On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
When a brane and antibrane meet, they do not annihilate directly to energy. Instead they first fragment into shards. These shards are smaller branes and antibranes; they occupy two fewer dimensions than the original ones did. For instance, if the initial brane and antibrane spanned seven spatial dimensions (a D7-brane and antibrane), they fragment into many D5-branes and antibranes. These shards, in turn, annihilate into D3-branes and antibranes and thence into D1-branes. Only at that point do they vanish altogether.
The cascade of brane-antibrane annihilation tends to remove large branes, which easily find their antibrane doppelgangers and so annihilate. Smaller branes, such as the D3 and D1 varieties, have greater difficulty bumping into antibranes in the vastness of nine-dimensional space. Lisa Randall of Harvard University and Andreas Karch of the University of Washington generalized our results to include nine expanding dimensions. This process may help explain why most branes, like ours, tend to have fairly few dimensions.
—C.B. and F.Q.
Subscribe to Support Independent Journalism
Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.
When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.
Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber
