Events

 John Martinis, University of California,
Santa Barbara

As microelectronics technology nears the end of exponential growth over time, known as Moore’s law, there is a renewed interest in new computing paradigms. I will discuss recent research at UCSB on superconducting quantum bits, as well as our recent start at Google to build a useful quantum computer to solve machine learning problems.  A recent experiment will be highlighted that extends the lifetime of a qubit state using quantum error correction.

Marco Piani, University of Strathclyde, Glascow

Quantum correlations exhibit a variety of non-classical features, which include quantum entanglement, quantum steering, and quantum discord. Such richness and diversity of quantum features calls for meaningful and quantitative approaches to their study. In this talk I will illustrate how it is possible to exploit techniques and insight from convex optimization, especially from semidefinite programming, to provide an operational quantification and interpretation of all the above aspects of the quantumness of correlations.

Ying Dong, Hangzhou Normal University

Thermodynamics has been highly successful, impacting strongly on the natural sciences and enabling the development of technologies that have changed our lives, from fridges to jet planes. Until recently, it was applied to large systems described by the laws of classical physics. However, with modern technologies miniaturizing down to the nanoscale and into the quantum regime, testing the applicability of thermodynamics in this new realm has become an exciting technological challenge.

Ibrahim Nsanzineza, Syracuse University

Nonequilibrium quasiparticles and trapped magnetic flux vortices can significantly impact the performance of superconducting microwave resonant circuits and qubits at millikelvin temperatures. Quasiparticles result in excess loss, reducing resonator quality factors and qubit lifetimes. Vortices trapped near regions of large microwave currents also contribute excess loss. However, vortices located in current-free areascan actually trap quasiparticles and lead to a reduction in the quasiparticle loss.

Si-Hui Tan, Singapore University of Technology and Design

We introduce an approach to homomorphic encryption on quantum data.
Homomorphic encryption is a cryptographic scheme that allows
evaluations to be performed on ciphertext without giving the evaluator
access to the secret encryption key. Random operations from an finite
abelian unitary group chosen using an encryption key chosen
uniformly at random perform the encryption, and operations that lie
within the centralizer of the encryption group perform the

Nitin Jain, Northwestern University

Quantum-optical frequency conversion (QFC) provides a method, usually via a nonlinear interaction with an optical ‘pump’ beam, to keep the quantum features of an optical ‘signal’ intact. Most QFC experiments
upconvert near-infrared signal photons to those in the visible or near-visible regime due to the availability of highly-efficient detectors that can be operated at high speeds without incurring a severe noise penalty.

The Institute for Quantum Computing (IQC) will open its doors to all members of the community as part of Reunion at the University of Waterloo. Bring the whole family to discover the excitement of quantum mechanics and learn about the world-class research that is happening right here in our community!

Take a look at what's happening at this year's open house!

Sean Walker of the Department of Chemistry will be defending his thesis:

Molecular nanomagnets for novel spintronics devices

Sean is supervised by Professor Jonathan Baugh.

Poompong Chaiwongkhot of the Department of Physics and Astronomy will be defending his thesis:

Detection Efficiency Mismatch and Finite-Key-Size Attacks on Practical Quantum Cryptography Systems

Poompong is supervised by Research Assistant Professor Vadim Makarov.

Separations in query complexity using cheat sheets

Shalev Ben-David, Massachusetts Institute of Technology (MIT)

We show a power 2.5 separation between bounded-error randomized and quantum query complexity for a total Boolean function, refuting the widely believed conjecture that the best such separation could only be quadratic (from Grover's algorithm). We also present a total function with a power 4 separation between quantum query complexity and approximate polynomial degree, showing severe limitations on the power of the polynomial method.