Current undergraduate students

Monday, June 2, 2014 2:30 pm - 3:30 pm EDT (GMT -04:00)

Gharibian: Ground state connectivity of local Hamiltonians

Sevag Gharibian, University of California, Berkeley

The study of ground spaces of local Hamiltonians is a fundamental task
in condensed matter physics. In terms of computational complexity
theory, a common focus in this area has been to estimate a given
Hamiltonian’s ground state energy. However, from a physics
perspective, it is often more relevant to understand the structure of
the ground space itself. In this paper, we pursue the latter direction
by introducing the notion of “ground state connectivity” of local

IQC researchers, led by Thomas Jennewein, have been awarded $250,000 by the Canadian Space Agency to train and develop Canadian grad students through a space science and technology project.

The Canadian Space Agency (CSA) funding will support Thomas Jennewein (Physics and Astronomy) and his QEYSSat team in conducting a demonstration of Quantum Key Distribution (QKD) between a receiver payload on an airborne platform and a transmitter on the ground.

Wednesday, May 21, 2014 1:00 pm - 2:00 pm EDT (GMT -04:00)

Elkouss: Analysis of a rate-adaptive reconciliation protocol

David Elkouss, Universidad Complutense de Madrid

"Quantum key distribution performs the trick of growing a secret key in two distant places connected by a quantum channel. In practical systems, whether because of finite resources or external conditions, the quantum channel is subject to fluctuations. A rate adaptive information reconciliation protocol, that adapts to the changes in the communication channel, is then required to minimize the leakage of information in the classical postprocessing.

Monday, May 12, 2014 2:30 pm - 3:30 pm EDT (GMT -04:00)

Fawzi: Achieving the limits of the bounded/noisy quantum-storage model

Omar Fawzi, McGill University

The goal of two-party cryptography is to enable Alice and Bob to solve tasks in cooperation even if they do not trust each other. Examples of such tasks include bit commitment, coin flipping and oblivious transfer. Unfortunately, it has been shown that even using quantum communication, none of these tasks can be implemented when the adversary is completely general.

Monday, April 28, 2014 11:00 am - 12:00 pm EDT (GMT -04:00)

Stobinska: Quantum state engineering of multiphoton quantum superpositions

Magdalena Stobinska, University of Gdańsk/Polish Academy of Sciences, Warsaw

We discuss a device capable of filtering out two-mode states of light with mode populations differing by more than a certain threshold, while not revealing which mode is more populated. It would allow engineering of macroscopic quantum states of light in a way which is preserving specific superpositions. As a result, it would enhance optical phase estimation with these states. We propose an optical scheme, which is a relatively simple, albeit non-ideal, operational implementation of such a filter.

Amir Jafari-Salim, IQC

In this talk, I will give a summary of my recent research on superconducting nanostructures for quantum detection of electromagnetic radiation. In this regard, electrodynamics of topological excitations in 1D superconducting nanowires and 2D superconducting nanostrips is investigated. Topological excitations in superconducting nanowires and nanostrips lead to crucial deviation from the bulk properties.

Tuesday, April 22, 2014 11:00 am - 12:00 pm EDT (GMT -04:00)

Hilke: Graphene growth and characterization for device applications

Michael Hilke, McGill University

We will review several proof of principle applications for graphene based devices performed in our group, including in field sensors, electronics, THz spectroscopy, spintronics, nanofluidics, and even musical instruments. We will then discuss the synthesis mechanism of graphene as well as the synthesis of very large single layered graphene monocrystals with various shapes, ranging from hexagons to fractals, dubbed graphlocons.

Thursday, April 17, 2014 12:00 pm - 1:00 pm EDT (GMT -04:00)

Kothari: Exponential improvement in precision for simulating sparse Hamiltonians

Robin Kothari

We provide a quantum algorithm for simulating the
dynamics of sparse Hamiltonians with complexity sublogarithmic in
the inverse error, an exponential improvement over previous methods.
Unlike previous approaches based on product formulas, the query
complexity is independent of the number of qubits acted on, and for
time-varying Hamiltonians, the gate complexity is logarithmic in the
norm of the derivative of the Hamiltonian. Our algorithm is based on
a significantly improved simulation of the continuous- and

Tuesday, April 8, 2014 11:00 am - 11:00 am EDT (GMT -04:00)

Fan: Quantum receivers beyond the stand quantum limit of coherent optical communications

Jingyun Fan, National Institute of Standards and Technology

Measurements based on the quantum properties of physical system have enabled many tasks which are not possible by any classical means. In this talk, I introduce two quantum receivers that discriminate nonorthogonal optical coherent states unconditionally surpassing the standard quantum limit, with mean photon numbers ranging from single photon level to many photons, thus bridging the gap between quantum information technology and state-of-the art coherent communications.