Quantinuum Emulators¶
To support quantum algorithm development and design, emulators are available that model each machine’s specific ion transport and error rates. The emulators operate on a physical model as well as include a detailed error model of each Quantinuum quantum computer. In addition, options are provided to the user to experiment with the noise parameters of the emulator. The workflow to access is here.
Use Cases¶
Quantinuum emulators provide high-fidelity emulation of Quantinuum quantum computers. Use cases include:
Debugging of quantum code before running on Quantinuum hardware
Optimization of quantum code in the presence of noise mechanisms
Exploring new algorithms and techniques for quantum error correction
Introduction to Quantinuum quantum computers’ unique differentiating capabilities such as qubit reuse after mid-circuit measurement, all-to-all connectivity, and high-fidelity gates
Emulator Access and Output¶
Direct communication with Quantinuum end points occurs via API endpoints based on the Quantum Intermediate Representation (QIR) or OpenQASM 2.0. The documentation on this website details examples in pytket and qnexus[1].
Quantinuum emulators are designated with the E, LE or Emulator suffix machine name. The output of a Quantinuum emulator is identical to the output format of Quantinuum quantum computers.
Features¶
Common features across all Quantinuum emulators:
TKET supported in the stack provides circuit optimization to all submitted circuits.
OPENQASM 2.0 circuits
Quantinuum QASM enhancements, including classical logic, math, and program flow control
Common compound gates from OPENQASM library, e.g., CX, H
User-defined compound gates
High fidelity noise models and parameters closely mimicking Quantinuum quantum computers performance. Each emulator uses the same physical noise model, but noise parameters reflect the performance of the device being emulated.
Uses identical API for job submission as Quantinuum quantinum computers, enabling seamless translation from emulator to quantum computer
Uses identical compiler as Quantinuum quantum computers, containing all the native gates, transport operations and classical operations used in Quantinuum quantum computers
Provides identical output format as Quantinuum quantum computers
Allows usage of Quantinuum quantum computer attributes: all-to-all connectivity and qubit reuse after mid-circuit measurement
Available even while Quantinuum quantum computers are offline to enable maximized productivity and development time
Large quantum circuits with a limit of 10,000 on the number of shots
Identical queuing prioritization as Quantinuum quantum computers
Emulation Method¶
The Quantinuum emulators, accessible via the API, receive instructions directly from the same compilers used by the physical quantum computer. These compilers translate the submitted quantum program into a set of instructions comprising the native gate operations and the transport operations necessary to reconfigure the ion trap at each step of the program. Users can choose between either a state vector or stabilizer emulation method; in both cases results are performed shot-by-shot. The state vector emulation method can run any general quantum circuits, while the stabilizer emulation method is restricted to circuits involving only quantum unitary gates that are Clifford operations.
For System Model H1, state vector emulation is supported up to all 20 qubits. For System Model H2, state vector emulation is supported up to 32 qubits, with stabilizer emulation supported up to 56 qubits.
The error model for the emulation can be turned on or off, allowing noisy or noise-free emulations, respectively. The emulated error model includes:
Asymmetric depolarizing gate noise
Leakage errors
Crosstalk noise
Dephasing noise due to transport and qubit idling
Except for dephasing, errors on physical qubits are modeled as stochastic processes. For the state vector emulation, dephasing is handled as a coherent \(Z\) rotation according to a dephasing rate and the duration the qubit spends in transport or while idling while other qubits are being gated. For the stabilizer emulation, the dephasing noise is treated as a stochastic Pauli-\(Z\) error where the probability of a Pauli-\(Z\) error is equal to the Pauli twirled approximation of the coherent dephasing channel, which is proportional to the square of the dephasing rate multiplied by the duration.