Software quantum simulators are essential tools for designing and testing quantum algorithms on classical computing architectures, especially given the current limitations of physical quantum hardware. This work focuses on studying and evaluating memory management strategies for scalable quantum state simulation. We examine full-state representation, dynamic state pruning, shared-memory parallelization with OpenMP, distributed memory execution using MPI, and error-bounded floating-point compression with ZFP. These techniques are implemented in a prototype simulator and assessed using the quantum Fourier transform as a benchmark, with performance compared against leading open-source simulators such as Intel-QS, QuEST, and qsim. The results show the trade-offs between computational overhead and memory efficiency, and demonstrate that hybrid approaches combining distributed memory and compression can significantly extend the number of qubits that can be simulated. This work contributes practical insights for improving the scalability of software quantum simulators on classical hardware through optimized memory usage.
Software quantum simulators are essential tools for designing and testing quantum algorithms on classical computing architectures, especially given the current limitations of physical quantum hardware. This work focuses on studying and evaluating memory management strategies for scalable quantum state simulation. We examine full-state representation, dynamic state pruning, shared-memory parallelization with OpenMP, distributed memory execution using MPI, and error-bounded floating-point compression with ZFP. These techniques are implemented in a prototype simulator and assessed using the quantum Fourier transform as a benchmark, with performance compared against leading open-source simulators such as Intel-QS, QuEST, and qsim. The results show the trade-offs between computational overhead and memory efficiency, and demonstrate that hybrid approaches combining distributed memory and compression can significantly extend the number of qubits that can be simulated. This work contributes practical insights for improving the scalability of software quantum simulators on classical hardware through optimized memory usage.
Software quantum simulators are the most accessible tools for designing and testing quantum algorithms. This paper presents a comprehensive approach to building a software-based quantum simulator based on classical computing architectures. We explore fundamental quantum computing concepts, including state vector representations, quantum gates, and memory management techniques. The simulator prototype implements various memory optimization strategies, such as full-state representation, dynamic state pruning, and shared memory parallelization with OpenMP and distributed memory models using MPI. Additionally, data compression techniques, like ZFP, are explored to enhance simulation performance by reducing memory footprint. The results are validated through performance comparisons with leading open-source quantum simulators, such as Intel-QS, QuEST, and qsim. Our findings highlight the trade-offs between computational overhead and memory efficiency. This demonstrates that a hybrid approach using distributed memory and compression offers the best scalability for simulating large quantum systems. This work provides a foundation for developing efficient quantum simulators supporting more complex quantum algorithms on classical hardware.
Scalable classical simulation of quantum circuits is crucial for advancing quantum algorithm development and validating emerging hardware. This work focuses on performance enhancements through targeted low-level and NUMA-aware tuning on a single-node system, thereby not only advancing the efficiency of classical quantum simulations but also establishing a foundation for scalable, heterogeneous implementations that bridge toward noiseless quantum computing. Although few prior studies have reported similar hardware-level optimizations, such implementations have not been released as open-source software, limiting independent validation and further development. We introduce an open-source, high-performance extension to the QuEST state vector simulator that integrates state-of-the-art low-level and NUMA-aware optimizations for modern processors. Our approach emphasizes locality-aware computation and incorporates hardware-specific techniques including NUMA-aware memory allocation, thread pinning, AVX-512 vectorization, aggressive loop unrolling, and explicit memory prefetching. Experiments demonstrate substantial speedups--5.5-6.5x for single-qubit gate operations, 4.5x for two-qubit gates, 4x for Random Quantum Circuits (RQC), and 1.8x for the Quantum Fourier Transform (QFT). Algorithmic workloads further achieve 4.3-4.6x acceleration for Grover and 2.5x for Shor-like circuits. These results show that systematic, architecture-aware tuning can significantly extend the practical simulation capacity of classical quantum simulators on current hardware.
In this paper we describe, implement, and test the performance of distributed memory simulations of quantum circuits on the MSU Laconia Top500 supercomputer. Using OpenMP and MPI hybrid parallelization, we first use a distributed matrix-vector multiplication with one-dimensional partitioning and discuss the shortcomings of this method due to the exponential memory requirements in simulating quantum computers. We then describe a more efficient method that stores only the 2n amplitudes of the n qubit state vector ∣ψ⟩ and optimize its single node performance. In our multi-node implementation, we use a single amplitude communication protocol that maximizes the number of qubits able to be simulated and minimizes the ratio of qubits that require communication to those that do not, and we present an algorithm for efficiently determining communication pairs among processors. We simulate up to 30 qubits on a single node and 33 qubits with the state vector partitioned across 64 nodes. Lastly, we discuss the advantages and disadvantages of our communication scheme, propose potential improvements, and describe other optimizations such as storing the state vector non-sequentially in memory to map communication requirements to idle qubits in the circuit.
Full-state quantum circuit simulation requires exponentially increased memory size to store the state vector as the number of qubits scales, presenting significant limitations in classical computing systems. Our paper introduces BMQSim, a novel state vector quantum simulation framework that employs lossy compression to address the memory constraints on graphics processing unit (GPU) machines. BMQSim effectively tackles four major challenges for state-vector simulation with compression: frequent compression/decompression, high memory movement overhead, lack of dedicated error control, and unpredictable memory space requirements. Our work proposes an innovative strategy of circuit partitioning to significantly reduce the frequency of compression occurrences. We introduce a pipeline that seamlessly integrates compression with data movement while concealing its overhead. Additionally, BMQSim incorporates the first GPU-based lossy compression technique with point-wise error control. Furthermore, BMQSim features a two-level memory management system, ensuring efficient and stable execution. Our evaluations demonstrate that BMQSim can simulate the same circuit with over 10 times less memory usage on average, achieving fidelity over 0.99 and maintaining comparable simulation time to other state-of-the-art simulators.
Due to the lack of quantum hardware, quantum simulation (QS) is still the most common method to study quantum computing.Due to the great number of operations and memory requirements, simulators should be properly built to efficiently explore modern classic computers.This work focuses on the memory access requirements that present a bottleneck not just for QS, but for computer science research as a whole.Our proposed methodology collaborates with the memory usage reduction, mitigating the effects of the memory wall.Our results show improvements in memory usage and the overall speed of circuit simulations.Our case test in the D-GM simulator with controlled operators, such as dense, primary and secondary diagonal patterns, showed an improvement for execution time in the order of 50 %.Our methodology can be applied not only in QS, but also for related applications with complex memory access patterns.
In the nearest future quantum computers will be suitable for practical use. The development of quantum algorithms can be carried out using classical computers and specialized software that allows simulating of a quantum circuit functioning. Simulation results can be used to analyze the algorithm and also contribute to co-design when developing quantum architectures. However, when planning and performing numerical experiments, it is necessary to understand the capabilities of simulators and the limitations on the parameters of the quantum circuit imposed by the characteristics of the available classical computational resources (computers). This paper presents the results of computational experiments on simulating the operation of quantum circuits on an ideal quantum computer using the QuEST and Intel-QS packages, as well as our own "naïve" implementation. Restrictions on the size of a simulated quantum system N are shown when using computing systems of various classes — a virtual machine, a computing server, a computing server with a graphics accelerator (GPU), a supercomputer (the maximum achieved size is N = 33). The performance and scalability characteristics of the considered implementations on shared and distributed memory are given (the observed scaling efficiency is 30 % and 70 %, respectively). For the QuEST package and our own implementation the performance is presented for systems with graphics accelerator (GPU).