PhD Defence
Single-photon detectors for satellite-based quantum communications
Nigar Sultana
Nigar Sultana
Practical and useful quantum information processing will require significant jumps with respect to current systems in error rates and robustness of basic operations, and at the same time in scale and integration. Individual ion qubits’ fundamental qualities are compelling for long-term systems, but a significant challenge in scaling to large ion numbers lies in the optics used to precisely initialize, manipulate and measure their quantum states.
In current classical calculations of quantum many-body systems, the exponentially-growing framework of modern quantum mechanics dictates that a large portion of the universe is required to calculate properties of an infinitesimal version of itself. This fundamental resource requirement suggests that simulating the complexity of quantum systems with purely classical devices is simply not natural.
"Topological classification of materials has revolutionized condensed matter physics over the last decade and lead to a vast array of predicted novel technologies relying on topological electronic states. The search for novel topological semimetals and superconductors is particularly interesting, and the transition metal dichalcogenides are promising hosts of these states.
In this talk Dr. Yang will talk about a few quantum devices studied during past years. In the first half, Dr. Yang will talk about his research on nanodevices made of 2d materials. The focus will be on the study of the magnetic impurities in graphene by phase coherent transport. In the second half, the talk will focus on Dr. Yang’s research on the superconducting quantum computation system. The focus will be on the study of a broad-band Josephson Parametric Amplifier.
It is known that quantum phase transitions occur in the process of quantum annealing. The order of phase transition and computational efficiency are closely related with each other. Quantum computation starts with a non-entangled state and evolves into some entangled states, due to many body interactions and the dynamical delocalization of quantum information over an entire system's degrees of freedom (information scrambling).
Approximate counting -- given a black-box function f:[N]->{0,1}, multiplicatively estimate the number of x's such that f(x)=1 -- is one of the most basic problems in quantum algorithms. In 1998, Brassard, Hoyer, Mosca, and Tapp (BHMT) gave a fully quadratic quantum speedup for the problem, while Nayak and Wu showed that this speedup was optimal. What else is there to say?
Variational quantum algorithms such as VQE or QAOA aim to simulate low-energy properties of quantum many-body systems or find approximate solutions of combinatorial optimization problems. Such algorithms employ variational states generated by low-depth quantum circuits to minimize the expected value of a quantum or classical Hamiltonian.
Optical and microwave photonics are promising resources for quantum information processing and quantum simulation. Engineering suitable matter-light interactions to control and maintain quantum coherence in the presence of noise lies at the heart of practical quantum computing in such systems. I will first present a Hamiltonian engineering scheme for a photonic cavity using an ancilla qubit.
This Mitacs information session will provide details on the Mitacs funding programs for collaborative research and international research partnerships. A particular focus will be the strategic partnerships Mitacs has developed with like-minded industry partners and other organizations across Canada to further support the development and deployment of quantum science and technologies.