Chuck Darwin<p>Arıkan's new solution was to create near-perfect channels from ordinary channels by a process he called “<a href="https://c.im/tags/channel" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>channel</span></a> <a href="https://c.im/tags/polarization" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>polarization</span></a>.” </p><p>Noise would be transferred from one channel to a copy of the same channel to create a cleaner copy and a dirtier one. </p><p>After a recursive series of such steps, two sets of channels emerge, one set being extremely noisy, the other being almost noise-free. </p><p>The channels that are scrubbed of noise, in theory, can attain the Shannon limit. </p><p>He dubbed his solution <a href="https://c.im/tags/polar" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>polar</span></a> <a href="https://c.im/tags/codes" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>codes</span></a>. <br>It's as if the noise was banished to the North Pole, allowing for pristine communications at the South Pole.</p><p>After this discovery, Arıkan spent two more years refining the details. <br>He had read that before Shannon released his famous paper on information theory, his supervisor at Bell Labs would pop by and ask if the researcher had anything new. <br>“Shannon never mentioned information theory,” says Arıkan with a laugh. <br>“He kept his work undercover. He didn't disclose it.” </p><p>That was also Arıkan's MO. “I had the luxury of knowing that no other person in the world was working on this problem,” Arıkan says, “because it was not a fashionable subject.”</p><p>In 2008, three years after his eureka moment, Arıkan finally presented his work. </p><p>He had understood its importance all along. Over the years, whenever he traveled, he would leave his unpublished manuscript in two envelopes addressed to “top colleagues whom I trusted,” with the order to mail them “if I don't come back.” </p><p>In 2009 he published his definitive paper in the field's top journal, IEEE Transactions on Information Theory. </p><p>It didn't exactly make him a household name, but within the small community of information theorists, polar codes were a sensation. </p><p>Arıkan traveled to the US to give a series of lectures. (You can see them on YouTube; they are not for the mathematically fainthearted. The students look a bit bored.)</p><p>Arıkan was justifiably proud of his accomplishment, but he didn't think of polar codes as something with practical value. </p><p>It was a theoretical solution that, even if implemented, seemed unlikely to rival the error-correction codes already in place. </p><p>He didn't even bother to get a patent.</p><p> <a href="https://c.im/tags/channel" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>channel</span></a> <a href="https://c.im/tags/capacity" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>capacity</span></a> <a href="https://c.im/tags/Shannon" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>Shannon</span></a> <a href="https://c.im/tags/limit" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>limit</span></a> <a href="https://c.im/tags/correcting" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>correcting</span></a> <a href="https://c.im/tags/errors" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>errors</span></a> <a href="https://c.im/tags/Bilkent" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>Bilkent</span></a> <a href="https://c.im/tags/University" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>University</span></a> <a href="https://c.im/tags/eureka" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>eureka</span></a> <a href="https://c.im/tags/accurately" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>accurately</span></a> <a href="https://c.im/tags/redundancy" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>redundancy</span></a> <a href="https://c.im/tags/channel" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>channel</span></a> <a href="https://c.im/tags/coding" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>coding</span></a> <a href="https://c.im/tags/problem" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#<span>problem</span></a></p>