4 Corners Southwest Ontario Condensed Matter Physics Symposium 2014

Systems that are many-body Anderson localized can exhibit symmetry-breaking long-range order or topological order in regimes where such order would be destroyed at equilibrium by thermal fluctuations. The ordering is dynamical: an ordered initial state stays ordered, being "protected" by the…

We are used to describing systems of many particles by statistical mechanics. However, the basic postulate of statistical mechanics – ergodicity – breaks down in so-called many-body localized systems, where disorder prevents particle transport and thermalization. In this talk, I will present a…

In the search for new exotic quantum states, the impact of strong spin-orbit interaction has been recently underlined with the discovery of the Jeff = ½ spin orbital Mott state in the 5d5 layered perovskites iridates [1]. The double perovskite structure, where the magnetic ions form a face-centered…

We devise a renormalization group analysis for quantum field theories with Fermi surface to study scaling behaviour of non- Fermi liquid states in a controlled approximation. The non-Fermi liquid fixed points are identified from a Fermi surface in (m+1) spatial dimensions, while the co-dimension of…

String and particle excitations are examined in a class of 3+1D topological order described by a discrete gauge theory with a gauge group G and a 4-cocycle twist ω4∈H4(G,R/Z) of G's cohomology group. We demonstrate the topological spin and the spin-statistics relation for the closed strings, and…

New states of matter may be produced if quantum effects and frustration conspire to prevent the ground state from achieving classical order. An example of a new quantum phase is the quantum spin liquid. Such spin liquids cannot be characterized by local order parameters; rather, they are distinctive…

Electron charge may fractionalize in a quantum spin liquid Mott insulator. We study the Mott transition from a metal to a cluster Mott insulator in the 1/4- and 1/8-filled pyrochlore lattice systems. Such Mott transitions can arise due to charge localization in clusters or in tetrahedron units…

Recently, realizations of Kitaev physics have been sought in the A2IrO3 family of honeycomb iridates, originating from oxygen-mediated exchange through edge-shared octahedra. However, for the J=1/2 Mott insulator in these materials exchange from direct d-orbital overlap is relevant, and it was…

Beta-detected nuclear spin relaxation of 8Li+ has been used to study important problems in polymer physics. In the first case we probe the depth dependence of molecular dynamics in high- and low-molecular-weight deuterated polystyrene (PS-d8). The average nuclear spin-lattice relaxation rate, 1/T1…

Topological crystalline insulators in IV-VI compounds host novel topological surface states, that at low energy, consist of multi-valley massless Dirac fermions. We show that strain generically acts as an effective gauge field on these Dirac fermion surface states and creates pseudo-Landau orbitals…

Superconducting qubits based on Josephson junctions and resonators are presently leading candidates for the implementation of quantum computing. These systems couple strongly to their environment, which often makes preservation of coherence challenging. This strong coupling can be turned into an…