This study presents a reproducible, framework-level comparison of three open-source quantum software environments: PennyLane 0.45.1, Qiskit 2.5.2, and Snowflurry 0.6.0. Equivalent parameterized circuits were constructed in Python for PennyLane and Qiskit and in Julia for Snowflurry. Every circuit consisted of repeated layers of single-qubit rotations followed by a ring of controlled-NOT gates, and every framework returned the complete ideal statevector. Circuit construction time, first-execution time, warmed execution time, whole-process wall time, output probability, and state normalization were recorded. All common numerical thread controls were fixed to one, so the experiment measures controlled single-thread behavior rather than the maximum throughput of the tested computers. On the laptop, Snowflurry produced the lowest warmed median at 10 qubits, Qiskit at 12 qubits, PennyLane and Qiskit were nearly tied at 14 qubits, and PennyLane was fastest at 18 qubits. On an Intel Xeon E5-2697 v3 workstation, PennyLane was fastest at both 14 and 16 qubits. Snowflurry constructed circuits rapidly but exhibited greater simulation time as the statevector increased. Identical probabilities and unit state norms across all implementations support functional equivalence. The results characterize these particular built-in statevector paths; they do not constitute a general comparison of Python and Julia, nor of optimized accelerators such as PennyLane Lightning or Qiskit Aer.
This study presents a reproducible, framework-level comparison of three open-source quantum software environments: PennyLane 0.45.1, Qiskit 2.5.2, and Snowflurry 0.6.0. Equivalent parameterized circuits were constructed in Python for PennyLane and Qiskit and in Julia for Snowflurry. Every circuit consisted of repeated layers of single-qubit rotations followed by a ring of controlled-NOT gates, and every framework returned the complete ideal statevector. Circuit construction time, first-execution time, warmed execution time, whole-process wall time, output probability, and state normalization were recorded. All common numerical thread controls were fixed to one, so the experiment measures controlled single-thread behavior rather than the maximum throughput of the tested computers. On the laptop, Snowflurry produced the lowest warmed median at 10 qubits, Qiskit at 12 qubits, PennyLane and Qiskit were nearly tied at 14 qubits, and PennyLane was fastest at 18 qubits. On an Intel Xeon E5-2697 v3 workstation, PennyLane was fastest at both 14 and 16 qubits. Snowflurry constructed circuits rapidly but exhibited greater simulation time as the statevector increased. Identical probabilities and unit state norms across all implementations support functional equivalence. The results characterize these particular built-in statevector paths; they do not constitute a general comparison of Python and Julia, nor of optimized accelerators such as PennyLane Lightning or Qiskit Aer.
Classical simulation supports the development and validation of quantum algorithms through full-state inspection, controlled noise models and backpropagation, albeit for small quantum systems. Existing frameworks offer gate-level execution, differentiable pulse-level dynamics or optimised hardware execution. Just another quantum simulator (JAQSI) combines gate- and pulse-level simulation in one differentiable circuit model built upon JAX. Circuits are represented as pure functions of numerical inputs which support vectorised batches and JIT compilation. Within a single circuit, matrix-defined operations, gates synthesised from Hamiltonian time evolution and noise channels can be composed freely. For a fast simulation, gate and channel fusion reduces passes over the state, while adjoint differentiation computes expectation-value gradients with a constant number of statevectors. At pulse level, JAQSI reduces evolution under single-term Hamiltonians to a scalar pulse-area integral and reuses cached execution plans and compiled solvers. In a benchmark we compare JAQSI with PennyLane, Qiskit, Qibo, Qulacs, QuTiP and dynamiqs. At gate level, we observe performance either on par or an order of magnitude faster across statevector, density, noise and gradient simulation than the compared simulators up to 12 qubits. Beyond 18 qubits, JAQSI is on par with PennyLane Lightning in both statevector and gradient simulation. In the statevector and noisy density-matrix pulse benchmarks, it is at least 5 times faster than the other simulators, even with its closed-form solve disabled. Disabling the latter increases its runtime by at most a factor of 1.5. We provide JAQSI as open-source software on GitHub and PyPI.
Quantum circuit simulators are essential for quantum algorithm development, yet systematic runtime benchmarks comparing major frameworks across CPU and GPU backends are limited. We benchmark three open-source frameworks - Cirq (qsim), CUDA-Q, and Qiskit (Aer) - on statevector simulation of the 2D quantum acoustic wave equation, evolved via Trotterized Hamiltonian dynamics, for problem sizes from 7 to 29 qubits on a single Azure virtual machine. The evaluation spans four categories: CPU runtime versus qubit count, strong scalability on multi-core CPUs at 27 qubits, GPU runtime versus qubit count, and GPU-over-CPU speedup. Relative rankings shift from one category to the next. On CPU, Cirq is fastest up to 23 qubits (2.4x faster than Qiskit at 21 qubits), but Qiskit overtakes it at larger sizes and higher thread counts, sustaining 80% parallel efficiency at 16 threads. On GPU, CUDA-Q leads between 13 and 21 qubits, while Cirq becomes the fastest GPU backend at large problem sizes, achieving 1.5x and 2.3x speedups over CUDA-Q and Qiskit at 29 qubits. GPU-over-CPU speedup ratios should be interpreted alongside absolute GPU runtimes; CUDA-Q's 1500x at 21 qubits is largely driven by the limited scaling of its CPU backend (qpp), and the absolute GPU runtimes show that the three frameworks' GPU backends differ by less than these ratios alone suggest. These results indicate that no single framework dominates across configurations, and that backend selection for statevector simulation should be guided by both target hardware and problem size.
The increasing complexity of quantum algorithms and the limitations of current Noisy Intermediate-Scale Quantum (NISQ) hardware underscore the importance of efficient classical simulators. To support informed decision-making by users of quantum circuit simulators, we benchmark seven statevector-based quantum circuit simulators (Qiskit, Qulacs, Qibo, Qsimov, Cirq, Pennylane and the Intel Quantum Simulator (IQS)) on a multicore node of the Lusitania high-performance computing (HPC) system. We evaluate their performance in terms of execution time, memory usage and core scalability using Grover’s algorithm, the quantum Fourier transform (QFT), and quantum volume (QV) circuits, across qubit counts ranging from 3 to 30. Our results reveal that Qulacs offers the best performance for circuits below 22 qubits, while Qiskit becomes the fastest for larger and more complex circuits. Qiskit and Qulacs achieve the most efficient parallel performance across multiple cores, while others display limited scaling benefits. IQS shows the lowest memory consumption in QFT and QV benchmarks for systems under 24 qubits; however, it suffers from higher execution times, particularly for Grover’s algorithm. The experimental implementation of Qsimov consistently underperforms in both runtime and scalability; for this reason, it is employed as a baseline in our measurements, serving to highlight the importance of performance optimizations in statevector-based quantum circuit simulators. Previous findings provide a comprehensive performance landscape to guide researchers in selecting appropriate simulators for both standard and large-scale quantum workloads on HPC infrastructures.
We introduce PennyLane's Lightning suite, a collection of high-performance state-vector simulators targeting CPU, GPU, and HPC-native architectures and workloads. Quantum applications such as QAOA, VQE, and synthetic workloads are implemented to demonstrate the supported classical computing architectures and showcase the scale of problems that can be simulated using our tooling. We benchmark the performance of Lightning with backends supporting CPUs, as well as NVidia and AMD GPUs, and compare the results to other commonly used high-performance simulator packages, demonstrating where Lightning's implementations give performance leads. We show improved CPU performance by employing explicit SIMD intrinsics and multi-threading, batched task-based execution across multiple GPUs, and distributed forward and gradient-based quantum circuit executions across multiple nodes. Our data shows we can comfortably simulate a variety of circuits, giving examples with up to 30 qubits on a single device or node, and up to 41 qubits using multiple nodes.
Quantum machine learning (QML) has emerged as a promising field, combining the power of quantum computing with classical machine learning techniques to solve complex computational tasks. As the demand for efficient quantum simulations grows, multiple QML frameworks, including PennyLane, Qiskit, and TensorFlow Quantum (TFQ), have been developed to facilitate hybrid quantum-classical computations. This study aims to evaluate and compare the performance of three leading QML frameworks PennyLane, Qiskit, and TensorFlow Quantum in simulating quantum machine learning models, focusing on accuracy, execution time, and noise tolerance. The study examined three leading quantum machine learning (QML) frameworks PennyLane (v0.24), Qiskit (v0.43.2), and TensorFlow Quantum (TFQ, v0.7) each tested on a 64-bit Ubuntu Linux system with an Intel Core i7 processor, 32 GB RAM, and NVIDIA GeForce RTX 3080 GPU. Quantum algorithms like variational quantum circuits (VQCs) and quantum support vector machines (QSVMs) were simulated using these frameworks. Various quantum gates, including Pauli-X, Y, Z, Hadamard, CNOT, and Rotation gates (Rx, Ry, Rz), were used for parameter optimization and quantum superposition. The Iris and MNIST datasets were adapted for quantum encoding using Amplitude and Angle Encoding for binary classification tasks. Simulations were run on classical computers, while select circuits were executed on IBM Quantum’s Falcon r5.11 processor to compare hardware performance. PennyLane achieved the highest accuracy (92%) in quantum simulations, excelling in hybrid quantum-classical model integration. TensorFlow Quantum provided the fastest execution time, especially in classical simulations, making it suitable for rapid prototyping. Qiskit produced deeper quantum circuits but had higher error rates (6%) on real quantum hardware, highlighting noise and decoherence effects. The VQC models optimized by stochastic gradient descent (SGD) showed significant improvements in model performance, and QSVMs effectively classified both linearly separable and non-separable datasets, demonstrating the potential of quantum algorithms over classical approaches. Statistical analysis confirmed the significance of the results (p < 0.05). PennyLane is the most robust framework for hybrid quantum-classical models, while TensorFlow Quantum is suited for rapid prototyping. Qiskit, despite longer execution times, excels in hardware implementation. The choice of framework should align with the specific needs of quantum machine learning tasks.
This article presents a comprehensive study of the performance of quantum circuit simulation using the Matrix Product State (MPS) method within Qiskit Aer. The primary focus is on comparing the computational efficiency of implementations on central processing unit (CPU) and graphics processing unit (GPU) across various simulation platforms. Four key quantum algorithms are experimentally examined: the Variational Quantum Eigensolver (VQE), the Quantum Fourier Transform (QFT), the Quantum Approximate Optimization Algorithm (QAOA), and the Greenberger– Horne–Zeilinger (GHZ) state. For each algorithm, graphs are constructed showing the dependence of execution time on the number of qubits and the type of simulator. A single diagram is also provided to compare all four algorithms using the MPS method in Qiskit Aer. The results indicate that although the MPS simulator in Qiskit Aer is currently implemented only for CPU, it outperforms the traditional statevector simulator for low-entanglement circuits. At the same time, the lack of GPU acceleration limits the scalability of the MPS simulator. Analysis shows that implementing hardware acceleration of SVD operations using NVIDIA's cuQuantum and cuTensorNet libraries can provide a speedup of up to seven times. A comparative analysis of GPU implementations in Qiskit Aer and CUDA-Q is also conducted, including libraries such as cuStateVec, LAPACK, and cuSOLVER. Graphs are created to demonstrate the strengths and weaknesses of the simulators and simulation methods in Qiskit Aer. Notably, the MPS method remains one of the fastest by computation speed on CPU, but is sometimes surpassed by other methods on GPU. Further optimization directions for MPS are proposed, including the development of a hybrid CPU/GPU architecture and the utilization of modern GPU libraries to accelerate critical operations. Keywords: quantum computing, quantum simulation, Qiskit Aer, MPS, statevector, cudaq.