diff --git a/src/qibotn/backends/cpu.py b/src/qibotn/backends/cpu.py
deleted file mode 100644
index ce4a3c7..0000000
--- a/src/qibotn/backends/cpu.py
+++ /dev/null
@@ -1,83 +0,0 @@
-from qibo.backends.numpy import NumpyBackend
-from qibo.config import raise_error
-from qibo.states import CircuitResult
-
-
-class QuimbBackend(NumpyBackend):
-    def __init__(self, runcard):
-        super().__init__()
-        import quimb  # pylint: disable=import-error
-
-        if runcard is not None:
-            self.MPI_enabled = runcard.get("MPI_enabled", False)
-            self.NCCL_enabled = runcard.get("NCCL_enabled", False)
-            self.expectation_enabled = runcard.get("expectation_enabled", False)
-
-            mps_enabled_value = runcard.get("MPS_enabled")
-            if mps_enabled_value is True:
-                self.MPS_enabled = True
-            elif mps_enabled_value is False:
-                self.MPS_enabled = False
-            else:
-                raise TypeError("MPS_enabled has an unexpected type")
-
-        else:
-            self.MPI_enabled = False
-            self.MPS_enabled = False
-            self.NCCL_enabled = False
-            self.expectation_enabled = False
-
-        self.name = "qibotn"
-        self.quimb = quimb
-        self.platform = "qutensornet"
-        self.versions["quimb"] = self.quimb.__version__
-
-    def apply_gate(self, gate, state, nqubits):  # pragma: no cover
-        raise_error(NotImplementedError, "QiboTN cannot apply gates directly.")
-
-    def apply_gate_density_matrix(self, gate, state, nqubits):  # pragma: no cover
-        raise_error(NotImplementedError, "QiboTN cannot apply gates directly.")
-
-    def assign_measurements(self, measurement_map, circuit_result):
-        raise_error(NotImplementedError, "Not implemented in QiboTN.")
-
-    def set_precision(self, precision):
-        if precision != self.precision:
-            super().set_precision(precision)
-
-    def execute_circuit(
-        self, circuit, initial_state=None, nshots=None, return_array=False
-    ):  # pragma: no cover
-        """Executes a quantum circuit.
-
-        Args:
-            circuit (:class:`qibo.models.circuit.Circuit`): Circuit to execute.
-            initial_state (:class:`qibo.models.circuit.Circuit`): Circuit to prepare the initial state.
-                If ``None`` the default ``|00...0>`` state is used.
-
-        Returns:
-            xxx.
-        """
-
-        import qibotn.eval_qu as eval
-
-        if self.MPI_enabled == True:
-            raise_error(NotImplementedError, "QiboTN quimb backend cannot support MPI.")
-        if self.NCCL_enabled == True:
-            raise_error(
-                NotImplementedError, "QiboTN quimb backend cannot support NCCL."
-            )
-        if self.expectation_enabled == True:
-            raise_error(
-                NotImplementedError, "QiboTN quimb backend cannot support expectation"
-            )
-
-        state = eval.dense_vector_tn_qu(
-            circuit.to_qasm(), initial_state, is_mps=self.MPS_enabled, backend="numpy"
-        )
-
-        if return_array:
-            return state.flatten()
-        else:
-            circuit._final_state = CircuitResult(self, circuit, state.flatten(), nshots)
-            return circuit._final_state