Events

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.

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. 

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.

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.

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. 

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.

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.

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.

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.

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.