We take our quantum key distribution system out of the laboratory and mount it in the back of a small truck. Integrating a two-axis pointing system at both sites, polarization correction, and time-of-flight compensation, we demonstrate quantum key distribution from a stationary transmitter to a receiver moving at an angular speed (relative to the transmitter) equivalent to the maximum angular speed of a typical low-Earth-orbit satellite.

Bonus: Read the IQC's news release, which covers both this and the previous paper for a general audience.

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Fundamental laws of quantum physics guarantee the security of encryption keys generated through quantum key distribution, in contrast to standard encryption techniques which rely on assumptions about an eavesdropper's computational ability. That said, special technology is necessary to facilitate quantum key distribution transmissions between parties that are more than a couple of hundred kilometers apart.

A near-term solution is to use an orbiting satellite as a trusted quantum receiver. Here we detail specifically chosen algorithms that make up an implementation of quantum key distribution, suitable for a satellite receiver platform. We examine these algorithms' computational requirements while demonstrating them experimentally as we emulate the variable channel losses that would be experienced during a satellite pass (following those we published about previously).

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As a consequence of their recent effort to boost the numbers of Windows 10 installs using any means possible, however questionable, and turn their paying customers into beta testers, Microsoft have been especially hostile to their users as of late, installing nag-screens and “telemetry” code (also known as “spyware”) under the guise of important updates to existing installs of previous versions of Windows. While I would happily eschew Windows for Linux on all the machines I use, and have largely done so, the idea of avoiding Windows in totality is, sadly, not yet practical―the common-use machines I maintain in our lab required it for various reasons, and even I still keep a Wintendo partition.

There are plenty of discussions around about what to do about this. Here's a fine example. Though this is intended for my own reference, I've had success with the following:

wusa /uninstall /kb:2952664 /norestart /quiet
wusa /uninstall /kb:2976978 /norestart /quiet
wusa /uninstall /kb:2977759 /norestart /quiet
wusa /uninstall /kb:2990214 /norestart /quiet
wusa /uninstall /kb:3021917 /norestart /quiet
wusa /uninstall /kb:3022345 /norestart /quiet
wusa /uninstall /kb:3035583 /norestart /quiet
wusa /uninstall /kb:3044374 /norestart /quiet
wusa /uninstall /kb:3068708 /norestart /quiet
wusa [...]

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So it seems my face has now graced (or disgraced, perhaps) North American television. Some folks from DMG Productions were in the lab a while ago gathering footage for a segment on IQC for Innovations with Ed Begley, Jr. Though my supervisor fielded the actual spoken material, you can spot me in the background of various “action shots” discussing clearly very important things™ with students and colleagues.

Here's the segment in question, first broadcast on Discovery Channel, May 25, 2015.

I've similarly been on Australian TV before, so that makes two continents that have had to deal with my mug on air.

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It's well known that quantum entangled systems can exhibit correlations that go beyond those that could be seen if Nature worked in intuitive “classical” ways. However, as Richard Feynman noted, classical theory can support exhibiting such correlations if we invoke negative probabilities to describe their properties. What he did not do was specify how these negative probabilities ought to be chosen, and without any justification, an infinite number of different combinations could be chosen that will satisfy the relevant equations.

The concept of negative probabilities seems nonsensical because they cannot actually be observed—indeed, they cannot be observed even within the framework of quantum theory due to the effects of measurement back-action. Here, we show how they can instead be inferred through the use of weak measurements, where a meter is only weakly coupled to the property of interest, thereby avoiding the back-action problem. Each individual weak measurement has a high uncertainty, but by measuring many instances of a larger ensemble, an average can be found that implies a specific set of anomalous (i.e. beyond 0–1) probabilities. With an experimental demonstration, we thus give an empirically justified method for choosing the anomalous probabilities that allow the classical model [...]

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You might have noticed that I'm running a little Raspberry Pi, acting as a server for my website as well as some other small server-ish tasks. This machine is actually on my home network and I also use it as the front-face to that network for incoming connections. There are other machines on this network, and while they are behind a NAT and so not addressible from the outside world, this is fine most of the time. But on the odd occasion where I'd like to directly address any other machine on that network, I have to do so through the Raspberry Pi. Depending on what it is I'm trying to do, exactly, that can be tricky.

I've just discovered sshuttle. It acts similarly to a VPN, using SSH under the hood to transport TCP packets through a server that you specify. The cool thing is that it doesn't require any complicated pre-configuration on the server—just Python. All you have to do is run it on the client machine you want to connect from. Nifty!

Debian has it packaged: run sudo aptitude install sshuttle. The binary itself apparently installs under /usr/sbin, which doesn't seem to be in a [...]

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