Noah Bray-Ali

Tunneling into the Mott Insulator Sr 2 IrO 4

The single-layer Mott insulator Sr2IrO4 was studied using a scanning tunneling microscope. This measurement technique is unique due to the transport properties of this Mott insulator allowing tunneling measurements to be performed, even at cryogenic temperatures. We obtained high-resolution images of the sample surface and the differential tunneling conductance at different cryogenic temperatures. The differential conductance is a direct measurement of the local electronic density of states which provided an insulating gap consistent with optical conductivity, angle resolved photoemission spectroscopy and resonant inelastic x-ray scattering (RIXS) experiments. The observed widths of these features is broader than predicted by the Slater approximation and narrower than predicted by dynamical mean field theory. Additionally, the observed density of states due to magnetic fluctuations is found in the derivative of the differential conductance and is consistent with results from Raman scattering and RIXS. At low temperatures, additional low-energy features were observed, suggesting a change in the dispersion of the collective magnetic excitations, which is consistent with the magnetic susceptibility.

Fidelity approach to the Hubbard model

We use the fidelity approach to quantum critical points to study the zero-temperature phase diagram of the one-dimensional Hubbard model. Using a variety of analytical and numerical techniques, we analyze the fidelity metric in various regions of the phase diagram with particular care to the critical points. Specifically we show that close to the Mott transition, taking place at on-site repulsion

Topological order in paired states of fermions in two-dimensions with breaking of parity and time-reversal symmetries

U=0

Subarea law of entanglement in nodal fermionic systems.

and electron density

Scaling analysis and application: Phase diagram of magnetic nanorings and elliptical nanoparticles

n=1

Conservation and persistence of spin currents and their relation to the Lieb-Schulz-Mattis twist operators

, the fidelity metric satisfies an hyperscaling form which we calculate. This implies that in general, as one approaches the critical point

Chern Numbers Hiding in Time-of-Flight Images | NIST

U=0

How to turn a topological insulator into a superconductor

,

Bilayer quantum Hall ferromagnet in a periodic potential

n=1

Tunneling into Bilayer Iridate Sr 3 Ir 2 O 7

, the fidelity metric tends to a limit which depends on the path of approach. At half-filling, the fidelity metric is expected to diverge as