Abstract: Despite the development of increasingly capable quantum computers, an experimental demonstration of an algorithmic quantum speedup employing today’s non-fault-tolerant devices has remained elusive. In this talk, I will report on three very recent demonstrations of such a speedup, focusing on how solution times scale with problem size. Two of the demonstrations use IBM’s superconducting quantum computers and involve modified versions of foundational black-box quantum algorithms. In contrast with recent quantum supremacy demonstrations, these quantum speedups do not rely on complexity-theoretic conjectures. The third demonstration uses a D-Wave quantum annealer and involves approximate optimization in the context of spin glass problems. In all cases, our work incorporates tailored quantum error suppression methods, which we found to be necessary in order for the quantum speedup to appear. 

Abstract: This talk will describe the development of an atomic physics experiment into a quantum computer and quantum simulator. Our system is based on a chain of 171Yb+ ions with individual laser beam addressing. This fully connected device can be configured to run any sequence of single- and two-qubit gates, making it in effect an arbitrarily programmable quantum computer. The high degree of control can be used for digital quantum circuits, but also for analog and hybrid quantum simulations, including quantum-classical optimization routines. We operate this machine in user-facility mode, working with many external collaborators and growing its capabilities with every new application. I will present recent results from a lattice gauge theory simulation. Finally, I will describe our effort towards networking ion trap quantum computers in a city-sized network for new quantum technology applications.  

Abstract: Single spins associated with nitrogen-vacancy (NV) defects in diamond have emerged as a promising and versatile experimental platform for quantum information processing. They can be used as nodes in optically connected quantum networks, as sensors for magnetic imaging with sub-micron resolution, for detecting and engineering quantum states of nano-mechanical oscillators, and even as probes in biological systems. Our group has demonstrated improvements to dynamic range and sensitivity of magnetometry using phase estimation algorithms, and carried out electron paramagnetic resonance detection and spectroscopy of single Cu ions on the diamond surface. I will also discuss a unique system in our lab where we magnetically trap and laser cool diamond microcrystals under high-vacuum room-temperature conditions for the first time, and discuss the path forward to observing quantum superpositions of macroscopically separated motional states.