diff --git a/benchmark_tn.py b/benchmark_tn.py
index 6dae804..ced185d 100644
--- a/benchmark_tn.py
+++ b/benchmark_tn.py
@@ -128,7 +128,7 @@ def run_quimb_tn_statevector(circuit, nqubits, num_slices, load_path=None, save_
             print(f"  [path saved]  {save_path}")
 
     t0 = time.time()
-    sv = qc.to_dense(optimize=tree,implementation="cotengra").reshape(-1)
+    sv = qc.to_dense(optimize=tree).reshape(-1)
     t_contract = time.time() - t0
     print(f"  [contraction]  {t_contract:.3f}s")
     sv_tn = np.array(sv)