Severing independent email threads with KMail

I use KMail and it, like many other popular email clients, sorts messages into threads. It does this based on reference information embedded in the (usually hidden) headers of each message. Of course, sometimes those headers are off. Most commonly this happens because a sender uses a reply-to-all function to send a new message to an existing list of addresses—this new message has a completely different subject from the original (to which it's ostensibly replying), but the sorting at the receiver's email client still considers it part of the old thread because reply-to-all functions add headers referencing the original message, as well as others in the original thread.

Fortunately, KMail has the ability to remove those headers through manually applied filters. The bonus is that, once you do this, the corrected threading will propagate to other email clients—I use K-9 Mail (not related to KMail) on my phone …

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How to make private git repositories open for public access

Some of my personal projects are tracked using private git repositories, hosted on this server. I can access these via ssh, but for a while I've had in mind to make at least a couple of them publicly accessible... somehow. After finally getting around to looking into it, this turns out to be deceptively simple using git-daemon (instructions for Debian distros):

  1. Install the git-daemon-sysvinit package.
  2. Enable the daemon by editing /etc/default/git-daemon. Reboot, or start the git-daemon service by hand.
  3. Add a symlink to each git repo you want to make public under /var/lib/git. These will then be accessible via git://<hostname>/git/<linkname>.
  4. Ensure the git protocol port (9418) forwards to the server.

Simple! The git protocol is faster than serving over http(s), and the standard configuration ensures that anonymous clients can pull, but not push, which is exactly what I was after.

Over the …

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Published in EPJ Quantum Technology: Laser annealing heals radiation damage in avalanche photodiodes

Following our detector radiation and mitigation testing campaign, we tried an alternative approach for annealing detectors to mitigate radiation damage: laser annealing. High-power laser light was directed at irradiated and thermally-annealed detector samples, and subsequent performance measured. Notably, the results show that doing so provides performance improvements better than those achieved by thermal annealing.

J. G. Lim, E. Anisimova, B. L. Higgins, J.-P. Bourgoin, T. Jennewein, and V. Makarov
EPJ Quantum Technology 4, 11 (2017)

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Published in EPJ Quantum Technology: Mitigating radiation damage of single photon detectors for space applications

Quantum uplinks to Earth-orbiting satellites will necessitate single-photon detector technology that is robust to space radiation for the lifetime of the satellite. In this study, we experimentally assessed the effect of such radiation on a targetted selection of candidate detectors, with a focus on their impact to quantum key distribution. We then attempted to mitigate these effects, using thermal controls including deep cooling (during operation) and high-temperature annealing. Our results show that such techniques can maintain useful performance significantly beyond the one-year baseline lifetime.

E. Anisimova, B. L. Higgins, J.-P. Bourgoin, M. Cranmer, E. Choi, D. Hudson, L. P. Piche, A. Scott, V. Makarov, and T. Jennewein
EPJ Quantum Technology 4, 10 (2017)

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Published in Quantum Science and Technology: Airborne demonstration of a quantum key distribution receiver payload

This paper describes work I mentioned earlier. We successfully demonstrated quantum key distribution with signals transmitted from a ground station to a receiver on board a flying airplane. Our receiver (which is significantly upgraded in comparison to our prior truck demonstration) was designed and largely custom-built to have a clear path to flight on a satellite. Our demonstration illustrates the viability of such a payload.

C. J. Pugh, S. Kaiser, J.-P. Bourgoin, J. Jin, N. Sultana, S. Agne, E. Anisimova, V. Makarov, E. Choi, B. L. Higgins, and T. Jennewein
Quantum Science and Technology 2, 024009 (2017)

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QEYSSat moving forward

Some context:

I've been involved with the QEYSSat project, working on studies and prototypes, for the last 6 years. It's wonderful to see it selected as one of the two projects to receive funding, thereby allowing it to become an actual mission. Very exciting times!

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