NOVA’s Nobel Poll: Scientists Predict the 2013 Laureates

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<p>
  The selection process for the Nobel prizes—this year’s to be announced starting October 7—is highly secretive, but that doesn’t stop the speculation. In that spirit, we surveyed dozens of scientists in the fields of physics, chemistry, and physiology, asking who they think could win this year’s Nobel Prize.
 </p>
<h2>
  Physics
 </h2>
<p>
  For the physics prize, almost all of our respondents predicted that it will honor the discovery of the Higgs boson,
  <a href="http://www.pbs.org/wgbh/nova/physics/higgs-boson-revealed.html">
   announced tentatively in July 2012
  </a>
  and with
  <a href="http://www.pbs.org/wgbh/nova/next/physics/higgs-boson-discovered/">
   greater confidence in March 2013
  </a>
  . But with thousands of scientists involved in the discovery,
  <a href="http://www.pbs.org/wgbh/nova/physics/blog/2012/03/a-higgs-by-any-other-name/">
   eight or more
  </a>
  contributing to the origination of the theory, and the prize allowed to go to no more than three winners, how will the Nobel committee divvy up the laurels?
 </p>
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/nobel-medal.width-990_CHpDg2c.jpg"/>
<figcaption>The Nobel Prize medal
        
    </figcaption>
</figure>
<p>
  Most of the physicists responding to our poll felt that the prize would go to Peter Higgs and Francois Englert, who independently invoked a new field—known today as the Higgs field—to explain why subatomic particles have mass. Their ideas were published within just weeks of each other. As Peter G. O. Freund, a theoretical physicist at the University of Chicago, wrote, “For the better part of the past half century the phenomenon discovered by Englert, Brout [Englert’s coauthor] and Higgs has been a crucial ingredient of the standard model of physics, and repeatedly verified indirectly along with this model. Now, after the phenomenon’s beautiful direct verification at the LHC, it is high time to honor its discoverers with the Nobel Prize.”
 </p>
<h2>
  Chemistry
 </h2>
<p>
  The chemists selected David A. Evans, a synthetic organic chemist at Harvard. Evans’s work focuses on both total synthesis and stereoselectivity. Total synthesis involves creating synthetic versions of compounds found in nature. The pharmaceutical industry relies on the field’s techniques heavily, as they allow researchers to mine the natural world for compounds that may prove beneficial as treatments, even if those compounds are incredibly rare. Evans is something of a total synthesis wizard—he and his lab have synthesized over 50 natural products throughout the years.
 </p>
<p>
  Stereoselectivity, Evans’s other speciality, is where one chemical reaction spits out different three-dimensional orientations of the same molecule, or stereoisomers. Specifically, Evans is interested in enantiomers, a specific class of stereoisomer that involves mirror images of the same molecule. Evans has been developing techniques that vary the levels of stereoselectivity in the hopes that someday we’ll be able to completely control the configuration of the final product. Like total synthesis, it’s important in the development and production of pharmaceuticals. The painkiller naproxen is a perfect example. One enantiomer relieves pain, while the other simply causes liver damage. Producing and selecting the right enantiomer is crucial.
 </p>
<h2>
  Medicine
 </h2>
<p>
  For medicine and physiology, unfortunately our poll didn’t garner enough results to say anything conclusive, but one widely-watched Nobel prediction site, ScienceWatch, published by Thomson Reuters, has identified as possible winners A. Paul Alivisatos, Chad A. Mirkin, and Nadrian C. Seeman for their work on DNA nanotechnology, a promising and relatively new field that uses the unique properties of both DNA and nanoparticles to study biological processes and treat the human body. Mirkin’s research, for example,
  <a href="http://www.pbs.org/wgbh/nova/next/tech/nanoparticles-and-the-future-of-medicine/">
   uses gold nanoparticles studded with nucleic acids
  </a>
  to deliver drugs targeted at specific cells.
 </p>
<p>
  It’s important to keep in mind that these predictions are just that, predictions. We’ll have to wait until next week to see if any pan out. But in the meantime, you can
  <a href="http://svy.mk/19mOIwz">
   voice your opinion in our public Nobel poll
  </a>
  and see which scientists the crowd feels are this year’s frontrunners.
 </p>
</section>
<p>
 Photo credit: Public domain
</p>

Welcome to The Nature of Reality

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<p>
  When I was seven, I understood relativity perfectly. I
  <em>
   got
  </em>
  it. At least I thought I did. And it was glorious.
 </p>
<p>
  It all started with
  <em>
<a href="http://en.wikipedia.org/wiki/Flight_of_the_Navigator">
    The Flight of the Navigator
   </a>
</em>
  , that movie about the kid who accidentally stumbles upon a space ship and has a grand old afternoon traversing the galaxy in the company of its cargo of friendly creatures. The problem? When he returns to Earth he finds that eight years have elapsed. He has been declared missing; when he rings the bell at his old house, a stranger answers the door.
 </p>
<p>
<em>
   The Flight of the Navigator
  </em>
  is a story about
  <a href="http://www.pbs.org/wgbh/nova/physics/spacetime-trip.html" target="_blank" title="A Trip Through Spacetime">
   time dilation
  </a>
  . The ship was traveling close to the speed of light, so time passed significantly more slowly for its passengers than it did for those back on Earth. That’s special relativity for you. It seemed easy, elegant, amazing.
 </p>
<p>
  For the next few years, that was my relationship with relativity. Then came the equations, and suddenly relatively didn’t seem so easy any more. Elegant, maybe. But that first spark of intuition got lost in symbols, equations, calculations and miscalculations. So I wondered: Why can’t we have it both ways? Is it possible to be both wide-eyed and rigorous, methodical and amazed?
 </p>
<p>
  That’s a balance even physicists struggle with. As MIT theorist Max Tegmark told NOVA, “When I was in high school, physics was my most boring subject….It was only later that I realized that physics isn’t at all about just solving some equations. It’s about figuring out what reality is all about.”
 </p>
<p>
  That’s what we’re doing on this blog: taking on the biggest questions of all, the ones that get at the very nature of reality. What happens to information inside a black hole? What are we really talking about when we talk about teleportation? What if the laws of physics can’t be unified? Every week, we’ll have a new post from a scientist or science writer–look for James Stein, Sean Carroll, and Frank Wilczek in the coming weeks and months–with plenty of room for you to join the discussion with your own questions and ideas.
 </p>
<p>
  We hope you’ll let us know what subjects in fundamental physics you want to hear about—the stranger, the better. Can neutrinos really go
  <a href="http://www.nature.com/news/2011/110922/full/news.2011.554.html">
   faster than the speed of light
  </a>
  ? What is this
  <a href="http://www.pbs.org/wgbh/nova/physics/spacetime-lemonade.html">
   spacetime
  </a>
  thing anyway? Is our universe just one of countless others in a
  <a href="http://www.pbs.org/wgbh/nova/physics/johnson-multiverse.html">
   multiverse
  </a>
  ? Join us as we dive deep and discover how physics is changing what we thought we knew about the nature of reality.
 </p>
</section>

Live Webcasts: The Latest Higgs Results

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<p>
  Watch this space the week of July 2, 2012 for a series of live webcasts from Fermilab and CERN on the latest results in the search for the
  <a href="http://www.pbs.org/wgbh/nova/blogs/physics/2012/06/the-higgs-boson-explained/">
   Higgs boson
  </a>
  .
 </p>
<p>
<strong>
   Wednesday, July 4: CERN
  </strong>
</p>
<p>
  Come back at 3 am ET on July 4, 2012 for a
  <a href="http://webcast.web.cern.ch/webcast/">
   live webcast from CERN
  </a>
  revealing the latest results in the search for the Higgs boson. A scientific seminar will begin at 3 am ET followed by a press conference at 5 am ET. Stay tuned!
 </p>
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</figure>
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</section>

See scientists announce their latest findings in the ongoing search for the elusive Higgs boson.

Fermilab Rings in Higgs Week

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<p>
  Higgs week is here!
 </p>
<p>
  This week, the search for the
  <a href="http://www.pbs.org/wgbh/nova/blogs/physics/2012/06/the-higgs-boson-explained/">
   Higgs boson
  </a>
  —the elusive subatomic particle that is a critical piece of the Standard Model of physics—may reach its climax when, on Wednesday, two research teams
  <a href="http://webcast.web.cern.ch/webcast/">
   announce the results
  </a>
  of their work at the Large Hadron Collider (LHC) at CERN.
 </p>
<p>
  But before there was the LHC, there was the Tevatron, a particle accelerator at Fermilab. And before the LHC’s big announcement, there was a not-quite-so-big
  <a href="http://www.pbs.org/wgbh/nova/blogs/physics/2012/07/live-webcasts-the-latest-higgs-results/">
   announcement
  </a>
  from the Tevatron teams as they gathered with colleagues this morning to announce the results of the most detailed analysis so far of ten years’-worth of their Higgs search data.
  <br/>
<div class="wp-caption alignnone" id="attachment_774" style="max-width: 510px">
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/11-0226-01d.width-990_s3SrH33.jpg"/>
<figcaption>
</figcaption>
</figure>
<p class="wp-caption-text">
    The Tevatron at Fermilab. Image courtesy of Fermilab.
   </p>
</div>
</p>
<p>
  The Tevatron
  <a href="http://www.pbs.org/wgbh/nova/insidenova/2011/09/hail-and-farewell-grand-colliders.html">
   shut down last year
  </a>
  , passing the baton to the newer, more powerful LHC. But the scientists working on two of the Tevatron’s detectors, CDF and DZero, haven’t given up searching for traces of the Higgs in their own data. Using ever-smarter computer algorithms, they aim to wring as much information as they can out of the data they’ve accumulated. As Wade Fisher, the Michigan State University scientist representing DZero at this morning’s conference, put it: “We’re still working, we’re not stopping….There’s still gas in the tank.”
 </p>
<p>
  What they’ve found so far is suggestive of the Higgs, but doesn’t rise to the level of discovery. Combining data from both CDF and DZero, they’ve
  <a href="http://www.fnal.gov/pub/presspass/press_releases/2012/Higgs-Tevatron-20120702.html">
   eked out a signal
  </a>
  that might be due to the Higgs, but there is also a one-in-550 chance that it is down to random fluctuations.
 </p>
<p>
  To claim a
  <a href="http://www.symmetrymagazine.org/breaking/2012/06/29/what-does-it-take-to-claim-discovery-of-the-higgs/">
   discovery
  </a>
  , the physicists need to whittle that random-chance number down to one in three and a half million—“five sigma,” in stat-speak.
 </p>
<p>
  That’s what the physics world will be holding its breath for on Wednesday, when two LHC collaborations release their results.
 </p>
<p>
  Will they confirm the hints that the Tevatron has seen? Or will these inklings—and our hopes of completing the Standard Model of physics–evaporate into the mist of random fluctuations?
 </p>
<p>
  As Fermilab’s Eric James put it this morning: “We’re likely, after all this time, to find something out one way or the other.”
 </p>
</section>

Bittersweet Victory: Physics After the Higgs

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<p>
  When I see those victorious Olympic athletes all bedecked on the podium, beaming their gold-medal smiles and crying their gold-medal tears, I can’t help thinking:
  <em>
   Now what?
  </em>
</p>
<p>
  And now that the coming-out party for the Higgs (or the Higgs-like boson, if you must) is over—the bubbly popped, the headlines receded—are physicists asking themselves the same question?
 </p>
<p>
  Certainly, physicists are not crying into their champagne. The discovery of a new boson right where the Higgs should be is a scientific tour-de-force. “It confirms, as it completes, the Standard Model of fundamental physics,” Frank Wilczek wrote
  <a "="" 04="" 2012="" blogs="" href="http://www.pbs.org/wgbh/nova/blogs/physics/2012/07/thanks-mom/&lt;/a&gt; on the morning of the announcement. &lt;/p&gt;
&lt;p&gt;And yet, science thrives on observations that &lt;em&gt;don’t&lt;/em&gt; match up with predictions. Dark energy and dark matter, two of the greatest discoveries in a century of astrophysics, were hit upon because of the yawning gap between prediction and observation. If the universe is a puzzle, &lt;a href=" http:="" nova="" physics="" wgbh="" whos-afraid-of-the-dark-alternatives-to-dark-energy="" www.pbs.org="">
   dark energy
  </a>
  and
  <a href="http://www.pbs.org/wgbh/nova/blogs/physics/2012/04/whos-afraid-of-the-dark-alternatives-to-dark-matter/">
   dark matter
  </a>
  are odd-shaped pieces that puckishly refuse to be wedged into place and, in their refusal, open up the possibility that the puzzle is actually richer and more complex than we ever anticipated. The Higgs, on the other hand, snaps right into place with a satisfying “Eureka!”
 </p>
<p>
  But if the puzzle of the Standard Model is now complete, where does that leave physics?
 </p>
<p>
  “There’s this huge looming question: The Standard Model works impeccably, but it leaves a lot of things unexplained,” says David Kaiser, a physicist and science historian at MIT. The Standard Model does not account for gravity, for instance, and it provides no explanation for why the physical constants take the particular values that they do. Like the periodic table of the elements, the Standard Model is an utterly faithful census of the ingredients that make up our universe. But while we know the elegant atomic underpinnings of the motley periodic table, we are still seeking the deeper laws that are expressed in the Standard Model.
 </p>
<p>
  “I always felt the best possible thing for the LHC would be to
  <em>
   not
  </em>
  see the Higgs,” says Peter Woit, a theorist at Columbia University. That would have cracked the Standard Model wide open, perhaps giving scientists a glimpse of the deeper physics underlying it. In this sense, says Woit, “The Standard Model is a victim of its own success.” Though it fails to answer some fundamental questions about out universe, it is so impervious to experimental contradiction—so perfect in its predictions—that physicists may soon find themselves at an impasse.
 </p>
<p>
  “If this is really the Higgs, then we have completed the Standard Model,” says physicist Peter Fisher of MIT. “We have created this model that describes exquisitely the world around us. We could legitimately say that, as a field of endeavor, we’ve done all there is to be done, and ask: Is this a place to stop and reassess?”
 </p>
<p>
  Physicists do have some guesses at what may lie beyond the Standard Model. There’s
  <a href="http://www.pbs.org/wgbh/nova/blogs/physics/2012/07/supersymmetry-looking-in-natures-mirror/">
   supersymmetry
  </a>
  , for one, which suggests that elementary particles have mirror-image “superpartners” that differ in spin. Yet, to the surprise of some physicists, even the LHC has been unable to turn up any evidence of these superpartners. That suggests that, if superpartners are out there, they don’t possess the neat mirror-image symmetry we expected. Instead, the mirror that divides “us” from “them” may be warped.
 </p>
<p>
  “With the Higgs, you knew exactly what to look for,” says Woit. But the mirror of supersymmetry, if it exists, “could be warped in any arbitrary way,” leaving physicists to pursue an almost limitless game of hide-and-seek. And what if the superpartners—or other hints of new physics—are hiding where the LHC can’t find them?
 </p>
<p>
  But the story of the Higgs isn’t over yet. Over the coming months, physicists on the
  <a href="http://cms.web.cern.ch/org/cms-higgs-results">
   CMS
  </a>
  and
  <a href="http://atlas.ch/news/2012/latest-results-from-higgs-search.html">
   ATLAS
  </a>
  teams will look to see whether this thing they have found decays in the ways they expect. Perhaps the new boson will turn out to be not so “vanilla” after all. Historically, it is often the “one last measurement to nail it down” that ends up taking physics in a new direction, Kaiser points out.
 </p>
<p>
  To Nobel prize-winning physicist Frank Wilczek, finding the new boson is just the beginning. “Having won this glorious battle, I’m psyched up for complete victory. We need to see some of the new particles that low-energy supersymmetry predicts. I think that will eventually happen at the LHC.”
 </p>
<p>
  “There is also room for gratuitous, but not perverse, speculation about the Higgs being a ‘portal’ into hidden sectors—hypothetical worlds of particles that have neither strong nor weak nor electromagnetic interactions,” adds Wilczek.
 </p>
<p>
  Yet Steve Ahlen, a Boston University physicist who helped build the ATLAS detector, thinks that the story of the quest for the Higgs has a somewhat different moral: “The most impressive thing about the success of the LHC, CMS and ATLAS is that thousands of people from all over the world, supported by tax dollars from many hundreds of millions of people, achieved success without the promise of fortune, power or fame, but for the simple joy of observing the beautiful world we live in. I think there is an important lesson to be learned from that.”
 </p>
</section>

First Direct Evidence of Cosmic Inflation

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</div>
<p>
  When Alan Guth proposed the theory of
  <a href="http://www.amazon.com/The-Inflationary-Universe-Alan-Guth/dp/0201328402">
   cosmic inflation
  </a>
  almost 35 years ago, he wondered whether it would ever be possible to prove his hypothesis that the universe ballooned up exponentially in the first moments after the Big Bang. There was ample
  <a href="http://wmap.gsfc.nasa.gov/universe/bb_cosmo_infl.html">
   indirect evidence
  </a>
  : the universe’s surprisingly uniform temperature, the apparent “flatness” of spacetime, and the conspicuous absence of magnetic monopoles. In the years that followed, astronomers used satellites like
  <a href="http://www.skyandtelescope.com/news/3311206.html">
   WMAP
  </a>
  and
  <a href="http://www.nature.com/news/planck-snaps-infant-universe-1.12671">
   Planck
  </a>
  to search for echoes of the inflationary era in the cosmic microwave background radiation. Their results lined up with many inflationary predictions, but fell short of being the “smoking gun” that would have had Guth and other theorists popping their champagne.
 </p>
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<p>
  Well, bring on the bubbly: Using a telescope called
  <a href="http://www.cfa.harvard.edu/CMB/bicep2/">
   BICEP2
  </a>
  , a team of astronomers led by John Kovac (Harvard-Smithsonian Center for Astrophysics) has
  <a href="http://bicepkeck.org/b2_respap_arxiv_v1.pdf">
   detected a polarization pattern
  </a>
  in the microwave background radiation that is the first direct evidence for cosmic inflation. This “B-mode” polarization is a “twisty” pattern created by gravitational waves. The discovery is also the first direct image of gravitational waves.
 </p>
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<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/10mspt_mars_h_620.width-990_ZxNKyy9.jpg"/>
<figcaption>The 10-meter South Pole Telescope and the BICEP (Background Imaging of Cosmic Extragalactic Polarization) Telescope at Amundsen-Scott South Pole Station. Credit: Keith Vanderlinde, National Science Foundation
        
    </figcaption>
</figure>
<p>
  The news is generating plenty of buzz.  Here are our picks from some of the best coverage we’ve seen so far:
 </p>
<p>
<strong>
   Nature
  </strong>
  :
  <a href="http://www.nature.com/news/how-astronomers-saw-gravitational-waves-from-the-big-bang-1.14885">
   How astronomers saw gravitational waves from the Big Bang
  </a>
<br/>
  A suite of special coverage, including an explainer on gravitational waves and an interview with John Kovac, who maintains that he, for one, has held off on the champagne:
 </p>
<blockquote>
<p>
   My role in this process has been to remain calm at all times. The time to celebrate, I think, will be once we have published our results and presented them to the scientific community.
  </p>
</blockquote>
<p>
<strong>
   The New York Times
  </strong>
  :
  <a href="http://www.nytimes.com/2014/03/18/science/space/detection-of-waves-in-space-buttresses-landmark-theory-of-big-bang.html">
   Detection of Waves in Space Buttresses Landmark Theory of Big Bang
  </a>
</p>
<p>
  Dennis Overbye talks (or emails) with everyone-who’s-anyone as he traces the history of inflationary theory from its inception in 1979 to its greatest confirmation yet today, closing with the possibility that inflation is continuing elsewhere in the cosmos:
 </p>
<blockquote>
<p>
   Most of the hundred or so models that have been spawned by Dr. Guth’s original vision suggest that inflation, once started, is eternal. Even as our own universe settled down to a comfortable homey expansion with atoms, stars and planets, the rest of the cosmos will continue blowing up, spinning off other bubbles here and there endlessly, a concept known as the multiverse.
  </p>
</blockquote>
<p>
<strong>
   WIRED
  </strong>
  :
  <a href="http://www.wired.com/wiredscience/2014/03/gravitational-waves-b-mode-inflation/">
   Cosmologists Finally Capture an Elusive Signal From the Beginning of Time
  </a>
</p>
<p>
  Adam Mann explains “how primordial B-modes could be so important if you’ve never heard of them” and highlights the need for followup observations to confirm the result:
 </p>
<blockquote>
<p>
   In fact, BICEP’s data is somewhat at odds with other experiments, such as the Planck space telescope, which have carefully mapped the CMB but not seen primordial B-modes. But it’s also possible that these other teams simply missed what BICEP is seeing and, now that they know how to look for the primordial B-modes, can confirm the results fairly quickly using already existing datasets, perhaps within a matter of weeks. No doubt, other collaborations will begin taking new data to try and detect the primordial B-modes on their own.
  </p>
</blockquote>
<p>
<strong>
   Sky and Telescope
  </strong>
  :
  <a href="http://www.skyandtelescope.com/news/Proof-of-Inflationary-Universe-To-Be-Announced-Monday-250522521.html">
   Proof of Inflationary Universe To Be Announced Today?
  </a>
</p>
<p>
  In advance of today’s announcement, Sky and Telescope’s Alan MacRobert rounded up coverage of the search for B-modes and  explained what B-modes are and how gravitational waves create them.
 </p>
</section>

Is Information Fundamental?

<p></p><p>What if the fundamental “stuff” of the universe isn’t matter or energy, but information?</p><p>That’s the idea some theorists are pursuing as they search for ever-more elegant and concise descriptions of the laws that govern our universe. Could our universe, in all its richness and diversity, really be just a bunch of bits?</p><p>To understand the buzz over information, we have to start at the beginning: What is information?</p><p>This is.</p><p>So is an image like this:</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/info_booth_620.width-990_lOAtTkN.jpg"/>
<figcaption>
</figcaption>
</figure>
<p>And an equation like this:</p>
<figure class="richtext-image full-width">
<img alt="" class="richtext-image full-width" src="https://www.pbs.org/wgbh/nova/media/images/equation_wide.width-990_9sPTK6w.jpg"/>
<figcaption>
</figcaption>
</figure>
<p>“It doesn’t matter whether something consists of equations, words, images or sounds—you can encode any of that in strings of zeroes and ones,” or bits, says Scott Aaronson, associate professor of electrical engineering and computer science at MIT. Your computer is doing it right now, using tiny magnets, capacitors, and transistors to store billions or trillions of binary digits. “These might have been hard concepts for people to understand a century ago, but because of the computer revolution, we deal with these concepts all the time,” says Aaronson. In an age when a USB drive dangles from every keychain and an iPhone strains the seams of every pocket, it isn’t such a leap to agree that anything can be expressed in information.</p>
<div class="related"></div>
<p>To some theorists, though, information is more than just a description of our universe and the stuff in it: it is the most basic currency of existence, occupying what theorist Paul Davies terms the “ontological basement” of reality.</p><p>The rules of quantum information provide the most “compact” description of physics, says Vlatko Vedral, professor of quantum information theory at the University of Oxford and the National University of Singapore. “Information, it seems to me, requires fewer assumptions about anything else we could postulate. As soon as you talk about matter and energy, you have to write down the laws that govern matter and energy.”</p><p>Does this mean that our universe is made of information, as some headlines claim?</p><p>“It strikes me as a contentless question,” says Aaronson. “To say that matter and energy are important in physics is to say something with content.” You can imagine a universe barren of matter and energy, after all; specifying that our universe is furnished with both tells you something about it and distinguishes it from other possible universes. “But I don’t know how you could even conceive of a universe” without information, he says.</p><p>Yet, as a fresh way of thinking about, well, what the universe is about, information has touched off provocative work in computer science and theoretical astrophysics, apparently disparate fields that may share a deep link manifested by that cosmic Rosetta stone, the black hole. But before we dive into the black hole, let’s step back to take a deeper look at information itself.</p><p>All messages contain information, but not all messages are created equal. “Unexpected things have high information content,” says Vedral. Take a sunrise, for example. “If the sun rises tomorrow, you won’t see any newspaper writing about it. But of course if it didn’t rise, it would be a major event.”</p><p>We sense intuitively that “surprises,” like a missed sunrise, carry more information than routine events. Claude Shannon, widely considered the father of information theory, formalized this intuition by defining a quantity that’s now known as “Shannon entropy.” The Shannon entropy of a message is related to the sum of the logarithm of the probability of each bit taking on a particular value. That’s a mouthful, but, Vedral explains, it mathematically captures two important features of information: the value of surprises, and the fact that information is “additive”—that is, that the total information contained in two, three, four, or a billion unrelated events is equal to the sum of the information in each one.</p><p>Physicists describe entropy a little differently, often speaking in terms of the “disorder” of a system. More precisely, entropy is the number of different ways you can rearrange the littlest parts of a system and still get the same big system. A bucket full of red Legos, for instance, has high entropy. Shake it up, spin it around, and you still have what you began with: a bucket of red Legos. Assemble those same blocks into a Lego castle, though, and you’ve slashed the entropy; moving a single block nets you a different “macroscopic” system.</p><p>Whichever perspective you choose, the essential result is the same. Take the paragraph you’re reading right now, for instance, with its many different letters, punctuation marks, and spaces arranged in a very particular order. It contains more information, and thus has higher entropy, than a paragraph like this one—</p><p>aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa<br/> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa<br/> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa<br/> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa<br/> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa<br/> aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa<br/> aaaaa</p><p>—even though they contain the same number of characters. Entropy, then, provides a measure of not just the length but the information content of a message.</p><p>Now imagine trying to build the ultimate hard drive, one that holds the maximum amount of information allowed by physics. Why should physics place a limit on the information storage capacity of this hypothetical hard drive? Thinking it over from a purely classical perspective, it seems that you could store an infinite amount of information. But when we add quantum mechanics to the mix, we introduce fundamental limits on the accuracy of our measurements. These limits cause entropy to max out at about 10 69 bits per square meter. “If you tried to pack information more densely than that,” says Aaronson, “your hard drive would collapse into a black hole.” That’s not just a whimsical footnote. Black holes, it turns out, are the universe’s very best information repositories. (Of course, Aaronson points out, they don’t make very practical hard drives, unless you’re willing to wait about 10 70 years to retrieve your data.)</p><p>But there’s something odd about the way the entropy of a black hole grows. As physicists Stephen Hawking and Jacob Bekenstein discovered in the 1970s, the entropy of a black hole increases with the black hole’s two-dimensional surface area, as defined by an imaginary spherical shell with radius <a href="http://en.wikipedia.org/wiki/Schwarzschild_radius">R s</a> . This is bizarre; you would expect the amount of information you can pack into any object, like a book or a hard drive, to grow with the three-dimensional volume of the object, not its surface area.</p><p>This discrepancy is more than just theoretical arcana. To physicists, it suggests that the fundamental laws of physics may have a simpler representation in two dimensions rather than the traditional three. In 1997, the Argentinian physicist Juan Maldacena, now at the Institute for Advanced Study, took advantage of this idea to work out a mathematical “duality” between our universe and one with fewer dimensions, one time dimension, and no gravity. This provides a handy mathematical back door; problems that are difficult to solve in one domain may shake out easily in the other.</p>
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<p>To some theorists, the duality isn’t just mathematical. The universe as we experience it, they say, may actually be the projection of information encoded on some distant cosmic boundary. Where this boundary lies and how the projection occurs are still open questions, but these theorists argue that our reality may be, in essence, a hologram analogous to the silvery images on museum store postcards.</p><p>We have information theory to thank for this peculiar plot twist. But if it’s hard to imagine a practical application for this “ <a href="http://www.pbs.org/wgbh/nova/blogs/physics/2011/11/holograms-black-holes-and-the-nature-of-the-universe/">holographic principle</a> ,” it’s far easier to see how quantum information is changing computing. That’s because quantum information has different basic properties from classical information. The bits that make up classical information can be either one or zero. But the “qubits” that make up quantum information can exist in a superposition of the “one” and “zero” states; in a sense, they can take on both states at once. To maintain this superposition, though, qubits must exist in perfect isolation. As soon as that isolation is disturbed, the superposition crumbles.</p><p>“Quantum information is like the information in a dream,” explained Charles Bennett, a quantum information scientist at IBM Research, in a recent talk at the annual meeting of the American Association for the Advancement of Science. “In describing it, you change you memory of it.” This may not sound like a desirable quality in a computer, but in combination with entanglement, it can be exploited to dramatically speed up certain types of calculations and to send perfectly secure encrypted messages. As Steve Girvin, a theoretical physicist at Yale University, points out, it can also be used to generate genuinely random numbers suitable for encryption keys. Quantum cryptography is already being used commercially for some bank transfers and other highly secure transmissions.</p><p>“This second quantum revolution—the revolution of information—is a complete surprise,” says Girvin. “It took decades to come to grips with the weirdness and realize that the information of quantum mechanical systems is different than the information content of classical systems, and being uncertain about something can actually be good instead of bad.”</p>
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<p>Quantum information is useful stuff—but what is it telling us about the essential nature of our reality? Some thinkers argue that it suggests our entire universe is itself a quantum computer. “I like this image,” says Vedral, while admitting that the analogy is imperfect. “You could ask, can I treat the rest of the universe as something that I can program in the way that I program my [ordinary] computer?” No, says Vedral. “You’re still limited by the laws of physics, and you have a certain amount of resources which are finite. There are computations you will never be able to execute.” The computation at which this cosmic quantum computer is uniquely capable is that of computing its own evolution.</p><p>Whether information is a useful strategy of thought or something deeper, we still don’t know. “We’re still struggling with what our theories are really telling us,” says Vedral. “You have to take a leap of imagination.”</p><p><b>Go Deeper</b><br/> <i>Editor’s picks for further reading</i></p><p>arXiv: <a href="http://arxiv.org/abs/quant-ph/0110141">Computational capacity of the universe</a> Treating the entire universe as a computer, MIT “quantum mechanic” Seth Lloyd derives the information storage and operational limits of the universe.</p><p>FQXi: <a href="http://www.fqxi.org/community/essay/winners/2013.1">It From Bit or Bit From It?</a><br/> Read prize-winning essays from the Foundational Questions Institute’s 2013 essay contest on the theme of information and its role in reality.</p><p><a href="http://www.amazon.com/Information-Nature-Reality-Physics-Metaphysics/dp/0521762251">Information and the Nature of Reality</a><br/> With contributions from physicists, philosophers, theologians, and biologists, this volume of essays looks at the meaning and significance of information from multiple perspectives.</p>

<p>Could information be the fundamental &quot;stuff&quot; of the universe?</p>

Kate Becker

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