1,658 research outputs found
Strong-randomness infinite-coupling phase in a random quantum spin chain
We study the ground-state phase diagram of the Ashkin-Teller random quantum
spin chain by means of a generalization of the strong-disorder renormalization
group. In addition to the conventional paramagnetic and ferromagnetic (Baxter)
phases, we find a partially ordered phase characterized by strong randomness
and infinite coupling between the colors. This unusual phase acts, at the same
time, as a Griffiths phase for two distinct quantum phase transitions both of
which are of infinite-randomness type. We also investigate the quantum
multi-critical point that separates the two-phase and three-phase regions; and
we discuss generalizations of our results to higher dimensions and other
systems.Comment: 9 pages, 6 eps figures, final version as publishe
Multiple Shocks
Using gauge/gravity duality, we explore a class of states of two CFTs with a
large degree of entanglement, but with very weak local two-sided correlation.
These states are constructed by perturbing the thermofield double state with
thermal-scale operators that are local at different times. Acting on the dual
black hole geometry, these perturbations create an intersecting network of
shock waves, supporting a very long wormhole. Chaotic CFT dynamics and the
associated fast scrambling time play an essential role in determining the
qualitative features of the resulting geometries.Comment: 24 pages, 10 figures. v2: reference adde
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