Publications
Visualizing probabilistic models in Minkowski space with intensive symmetrized Kullback-Leibler embedding
We show that the predicted probability distributions for any N-parameter statistical model taking the form of an exponential family can be explicitly and analytically embedded isometrically in a N+N-dimensional Minkowski space. That is, the model predictions can be visualized as control parameters are varied, preserving the natural distance between probability distributions. All pairwise distances between model instances are given by the symmetrized Kullback-Leibler divergence.
Linear resistivity and Sachdev-Ye-Kitaev (SYK) spin liquid behavior in a quantum critical metal with spin-1=2 fermions
"Strange metals" with resistivity depending linearly on temperature T down to low T have been a long-standing puzzle in condensed matter physics. Here, we consider a lattice model of itinerant spin-1=2 fermions interacting via onsite Hubbard interaction and random infinite-ranged spin-spin interaction.We show that the quantum critical point associated with the melting of the spin-glass phase by charge fluctuations displays non-Fermi liquid behavior, with local spin dynamics identical to that of the Sachdev-Ye-Kitaev family of models.
Gate-tunable spin waves in antiferromagnetic atomic bilayers
Remarkable properties of two-dimensional (2D) layer magnetic materials, which include spin filtering in magnetic tunnel junctions and the gate control of magnetic states, were demonstrated recently1–12. Whereas these studies focused on static properties, dynamic magnetic properties, such as excitation and control of spin waves, remain elusive. Here we investigate spin-wave dynamics in antiferromagnetic CrI3 bilayers using an ultrafast optical pump/magneto-optical Kerr probe technique.
Machine Learning for Phase Retrieval from 4D-STEM Data
Realization of Epitaxial Thin Films of the Topological Crystalline Insulator Sr3SnO
Topological materials are derived from the interplay between symmetry and topology. Advances in topological band theories have led to the prediction that the antiperovskite oxide Sr3SnO is a topological crystalline insulator, a new electronic phase of matter where the conductivity in its (001) crystallographic planes is protected by crystallographic point group symmetries. Realization of this material, however, is challenging.
Comment on "stabilized Pair Density Wave via Nanoscale Confinement of Superfluid He 3 "
Ultracold Electrons via Near-Threshold Photoemission from Single-Crystal Cu(100)
Achieving a low mean transverse energy or temperature of electrons emitted from the photocathode-based electron sources is critical to the development of next-generation and compact X-ray free electron lasers and ultrafast electron diffraction, spectroscopy, and microscopy experiments. In this Letter, we demonstrate a record low mean transverse energy of 5 meV from the cryo-cooled (100) surface of copper using near-threshold photoemission.
Topological phase transition on the edge of two-dimensional Z2 topological order
The unified mathematical theory of gapped and gapless edges of two-dimensional (2d) topological orders was developed by two of the authors. According to this theory, the critical point of a purely edge topological phase transition of a 2d topological order can be mathematically characterized by an enriched fusion category. In this work, we provide a physical proof of this fact in a concrete example: the 2d Z2 topological order. In particular, we construct an enriched fusion category, which describes a gappable nonchiral gapless edge of the 2d Z2 topological order.
Chemistry of the spin- 12 kagome Heisenberg antiferromagnet
We believe that a necessary first step in understanding the ground-state properties of the spin-12 kagome Heisenberg antiferromagnet is a better understanding of this model's very large number of low-energy singlet states. A description of the low-energy states that is both accurate and amenable for numerical work may ultimately prove to have greater value than knowing only what these properties are, in particular, when they turn on the delicate balance of many small energies.
Bidirectional Self-Folding with Atomic Layer Deposition Nanofilms for Microscale Origami
Origami design principles are scale invariant and enable direct miniaturization of origami structures provided the sheets used for folding have equal thickness to length ratios. Recently, seminal steps have been taken to fabricate microscale origami using unidirectionally actuated sheets with nanoscale thickness. Here, we extend the full power of origami-inspired fabrication to nanoscale sheets by engineering bidirectional folding with 4 nm thick atomic layer deposition (ALD) SiNx-SiO2 bilayer films.