Events

Pan Zheng

Creating and Measuring Two-Mode Cat States

IQC/Physics Special Seminar - Loren Swenson, D-Wave Systems

I will introduce quantum annealing as a technique for harnessing quantum mechanics to solve hard problems. The design of a quantum annealing processor based on superconducting flux qubits, some of the challenges we have encountered in constructing it, and measurements confirming the role of quantum mechanics in such processors will be presented. Finally, I will briefly discuss recent benchmarking and simulation results using the D-Wave 2000Q processor.

Brandon Buonacorsi - Modeling the Exchange Interaction in Silicon Quantum Dots

Silicon metal-oxide-semiconductor field effect transistor (MOSFET) quantum dots are promising candidates for scalable quantum computing using electron spin qubits due to their long coherence times, compact size, and ease of integration into existing fabrication technologies.  I will introduce how we fabricate these devices and describe the experimental characterizations we do to check the stability and tunability of our quantum dots.  In a double quantum dot device, two qubit gates are realized

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.

Ke He, Tsinghua University

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.

Jiawei Ji - The University of Calgary

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.

David Gosset, IBM TJ Watson Research Center

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?

Andrew N. Cleland, University of Chicago

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.

Kyle Willick: Carbon Nanotube Mechanical Resonators - Magnetic force detection and fast sensing

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.

Hydrogen and hydride superconductors, a new path to room temperature superconductivity?

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.