Emulator backends

QX Emulator

Quantum Inspire offers a powerful quantum computer emulator backend: QX.

QX Emulator is a quantum computer emulator that can simulate up to 34 qubits (on the Lisa supercomputer) on a classical computer setup. It can execute quantum circuits and allows inspection of the simulated quantum state.

QX uses vector state representation of the qubit states. All qubits can be in full superposition and any arbitrary rotation can be applied to the qubits, thus supporting both Clifford gates and non-Clifford gates.

Emulator versions

Quantum Inspire offers three different instances of the QX Emulator. They vary in terms of turn-around time and available resources. They are hosted on succinct platforms:

QX single-node emulator

This version of QX runs on a commodity cloud-based server, with 4GB RAM. It has a fast turn-around time for simulations up to 26 qubits. For basic users, the commodity cloud-based server will be sufficient.

QX emulator on Cartesius SurfSara Backend (QX-31)

This QX Emulator instance on the Cartesius single-node computer uses the Knights Landing partition (knl) of SurfSara. With 96GB of memory, this allows simulation jobs of up to 31 qubits.

QX emulator on Lisa SurfSara Backend (QX-34-L)

This QX Emulator instance on the Lisa cluster computer uses four nodes of the fat_soil_shared partition of Lisa. With 1.5TB of memory each, this allows simulation jobs of up to 34 qubits.

Waiting time considerations

SurfSara supports the Dutch scientific community by providing advanced ICT infra-structure and hosts the Dutch national supercomputer Lisa. QuTech is collaborating with SurfSara to make it possible to simulate more qubits. Because the supercomputer infra-structure is shared with the entire Dutch scientific community, simulations have to wait in line. The time a simulation has to wait depends on the number of other users that want to use supercomputer resources, and can vary from minutes to hours.

For small jobs, this wait time will dominate the total turn-around time. For such jobs the commodity hardware instance (QX single-node emulator) is better suited. For larger jobs the wait time is offset by the faster execution time. For even larger jobs, the commodity hardware won’t run those jobs at all and the wait time is inevitable.

Waiting times on the SurfSara backends (QX emulator on Cartesius or Lisa) vary from minutes to hours, depending on overall usage patterns on the supercomputer.

Choosing a emulator instance depends largely on the number of qubits that need to be simulated. Larger jobs require more resources. More resources means longer wait times to acquire the required resources.

Single-node commodity hardware

Waiting time: seconds to minutes
Maximum number of qubits: 26

Cartesius SurfSara single-node backend (QX-31)

Waiting time: minutes to hours
Maximum number of qubits: 31

Lisa SurfSara cluster backend (QX-34-L)

Waiting time: minutes to hours
Maximum number of qubits: 34

Note that the waiting time is a combination of execution time and scheduling/queueing time.

More information

The following links provide more information about QX and cQASM, the Quantum Assembly Language that is used by QX: