The machines: differences and a few details

The three machines are genuinely different, in ways that change what a circuit even looks like. Please check the following table for details, and the white paper on Zenodo.

Euro-Q-Exa

VLQ

Piast-Q

Technology

Superconducting

Superconducting

Trapped ion

Qubits available

54

24

20

Connectivity

Square lattice

Star, through one resonator

All to all

Native gates

r, cz

prx, cz, move

RZ, R, RXX

What you send

An abstract circuit; the site maps it

Native gates, mapped to physical qubits

Native gates, mapped to physical qubits

Authentication

Bearer token from a portal

Federated identity token

API key header

Time is billed in

Wall-clock QPU seconds

Device execution time

Device time, including ion loading

Access shape

One REST call

Two jobs

One REST call

The row that matters most is what you send. On Euro-Q-Exa you can send an abstract circuit and the site maps it for you. On the other two you must send native gates, already mapped to physical qubits. The same Bell pair is three different objects.

Note

The billing row is expanded in “QPU hours” on the devices. How the machines sit alongside classical HPC is in HPC and HPC-QC.

What you send, and where

Block diagram with three lanes, one per machine. Euro-Q-Exa, superconducting lattice, an abstract circuit in OpenQASM, one REST call with a bearer token, the site transpiles, then the machine. VLQ, superconducting star, job 1 initialises the backend, the native, mapped circuit is staged as a file into job 2, job 2 executes, then the machine. Piast-Q, trapped ions, a native gate list with angles in units of pi, one REST call with an API key header, the site broker, then the machine.

What you send and where you send it, for each of the three machines.

Note

The star topology. On VLQ every two-qubit gate locus is (qubit, resonator); there is no qubit-to-qubit coupling at all. An entangling operation between two qubits is a MOVE of one qubit’s state into the resonator, a CZ between the resonator and the other qubit, and a MOVE back. Since that site does not transpile for you, the MOVEs have to be in the circuit you send, whether you write them or a compiler inserts them. Any depth estimate you carried over from a lattice machine will not hold.

For the design, see the IQM Star paper and IQM’s MOVE gate.

Official pages