Abstract: A quantum element (QE) at a network node stores a first quantum state constituent (QSC) of an entangled quantum state characterized by a non-factorable quantum relationship among QSCs comprising the first QSC and a second QSC stored at another QE at another network node. Managing one or more quantum error management (QEM) operations includes: (1) providing a schedule for the QEM operations that is based at least in part on at least a portion of a time over which the first QSC is stored at the first QE and an estimated fidelity of the entangled quantum state after at least one of the QEM operations, or (2) providing a type of one or more QEM operations selected from two or more different types based at least in part on a number of resource quantum elements available at the first node after the first QSC is stored at the first QE.

Abstract: A first message is sent from a first node in a network indicating that a first quantum element at the first node is entangled with a second quantum element at a second node in the network. The first message comprises a first estimate of a fidelity of entanglement between the first and second quantum elements, and a timestamp indicating a time associated with the first estimate. Based at least in part on the first message, a second estimate of a fidelity of the entanglement between the first and second quantum elements is generated, at a second time after the time indicated by the timestamp, and is compared to each of multiple thresholds. At least a first (second) action is performed in response to a result of comparing the second estimate to a first (second) threshold.

Abstract: At a first node in a network, a first (second) message is received indicating that a first (second) quantum element at the first node is entangled with a quantum element at a second (third) node in the network. The first (second) message comprises a first (second) identifier that uniquely identifies one of a plurality of entanglement generation operations between the first and second (third) nodes over a first time period. At the first node, a third identifier is generated that identifies an entanglement resulting from an entanglement swap operation based on the entangled quantum elements at the first and second nodes and the entangled quantum elements at the first and third nodes. At least a portion of the first identifier is included in the third identifier, and at least a portion of the second identifier is included in the third identifier.

Abstract: A first (second) message is sent from a controller in a network to a first (second) node in the network. The first (second) message comprises at least a portion of scheduling information that specifies a procedure to be executed for scheduling entanglement swap operations associated with portions of a plurality of paths through nodes in the network. At least a portion of the procedure is executed at the first node based at least in part on the first message and information associated with one or more previous attempts to establish entanglement between nodes on a first path that includes the first node. At least a portion of the procedure is executed at the second node based at least in part on the second message and information associated with one or more previous attempts to establish entanglement between nodes on a second path that includes the second node.

Abstract: Qubit allocation for noisy intermediate-scale quantum computers is provided. A quantum circuit comprises a plurality of logical qubits. A hardware specification comprising a connectivity graph of a plurality of physical qubits. A directed acyclic allocation graph is determined based on the plurality of logical qubits and the connectivity graph. The allocation graph comprises a node for each possible allocation of the plurality of logical qubits to the plurality of physical qubits, each allocation having a fidelity, and a plurality of directed edges, each edge connecting to its corresponding first node from its corresponding second node, the first node corresponding to a first allocation, the second node corresponding to a sub-allocation of the first allocation. The allocation graph is searched for a weighted shortest path from a root node of the allocation graph to a leaf node of the allocation graph. The allocation corresponding to the weighted shortest path is outputted.

Abstract: Qubit allocation for noisy intermediate-scale quantum computers is provided. In various embodiments, a description of a quantum circuit is received. The quantum circuit comprises a plurality of logical qubits. A hardware specification is received. The hardware specification comprises a connectivity graph of a plurality of physical qubits. A directed acyclic allocation graph is determined based on the plurality of logical qubits and the connectivity graph. The allocation graph comprises a node for each possible allocation of the plurality of logical qubits to the plurality of physical qubits, each allocation having a fidelity, and a plurality of directed edges, each edge connecting to its corresponding first node from its corresponding second node, the first node corresponding to a first allocation, the second node corresponding to a sub-allocation of the first allocation.