MSc Thesis Presentation
Candidate: Matthew Brown
Speaker: Heather Hoff
Abstract: Software is a key asset of any new business. How do you protect the results of weeks or months of hard labour? Who owns the software and how do I mange its development to ensure its inherent value is maintained? Should I use Open Source, or even contribute to Open Source? What are the benefits and how does this measure up against the risks?
The equilibrium states of Hamiltonians without a sign problem can in many cases be efficiently sampled using classical Markov chain Monte Carlo methods. These simulation algorithms present a challenge to the possibility of obtaining quantum speedups using transverse-field quantum annealing, and in this talk I'll describe rigorous results on the convergence of simulated quantum annealing to a class of problems that take exponential time to solve by local search.
Tarun Patel: Photocurrent imaging of charge density wave transitions in ultrathin 1T-TaS2 1T-TaS2 is a layered van-der Waals material which shows multiple charge density wave (CDW) transitions as a function of temperature. Ultrathin flakes fabricated by mechanical exfoliation and protected from oxidation with h-BN capping in inert atmosphere have been shown to retain these transitions.
The quantum anomalous Hall (QAH) effect is a quantum Hall effect induced by spontaneous magnetization instead of an external magnetic field. The effect occurs in two-dimensional (2D) insulators with topologically nontrivial electronic band structure which is characterized by a non-zero Chern number. The experimental observation of the QAH effect in thin films of magnetically doped (Bi,Sb)2Te3 topological insulators (TIs) paves the way for practical applications of dissipationless quantum Hall edge states.
Quantum circuits based only on matchgates are able to perform non-trivial (but not universal) quantum algorithms. Because matchgates can be mapped to non-interacting fermions, these circuits can be efficiently simulated on a classical computer. One can perform universal quantum computation by adding any non-matchgate parity-preserving gate, implying that interacting fermions are natural candidates for universal quantum computation within the circuit model.
There is strong evidence that a sufficiently large fault-tolerant quantum computer would solve certain computational problems exponentially faster than any classical computer. How can quantum algorithms and complexity theory help guide the way forward in our current era of small and noisy quantum computers?
Superconducting qubits offer excellent prospects for manipulating quantum information, with good qubit lifetimes, high fidelity single- and two-qubit gates, and straightforward scalability (admittedly with multi-dimensional interconnect challenges). One interesting route for experimental development is the exploration of hybrid systems, i.e. coupling superconducting qubits to other systems.
Suspended carbon nanotube (CNT) resonators have demonstrated excellent sensitivity in mass and force sensing applications to date. I will introduce these mechanical resonators, and how they can be combined with magnetic field gradients to realize magnetic moment readout.
The recent discovery of superconductivity in H3S under high pressure by the group of Mikhail Eremets at the record breaking temperature of 203 K has opened a whole new path to potential room temperature superconductivity. I will describe recent experiments designed to verify the pairing mechanism in this new material using infrared spectroscopy.