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# Quantum Matter

This series consists of talks in the area of Quantum Matter.

## Seminar Series Events/Videos

Currently there are no upcoming talks in this series.

## Stable Flat Bands, Topology, and Superconductivity of Magic Honeycomb Network

Mardi juil 30, 2019
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We uncover a rich phenomenology of the self-organized honeycomb network superstructure of one-dimensional metals in a nearly-commensurate charge-density wave 1T-TaS${}_2$, which may play a significant role in understanding global topology of phase diagrams and superconductivity. The key observation is that the emergent honeycomb network magically supports a cascade of flat bands, whose unusual stability we thoroughly investigate.

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## Self-learning Monte Carlo method and structured self-attention network

Mardi juil 16, 2019
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Self-learning Monte Carlo (SLMC) method is a general-purpose numerical method to simulate many-body systems. SLMC can efficiently cure the critical slowing down in both bosonic and fermionic systems. Moreover, for fermionic systems, SLMC can generally reduce the computational complexity and speed up simulations even away from the critical points. For example, SLMC is more than 1000 times faster than the conventional method for the double exchange model in 8*8*8 cubic lattice.

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## Criticality, self-organization and scale invariant avalanches in spin dynamics away from thermal equilibrium

Mercredi juin 26, 2019
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The appearance of scale invariance and diverging response functions in many-body systems is inseparably linked to the presence of a critical point and spontaneous symmetry breaking. In thermal equilibrium critical points mostly correspond to isolated spots in parameter space, which require rather strong fine tuning of e.g., the temperature of magnetic fields, in order to be reached. Pushing systems away from thermal equilibrium, e.g., by exposing them to external drive fields or dissipation, can give rise to more unconventional forms of criticality.

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## Beyond Topological Order and Back Again: Foliated TQFT of Fractons

Mardi juin 11, 2019
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Fracton order is a new kind of phase of matter which is similar to topological order, except its excitations have mobility constraints. The excitations are bound to various n-dimensional surfaces with exotic fusion rules that determine how excitations on intersecting surfaces can combine.

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## Conformal dimensions in the large charge sectors at the Wilson-Fisher fixed point using qubit formulations

Mardi mai 28, 2019

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## The "Zero Mode" in Kac Table: Revisiting the Ramond Sector of N=1 Superconformal Minimal Models

Mardi mai 21, 2019
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## Kitaev spin liquids in spin-orbit coupled correlated materials

Mardi mai 14, 2019
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Recently, a new family of correlated honeycomb materials with strong spin-orbit coupling have been promising candidates to realize the Kitaev spin liquid.

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## Field-driven spin liquids in Kitaev materials

Jeudi mai 02, 2019
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Kitaev materials — spin-orbit assisted Mott insulators, in which local, spin-orbit entangled j=1/2 moments form that are subject to strong bond-directional interactions — have attracted broad interest for their potential to realize spin liquids. Experimentally, a number of 4d and 5d systems have been widely studied including the honeycomb materials Na2IrO3, α-Li2IrO3, and RuCl3 as candidate spin liquid compounds — however, all of these materials magnetically order at sufficiently low temperatures.

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## Quantum Many-Body Scars and Space-Time Crystalline Order from Magnon Condensation

Mardi avr 30, 2019
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We study the eigenstate properties of a nonintegrable spin chain that was recently realized experimentally in a Rydberg-atom quantum simulator. In the experiment, long-lived coherent many-body oscillations were observed only when the system was initialized in a particular product state. This pronounced coherence has been attributed to the presence of special "scarred" eigenstates with nearly equally-spaced energies and putative nonergodic properties despite their finite energy density.

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## Emergent O(4) Symmetry and Signatures of Deconfined Quantum Critical Point in Shastry-Sutherland Lattice Material SrCu2(BO3)2

Mardi avr 16, 2019
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We study the possibility of a deconfined quantum phase transition in a realistic model of a two dimensional Shastry-Sutherland quantum magnet, using both numerical and field theoretic techniques. We argue that the quantum phase transition between a two fold degenerate plaquette valence bond  solid (pVBS) order and N\'eel ordered phase may be described by a deconfined quantum critical point (DQCP) with emergent O(4) symmetry.

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## LECTURES ON-DEMAND

### Gabriela González, Louisiana State University

Speaker: Gabriela Gonzalez