Fall 2016

Adiabatic quantum computation (AQC) is one of the paradigms of quantum computation that has recently gained great attention by advancements in manufacturing superconducting qubits. In this talk, I will overview the advantages and limitations of quantum annealers and methods of simulation of the behavior of futuristic devices. I will then discuss applicability of AQC in solving integer programming problems using a branch and bound framework implemented on a hybrid of a digital and a quantum processor.

The term “nanofabrication” encompasses the myriad of techniques that can be used to make nanostructures, but only a small subset can make the transition to economic viability that defines “nanomanufacturing”.  I will discuss how market and technical constraints come into play for a variety of nanoscale products, and illustrate key concepts such as speed, yield, precision, defectivity, and modularity by comparing semiconductor manufacturing with the emerging field of DNA-directed self-assembly.  Finally, I will show how nanofabrication techniques can create the...

Hugh Everett III presented pure wave mechanics, sometimes referred to as the many-worlds interpretation, as a solution to the quantum measurement problem. While pure wave mechanics is a deterministic physical theory with no probabilities, Everett sought to show how the theory might be understood as making the standard quantum statistical predictions as appearances to observers who were themselves described by the theory. We will consider his argument and how it depends on a particular notion of branch typicality. We will also consider the relationship between...

The high energy density and low cost of lithium-ion batteries have created a revolution in personal electronics through laptops, tablets, smart phones and wearables, permanently changing the way we interact with people and information. We are at the threshold of similar transformations in transportation to electric cars and in the electricity grid to renewable generation, smart grids and distributed energy resources. Many aspects of these transformations require new levels of energy storage performance and cost that are beyond the reach of Li-ion batteries....

Single-layer of molybdenum disulfide (MoS2) and other transition metal dichalcogenides (TMDC) appear to be promising materials for next generation applications (optoelectronic and catalysis), because of their low-dimensionality and intrinsic direct band-gap which typically lies in the visible spectrum. Several experimental groups have already reported novel electronic and transport properties which place these materials beyond graphene for device applications. MoS2 is also known to be a leading hydrodesulfurization catalyst. Efforts are underway to further tune...

Carbon materials have extraordinary properties, but utilizing these properties in applications requires a deep understanding of the materials. Modelling and simulations can here be a very useful complement to experiments and even be used to predict properties ahead of the experiments. This is particularly relevant for graphene, which was investigated theoretically in great detail long before it was possible to perform any experiments. The first investigations were performed on ideal sheets using pencil and paper, but as grown grown graphene sheets are often...

We demonstrate that spatially separated populations of one-dimensional electrons and holes may form a true condensate of dipolar excitons characterised by off-diagonal long range order and global phase coherence. This is unexpected, since the Mermin-Wagner theorem states that long range order should not exist in 1D systems. 
However, we show that adding a single particle hybridization between the electron and hole populations breaks a continuous symmetry and allows many body effects to dominate the ground state. The superfluid condensate may have...

Strong repulsive interactions and potential in homogeneities both tend to localize Fermions on a lattice and lead to loss of superconductivity. The natural question that comes up is whether they compete or complement each other when both are present in a system at the same time. In this talk, we will use a effective Hamiltonian approach which treats both interactions and in homogeneities on the same footing to look at two systems: (a) the Ionic Hubbard Model at half-filling, where a staggered potential on a bipartite lattice competes with interactions to...