The essential insight of quantum error correction was that quantum information can be protected by suitably encoding this quantum information across multiple independently erred quantum systems. Recently it was realized that, since the most general method for encoding quantum information is to encode it into a subsystem, there exists a novel form of quantum error correction beyond the traditional quantum error correcting subspace codes. These new quantum error correcting subsystem codes differ from subspace codes in that their quantum correcting routines can be considerably simpler than related subspace codes. Here we present a class of quantum error correcting subsystem codes constructed from two classical linear codes. These codes are the subsystem versions of the quantum error correcting subspace codes which are generalizations of Shor’s original quantum error correcting subspace codes. For every Shor-type code, the codes we present give a considerable savings in the number of stabilizer measurements needed in their error recovery routines.
In quantum information, one can prove that a secure quantum cryptography channel based on photon key distribution requires reliable single photon sources. If not, a potential eavesdropper may be able to get information using the extra photons. Current sources are based on either attenuated laser beams, which may produce randomly 2 or even more photons at a time following a poissonian statistics, or either based on two level-systems providing single photon sources often requiring cooling or complex set-ups.The goal of our experiment is to provide an easy, robust and compact single photon source using nonlinear optics (parametric down-conversion). We want to study its statistics and compare it to other photon sources. We could use this heralded single photon source to create a quantum communication channel.
Ever wondered just what Einstein did? Thought about what goes on inside a black hole? Been curious about the way the universe works? If so, then this is the presentation for you. This talk will cover a wide range of topics and give you an idea of the sorts of things researchers at Perimeter Institute are working on. Along the way, you’ll learn about how important it is to be curious and ask lots of questions.
An introduction to the fascinating world of subatomic particles, entanglement, quantum computers and the like. This presentation will outline some of the main ideas behind quantum theory, arguably the most successful theory in the history of science. It will also connect these concepts to some of the topics researchers at the cutting-edge of this field are working on today.
Historically, astronomy has always been about light. Light from distant stars, galaxies and so forth. However, over the last few decades, researchers have come to think that the vast majority of the ‘stuff’ making up the universe does not emit any light whatsoever and so is unseen. This presentation will focus something called dark matter, an exotic substance researchers now think dominates the mass of every single galaxy in the universe, including our own.It will discuss evidence supporting the existence of dark matter, and talk about how scientists around the world today are currently trying to directly detect dark matter through a range of highly sensitive experiments around the globe.