:py:mod:`kosmos.quantum_logic.quantum_register_manager`
=======================================================

.. py:module:: kosmos.quantum_logic.quantum_register_manager






Module Attributes
-----------------

.. py:data:: BELL_PAIR_QUBITS
   :value: 2


.. py:data:: MIN_FIDELITY_THRESHOLD
   :value: 0.25





Classes
-------

.. py:class:: QuantumRegisterManager(network: kosmos.topology.net.Network)


   Manager for quantum logic in the network.

   This manager handles all qubits, entanglements and quantum states in the system.


   Initialize quantum register manager.

   :param network: The network topology.
   :type network: Network





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   .. rubric:: Methods

   .. py:method:: allocate_qubit(*, node: kosmos.topology.typing.NodeReference, qubit_id: kosmos.quantum_logic.qubit.QubitId | str, qubit_type: kosmos.quantum_logic.qubit.QubitType = QubitType.COMMUNICATION) -> kosmos.quantum_logic.qubit.Qubit

      Allocate a new qubit in the system for a given node and type.

      :param node: Reference to the node where the qubit resides.
      :type node: NodeReference
      :param qubit_id: Identifier for qubit.
      :type qubit_id: QubitId | str
      :param qubit_type: Type of qubit to allocate. Defaults to Communication qubit.
      :type qubit_type: QubitType

      :returns: The newly created and registered qubit.
      :rtype: Qubit


   .. py:method:: move_qubit(qubit: kosmos.quantum_logic.typing.QubitReference, new_node: kosmos.topology.typing.NodeReference) -> None

      Allocate qubit to a new node.

      :param qubit: Qubit reference of the qubit to be moved.
      :type qubit: QubitReference
      :param new_node: Reference to the node to which qubit is to be moved.
      :type new_node: NodeReference


   .. py:method:: remove_qubit(qubit: kosmos.quantum_logic.typing.QubitReference) -> None

      Remove qubit and corresponding state.

      :param qubit: Reference of the qubit to be removed.
      :type qubit: QubitReference


   .. py:method:: add_single_qubit_state(qubit: kosmos.quantum_logic.typing.QubitReference, state: kosmos.quantum_logic.quantum_state.QuantumState) -> None

      Add or update the state of a single qubit.

      If the qubit is part of a single-qubit state, update it.
      If the qubit is part of a multi-qubit state, raise an error.

      :param qubit: The qubit to assign the state to.
      :type qubit: QubitReference
      :param state: The QuantumState for the qubit.
      :type state: QuantumState


   .. py:method:: get_qubits_by_node(node: kosmos.topology.typing.NodeReference) -> list[kosmos.quantum_logic.qubit.QubitId]

      Get all qubits located at a specific node.

      :param node: Reference to the node.
      :type node: NodeReference

      :returns: QubitIds allocated at certain node.
      :rtype: list[QubitId]


   .. py:method:: add_entanglement(entanglement: kosmos.quantum_logic.entanglement_link.EntanglementLink, state: kosmos.quantum_logic.quantum_state.QuantumState) -> None

      Add entanglement to state system manager.

      If the qubits are part of single-qubit states, remove them.
      If the qubits are part of multi-qubit states, raise an error.

      :param entanglement: The entanglement we want to add to the system.
      :type entanglement: EntanglementLink
      :param state: The according QuantumState we want to add to the system.
      :type state: QuantumState


   .. py:method:: remove_entanglement(qubits: list[kosmos.quantum_logic.typing.QubitReference]) -> None

      Remove entanglement from system.

      :param qubits: The list of qubits we want to remove.
      :type qubits: list[QubitReference]


   .. py:method:: allocate_bell_pair(nodes: list[kosmos.topology.typing.NodeReference], qubit_ids: list[kosmos.quantum_logic.qubit.QubitId | str], current_time: int = 0, fidelity: float = 1.0) -> None

      Allocates two new communication qubits and a Bell state.

      :param nodes: References of the nodes.
      :type nodes: list[NodeReference]
      :param qubit_ids: Identifier of qubits.
      :type qubit_ids: list[QubitId | str]
      :param current_time: Time of Bell pair generation. Defaults to 0.
      :type current_time: int
      :param fidelity: Fidelity of the entangled state. Defaults to 1.0.
      :type fidelity: float


   .. py:method:: get_partial_trace(state: kosmos.quantum_logic.quantum_state.QuantumState, keep: list[int], dims: list[int]) -> kosmos.quantum_logic.quantum_state.QuantumState

      Retrieve state of a subsystem.

      :param state: Quantum state we want to retrieve the substate from.
      :type state: QuantumState
      :param keep: List of indices of qubits to keep.
      :type keep: list[int]
      :param dims: Dimension for subsystem.
      :type dims: list[int]

      :returns: The quantum state for specific qubit or qubits.
      :rtype: QuantumState


   .. py:method:: get_state(qubits: list[kosmos.quantum_logic.typing.QubitReference], *, return_partial_state: bool | None) -> kosmos.quantum_logic.quantum_state.QuantumState | None

      Retrieve (specific) state from system.

      If return_partial_state = True we return only the state of the input subsystem.

      :param qubits: Qubits we want to receive the state from.
      :type qubits: list[QubitReference]
      :param return_partial_state: Whether a substate is returned or not.
      :type return_partial_state: bool | None

      :returns: The quantum state for the specified qubits, or None if not found.
      :rtype: QuantumState or None