Chiral magnetic effect (CME) is the generation of electric current along an external magnetic field induced by chirality imbalance. Fermions are said to be chiral if they keep a definite projection of spin quantum number on momentum. The CME is a macroscopic quantum phenomenon present in systems with charged chiral fermions, such as the quark–gluon plasma, or Dirac and Weyl semimetals.[1] The CME is a consequence of chiral anomaly in quantum field theory; unlike conventional superconductivity or superfluidity, it does not require a spontaneous symmetry breaking. The chiral magnetic current is non-dissipative, because it is topologically protected: the imbalance between the densities of left-handed and right-handed chiral fermions is linked to the topology of fields in gauge theory by the Atiyah-Singer index theorem.
The experimental observation of CME in a Dirac semimetal ZrTe5 was reported in 2014 by a group from Brookhaven National Laboratory and Stony Brook University.[2][3] The material showed a conductivity increase in the Lorentz force-free configuration of the parallel magnetic and electric fields.
In 2015, the STAR detector at Relativistic Heavy Ion Collider, Brookhaven National Laboratory[4] and ALICE: A Large Ion Collider Experiment at the Large Hadron Collider, CERN[5] presented an experimental evidence for the existence of CME in the quark–gluon plasma.[6]
See also
editReferences
edit- ^ D. Kharzeev (2014). "The Chiral Magnetic Effect and anomaly-induced transport". Progress in Particle and Nuclear Physics. 75: 133–151. arXiv:1312.3348. Bibcode:2014PrPNP..75..133K. doi:10.1016/j.ppnp.2014.01.002. S2CID 118508661.
- ^ Q. Li, D. E. Kharzeev, C. Zhang, Y. Huang, I. Pletikosić, A. V. Fedorov, R. D. Zhong, J. A. Schneeloch, G. D. Gu & T. Valla (2016). "Chiral magnetic effect in ZrTe5". Nature Physics. 12 (6): 550–554. arXiv:1412.6543. Bibcode:2016NatPh..12..550L. doi:10.1038/nphys3648. S2CID 99424051.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Brookhaven National Laboratory (8 February 2016). "Chiral magnetic effect generates quantum current". Phys.org. Retrieved 4 Jan 2019.
- ^ L. Adamczyk et al. (STAR Collaboration) (2015). "Observation of charge asymmetry dependence of pion elliptic flow and the possible chiral magnetic wave in heavy-ion collisions". Physical Review Letters. 114 (25): 252302. arXiv:1504.02175. Bibcode:2015PhRvL.114y2302A. doi:10.1103/PhysRevLett.114.252302. PMID 26197122. S2CID 13186933.
- ^ R. Belmont et al. (ALICE Collaboration) (2014). "Charge-dependent anisotropic flow studies and the search for the Chiral Magnetic Wave in ALICE". Nuclear Physics A. 931: 981. arXiv:1408.1043. Bibcode:2014NuPhA.931..981B. doi:10.1016/j.nuclphysa.2014.09.070. S2CID 118833403.
- ^ Brookhaven National Laboratory (8 June 2015). "Scientists see ripples of a particle-separating wave in primordial plasma". Phys.org. Retrieved 4 Jan 2019.