1- Photon number discrimination without photon counting (theory and experiment)
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.
Quantum information is a very valuable, but also very fragile resource.
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.
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.
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.
I will discuss some new results we have recently obtained for the
problem of quantum states discrimination by Local Operations and
National Physical Laboratory (NPL) is developing a measurement infrastructure for traceably characterising the quantum optical components of Quantum Key Distribution (QKD) systems, one of the most commercially advanced quantum technologies, and among the first to directly harness the peculiar laws of quantum physics.
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.
With the rapid advance of quantum technology, it may become a real
threat that an adversary can take advantage of quantum side information
at hand to break security. In this talk, we consider the problem of
multi-source randomness extraction in the presence of a quantum
adversary, who collects quantum side information from several initially
independent classical random sources. The goal is then to extract almost