Branes, Qubits and black holes....

[docm]

<h1><font size="3"><font size="2"><font size="3"><font size="2">PhysOrg article...</font>&nbsp;</font></font></font></h1><p><strong>Quote:</strong></p><h1><font size="3">Qubits and Branes Share Surprising Features</font></h1><div id="author"><br /><img src="http://sitelife.space.com/ver1.0/Content/images/store/2/4/c24e140d-c5fb-46be-b44d-34692104f53b.Medium.png" alt="" /><br />&nbsp;</div><div class="snp_img"><div class="txtSub">(Left) A simulated view of a black hole, and (right) a qubit representation. Credit for black hole: Ute Kraus, physics education group, Theoretische Astrophysik T&uuml;bingen, Space Time Travel</div></div><div><strong>What do black holes and entangled particles have in common? Until about a year ago, physicists thought that the two entities existed in completely separate worlds. Then, in 2007, physicist Michael Duff from Imperial College London demonstrated a correlation between the entanglement of three qubits and the entropy of a black hole. In the past year, several studies have demonstrated even more connections.</strong></div><div></div><div></div><div><span>Most recently, Duff and colleagues from Imperial College London and the Institute for Research in Fundamental Sciences in Tehran, Iran, have discovered another correlation. They&rsquo;ve shown that the &ldquo;branes&rdquo; in string theory mathematically correlate to the qubits in quantum information theory. Their study, titled &ldquo;Wrapped Branes as Qubits,&rdquo; is published in a recent issue of <em>Physical Review Letters</em>. </span></div><div><span><br /><div>&ldquo;These relations between black holes and qubits are still mysterious,&rdquo; Duff told <em>PhysOrg.com</em>. &ldquo;The significance of this recent paper is that, by invoking branes wrapping around the extra dimensions, it resolved the puzzle of why black holes should display any kind of two-valuedness: &lsquo;To wrap or not to wrap; that is the qubit.&rsquo;&rdquo; <br /><br />In string theory, which requires extra dimensions, branes are theoretical objects that can be used to describe parts of the universe on a quantum scale. For instance, black holes can be described by four D3-branes intersecting at an angle, which can be useful for understanding the microscopic origins of black hole entropy. <br /><br />In the current study, the researchers have shown that four D3-branes can also be wrapped around the six extra dimensions of space (that exist in 10-dimensional string theory) in a way that closely resembles an entangled three-qubit state. <br /><br />As the physicists explained, the way that each D3-brane can wrap one way or the other around dimensions resembles the two states that a qubit can have. The researchers showed that a similar correlation exists between M2-branes, which can wrap in one of three ways around dimensions, and qutrits, which have three possible states. <br /><br />To mathematically demonstrate this connection, the physicists used a well-known fact from quantum information theory: a three-qubit state can be described by five parameters (four real numbers and an angle). They showed how these five parameters correspond to the four D3 branes and the branes&rsquo; angle of intersection. <br /><br />The work adds to a growing body of papers published in the past year on correlations between entanglement and black holes (or quantum gravity). As the physicists described, these papers are building a kind of dictionary of translations between phenomena in one language to the phenomena in the other. <br /><br />&ldquo;When two very different areas of physics share the same mathematics, one can learn new things about each field by borrowing techniques from the other,&rdquo; Duff said. &ldquo;This has been a two-way pay-off and we are certain that yet more correlations will be discovered.&rdquo; <br /><br />However, no one yet knows whether there are any physical reasons underlying these mathematical coincidences. As Duff said, &ldquo;an underlying physical basis, if it exists, would be an extra bonus.&rdquo; <br /><br />Still, understanding the mathematical correlations could be enough to lead to some interesting applications in quantum information theory. <br /><br />&ldquo;The weird kind of numbers known as octonions have fascinated both mathematicians and physicists for decades,&rdquo; Duff said. &ldquo;But in their recent books, both Roger Penrose and Ray Streater have written them off as &lsquo;lost causes in physics' because they have so far failed to find any application. However, we believe that the tripartite entanglement of seven qubits (inspired by stringy black holes) provides a way of testing octonions in the laboratory, and this might find applications in QI, for example, in cryptography.&rdquo; <br /><br /><u>More information:</u> Borsten, L.; Dahanayake, D.; Duff, M. J.; Ebrahim, H.; and Rubens, W. &ldquo;Wrapped Branes as Qubits.&rdquo; <em>Physical Review Letters</em> 100, 251602 (2008). </div></span></div> <div class="Discussion_UserSignature"> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>...More information: Borsten, L.; Dahanayake, D.; Duff, M. J.; Ebrahim, H.; and Rubens, W. &ldquo;Wrapped Branes as Qubits.&rdquo; Physical Review Letters 100, 251602 (2008). <br />Posted by docm</DIV></p><p>Here is the&nbsp; paper</p><p>http://arxiv.org/PS_cache/arxiv/pdf/0802/0802.0840v2.pdf<br /></p> <div class="Discussion_UserSignature"> </div>