Unitary-transformed projective squeezing: applications for circuit-knitting and state-preparation of non-Gaussian states

Fuente: arXiv
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Main Authors: Anai, Keitaro, Suzuki, Yasunari, Tokunaga, Yuuki, Matsuzaki, Yuichiro, Takeda, Shuntaro, Endo, Suguru
Format: Preprint
Published: 2024
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author Anai, Keitaro
Suzuki, Yasunari
Tokunaga, Yuuki
Matsuzaki, Yuichiro
Takeda, Shuntaro
Endo, Suguru
author_facet Anai, Keitaro
Suzuki, Yasunari
Tokunaga, Yuuki
Matsuzaki, Yuichiro
Takeda, Shuntaro
Endo, Suguru
contents Continuous-variable (CV) quantum computing is a promising candidate for quantum computation because it can, even with one mode, utilize infinite-dimensional Hilbert spaces and can efficiently handle continuous values. Although photonic platforms have been considered as a leading platform for CV computation, hybrid systems that use both qubits and bosonic modes, e.g., superconducting hardware, have shown significant advances because they can prepare non-Gaussian states by utilizing the nonlinear interaction between the qubits and the bosonic modes. However, the size of hybrid hardware is currently restricted. Moreover, the fidelity of the non-Gaussian state is also restricted. This work extends the projective squeezing method to establish a formalism for projecting quantum states onto the states that are unitary-transformed from the squeezed vacuum at the expense of the sampling cost. Based on this formalism, we propose methods for simulating larger quantum devices and projecting states onto the cubic phase state, a typical non-Gaussian state, with a higher squeezing level and higher nonlinearity. To make implementation practical, we can, by leveraging the interactions in hybrid systems of qubits and bosonic modes, apply the smeared projector by using either the linear-combination-of-unitaries or virtual quantum error detection algorithms. We numerically verify the performance of our methods and show that projection can suppress the effect of photon-loss errors.
format Preprint
id arxiv_https___arxiv_org_abs_2411_19505
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Unitary-transformed projective squeezing: applications for circuit-knitting and state-preparation of non-Gaussian states
Anai, Keitaro
Suzuki, Yasunari
Tokunaga, Yuuki
Matsuzaki, Yuichiro
Takeda, Shuntaro
Endo, Suguru
Quantum Physics
Continuous-variable (CV) quantum computing is a promising candidate for quantum computation because it can, even with one mode, utilize infinite-dimensional Hilbert spaces and can efficiently handle continuous values. Although photonic platforms have been considered as a leading platform for CV computation, hybrid systems that use both qubits and bosonic modes, e.g., superconducting hardware, have shown significant advances because they can prepare non-Gaussian states by utilizing the nonlinear interaction between the qubits and the bosonic modes. However, the size of hybrid hardware is currently restricted. Moreover, the fidelity of the non-Gaussian state is also restricted. This work extends the projective squeezing method to establish a formalism for projecting quantum states onto the states that are unitary-transformed from the squeezed vacuum at the expense of the sampling cost. Based on this formalism, we propose methods for simulating larger quantum devices and projecting states onto the cubic phase state, a typical non-Gaussian state, with a higher squeezing level and higher nonlinearity. To make implementation practical, we can, by leveraging the interactions in hybrid systems of qubits and bosonic modes, apply the smeared projector by using either the linear-combination-of-unitaries or virtual quantum error detection algorithms. We numerically verify the performance of our methods and show that projection can suppress the effect of photon-loss errors.
title Unitary-transformed projective squeezing: applications for circuit-knitting and state-preparation of non-Gaussian states
topic Quantum Physics
url https://arxiv.org/abs/2411.19505