Backend Snapshots

Nexus stores a snapshot - a representation of the state of a backend - when important events take place, including compilation and execution.

Unlike a backend, which is a provider of quantum or other computation, a backend snapshot stores data about a provider at a certain moment in time.

Nexus captures and stores backend snapshots automatically and associates them with relevant resources such as compilation jobs or execution jobs. You can see all the backend snapshots in a project on its “Resources” tab, or for an individual result or compilation, linked from the result or compilation page itself.

In python code, backend snapshots are often represented as instances of pytket’s BackendInfo class. For example, an execution result in qnexus is represented by an ExecutionResultRef instance, whose download_backend_info() method returns a pytket BackendInfo representing the state of the compute provider at the time of execution.