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 A semiclassical formulation of the chiral magnetic effect and chiral anomaly in even d + 1 dimensions

2016 ◽  
Vol 31 (13) ◽  
pp. 1650074 ◽  
Author(s):  
Ömer F. Dayi ◽  
Mahmut Elbistan
Keyword(s):  
Symplectic Form ◽  
Magnetic Effect ◽  
Chiral Anomaly ◽  
Simple Method ◽  
New Approach ◽  
Chiral Magnetic Effect ◽  
Integral Measure ◽  
The Matrix ◽  
External Electromagnetic Fields ◽  
Definition Of

In terms of the matrix valued Berry gauge field strength for the Weyl Hamiltonian in any even space–time dimensions a symplectic form whose elements are matrices in spin indices is introduced. Definition of the volume form is modified appropriately. A simple method of finding the path integral measure and the chiral current in the presence of external electromagnetic fields is presented. It is shown that within this new approach the chiral magnetic effect as well as the chiral anomaly in even [Formula: see text] dimensions are accomplished straightforwardly.

scholarly journals Far from equilibrium Chiral Magnetic Effect in Strong Magnetic Fields from Holography

2022 ◽  
Vol 258 ◽  
pp. 10007
Author(s):  
Sebastian Grieninger ◽  
Sergio Morales-Tejera
Keyword(s):  
Heavy Ion ◽  
Magnetic Effect ◽  
Chiral Anomaly ◽  
Equilibration Time ◽  
Strong Magnetic Fields ◽  
Strongly Coupled ◽  
Anomalous Field ◽  
Ion Collisions ◽  
Chiral Magnetic Effect ◽  
Far From Equilibrium

We study the real time evolution of the chiral magnetic effect out-ofequilibrium in strongly coupled anomalous field theories. We match the parameters of our model to QCD parameters and draw lessons of possible relevance for the realization of the chiral magnetic effect in heavy ion collisions. In particular, we find an equilibration time of about ~ 0:35 fm/c in presence of the chiral anomaly for plasma temperatures of order T ~ 300 - 400 MeV.

scholarly journals Constraining the Chiral Magnetic Effect with charge-dependent azimuthal correlations in Pb-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ = 2.76 and 5.02 TeV

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
S. Acharya ◽  
◽  
D. Adamová ◽  
A. Adler ◽  
J. Adolfsson ◽  
...  
Keyword(s):  
Charged Particles ◽  
Magnetic Effect ◽  
Anisotropic Flow ◽  
Charge Conservation ◽  
Particle Correlations ◽  
Azimuthal Correlations ◽  
Chiral Magnetic Effect ◽  
Local Charge ◽  
Peripheral Collisions ◽  
Dependent Signal

Abstract Systematic studies of charge-dependent two- and three-particle correlations in Pb-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 2.76 and 5.02 TeV used to probe the Chiral Magnetic Effect (CME) are presented. These measurements are performed for charged particles in the pseudorapidity (η) and transverse momentum (pT) ranges |η| < 0.8 and 0.2 < pT< 5 GeV/c. A significant charge-dependent signal that becomes more pronounced for peripheral collisions is reported for the CME-sensitive correlators γ1, 1 = 〈cos(φα + φβ − 2Ψ2)〉 and γ1, − 3 = 〈cos(φα − 3φβ + 2Ψ2)〉. The results are used to estimate the contribution of background effects, associated with local charge conservation coupled to anisotropic flow modulations, to measurements of the CME. A blast-wave parametrisation that incorporates local charge conservation tuned to reproduce the centrality dependent background effects is not able to fully describe the measured γ1,1. Finally, the charge and centrality dependence of mixed-harmonics three-particle correlations, of the form γ1, 2 = 〈cos(φα + 2φβ − 3Ψ3)〉, which are insensitive to the CME signal, verify again that background contributions dominate the measurement of γ1,1.

scholarly journals Chiral Magnetic Effect of Hot Electrons

2020 ◽  
Vol 125 (26) ◽  
Author(s):  
S. Nandy ◽  
D. A. Pesin
Keyword(s):  
Magnetic Effect ◽  
Hot Electrons ◽  
Chiral Magnetic Effect

scholarly journals Probing charge pumping and relaxation of the chiral anomaly in a Dirac semimetal

2021 ◽  
Vol 7 (16) ◽  
pp. eabg0914
Author(s):  
Bing Cheng ◽  
Timo Schumann ◽  
Susanne Stemmer ◽  
N. P. Armitage
Keyword(s):  
Terahertz Spectroscopy ◽  
Point Group ◽  
Spectral Weight ◽  
Chiral Anomaly ◽  
Group Representations ◽  
Field Independence ◽  
Transport Channel ◽  
Scattering Rate ◽  
Chiral Magnetic Effect ◽  
A Charge

The linear band crossings of 3D Dirac and Weyl semimetals are characterized by a charge chirality, the parallel or antiparallel locking of electron spin to its momentum. These materials are believed to exhibit an E · B chiral magnetic effect that is associated with the near conservation of chiral charge. Here, we use magneto-terahertz spectroscopy to study epitaxial Cd3As2 films and extract their conductivities σ(ω) as a function of E · B. As field is applied, we observe a markedly sharp Drude response that rises out of the broader background. Its appearance is a definitive signature of a new transport channel and consistent with the chiral response, with its spectral weight a measure of the net chiral charge and width a measure of the scattering rate between chiral species. The field independence of the chiral relaxation establishes that it is set by the approximate conservation of the isospin that labels the crystalline point-group representations.

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