We study the thermal diffusivity D[subscript T] in models of metals without quasiparticle excitations (“strange metals”). The many-body quantum chaos and transport properties of such metals can be efficiently described by a holographic representation in a gravitational theory in an emergent curved spacetime with an additional spatial dimension. We find that at generic infrared fixed points D[subscript T] is always related to parameters characterizing many-body quantum chaos: the butterfly velocity v[subscript B] and Lyapunov time τ[subscript L] through D[subscript T]∼v[subscript B][superscript 2]τ[subscript L]. The relationship holds independently of the charge density, periodic potential strength, or magnetic field at the fixed point. The generality of this result follows from the observation that the thermal conductivity of strange metals depends only on the metric near the horizon of a black hole in the emergent spacetime and is otherwise insensitive to the profile of any matter fields.We study the thermal diffusivity D[subscript T] in models of metals without quasiparticle excitations (“strange metals”). The many-body quantum chaos and transport properties of such metals can be efficiently described by a holographic representation in a gravitational theory in an emergent curved spacetime with an additional spatial dimension. We find that at generic infrared fixed points D[subscript T] is always related to parameters characterizing many-body quantum chaos: the butterfly velocity v[subscript B] and Lyapunov time τ[subscript L] through D[subscript T]∼v[subscript B][superscript 2]τ[subscript L]. The relationship holds independently of the charge density, periodic potential strength, or magnetic field at the fixed point. The generality of this result follows from the observation that the thermal conductivity of strange metals depends only on the metric near the horizon of a black hole in the emergent spacetime and is otherwise insensitive to the profile of any matter fields.

Physical Review LettersNov 1, 20170 citations

ENTANGLEMENT IN MANY-BODY QUANTUM PHYSICS

Frank Verstraete

Recent Progress in Many-Body TheoriesJun 1, 20080 citations

Strange half-metals and Mott insulators in Sachdev-Ye-Kitaev models

Arijit Haldar, Vijay B. Shenoy

We study a two-flavor fermion model where each of the flavors form a Sachdev-Ye-Kitaev (SYK) system with arbitrary $q$ -body interactions. The crucial new element is an all-to-all $r$ -body interaction between the two flavors. At high temperatures, the model shows a strange metal phase where both flavors are gapless, similar to the usual single-flavor SYK model. Upon reducing temperature, the coupled system undergoes transitions to previously unseen phases in the SYK framework---first, a strange half-metal phase where one flavor remains a strange metal while the other is gapped, and second, an insulating phase of the Mott kind where both flavors are gapped. At a fixed low temperature, we obtain transitions between these phases by tuning the relative fraction of sites for each flavor. We discuss the physics of these phases and the nature of transitions between them. This work provides an example of an instability of the strange metal with potential to provide new routes to study strongly correlated systems through the rich physics contained in SYK-like models.We study a two-flavor fermion model where each of the flavors form a Sachdev-Ye-Kitaev (SYK) system with arbitrary $q$-body interactions. The crucial new element is an all-to-all $r$-body interaction between the two flavors. At high temperatures, the model shows a strange metal phase where both flavors are gapless, similar to the usual single-flavor SYK model. Upon reducing temperature, the coupled system undergoes transitions to previously unseen phases in the SYK framework---first, a strange half-metal phase where one flavor remains a strange metal while the other is gapped, and second, an insulating phase of the Mott kind where both flavors are gapped. At a fixed low temperature, we obtain transitions between these phases by tuning the relative fraction of sites for each flavor. We discuss the physics of these phases and the nature of transitions between them. This work provides an example of an instability of the strange metal with potential to provide new routes to study strongly correlated systems through the rich physics contained in SYK-like models.

arXiv:1703.05111Physical review. B./Physical review. BOct 24, 201821 citations

Entanglement in many body systems

Alexandre M. Souza, Roberto S. Sarthour, Ivan S. Oliveira

Physica B Condensed MatterNov 17, 202215 citations

We study a two-flavor fermion model where each of the flavors form a Sachdev-Ye-Kitaev (SYK) system with arbitrary

q

-body interactions. The crucial new element is an all-to-all

r

-body interaction between the two flavors. At high temperatures, the model shows a strange metal phase where both flavors are gapless, similar to the usual single-flavor SYK model. Upon reducing temperature, the coupled system undergoes transitions to previously unseen phases in the SYK framework---first, a strange half-metal phase where one flavor remains a strange metal while the other is gapped, and second, an insulating phase of the Mott kind where both flavors are gapped. At a fixed low temperature, we obtain transitions between these phases by tuning the relative fraction of sites for each flavor. We discuss the physics of these phases and the nature of transitions between them. This work provides an example of an instability of the strange metal with potential to provide new routes to study strongly correlated systems through the rich physics contained in SYK-like models.