We discover a new tricritical point realized only in nonequilibrium steady states, using the $\mathrm{AdS}/\mathrm{CFT}$ correspondence. Our system is a ($3+1$)-dimensional strongly coupled large-$N_c$ gauge theory. The tricritical point is associated with a chiral symmetry breaking under the presence of an electric current and a magnetic field. The critical exponents agree with those of the Landau theory of equilibrium phase transitions. This suggests that the presence of a Landau-like phenomenological theory behind our nonequilibrium phase transitions.

• Received 19 November 2019
• Revised 14 April 2020
• Accepted 27 April 2020

DOI:https://doi.org/10.1103/PhysRevLett.124.191603

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Published by the American Physical Society