Fixed: Dot product symbol used instead of fullstop (#1031)

Co-authored-by: Paul Nation <nonhermitian@gmail.com>

Author: TanveshT

tutorials/simulators/1_aer_provider.ipynb

@@ -452,10 +452,10 @@
    "source": [
     "### Setting a custom initial unitary\n",
     "\n",
-    "We may also set an initial state for the `UnitarySimulator`, however this state is an initial *unitary matrix* $U_i$, not a statevector. In this case the returned unitary will be $U.U_i$ given by applying the circuit unitary to the initial unitary matrix.\n",
+    "We may also set an initial state for the `UnitarySimulator`, however this state is an initial *unitary matrix* $U_i$, not a statevector. In this case the returned unitary will be $U \\cdot U_i$ given by applying the circuit unitary to the initial unitary matrix.\n",
     "\n",
     "**Note:**\n",
-    "* The initial unitary must be a valid unitary matrix $U^\\dagger.U =\\mathbb{1}$. If not, an exception will be raised. \n",
+    "* The initial unitary must be a valid unitary matrix $U^\\dagger \\cdot U =\\mathbb{1}$. If not, an exception will be raised. \n",
     "* If a `Qobj` contains multiple experiments, the initial unitary must be the correct size for *all* experiments in the `Qobj`, otherwise an exception will be raised.\n",
     "\n",
     "Let us consider preparing the output unitary of the previous circuit as the initial state for the simulator:"
@@ -604,4 +604,4 @@
  },
  "nbformat": 4,
  "nbformat_minor": 2
-}
+}