diff --git a/nifty6/minimization/quadratic_energy.py b/nifty6/minimization/quadratic_energy.py
index 7911910b19f484a4a30ae315f2010c729c4238a9..f921caa30f35a258275f9ecc161c186a08440c14 100644
--- a/nifty6/minimization/quadratic_energy.py
+++ b/nifty6/minimization/quadratic_energy.py
@@ -34,9 +34,9 @@ class QuadraticEnergy(Energy):
         else:
             Ax = self._A(self._position)
             self._grad = Ax if b is None else Ax - b
-        self._value = 0.5*self._position.s_vdot(Ax)
+        self._value = 0.5*self._position.s_vdot(Ax).real
         if b is not None:
-            self._value -= b.s_vdot(self._position)
+            self._value -= b.s_vdot(self._position).real
 
     def at(self, position):
         return QuadraticEnergy(position, self._A, self._b)