Seminar

Introducing the next installment of the Quantum Industry Lecture Series (QuILS). Nathan Wiebe, a former IQC postdoctoral fellow who is currently working at Microsoft, will talk to us about what it's like to work in research for a technological powerhouse.

Krysta Svore, Microsoft Research

Recently it has been shown that Repeat-Until-Success (RUS) circuits can approximate a given single-qubit unitary with an expected number of T gates of about 1/3 of what is required by optimal, deterministic, ancilla-free decompositions over the Clifford+T gate set. In this work, we introduce a more general and conceptually simpler circuit decomposition method that allows for synthesis into protocols that probabilistically implement quantum circuits over several universal gate sets including, but not restricted to, the Clifford+T gate set.

Sean Hallgren, Pennsylvania State University

Computing the group of units in a field of algebraic numbers is one of the central tasks of computational algebraic number theory. It is believed to be hard classically, which is of interest for cryptography. In the quantum setting, efficient algorithms were previously known for fields of constant degree. We give a quantum algorithm that is polynomial in the degree of the field and the logarithm of its discriminant. This is achieved by combining three new results.

Nathan Wiebe, Microsoft Research

We develop a method for approximate synthesis of single--qubit rotations of the form e^{-i f(\phi_1,\ldots,\phi_k)X} that is based on the Repeat-Until-Success (RUS) framework for quantum circuit synthesis. We demonstrate how smooth computable functions, f, can be synthesized from two basic primitives. This synthesis approach constitutes a manifestly quantum form of arithmetic that differs greatly from the approaches commonly used in quantum algorithms.

Alessandro Cosentino, IQC

I will discuss some new results we have recently obtained for the
problem of quantum states discrimination by Local Operations and

Val Zwiller, Delft University of Technology, Netherlands

Nanowires offer exciting opportunities in quantum optics. Using quantum dots in semiconducting nanowires, we demonstrate the generation of single photons as well as pairs of entangled photons. Making electrical contacts to semiconducting nanowires, we make a single quantum dot LED where electroluminescence from a single quantum dot can be studied. Similar devices operated as photodiodes enable the operation of single nanowire avalanche photodiodes.

Dieter Suter, Universität Dortmund

Quantum information is a very valuable, but also very fragile resource.

Yury Kurochkin, Russian Quantum Center in Skolkovo, Moscow

In this talk I want to present progress of our quantum optics laboratory. Our laboratory was built in the summer 2013. During the past year we've performed number of beautiful experiments. One of the featured experiments is "Quantum vampire" which demonstrates non-local properties of the annihilation operator. This beautiful effect predicts that if you take particular number of photons from the part of the light beam there will be now shadow.

Julien Bernu, Australian National University (ANU)

1- Photon number discrimination without photon counting (theory and experiment)

Vern Paulsen, University of Houston

The chromatic number of a graph has a description as the classical value of a three-person game. If instead one plays a quantum version of this game, then this yields a smaller value--the quantum chromatic number of the graph. However, using the Algebraic Quantum Field Theory (AQFT) model could yield a larger set of quantum correlations, and a different value for the quantum chromatic number.