Differentiating D3 brane worldvolume theories with NS5 brane and NS5 antibrane boundary conditions - Physics Stack Exchange most recent 30 from physics.stackexchange.com 2019-07-22T23:39:29Z https://physics.stackexchange.com/feeds/question/452839 http://www.creativecommons.org/licenses/by-sa/3.0/rdf https://physics.stackexchange.com/q/452839 1 Differentiating D3 brane worldvolume theories with NS5 brane and NS5 antibrane boundary conditions Mtheorist https://physics.stackexchange.com/users/110206 2019-01-08T05:16:04Z 2019-01-08T08:50:39Z <p>In <a href="https://arxiv.org/abs/0804.2902" rel="nofollow noreferrer">'Supersymmetric Boundary Conditions in N=4 Super Yang-Mills Theory'</a>, Gaiotto and Witten derive boundary conditions for the worldvolume theory of the D3 brane. In particular the boundary conditions (see pages 8-10) on the fermionic field <span class="math-container">$\Psi$</span> is <span class="math-container">$\Gamma_3\Psi=\Psi' \otimes \vartheta$</span> where <span class="math-container">$\Psi'$</span> transforms under the boundary Lorentz and R-symmetry, while <span class="math-container">$$\vartheta= \begin{pmatrix} a \\ 1\end{pmatrix},$$</span> up to scaling.</p> <p>It is stated later on below equation (4.32) that the choices <span class="math-container">$a=\infty$</span> and <span class="math-container">$a=0$</span> correspond to NS5-brane and NS5-antibrane boundary conditions. </p> <p>My question is, how does one discern which value of <span class="math-container">$a$</span> corresponds to NS5-brane or NS5-antibrane? Can this even be determined, or is the notion of brane and antibrane only defined relative to each other in this case?</p>