Month: October 2016

(credit: Louis Lanzano/Bloomberg via Getty Images)

4chan, the infamous message board whose users once labelled it "the asshole of the Internet," is nearly out of money and will have to take drastic action if it wants to survive, according to its new owner. Meanwhile, the notorious hedge fund manager Martin Shkreli has offered to help out.

The site, which hosts notoriously racist and sexist message boards, and which in the form of its /b/ board launched 1,000 unpleasant trolling campaigns, has long suffered money troubles, with users unwilling to subscribe and legitimate advertisers put off by unpalatable content. Its founder Christopher "Moot" Poole sold up in January 2015, to Hiroyuki Nisimura, the man who founded the board that inspired 4chan, Japan's almost equally unpleasant 2Channel.

In a post on Sunday, entitled "Winter is Coming," Nisimura wrote that he "had tried to keep 4chan as is. But I failed. I am sincerely sorry." He added:

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Amazon is cracking down on inaccurate product reviews by banning any that were "incentivised," except—that is—for those that come from its own Amazon Vine program.

Until now, Amazon allowed businesses to offer products to customers in exchange for a review, provided the affiliation was disclosed in the text. It's common to see something like "I received this product for free or at a discount in exchange for my honest, unbiased review" while browsing the site. Unfortunately, while some incentivised reviews may be authentic, many tend to be overwhelmingly positive. For shoppers looking for accurate reviews on potential purchases, this is a big problem.

A recent study of over seven million reviews by ReviewMeta found that incentivised reviews (those that contained some kind of disclaimer text) were rated 0.38 stars higher than non-incentivised reviews. That might not sound like much, but even with this small bump, products could be boosted from the 54th percentile to the 94th percentile, effectively creating a "Top Rated" product. The study also found that incentivised reviewers were 12 times less likely to give a 1-star rating, and nearly four times less likely to leave a critical review.

Enlarge / This is a more traditional beam splitter. Note the lack of white paint. (credit: Colorado State)

Once a year, everyone at the MESA+ Institute^*, where I work, gets together to celebrate the achievements of the past 365 days. Everyone listens to talks by students, post docs, and learned professors. If something catches my interest, I grab the publications and have a closer look. This year was no different.

In one of the optics sessions, a soon-to-be minted Ph.D. presented one of his key findings: a funny kind of optical hardware that offers unique opportunities for researchers doing quantum experiments. Although simple and boring on the surface (it's a beamsplitter, nothing more than a partially reflective mirror), his simple component is exactly what makes optical quantum computing possible. I promise his results are exciting and unexpected.

An ode to the beamsplitter

A beamsplitter is just a partially reflective mirror. In a standard optics text book, a beamsplitter is a plate of glass that reflects exactly half the light that strikes it and allows the other half to pass unimpeded (so no light is absorbed). But a light wave has more than just an amplitude (how bright it is)—it also has a phase. The phase of the transmitted and reflected light beams are not the same. Essentially, when light crosses and/or reflects from a surface, the electric field has to obey certain rules of continuity (just like movie fans, nature abhors discontinuities). So, for instance, the electric field is not allowed to suddenly jump from one value to another as it crosses the interface. The only way that this can be satisfied is if the reflected light and the transmitted light have a phase difference of 180 degrees.