LAGRANGE documentation

This is the public documentation page for the Lagrange quantum computer managed by Fondazione LINKS and hosted at Politecnico di Torino, as part of the L-QCS initiative, also involving the Italian National Institute of Metrology.

Status

The status of the various components of the machine and the software stack is reported in the status page.

Machine and QPU Specifications

Lagrange is based on the IQM Spark superconducting quantum computer. The system and its QPU are described in detail in the paper:

"On-premises superconducting quantum computer for education and research", EPJ Quantum Technology, 2024. DOI: 10.1140/epjqt/s40507-024-00243-z

QPU

Parameter	Value
Qubit count	5 transmon qubits
Topology	Star — 1 central qubit (QB3) connected to 4 peripheral qubits (QB1, QB2, QB4, QB5)
Coupling	4 tunable couplers
Two-qubit gate	CZ gate

Gate fidelities

Metric	Typical	Minimum spec
Single-qubit gate fidelity	≥ 99.9 %	≥ 99.7 %
Two-qubit (CZ) gate fidelity	≥ 99.0 %	≥ 98.0 %
Readout fidelity	≥ 97 %	≥ 95 %

Gate durations

Gate	Typical	Maximum spec
Single-qubit	≤ 20 ns	≤ 40 ns
Two-qubit (CZ)	≤ 60 ns	≤ 100 ns

Architecture and access

The machine can be accessed through the standard IQM clients, and it is possible to refer to the official documentation for IQM OS 4.6.

An overview of the access architecture is available here.

Usage

Here you can find the machine usage documentation.

Projects, budget and billing

To run a job on the machine, the user must be part of a project with non-zero budget. Moeover, exclusive reservations may be in place. Refer to the portal guide for the details. The portal itself can be found at dashboard.quantum.linksfoundation.com.

Machine Monitoring

Here you can find some dashboards that report relevant machine metrics.

Citation

Use of Lagrange should be acknowledged by referencing:

Viviani, Paolo, et al. "Lagrange: Operating Italy's First Publicly-Accessible Quantum Computer for Research and Education." arXiv preprint arXiv:2604.21695 (2026).