**Chirality, topology, and hydrodynamics**

Speaker

Dr. Yuji Hirono

Physics Department, Brookhaven National Laboratory

Date 2018.02.27 (Tue)

Time 14:00

Place S4-625

Abstract:

The concept of “chirality” appears in various fields of science.

In particle physics, massless fermions are characterized by chiralities (left- and right-handed ones). The conservation of chirality is broken by a quantum effect, called the chiral anomaly. Recent studies revealed that the chiral quantum anomaly gives rise to a new type of non-dissipative macroscopic transport phenomena, leading to the modification of the hydrodynamic theory. One such example is the Chiral Magnetic Effect (CME), which is the generation of an electric current along an applied magnetic field, in a chiral fluid where the number of left- and right-handed fermions are different.

Experimentally, the CME is discovered in Dirac semimetals in 2016 [1].It is also expected to occur at extremely high temperatures (~10^12 degrees) realized in ultra-relativistic heavy-ion collision experiments.In this talk, I’ll give an introduction to those fascinating phenomena. A close relation of the chiral anomaly with the topology of magnetic fields will be discussed [2]. The coupling of chiral fluids to dynamical electromagnetic fields leads to interesting phenomenological consequences such as the emergence of helical collective excitations and an inverse turbulent cascade [3].

[1] Q. Li, et al., Nature Physics 12, no. 6 (2016): 550-554.

[2] Y. Hirono, D. E. Kharzeev and Y.Yin, Phys. Rev. Lett. 117, no. 17,

172301 (2016).

[3] Y. Hirono, D. E. Kharzeev, Y. Yin, Phys.Rev. D92 (2015) no.12, 125031; K. Hattori, Y. Hirono, H. U. Yee, and Y. Yin [arXiv:1711.08450].