Thursday, December 15, 2016 — 2:00 PM EST
Guillaume Verdon-Akzam

Guillaume Verdon-Akzam of the Department of Applied Mathematics is defending his thesis:

Probing Quantum Fields: Measurements and Quantum Energy Teleportation

Guillaume is supervised by IQC Associate Achim Kempf.

Tuesday, December 13, 2016 — 2:00 PM EST

Experimental demonstration of Gaussian protocols for one-sided device-independent quantum key distribution

Sara Hosseini, The Australian National University

Nonlocal correlations, which was a longstanding foundational topic in quantum information, have recently found application as a resource for cryptographic tasks where not all devices are trusted. For example, the asymmetric phenomena of Einstein-Podolsky-Rosen steering plays a key role in one-sided device-independent quantum key distribution (1sDI-QKD) protocols.

Monday, December 12, 2016 — 11:45 PM EST

The 2xM separability problem investigated via semidefinite programming and normal completions

Hugo J. Woerdeman, Drexel University

Monday, December 12, 2016 — 2:30 PM EST

Two-dimensional coherent photocurrent excitation spectroscopy of a hybrid lead-halide perovskite solar cell

Carlos Silva, Université de Montréal

Monday, December 12, 2016 — 2:30 PM EST
Matthew Graydon

Matthew Graydon of the Department of Physics and Astronomy is defending his thesis:

Conical Designs and Categorical Jordan Algebraic Post-Quantum Theories

Matthew is supervised by Associate Professor Kevin Resch and Rob Spekkens (Perimeter Institute for Theoretical Physics).

Friday, December 9, 2016 — 11:45 AM EST

NMR 'diffraction' in solids

Holger Haas, IQC

Peter Mansfield and Peter Grannell discussed the possibility of NMR crystallography in their 1973 seminal paper 'NMR 'diffraction' in solids?', however, an experimental realisation of NMR 'diffraction' is yet to be demonstrated. I will discuss the feasibility of NMR crystallography in the light of recent advances in nanoscale MRI which combine numerical control finding algorithms and state of the art force detected magnetic resonance techniques.

Tuesday, December 6, 2016 — 2:00 PM EST
Greg Holloway

Greg Holloway of the Department of Physics and Astronomy is defending his thesis:

Electron transport in semiconducting nanowires and quantum dots

Greg is supervised by Associate Professor Joanthan Baugh.

Monday, December 5, 2016 — 11:45 AM EST

Exponential Separation between Quantum Communication Complexity and Classical Information Complexity

Dave Touchette, IQC

We exhibit a Boolean function for which the quantum communication complexity is exponentially larger than the classical information complexity. An exponential separation in the other direction was already known from the work of Kerenidis et. al. [SICOMP 44, pp. 1550--1572], hence our work implies that these two complexity measures are incomparable. As classical information complexity is an upper bound on quantum information complexity, which in turn is equal to amortized quantum communication complexity, our work implies that a tight direct sum result for distributional quantum communication complexity cannot hold.

Friday, December 2, 2016 — 12:30 PM EST

Structured Hadamard matrices and quantum information

Karol Zyczkowski, Jagiellonian University, Poland

Two classes of complex Hadamard matrices with certain special properties found recently applications in quantum physics. Consider a four index tensor $T_{ijkl}$ of size M. It can be reshaped into a square matrix $A_{\mu,\nu}$ of size $M^2$ with three different choices of composed indices e.g. $\mu=(i,j); \nu=(k,l)$ or $\mu=(i,k); \nu=(j,l)$, or $\mu=(i,l); \nu=(j,k)$.

Wednesday, November 30, 2016 — 4:00 PM EST

Dicke's Superradiance in Astrophysics

Fereshteh Rajabi, University of Western Ontario

It is generally assumed that in the interstellar medium much of the emission emanating from atomic and molecular transitions within a radiating gas happen independently for each atom or molecule, but as was pointed out by R. H. Dicke in a seminal paper several decades ago this assumption does not apply in all conditions. As will be discussed in my presentation, and following Dicke's original analysis, closely packed atoms/molecules can interact with their common electromagnetic field and radiate coherently through an effect he named superradiance.

Tuesday, November 29, 2016 — 2:00 PM EST

Entanglement and Purcell Effects in Systems for Quantum Information and Sensing

Stephen K. Gray, Argonne National Laboratory

I discuss how to propagate the quantum mechanical density matrix, including dephasing, spontaneous emission and dissipation for systems relevant to quantum information and sensing. Two applications are then presented. In the first example, a plasmonic system is coupled to quantum dots. The plasmonic system could be a single metal nanoparticle or an array of metal nanoparticles and can be viewed as an optical resonator.

Monday, November 28, 2016 — 2:30 PM EST

Graphs and Multi-mode Coupling: How to build a programmable, directional parametric amplifier

Jose Aumentado, National Institute of Standards and Technology, Boulder

Parametric amplification is a big deal these days, especially for research in superconducting quantum information. This is because, in principle, parametric amplifiers can amplify a signal while adding the minimum amount of noise that quantum mechanics allows. In practice, the situation is a little more complicated and the practical measurement chains can degrade this ideal performance.

Monday, November 28, 2016 — 11:45 AM EST

Efficient Quantum Algorithms for Simulating Lindblad Evolution

Chunhao Wang

Tuesday, November 22, 2016 — 11:00 AM EST

Cybersecurity is Hard. Up for a Challenge?

Mark McArdle, eSentire

Pure technology approaches to cybersecurity consistently fail to prevent hackers from breaching networks and systems. The pursuit of a pure technology solution to cybersecurity is going to require significant breakthroughs in AI and machine learning. Come join a discussion about why cybersecurity is such a hard problem and review some promising areas of research that may bring positive changes.

Thursday, November 17, 2016 — 3:30 PM EST

Generation and Spectral Characterization of High-Purity Biphotons

Franco Wong, Massachusetts Institute of Technology

Spectrally factorable biphotons are highly desirable for many photonic quantum information processing tasks such as quantum computation, boson sampling, and quantum repeaters. We generate biphotons with spectral purity of 99%, the highest to date without any spectral filtering, by pulsed spontaneous parametric downconversion in a custom-fabricated PPKTP crystal under extended Gaussian phase-matching conditions.

Thursday, November 17, 2016 — 11:30 AM EST
John Donohue

John Donohue of the Department of Physics and Astronomy is defending his thesis:

Ultrafast manipulation of single photons using dispersion and sum-frequency generation

John is supervised by Associate Professor Kevin Resch.

Tuesday, November 15, 2016 — 7:00 PM EST

Public lecture by Charles W. Clark

Much of what we understand about the world comes from our eyes, which sense the colors from red to violet that are expressed in the rainbow.

Tuesday, November 15, 2016 — 11:00 AM EST

Twisting the neutron wavefunction

Charles W. Clark, National Institute of Standards and Technology

Wave motions in water were already familiar in antiquity. The mathematical representation of waves in physics today is essentially the same as that first provided by d'Alembert and Euler in the mid-18th century. Yet it was only in the early 1990s that physicists managed to control a basic property of light waves: their capability of swirling around their own axis of propagation.

Monday, November 14, 2016 — 2:30 PM EST

Post-Quantum Key Exchange for the Internet and the Open Quantum Safe Project

Douglas Stebila, McMaster University

Most public key cryptography algorithms used on the Internet are based on mathematical problems which could be broken by large-scale quantum computers. This motivates the field of post-quantum cryptography, which aims to construct public key cryptosystems that are believed to be secure even against quantum computers. Since a future quantum computer could retroactively break the confidentiality of today's communications, it is important to begin transitioning public key encryption and key exchange to quantum-resistant algorithms.

Monday, November 14, 2016 — 11:45 AM EST

SIC-POVMs and algebraic number theory

John Yard, Institute for Quantum Computing

SIC-POVMs (Symmetric Informationally Complete Positive Operator-Valued Measures) are certain extremal rank-1 projective measurements corresponding to maximal sets of complex equiangular lines as well as to minimal complex projective 2-designs. They are conjectured to exist in every finite-dimensional complex Hilbert space as orbits of generalized Pauli groups. 

Friday, November 11, 2016 — 11:45 AM to 1:00 PM EST

Title TBA

If you're coming from the Lazaridis Centre, take the 11:35am shuttle from QNC to RAC1, and they can return to QNC from RAC1 @ 1:15pm.

A light lunch will be provided.

Thursday, November 10, 2016 — 11:00 AM EST

Contextuality as a resource for quantum computation

Juan Bermejo Vega

A central question in quantum computation is to identify the resources that are responsible for quantum speed-up. Quantum contextuality has been recently shown to be a resource for quantum computation with magic states for odd-prime dimensional qudits and two-dimensional systems with real wavefunctions. The phenomenon of state-independent contextuality poses a priori an obstruction to characterizing the case of regular qubits, the fundamental building block of quantum computation.

Monday, November 7, 2016 — 2:30 PM EST

Quantum Engineering of Superconducting Qubits

William Oliver, Massachusetts Institute of Technology

Superconducting qubits are coherent artificial atoms assembled from electrical circuit elements and microwave optical components. Their lithographic scalability, compatibility with microwave control, and operability at nanosecond time scales all converge to make the superconducting qubit a highly attractive candidate for the constituent logical elements of a quantum information processor. 

Monday, November 7, 2016 — 11:30 AM EST

A proof of the quantum data processing inequality with a combinatorial flavour

Ashwin Nayak, Institute for Quantum Computing

The quantum data processing inequality (equivalently, the strong sub-additivity of von Neumann entropy) is a cornerstone of quantum information theory.  It has been proven in numerous ways, each proof highlighting different aspects of the property.

Monday, October 31, 2016 — 2:30 PM EDT

Efficient Fault-Tolerant Quantum Computing

Martin Suchara, AT&T Labs Research

Quantum error correction presents some of the most significant and interesting challenges that must be resolved before building an efficient quantum computer. Quantum error correcting codes allow to successfully run quantum algorithms on unreliable quantum hardware. Because quantum hardware suffers from errors such as decoherence, leakage or qubit loss, and these errors corrupt delicate quantum states rather than binary information, the known error correction techniques are complex and have a high overhead. 


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