Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events using video cameras installed in our lecture theatres. Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities. Recordings of events in these areas are all available On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA). PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.
Quantum computers have the potential to solve certain problems dramatically faster than classical computers. One of the main quantum algorithmic tools is the notion of quantum walk, a quantum mechanical analog of random walk. I will describe quantum algorithms based on this idea, including an optimal algorithm for evaluating Boolean formulas and one of the best known algorithms for simulating quantum dynamics. I will also show how quantum walk can be viewed as a universal model of quantum computation.
Lorentz invariance is considered a fundamental symmetry of physical theories. However, while Lorentz violations are strongly constrained in the matter sector, constraints in the gravitational sector are weaker, allowing to contemplate the idea of Lorentz-violating gravity theories. In this talk I will discuss the effects of Lorentz violations in the quantum cosmology scenario by analyzing the properties of a simple anisotropic model in the framework of Horava-Lifshitz gravity and, if time permitting, some partial results on the viability of this class of theories.
We propose a non-commutative extension of the Pauli stabilizer formalism. The aim is to describe a class of many-body quantum states which is richer than the standard Pauli stabilizer states. In our framework, stabilizer operators are tensor products of single-qubit operators drawn from the group {\alpha I, X,S}, where \alpha=e^{i\pi/4} and S=diag(1,i). We provide techniques to efficiently compute various properties, related to e.g. bipartite entanglement, expectation values of local observables, preparation by means of quantum circuits, parent Hamiltonians etc.
Quantum theory is successfully tested in any experimental lab every day. Apart from its experimental validity, quantum theory also constitutes a robust theoretical framework: small variations of its formalism often lead to highly implausible consequences, such as violation of the no-signalling principle or a significant increase of the computational power. In fact, it has been argued that quantum theory may represent an island in theory space. We show that, at the level of correlations, quantum theory may not be as special as initially thought.