64-qubit quantum circuit simulation

Abstract

Classical simulations of quantum circuits are limited in both space and time when the qubit count is above 50, the realm where quantum supremacy reigns. However, recently, for the low depth circuit with more than 50 qubits, there are several methods of simulation proposed by teams at Google and IBM. Here, we present a scheme of simulation which can extract a large amount of measurement outcomes within a short time, achieving a 64-qubit simulation of a universal random circuit of depth 22 using a 128-node cluster, and 56-and 42-qubit circuits on a single PC. We also estimate that a 72-qubit circuit of depth 23 can be simulated in about 16 h on a supercomputer identical to that used by the IBM team. Moreover, the simulation processes are exceedingly separable, hence parallelizable, involving just a few inter-process communications. Our work enables simulating more qubits with less hardware burden and provides a new perspective for classical simulations.

A flexible high-performance simulator for verifying and benchmarking quantum circuits implemented on real hardware

“…Qubit complexity Figure C4. Qubit complexity of the simulation of Bristlecone-60 with depth (1+32+1) with Schrödinger-Feynman simulators [17,28,38] for different partition schemes. Top: From left to right, partition schemes considered for two partitions, three partitions, and four partitions; in the three partition case, d is the number of cuts avoided in the diagonal towards the top-right region, which for the example plotted is d = 2, and is extended to d = 1 .…”

“…To study the time complexity of Schrödinger-Feynmantype simulators [17,28,38], i.e., those that partition the circuit in sub-circuits and perform a full wave-function evolution of the sub-circuits for all the paths defined by the partition, we use the "qubit complexity" [38] for a given depth defined as follows.…”

Scaling reconfigurable emulation of quantum algorithms at high precision and high throughput

“…Furthermore, their simulator is shown to evaluate only one out of all possible output states. Chen et al achieved 64‐qubit simulation of a universal random circuit of depth 22, using a 128‐node cluster. A list of other quantum simulators can be found in the website of Quantiki…”

“…Among related efforts, we reviewed large-scale parallel quantum simulators [29][30][31][32][33][34] and works of quantum emulation on field-programmable gate array (FPGA) hardware. [35][36][37][38][39][40][41][42][43] The FPGA emulators, similar to parallel simulation platforms, can exploit the concurrent nature of quantum algorithms and demonstrate parallelism by instantiating concurrent hardware kernels.…”

A novel approach for emulating quantum computers on classical platforms

“…Before the universal quantum computer solving some hard problems with the significant speedup arrives, emulating quantum computers in the classical platforms is the advisable approach for better learning quantum mechanics and demonstrating quantum algorithms . Recently, many continuous ongoing efforts are contributed to research the methods for emulating quantum computers, such as parallel quantum simulators and FPGA‐based (field‐programmable gate arrays) quantum emulators . The existing methods usually have some limitations including the aspects of scalability, accuracy, and efficiency.…”