> ## Documentation Index
> Fetch the complete documentation index at: https://docs.haiqu.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Benchmarks data sheet

> Specifications and benchmarks of core functions

## Error suppression & mitigation stack

### Benchmark: 2D transverse-field Ising model

We reproduce the experiment from [IBM's Nature publication](https://www.nature.com/articles/s41586-023-06096-3) using Haiqu's lightweight error mitigation techniques.

<img src="https://mintcdn.com/haiqu/dSRoSE63jQ9HbUY3/catalog/ising_evolution_127_q_Magnetization_ibm_kingston.png?fit=max&auto=format&n=dSRoSE63jQ9HbUY3&q=85&s=4f55c25679d6002ab4372f3e27685bfd" alt="Ising Model simulation, 127 qubits, IBM Kingston" height="150" className="rounded-lg" data-path="catalog/ising_evolution_127_q_Magnetization_ibm_kingston.png" />

In [the paper](https://www.nature.com/articles/s41586-023-06096-3) (see Figure 3 a)), the authors used Sparse Pauli-Lindblad Noise Learning to perform zero-noise extrapolation (ZNE) with Probabilistic Error Amplification (PEA) which comes at significant overhead in terms of total number of shots (more than 100x) and number of extra circuits.

<Tip>
  Haiqu delivers similar error suppression using essentially the same quantum resources you'd use for the raw, uncorrected experiment.
</Tip>

Check for more details in **`IsingModelSimulation.ipynb`** notebook.

### Benchmark: GHZ state preparation

We prepare GHZ states on IBM Heron r2 processor by hardware-efficient circuits (found by breadth-first search (BFS) algorithm) with Haiqu's bitstring distribution error mitigation.

<img src="https://mintcdn.com/haiqu/dSRoSE63jQ9HbUY3/catalog/ghz_state_benchmark.png?fit=max&auto=format&n=dSRoSE63jQ9HbUY3&q=85&s=987d13a6db7042532f0d1b735365897a" alt="Ghz State Benchmark Pn" width="1800" height="1114" data-path="catalog/ghz_state_benchmark.png" />

You can reproduce the results using the `GHZStatePreparation.ipynb` notebook.

### Mitigation Loading Specifications

|                                 | Observable-based mitigation                                                                             | Bitstring distribution mitigation             |
| ------------------------------- | ------------------------------------------------------------------------------------------------------- | --------------------------------------------- |
| Supported backends              | IBM QPUs, AWS Braket (TBD)                                                                              | IBM QPUs, AWS Braket (TBD)                    |
| Max number of qubits            | up to 156 qubits (largest QPU)                                                                          | up to 156 qubits (largest QPU)                |
| Max. circuit depth / gate count | up to 1000 2q gates for up to weight-5 observables, up to 300 2q gates for highly non-local observables | up to 300 2q gates                            |
| Circuit execution overhead      | 2x more circuit executions per unique circuit                                                           | 2x more circuit executions per unique circuit |
| Shot overhead                   | 2x more shots per unique circuit                                                                        | 2x more shots per unique circuit              |
| Execution speed                 | O(1) seconds for QEM + execution time on QPU                                                            | O(10) seconds for QEM + execution time on QPU |

## State compression

### Benchmark: Utility-scale LR-QAOA

Following recent paper by [Montanez-Barrera et. al. "Evaluating the performance of quantum processing
units at large width and depth"](https://arxiv.org/abs/2502.06471), we use linear ramp quantum approximate optimization algorithm (LR-QAOA), a fixed-parameter, deterministic variant of QAOA, as a benchmarking protocol.

Haiqu's compression enables execution of nearly **20x** more layers of LR-QAOA with the increasing approximation ratio.

<img src="https://mintcdn.com/haiqu/dSRoSE63jQ9HbUY3/catalog/LR-QAOA_100_qubits_IBM_Kingston.png?fit=max&auto=format&n=dSRoSE63jQ9HbUY3&q=85&s=99b0e7efc4c92d5ec748e6f39ef1a0be" alt="LR-QAOA benchmark, 100 qubits, IBM Kingston" height="150" className="rounded-lg" data-path="catalog/LR-QAOA_100_qubits_IBM_Kingston.png" />

## State Compression Specifications

| **Parameter**               | **Details**                                                                                                                                                         |
| :-------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **Number of qubits**        | Up to 500                                                                                                                                                           |
| **Runtime (at 100 qubits)** | From few seconds and <br /> up to 2 minutes with no fine-tuning; <br /> up to 15 minutes with heavy fine-tuning                                                     |
| **Runtime scaling**         | Linear scaling with circuit size, problem-dependent                                                                                                                 |
| **Supported circuits**      | - Circuits decomposable into CNOT, RX, RY, RZ basis gates <br />  - Circuits with mid-circuit measurements are supported, but compression applies only prior to MCM |
| **Supported connectivity**  | Any. <br />  Not transpiled input with Linear connectivity is preferred.                                                                                            |
| **Compression rate**        | Up to 100× for various application circuits                                                                                                                         |
| **Returned metrics**        | - Compression rate <br /> - Quality of the compression (fidelity-like metric)                                                                                       |

\*runtime can vary for different circuit classes of the same size

## Data loading

## Distribution Loading Specifications

| **Parameter**                  | **Details**                                                                                                                                                            |
| :----------------------------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Number of qubits**           | Up to 500 qubits                                                                                                                                                       |
| **Number of distributions**    | 107 different classes of distributions are supported. Check SciPy docs for details.                                                                                    |
| **Runtime**                    | 1–15 seconds                                                                                                                                                           |
| **Runtime scaling**            | Linear scaling with number of qubits                                                                                                                                   |
| **Circuit size (gates count)** | O(n), n = number of qubits                                                                                                                                             |
| **Circuit depth**              | O(n/2), n = number of qubits                                                                                                                                           |
| **Circuit connectivity**       | Linear                                                                                                                                                                 |
| **Other circuit properties**   | - No mid-circuit measurements <br /> - Only CNOT and single-qubit rotation gates <br /> - No ancillary qubits <br /> - No post-selection required in state preparation |
| **Returned metrics**           | Quantum state fidelity is returned for the ideal state prepared by the circuit                                                                                         |

### Vector Loading specifications

| **Parameter**                  | **Details**                                                                                                                                                          |
| :----------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Number of qubits**           | Up to 20 qubits                                                                                                                                                      |
| **Input data**                 | 1D vector                                                                                                                                                            |
| **Data type**                  | Real and complex values                                                                                                                                              |
| **Data size**                  | Up to \~1M features in the vector                                                                                                                                    |
| **Runtime**                    | 0.5–2 minutes                                                                                                                                                        |
| **Runtime scaling**            | Linear scaling with number of qubits                                                                                                                                 |
| **Circuit size (gates count)** | O(n), n = number of qubits                                                                                                                                           |
| **Circuit depth**              | O(n/2), n = number of qubits                                                                                                                                         |
| **Circuit connectivity**       | Linear                                                                                                                                                               |
| **Other circuit properties**   | - No mid-circuit measurements <br /> - Only CNOT and single-qubit rotation gates <br /> - No ancilla qubits <br /> - No post-selection required in state preparation |
| **Returned metrics**           | Quantum state fidelity is returned for the ideal state prepared by the circuit                                                                                       |

### Block Vector Loading specifications

| **Parameter**                  | **Details**                                                                                                                                                          |
| :----------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Number of qubits**           | 1000+ qubits; no more than 20 qubits for a single block                                                                                                              |
| **Input data**                 | 1D vector <br /> 2D matrix                                                                                                                                           |
| **Data type**                  | Real and complex values                                                                                                                                              |
| **Data size**                  | Any, with no more than \~1M features for a single block                                                                                                              |
| **Runtime**                    | 0.5–2 minutes per block                                                                                                                                              |
| **Runtime scaling**            | Linear scaling with number of qubits                                                                                                                                 |
| **Circuit size (gates count)** | O(n), n = number of qubits                                                                                                                                           |
| **Circuit depth**              | O(m/2), m = number of qubits in each block                                                                                                                           |
| **Circuit connectivity**       | Linear within each block                                                                                                                                             |
| **Other circuit properties**   | - No mid-circuit measurements <br /> - Only CNOT and single-qubit rotation gates <br /> - No ancilla qubits <br /> - No post-selection required in state preparation |
| **Returned metrics**           | Quantum state fidelity is returned for the ideal state prepared by the circuit                                                                                       |
