LEE, DONG HWA Lee Jin-il Hong, Seong jin Lim, Hyang Tag Cho, Young Wook Han, Sang Wook Shin, H. Junaid ur Rehman Kim, Yong Su 2024-01-19T13:01:58Z 2024-01-19T13:01:58Z 2022-01-28 2022-01 2334-2536 https://pubs.kist.re.kr/handle/201004/115869 Variational quantum algorithms, a representative class of modern quantum algorithms, provide practical uses of nearterm quantum processors. The size of the problem that can be encoded and solved on a quantum processor is limited by the dimension of the Hilbert space associated with the processor. One common approach for increasing the system dimension is to utilize a larger number of quantum systems. Here, we adopt an alternative approach to utilize multiple degrees of freedom of individual quantum systems to experimentally resource-efficiently increase theHilbert space.We report experimental implementation of the variational quantum eigensolver (VQE) using four-dimensional photonic quantum states of single photons. The four-dimensional quantum states are implemented by utilizing polarization and path degrees of freedom of a single photon. Our photonic VQE is equipped with a quantum error mitigation protocol that efficiently reduces the effects of Pauli noise in the quantum processing unit.We apply our photonicVQEto estimate the ground state energy of theHe-H+ cation. Simulation and experimental results demonstrate that our experimental resource-efficient photonic VQE can accurately estimate the bond dissociation curve, even in the presence of large noise in the quantum processing unit. We also discuss further possible resource-efficient enhancement of the Hilbert space in photonic quantum processors. Our results propose that photonic systems utilizing multiple degrees of freedom can provide a resource-efficient avenue to implement practical near-term quantum processors. ？ 2022 Optical Society of America. English OSA Publishing Error-mitigated photonic variational quantum eigensolver using a single-photon ququart Article 10.1364/OPTICA.441163 1 Optica, v.9, no.1, pp.88 - 96 Optica 9 1 88 96 Y scie scopus 000746018800012 2-s2.0-85122854505 Optics Optics Article 양자시뮬레이터 광자 큐비트 양자계산화학 양자컴퓨터