◽  
Ward Identity ◽  
Gauge Theories ◽  
Minkowski Spacetime ◽  
Soft Gluon ◽  
Careful Study ◽  
Abelian Gauge ◽  
Gauge Sector ◽  
Vacuum States ◽  
The One

Abstract We perform a careful study of the infrared sector of massless non-abelian gauge theories in four-dimensional Minkowski spacetime using the covariant phase space formalism, taking into account the boundary contributions arising from the gauge sector of the theory. Upon quantization, we show that the boundary contributions lead to an infinite degeneracy of the vacua. The Hilbert space of the vacuum sector is not only shown to be remarkably simple, but also universal. We derive a Ward identity that relates the n-point amplitude between two generic in- and out-vacuum states to the one computed in standard QFT. In addition, we demonstrate that the familiar single soft gluon theorem and multiple consecutive soft gluon theorem are consequences of the Ward identity.

scholarly journals Complex Langevin calculations in QCD at finite density

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Yuta Ito ◽  
Hideo Matsufuru ◽  
Yusuke Namekawa ◽  
Jun Nishimura ◽  
Shinji Shimasaki ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Chemical Potential ◽  
Expansion Method ◽  
Finite Density ◽  
Fermi Sphere ◽  
Expectation Value ◽  
Sign Problem ◽  
Zero Momentum ◽  
Effective Theories ◽  
Severe Sign

Abstract We demonstrate that the complex Langevin method (CLM) enables calculations in QCD at finite density in a parameter regime in which conventional methods, such as the density of states method and the Taylor expansion method, are not applicable due to the severe sign problem. Here we use the plaquette gauge action with β = 5.7 and four-flavor staggered fermions with degenerate quark mass ma = 0.01 and nonzero quark chemical potential μ. We confirm that a sufficient condition for correct convergence is satisfied for μ/T = 5.2 − 7.2 on a 83 × 16 lattice and μ/T = 1.6 − 9.6 on a 163 × 32 lattice. In particular, the expectation value of the quark number is found to have a plateau with respect to μ with the height of 24 for both lattices. This plateau can be understood from the Fermi distribution of quarks, and its height coincides with the degrees of freedom of a single quark with zero momentum, which is 3 (color) × 4 (flavor) × 2 (spin) = 24. Our results may be viewed as the first step towards the formation of the Fermi sphere, which plays a crucial role in color superconductivity conjectured from effective theories.

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