Fixed index in GEVP example (#261)

Co-authored-by: Fabian Joswig <fjosw@users.noreply.github.com>

Author: JanNeuendorf

examples/06_gevp.ipynb

@@ -151,7 +151,7 @@
     "\n",
     "$$C_{\\textrm{projected}}(t)=v_1^T \\underline{C}(t) v_2$$\n",
     "\n",
-    "If we choose the vectors to be $v_1=v_2=(0,1,0,0)$, we should get the same correlator as in the cell above. \n",
+    "If we choose the vectors to be $v_1=v_2=(1,0,0,0)$, we should get the same correlator as in the cell above. \n",
     "\n",
     "Thinking about it this way is usefull in the Context of the generalized eigenvalue problem (GEVP), used to find the source-sink combination, which best describes a certain energy eigenstate.\n",
     "A good introduction is found in https://arxiv.org/abs/0902.1265."