diff --git a/src/tequila/quantumchemistry/qc_base.py b/src/tequila/quantumchemistry/qc_base.py
index c6f6b36d..369073c3 100644
--- a/src/tequila/quantumchemistry/qc_base.py
+++ b/src/tequila/quantumchemistry/qc_base.py
@@ -1639,7 +1639,7 @@ def rdm2(self):
 
     def compute_rdms(self, U: QCircuit = None, variables: Variables = None, spin_free: bool = True,
                      get_rdm1: bool = True, get_rdm2: bool = True, ordering="dirac", use_hcb: bool = False,
-                     rdm_trafo: QubitHamiltonian = False):
+                     rdm_trafo: QubitHamiltonian = None):
         """
         Computes the one- and two-particle reduced density matrices (rdm1 and rdm2) given
         a unitary U. This method uses the standard ordering in physics as denoted below.